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Recreational and Sports Recommendations for the Child with Heart Disease
Symposium on Pediatric Cardiology
Recreational and Sports Recommendations for the Child with Heart Disease Michael D. Freed, MD.*
Each year approximately 6 million children are engaged in competitive sports in high school with 20 million more, ages 6 to 16, participating in organized out-of-school recreational and competitive athletics. 26 For the vast majority, athletics are a wholesome and rewarding experience, both physically, and emotionally, but, for a few, the experience ends tragically with severe chronic disability or even death. While the absolute number of children dying during sports participation is small, especially compared with children of the same age who die each year in motor vehicle accidents,4 there are a significant number of sports-related deaths in children with congenital heart disease that are, at least in theory, preventable. 22 In addition, sports fatalities often get wide publicity in the media, increasing their visibility. 35 Common sense dictates that children with severe heart disease ought to be restricted from some strenuous physical activities, but unfortunately there is little data on which to rationally base recommendations. More than a decade ago, the American Heart Association published some guidelines, "Recreational and Occupational Recommendations for Use by Physicians Counseling Young Patients with Heart Disease,"7 based on "the combined experience of clinicians, surgeons, and scientists." Since then, further data have been accumulated, much on the basis of invasive and noninvasive assessments of children with heart disease during exercise, and individuals and committees have updated the guidelines. 23 . 28, 31 Nevertheless, much of the "data is very empiric, and restricting children on the basis of personal prejudices rather than on data remains all too common in both Pediatrics and Pediatric Cardiology. For some children affected, this may be tragic, since sports and activities are, in some sense, a miniature society containing person-to-person and group relationships
*Senior Associate in Cardiology, Children's Hospital, Boston; Associate Professor of Pediatrics, Harvard Medical School, Boston, Massachusetts Supported in part by grant No.5 T32 HL07193, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD
Pediatric Clinics of North America-Vol. 31, No.6, December 1984
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where race, religion, and ethnic origin are subservient to skill, experiences that should be a part of "growing up. "16 To label a child a "cardiac cripple" and deprive him of the benefits of participation on the basis of whim rather than data does a real disservice. In this paper, I would like to review some of the problems devising rational recreational and sports proscriptions for children with acquired or congenital heart disease. After a review of the normal cardiovascular response to exercise and the adaptations necessary in congenital or acquired heart disease, I will discuss the current status of exercise testing in children and finally present some newer guidelines on recreational and sports participation that I currently use when seeing children with heart disease at Children's Hospital, Boston.
DIFFICULTIES IN THE QUANTIFICATION OF CARDIOVASCULAR STRESS IN CHILDREN WITH HEART DISEASE There are major difficulties in quantifYing myocardial stress during exercise, derived in part from the nature of sports and recreational activities and in part from the varied nature of congenital and acquired heart disease, that make meaningful guidelines for the individual child elusive. For example, it has been difficult to generalize the metabolic demands of different recreational and competitive activities. There is an increasing body of literature on the energy requirements for the world-elite athletes training for, and performing in, Olympic events,l6 In the name of science (and possibly the quest of medals), athletes have been instrumented and studied during and after competition. As might be expected, the maximal oxygen uptakes recorded for those athletes performing individual endurance events such as cross-country skiing or long-distance running are higher than those participating in team sports such as soccer and ice hockey. Unfortunately, non-Olympic events, like football or baseball, more prevalent in our American society, have been less well studied. Even if these athletes could be instrumented and studied adequately, recreational and sports activities can be performed at such a variable intensity by different children that generalizations may be difficult, if not impossible. A visit to the local beach or pool will give one of the best examples, swimming. Since the specific gravity of the body is similar to that of water, recreational swimming can be performed with only a minimal expenditure of energy, perhaps twice basal metabolic rate, a reason it is used so extensively for the multiple handicapped. For distance swimming, the energy requirements are greater. Swimming the breast stroke recreationally requires about four times the basal metabolic rate,l3 while for competitive swimmers, energy expenditures of 20 times basal metabolic rate are not unusual. 1 All levels between lying on a raft reading a book to long-distance marathon swims are represented in the one term we call swimming. Another potential problem in assessing stress to the cardiovascular system is that there may be an enormous variability of energy require-
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ments over time in different sports. Some events, such as cross-country running or long-distance swimming require peak performance starting early and maintained throughout most, if not all, of the performance. Other activities-baseball and to a lesser extent basketball or tennismight require equally high levels of energy expenditure for short periods of time, but allow for a recovery period in between the bursts. Even if one could generalize the overall metabolic requirements of different activities, they may place different types of hemodynamic burdens on the cardiovascular system. For example, endurance sports may require a large augmentation of cardiac output increasing the volume work of the heart, but with little change in pressure work. Other activitiesweight lifting, wrestling, archery, and water skiing, for example-are primarily isometric; that is, they require exerting muscle tension against a fixed resistance. These latter activities do not require much increase in cardiac output but are associated with an acute reflex vasoconstriction that may suddenly increase, without warm-up, systemic blood pressure, and thereby increasing the pressure work of the heart. 5 Some activities may be combinations of isometric and dynamic exercise: the football player who must run and block is an example of this combination. Finally, in some athletic endeavors the increased metabolic requirements are minimal, but skill and concentration may be paramount; golf, horseback riding, bowling, and riflery are examples of this type of sport that may be performed by children with restrictions on pressure or volume work. When assessing the metabolic requirements of competitive sports, one must take into account not only the athletic event, but also the training program preceding. While there is ample evidence that training will improve performance,l it is not unusual to see coaches whose training programs are so vigorous that the actual performance is a "warm-down" in comparison. When allowing participation in a competitive sport, one must take the total activities into account, rather than what one might see at the athletic event itself. It should also be remembered that strong emotional factors may be involved in athletics. Competition may bring out maximal performance, but it also allows for the suppression of the normal warnings of fatigue and pain; for the cardiac, these warnings may playa crucial role in the prevention of serious harm. An additional problem making exercise proscription difficult is that there is tremendous variability in the severity of heart problems. There are 30 or so common types of congenital heart malformations, but each may have several different distinct varieties. Each disease may place a different hemodynamic burden on the heart and each has a different natural history, prognosis, and surgical option. In addition, each of these diseases may vary in severity-for example, mild or severe valvar pulmonic stenosis or mild tetralogy of Fallot with minimal systemic hypoxemia versus severe tetralogy with incapacitating hypoxemia and "spells" leading to unconsciousness. Finally, the severity of congenital diseases frequently change over time. Some almost invariable progress like valvar aortic stenosis, which typically increases in severity during the adolescent growth spurt as the growth of the valve lags behind the somatic growth and the need for increased cardiac output. Other diseases may improve over time like ven-
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tricular septal defects, that often get smaller and may even close during childhood. Another, perhaps insurmountable, problem, at least at present, is that, for some diseases, symptoms on severe exercise may be the presenting symptom. In children with myocarditis, cardiomyopathy, or certain anomalies of the coronary arteries, the pediatrician or even the pediatric cardiologist may be unaware of potentially serious disease present until syncope upon effort occurs. In spite of the rather formidable set of problems outlined above, it is important to attempt to outline the "state of the art" and attempt some meaningful recommendations that are neither too strict, so as not to eliminate those who could safely exercise if they were so inclined, nor too loose, so that children with heart disease but with an otherwise good prognosis will not be put in jeopardy.
CARDIOVASCULAR ADAPTATION TO EXERCISE: NORMAL AND IN CHILDREN WITH HEART DISEASE Physical activity, one of the essentials of life, may also be one of the most stressful to the cardiovascular system. Strenuous activity calls on a complex system of hormonal, neural, biochemical, respiratory, and circulatory adaptations acting in concert to deliver oxygen to metabolizing tissues as well as removing waste products. In this section I would like to review the normal circulatory adjustments to strenuous activity and the additional burdens placed by congenital or acquired heart disease. The review of normal hemodynamics on exercise will necessarily be short; those desiring a more in-depth review are encouraged to consult one of the current reviews'!, 27 During rigorous upright exercise the tissue demand for oxygen, and therefore the overall body oxygen consumption, increases. The cardiac output increases almost linearly with oxygen consumption and may be four or five times normal with peak exercise. Since the stroke volume increases only 25 to 50 per cent, most of the increase in cardiac output is due to increased heart rate. The increased flow is directed toward the involved skeletal muscle and the heart, with blood flow to the nonexercising tissues (brain, kidney, splanchnic bed, nonexercising muscles) normal or reduced slightly secondary to increased sympathetic tone and the concomitant vasoconstriction. On the systemic side of the circulation, the vascular resistance falls dramatically because of vasodilation of the exercising muscles, so that in spite of the markedly increased flow, the mean arterial pressure rises only slightly with the systolic pressure rising, accompanied by a drop in diastolic pressure. Pulmonary vasodilation is more limited, with pulmonary arterial pressure typically rising about 50 per cent from 12 mmHg to 18 mmHg with the fourfold increase in pulmonary flow. In the normal ventricle, the increase in output comes with little increase in end-diastolic pressure, the increased efficiency in part due to the beta-adrenergic system. At rest, there are normally no gradients across the
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four heart valves, but on maximal exercise small gradients have been observed, as four or five times the normal flow must traverse a fixed orifice valve. Obstructive Lesions Children with semilunar valve obstruction usually have loud murmurs and may have difficulty at peak exertion, although they may be asymptomatic at rest. As cardiac output increases with exercise, the stroke volume also increases by 20 to 25 per cent. Since the orifice of the abnormal valve is fixed, as the flow increases, the ventricular pressure and the pressure gradient across the valve increase in a parabolic fashion. At a valve area of less than 0.6 cm 2, considered moderate stenosis, the ventricle may be unable to generate a pressure that will allow normal flow during exertion. 12 In the hypertrophied heart with marginal flow to the endocardium at rest, the marked increase in heart rate with exercise reduces diastolic coronary flow and the combination of increased intraluminal pressure, increased pressure work of the heart, and diminished coronary flow may lead to ventricular ischemia. Children with pulmonic stenosis may develop increased right ventricular end-diastolic and right atrial pressures and an inability to adequately increase cardiac output that may result in shortness of breath or dyspnea,20 but in children with aortic stenosis the consequences may be even more dire, with the development of significant myocardial ischemia2 or even sudden death (Table 1). Aortic stenosis was the most common cause of sudden unexpected death in a collaborative study of children with heart disease,15 accounting for 18 per cent of all deaths. Almost 20 per cent of the children with aortic stenosis who died in this study expired during sports participation. Since the exercising muscles are usually distal to the aortic obstruction, children with coarctation of the aorta may develop very high gradients between ascending and descending aorta, as three or four times normal output must traverse the obstructed segment. This results in severe systemic hypertension in the vessels proximal to the obstruction, both subclavian and carotid arteries, and the increased pressure load on the left ventricle may lead to ischemic changes on the electrocardiogram. lO Myocardial ischemia on exertion may be even worse in children with idiopathic hypertrophic cardiomyopathy; a disease associated with a disproportionate thickness of the ventricular muscle mass, especially in the ventricular septum, with a marked disorganization of muscle cells that mayor
Table 1.
Congenital and Acquired Heart Disease Commonly Associated with Sudden Death During Exertion in Children and Adolescents
Idiopathic Hypertrophic Cardiomyopathy Aortic Stenosis Anomalous origin of the left coronary artery Cyanotic congenital heart disease Pulmonary vascular obstructive disease
Marfan·s syndrome Prolonged Q-T syndrome Coronary atherosclerosis Mitral valve prolapse
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may not be associated with left ventricular outflow obstruction (idiopathic hypertrophic sub aortic stenosis). This entity may be unsuspected clinically but is the most common cause of sudden death in young athletes, accounting for more than half the deaths in a large study by Maron et aU 8 Unfortunately this is one of the most difficult diseases to diagnose on the basis of routine sports physical examination. 17 A family history of sudden unexpected death in close relatives in the second or third decade or a history of chest pain, syncope, or dizziness on exercise that may be associated with a murmur along the left sternal border should alert the clinician to obtain an electrocardiogram or echocardiogram and to refer the child to a pediatric cardiologist. Right-To-Left Shunts
Children with cyanotic congenital heart disease usually become more hypoxic with exercise due to increased right-to-Ieft shunting. In many of these children, the ratio of pulmonary artery and aortic flow is a function of the relative ventricular outflow resistances. In children with a ventricular septal defect with pulmonary stenosis (tetralogy of Fallot) blood entering the right ventricle will exit into the pulmonary artery or through the ventricular septal defect into the aorta depending upon the relative resistances to each pathway. During strenuous exertion, the muscle arterioles dilate, lowering the systemic vascular resistance. Since the pulmonary valvar resistence is relatively fixed, more right ventricular blood will pass through the ventricular septal defect into the aorta, bypassing the lungs. This blood, lower in oxygen content, may result in severe systemic hypoxemia that may lead to myocardial hypoxemia and systemic acidosis. 29 Children with cyanosis because of pulmonary vascular obstructive disease are at risk with exercise for similar reasons. In these children the pulmonary vascular resistance is fixed secondary to obliterative changes in the pulmonary arteries due to long-standing damage from high pulmonary artery flow and pressure from lesions resulting in a large left-to-right shunt-for example, ventricular septal defect, single ventricle, patent ductus arteriosus or truncus arteriosus. In these children, increased right-toleft shunting and systemic hypoxemia with exercise results from the drop in systemic vascular resistance with the fixed pulmonary resistance secondary to the obliterative changes. 19 Recent evidence suggest that the pulmonary resistance can even increase in this situation, possibly due to the systemic hypoxemia or increased left atrial pressure. 14 Children with pulmonary vascular disease without an intracardiac communication (either because it has been surgically closed or on the basis of primary pulmonary hypertension) also have a fixed pulmonary resistance but these children lack a "blow off." They usually have pulmonary artery hypertension at rest with the level of the pressure roughly correlating with the severity of the disease. As cardiac output and therefore pulmonary blood flow increases with exercise in these children, the pulmonary artery pressure rises proportionately, often to levels far in excess of the systemic arterial pressure. This may lead to acute right ventricular decompensation with dyspnea or syncope and predisposes the myocardium to ischemic dysrhythmias and even death.
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Myocardial Dysfunction Children with primary "pump" failure either due to acute myocarditis or a more chronic dilated cardiomyopathy (now seen most commonly after treatment with adriomycin for anti-cancer therapy) may also be at increased risk with strenuous exercise. While the children may do quite well at rest, they may be unable to adequately increase cardiac output with the additional hemodynamic burdens of exercise, resulting in localized ischemia that predisposes to dysrhythmias that may further compromise the circulation and even led to sudden death. 22 Abnormalities of Rate or Rhythm Since the increase in cardiac output with exercise is for the most part due to increases in heart rate, diseases that limit the heart rate response may interfere with the ability to perform maximum exercise. At low levels of exercise, children with congenital heart block usually do well by modest increases in heart rate and stroke volume. As oxygen demands increase, however, they are unable to adequately increase cardiac output and symptoms of a localized myocardial ischemia like ectopy are not uncommon. 34 Paroxysmal supraentricular tachycardia is often associated with heart rates of up to 300 beats per minute. At very rapid heart rates myocardial perfusion and cardiac output may be compromised, resulting in symptoms of dizziness and shortness of breath or syncope. This arrhythmia may be precipitated by exercise in some children but is usually independent of activity level. Atrial or ventricular ectopic beats unassociated with structural heart disease do not seem to be associated with significant risk at exercise and, in fact, usually disappear at low levels of exercise as the sinus mechanism speeds up. Premature ventricular contractions that are not abolished by increasing the heart rate to 120 to 140 or those that are multifocal or associated with structural heart disease may suggest myocardial dysfunction and probably deserve further evaluation with stress testing (see below) and examination by a pediatric cardiologist. Volume Overload Congenital or acquired heart disease that imports a volume overload to the right or left ventricle is usually well tolerated, if mild. Children with left-to-right shunts associated with an atrial septal defect, ventricular septal defect, or patent ductus arteriosus are usually asymptomatic on exercise if they do not have associated pulmonary artery hypertension. Mitral or aortic insufficiency is not usually associated with symptoms on effort if the leakage is modest, possibly because of the reduced systemic resistance secondary to vasodilation that facilitates ventricular emptying even in the presence of an increased ventricular diastolic volume. When abnormalities in systolic or diastolic function of the heart are present at rest, however, the dysfunction usually will be exacerbated with exercise. Miscellaneous Lesions A few children have structurally normal hearts but have anomalies of the coronary arteries that are inconsequential at rest but that interfere with
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myocardial blood flow during exercise when the myocardial oxygen demands are increasing because of the increased work load of the heart. In adults this almost invariably is due to atherosclerosis involving the coronary arteries. While this occasionally may be seen in some children or young adults with one of the familiar hyperlipidemias, a more common problem is anomalous origin of the left coronary artery from the anterior sinus of Valsalva. In this lesion the left coronary artery arises anteriorly and passes between the aorta and the pulmonary artery before dividing into the circumflex and anterior descending branches. While this apparently causes no problems at rest, during exercise the increasingly pulsatile aorta and pulmonary artery ensnares the left main coronary artery, compromising flow and leading to syncope and occasionally death. 3, 11, 18, 32 The most common cause of death in patients with Marfan's syndrome is aortic dissection, While some children with this syndrome have no cardiovascular manifestations, dilation of the ascending aorta is frequently seen on chest x-ray or echocardiogram, Strenuous exercise increases both the volume and the velocity of aortic flow and may dilate the already weakened aortic wall and increase the likelihood of acute dissection. Contact sports where trauma to the chest is a possibility are contradicted in these children. 21 Children with a prolonged QT interval at rest associated with hereditary deafness as in the Jervell and Lange-Nielson syndrome or without the deafness in the otherwise identical Romano-Ward syndrome also seem to be at high risk of sudden death with exertional or emotional stress. 24, 33 In these children the increased sympathetic activity associated with exertion predisposes (in a mechanism not yet worked out but probably involving the stellate ganglion) to ventricular fibrillation, syncope, and sudden death. While this syndrome is uncommon, all children with syncope on exertion should have an ECG, and, if the QT interval corrected for rate exceeds 0.48 seconds, a referral to a pediatric cardiologist for further evaluation is indicated. Systolic hypertension increases the pressure work of the heart. While the systolic pressure increases with exercise in normal children, the increases may be extreme in children or adolescents with hypertension at rest. Interestingly there is some data in adults that suggests a lowering of the blood pressure associated with cardiovascular fitness induced by a moderate exercise program. The exact level of systolic pressure that results in myocardial ischemia is unknown, but a level of 230 to 250 mmHg has been suggested. 31 Recently Strong30 has commented that there is little available data to support risk on exercise for the adolescent with mildly elevated (170/100) blood pressure at rest,
EXERCISE TESTING Given the multiplicity of problems associated with quantitating the cardiovascular demands of different recreational and sports activities, and the variable alteration qualitatively and quantitatively in cardiovascular dynamics associated with acquired or congenital heart disease, it would appear virtually impossible to decide upon the level and type of activity re-
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strictions that one should allow to an individual child. While the exact metabolic demands of strenuous exercise cannot yet be well quantitated, recent work with graded exercise testing in children may be helpful in estimating cardiac reserve and provide clues to the mechanisms that may limit physical work capacity in children with heart disease. While one cannot exactly duplicate the intensity and duration of effort of specific athletic events, nevertheless exercise testing may be useful in obtaining an objective assessment of endurance and to ascertain which serious arrhythmias or evidences of ischemia are elicited with cardiovascular stress. Testing can be performed either on a treadmill or a bicycle. Each ha~ its own proponents but, in fact, each can stress the patient to anaerobic threshold and each can be adapted easily to children older than 5 and to young adults. 9 Most protocols involve continuous graded tests with increasing workloads until exhaustion. Three leads of the electrocardiogram are continuously monitored for heart rate and to evaluate dysrhythmias, and periodically all 12 leads are reviewed looking for evidence of myocardial ischemia. The blood pressure is measured before, during, and after exercise looking either for significant hypertension or, the more ominous, hypotension, a sign of limited cardiac reserve. Some centers are able to do more sophisticated studies, including measurements of cardiac output, systolic time intervals, and radionuclide studies that further ellucidate pathophysiologic mechanisms. 9 Exercise testing has been especially useful in evaluating the severity of aortic stenosis, where the ECG usually shows ischemic changes when the resting gradient is more than 50 mmHg,2 in patients following repair of coarctation of the aorta where severe systolic hypertension and/or ischemic changes on ECG may occur with residual gradients, and in the evaluation of dysrhythmias, associated with, or independent of, coexisting congenital heart disease. The procedure has a very low risk with serious complications in a high-risk group occuring only 1.7% of the time. S No deaths have been reported during exercise testing in children. The only contraindications to exercise testing in children are acute inflammatory disease, severe systolic hypertension in the range of 200/100, uncontrolled congestive heart failure, acute renal disease, or acute febrile disease, although special consideration should be given for children with heart disease associated with sudden death on exercise (Table 1) or those with malignant ventricular arrhythmias. Certainly if complications are going to occur during severe exercise, it is better that they happen in the exercise lab under the watchful eye of the physician with the electrocardiogram and blood pressure monitored and resuscitation equipment available than on the athletic field where help may be far away.
PERSONAL RECOMMENDATIONS ON EXERCISE PRESCRIPTION In view of the difficulties listed previously, recommendations must be viewed as only recommendations. Exceptions will almost certainly need to be made based on individual circumstances, and changes are likely as our knowledge increases. In addition, my recommendations follow, but do not
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necessarily mimic, others with an interest in the field. With these important caveats, I will proceed. Recreational and competitive activities may be divided into three categories: strenuous, moderately strenuous, and nonstrenuous (Table 2). While some overlap undoubtedly exists, the categorization seems a reasonable approximation of the energy requirements and hemodynamic burdens on the heart. In addition, a distinction is made between purely recreational and competitive athletics with the tacit assumption that the former are associated with a lower energy requirement and intensity of participation. For the child with trivial heart disease-that is, mild aortic or pulmonic stenosis; small atrial, ventricular, or great vessel communications; repaired coarctation of the aorta with no Significant gradient at rest; mild aortic or mitral regurgitation; mitral valve prolapse; mild dysrhythmias that disappear with exertion or more serious dysrhythmias unrelated to effortno activity restriction is required (Table 3). In this group, which usually comprises children with normal x-ray and ECGs, there is no conclusive evidence that athletics are harmful and little to suggest that restrictions are necessary. In the child with mild heart disease, including mild pulmonic stenosis; left-to-right shunts through atrial, ventricular, or great vessel defects with mild pulmonary hypertension; adequately repaired coarctation of the aorta; mild aortic or mitral insufficiency; systemic hypertension; or premature ventricular contractions not abolished by mild exercise, the ECG and/or x-ray will usually be abnormal. In these children, recreational activities need not be restricted (Table 4). Moderately strenuous or non strenuous competitive activities should be allowed, but it must be made clear to all concerned (child, parents, gym teacher) that the child should be allowed to rest if he or she becomes unduly fatigued. Strenuous competition may be acceptable in this group, but only if yearly exercise testing shows no
Table 2. Basketballt Crew Cross country Cyclingt Fencingt Field Hockey Football Gymnasticst
Classification of Sports by Activity Level* Strenuous Ice Hockey Lacrosse Racketball Rugby Skiingt Soccer Squash Swimmingt Moderately Strenuous Badminton Baseball Curling Golf Table Tennis
Tennist Track and Fieldt Volleyballt Water Polot Weight Lifting Wrestling
Nonstrenuous Archery Bowling Riflery
*Modified from Schaffer, T. E.: The health examination for participation in sports. Pediatr. Ann., 7: 66fH375, 1978. tpossible to perform at a moderate strenuous level of activity
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Table 3.
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Trivial Heart Disease
No restrictions on recreational or competitive sports. Peak systolic gradient less than 20 mmHg Peak systolic gradient less than 40 mmHg Operated or unoperated, normal pulmonary artery pressure Operated or unoperated, normal pulmonary Ventricular Septal Defect artery pressure Operated or unoperated, normal pulmonary Patent Ductus Arteriosus artery pressure Repaired; residual resting gradient less than Coarctation of the Aorta 10 mmHg Normal x-ray, ECe, pulse pressure, echo Aortic Insufficiency Normal x-ray, ECe, echo Mitral Insufficiency Normal x-ray, ECe Mitral Valve Prolapse If disappear on mild exertion Premature atrial contractions If disappear on mild exertion Premature ventricular contractions If no dysrhythmias on exercise by history Supraventricular tachycardia If no dysrhythmias on exercise by history Wolff-Parkillson-White syndrome Aortic Stenosis Pulmonic Stenosis Atrial Septal Defect
evidence of cardiac compromise (hypotension, ischemic changes or ectopy) at maximum activity levels. Children with moderate heart disease, including those with moderate aortic stenosis or insufficiency, unrepaired or incompletely repaired coarctation of the aorta, moderate mitral insufficiency, tetralogy of Fallot, repaired cyanotic congenital heart disease, those with prosthetic valve replacement, Marfan's syndrome without aortic root dilation, prolonged Q-T syndrome, coronary heart disease, or those with multifocal or repetitive premature ventricular contractions, may be at risk with severe exericse. In this group, strenuous competitive athletics ought to be prohibited (Table 5). Strenuous recreational, moderately strenuous, or nonstrenuous competitive activities may be allowed if exercise testing performed at least yearly fails to show evidence of hemodyanamic compromise. Although the child with repaired tetrology of Fallot or transposition may be doing quite well, there is a small but frightening incidence of sudden death that has Table 4.
Mild Heart Disease
No restrictions on recreation activities; no restrictions on nonstrenuous or moderately strenuous competitive athletics. Strenuous competitive athletics prohibited without normal stress test (yearly) Pulmonic Stenosis Resting gradient 40-60 mmHg Atrial Septal Defect Repaired or unrepaired; PA pressure
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Moderate Heart Disease
No strenuous competitive athletics. Strenuous recreational activities prohibited without normal stress test yearly. Moderately strenuous or nonstrenuous competitive activities prohibited without normal stress test yearly. Moderately strenuous or nonstrenuous recreational activities allowed. Aortic Stenosis Peak gradient 20---50 mmHg Aortic Insufficiency Abnormal ECG or x-ray but no ischemic changes at rest Coarctation of the Aorta Gradient <20 mm Hg at rest Mitral Insufficiency Abnormal x-ray and ECG Tetralogy of Fallot Postoperative Cyanotic Congenital Heart Disease Postoperative Prosthetic Valve Replacement Trivial gradient across prosthetic valve Marfan's Disease Prolonged Q-T Syndrome Without aortic root dilation Coronary Artery Disease Multifocal or repetitive PVC
}
been found to correlate with the presence of ventricular ectopy that may be exacerbated with exercise. 9 Until the etiology and correlates of this sudden death are further delineated, exercise testing is probably prudent in these groups. No restrictions are placed on moderately strenuous or nonstrenuous recreational activities in these children. Finally, those with severe heart disease, including aortic stenosis with ischemic changes, obstructive or nonobstructive cardiomyopathy, pulmonary vascular disease, unrepaired cyanotic congenital heart disease, Marfan's syndrome with a dilated aortic root, anomalous origin of the left coronary artery, or those with active myocarditis or congestive heart failure, are at real risk of sudden death with exercise (Table 6). In this group all strenuous competitive or recreational activities are prohibited, although moderately strenuous or nonstrenuous recreational activity may be allowed if yearly stress test is unremarkable except those with active myocarditis or congestive heart failure who should remain sedentary.
Table 6.
Severe Heart Disease
No strenuous competitive or recreational activities. No competitive moderately strenuous activities. Moderately strenuous recreational activity allowed if yearly stress test negative. Nonstrenuous recreational activity allowed (except myocarditis, congestive heart failure with ischemic changes). Aortic Stenosis With gradient >50 mm or ischemic changes on ECG Obstructive or Nonobstructive Cardiomyopathy Pulmonary Vascular Disease Cyanotic Congenital Heart Disease Marfan's Disease Anomalous Origin of Left Coronary Artery Myocarditis Congestive Heart Failure
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As mentioned earlier, these can only be guidelines. Consultation and dialogue between child, parent, school, pediatrician, and pediatric cardiologist to develop a program that meets the needs of the individual child is the goal. ACKNOWLEDGMENT I would like to thank Dr. Alexander S. Nadas for his helpful review of this manuscript and Ms. Ileana Fishlin for assistant in its preparation.
REFERENCES 1. Astrand, P.O., and Rodahl, K. J.: Textbook of Work Physiology: Physiologic Bases of Exercise. 2nd ed. New York, McGraw-Hill Book Co., 1977. 2. Chandramouli, B., Ehmke, D. A., and Lauer, R. M.: Exercise-induced electrocardiographic changes in children with congenital aortic stenosis. J. Pediatrics, 87:725-730, 1975. 3. Cheitlin, M. D., DeCastro, C. M., and McAllister, H. A.: Sudden death as a complication of anomalous left coronary origin from the anterior sinus of Valsalva. A not-sominor congenital anomaly. Circulation, 50:780-787, 1974. 4. Clark, K. S.: Calculated risk of sports fatalities. J.A. M.A., 197:8~96, 1966. 5. Donald, K. W., Lind, A. R., McNicol, G. W., et al.: Cardiovascular responses to sustained (static) contractions. Circ. Res. 20: and 21:1 15-30, 1967. 6. Doyle, E. F., Arumugham, P., Lara, E., et al.: Sudden death in young patients with congenital aortic stenosis. Pediatrics, 53:481-489, 1974. 7. Engle, M. A. Chairman, Congenital Heart Disease Study Group: Resources for optimal long-term care of congenital heart disease. Circulation, 44:A205-219, 1971. 8. Freed, M. D.: Exercise testing in children: A survey of techniques and safety. Circulation, 64(Suppl. l):IV 278, 1981. 9. James, F. W., Chairman, Ad Hoc Committee on Exercise Testing, American Heart Association Council on Cardiovascular Disease of the Young: Standards for exercise testing in the pediatric age group. Circulation, 66:1377A-1397A, 1982. 10. James, F. W., and Kaplan, S.: Systolic hypertension during submaximal exercise after correction of coarctation of the aorta. Circulation, 49, 50(Suppl. 11):1127-34, 1974. 11. Jokl, E., McClellan, J. T., and Ross, G. D.: Congenital anomaly of the left coronary artery in a young athlete. J.A.M.A., 182:572-573, 1962. 12. Jonsson, B.: Circulatory adaptation to exercise in congenital heart disease. Proc. Assoc. Eur. Pediatr. Cardiol., 9:2-8, 1973. 13. Karvonen, M. J.: Work and activity classifications. In Larson, L. A., (ed.): Fitness, Health, and Work Capacity: International Standards for Assessment. New York, Macmillan Publishing Co., Inc., 1974. 14. Kulik, T. J., Bass, J. L., Fuhrman, B. P., et al.: Exercise-induced pulmonary vasoconstriction. Br. Heart J., 50:59--64, 1983. 15. Lambert, E. C., Menon, V. A., Wagner, H. R., et al.: Sudden unexpected death from cardiovascular disease in children. A cooperative international study. Am. J. Cardiol., 34:89--96, 1974. 16. Larson, L. A.: The organism at work. In Larson, L. A. (ed.): Fitness, Health, and Work Capacity, International Standards for Assessment. New York, MacMillan Publishing Co. Inc., 1974. 17. Maron, B. J., Roberts, W. C., and Epstein, S. E.: Sudden death in hypertrophic cardiomyopathy: A profile of 78 patients. Circulation, 65:1388--1394, 1982. 18. Maron, B. L Roberts, W. C., McAllister, H. A., et al.: Sudden death in young athletes. Circulation, 62:218--229, 1980. 19. Mocellin, R., Friedman, J., Sebening, W., et al.: Functional studies at rest and during exertion in children and adolescents with ventricular septal defects and pulmonary hypertension. Kardiologiia, 64:1036--1052, 1975.
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20. Moller, J. H., Rao, S., and Lucas, R. V., Jr.: Exercise hemodynamics of pulmonary valvular stenosis: A study of 64 children. Circulation, 46:1018--1026, 1972. 21. Pyeritz, R. E., and McKusick, V. A.: The Marfan Syndrome: Diagnosis and management. N. Eng!. J. Med., 300:772-777, 1979. 22. Rose, K. D.: The potential for cardiovascular accidents in athletes with a heart problem. Med. Sci. Sports, 1:144--151, 1969. 23. Rose, K. D.: Which cardiovascular problems should disqualifY athletes? Physician Sports Med., 3:62-68, 1975. 24. Schwartz, P. J., Periti, M., and Malliani, A.: The long Q-T syndrome. Am. Heart J., 89:378--390, 1975. 25. Schaffer, T. E.: The health examination for participation in sports. Pediatr. Ann., 7:666675, 1978. 26. Smith, N. J. (ed.): Health Care for Young Athletes. American Academy of Pediatrics, Evanston, IL, 1983, p. 1. 27. Sonnenblick, E. H., and Lesch, M., (eds.): Exercise and Heart Disease: A Progress in Cardiovascular Disease Reprint. New York, Grune and Stratton, 1977. 28. Strauzenberg, S. E.: Recommendations for physical activity and sports in children with heart disease. J. Sports Med., 22:401---406, 1982. 29. Streider, D. J., Mesko, Z. G., Zaver, A. G., et al.: Exercise tolerance in chronic hypoxia due to right-to-left shunt. J. App!. Physio!., 34:85~58, 1973. 30. Strong, W. B.: Hypertension and sports. Pediatrics, 64:693-695, 1979. 31. Thornton, M. L.: Cardiac evaluation for participation in sports. News and Comment. Vo!' 28, No.2, Apr., 1977, Evanston, IL. American Academy of Pediatrics, 1977. 32. Tsung, S. H., Huang, T. Y., and Chang, H. H.: Sudden death in young athletes. Arch. Patho!. Lab. Med., 106:168--170, 1982. 33. Vincent, G. M., Abildskov, J. A., and Burgess, M. J.: Q-T interval syndromes. Prog. Cardiovasc. Dis., 16:527-530, 1974. 34. Winkler, R. B., Freed, M. D., and Nadas, A. S.: Exercise-induced ventricular ectopy in children and young adults with complete heart block. Am. Heart J., 99:87-92, 1980. 35. Winezip, M.: Death in yonkers: Sports medicine at issue, A high-school football death: How the system "broke-down." New York Times, Nov. 22, 1983, Bl, B4. Department of Cardiology Children's Hospital 300 Longwood Ave Boston, Massachusetts 02215
Recreational and Sports Recommendations for the Child with Heart Disease Michael D. Freed, MD.*
Each year approximately 6 million children are engaged in competitive sports in high school with 20 million more, ages 6 to 16, participating in organized out-of-school recreational and competitive athletics. 26 For the vast majority, athletics are a wholesome and rewarding experience, both physically, and emotionally, but, for a few, the experience ends tragically with severe chronic disability or even death. While the absolute number of children dying during sports participation is small, especially compared with children of the same age who die each year in motor vehicle accidents,4 there are a significant number of sports-related deaths in children with congenital heart disease that are, at least in theory, preventable. 22 In addition, sports fatalities often get wide publicity in the media, increasing their visibility. 35 Common sense dictates that children with severe heart disease ought to be restricted from some strenuous physical activities, but unfortunately there is little data on which to rationally base recommendations. More than a decade ago, the American Heart Association published some guidelines, "Recreational and Occupational Recommendations for Use by Physicians Counseling Young Patients with Heart Disease,"7 based on "the combined experience of clinicians, surgeons, and scientists." Since then, further data have been accumulated, much on the basis of invasive and noninvasive assessments of children with heart disease during exercise, and individuals and committees have updated the guidelines. 23 . 28, 31 Nevertheless, much of the "data is very empiric, and restricting children on the basis of personal prejudices rather than on data remains all too common in both Pediatrics and Pediatric Cardiology. For some children affected, this may be tragic, since sports and activities are, in some sense, a miniature society containing person-to-person and group relationships
*Senior Associate in Cardiology, Children's Hospital, Boston; Associate Professor of Pediatrics, Harvard Medical School, Boston, Massachusetts Supported in part by grant No.5 T32 HL07193, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD
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where race, religion, and ethnic origin are subservient to skill, experiences that should be a part of "growing up. "16 To label a child a "cardiac cripple" and deprive him of the benefits of participation on the basis of whim rather than data does a real disservice. In this paper, I would like to review some of the problems devising rational recreational and sports proscriptions for children with acquired or congenital heart disease. After a review of the normal cardiovascular response to exercise and the adaptations necessary in congenital or acquired heart disease, I will discuss the current status of exercise testing in children and finally present some newer guidelines on recreational and sports participation that I currently use when seeing children with heart disease at Children's Hospital, Boston.
DIFFICULTIES IN THE QUANTIFICATION OF CARDIOVASCULAR STRESS IN CHILDREN WITH HEART DISEASE There are major difficulties in quantifYing myocardial stress during exercise, derived in part from the nature of sports and recreational activities and in part from the varied nature of congenital and acquired heart disease, that make meaningful guidelines for the individual child elusive. For example, it has been difficult to generalize the metabolic demands of different recreational and competitive activities. There is an increasing body of literature on the energy requirements for the world-elite athletes training for, and performing in, Olympic events,l6 In the name of science (and possibly the quest of medals), athletes have been instrumented and studied during and after competition. As might be expected, the maximal oxygen uptakes recorded for those athletes performing individual endurance events such as cross-country skiing or long-distance running are higher than those participating in team sports such as soccer and ice hockey. Unfortunately, non-Olympic events, like football or baseball, more prevalent in our American society, have been less well studied. Even if these athletes could be instrumented and studied adequately, recreational and sports activities can be performed at such a variable intensity by different children that generalizations may be difficult, if not impossible. A visit to the local beach or pool will give one of the best examples, swimming. Since the specific gravity of the body is similar to that of water, recreational swimming can be performed with only a minimal expenditure of energy, perhaps twice basal metabolic rate, a reason it is used so extensively for the multiple handicapped. For distance swimming, the energy requirements are greater. Swimming the breast stroke recreationally requires about four times the basal metabolic rate,l3 while for competitive swimmers, energy expenditures of 20 times basal metabolic rate are not unusual. 1 All levels between lying on a raft reading a book to long-distance marathon swims are represented in the one term we call swimming. Another potential problem in assessing stress to the cardiovascular system is that there may be an enormous variability of energy require-
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ments over time in different sports. Some events, such as cross-country running or long-distance swimming require peak performance starting early and maintained throughout most, if not all, of the performance. Other activities-baseball and to a lesser extent basketball or tennismight require equally high levels of energy expenditure for short periods of time, but allow for a recovery period in between the bursts. Even if one could generalize the overall metabolic requirements of different activities, they may place different types of hemodynamic burdens on the cardiovascular system. For example, endurance sports may require a large augmentation of cardiac output increasing the volume work of the heart, but with little change in pressure work. Other activitiesweight lifting, wrestling, archery, and water skiing, for example-are primarily isometric; that is, they require exerting muscle tension against a fixed resistance. These latter activities do not require much increase in cardiac output but are associated with an acute reflex vasoconstriction that may suddenly increase, without warm-up, systemic blood pressure, and thereby increasing the pressure work of the heart. 5 Some activities may be combinations of isometric and dynamic exercise: the football player who must run and block is an example of this combination. Finally, in some athletic endeavors the increased metabolic requirements are minimal, but skill and concentration may be paramount; golf, horseback riding, bowling, and riflery are examples of this type of sport that may be performed by children with restrictions on pressure or volume work. When assessing the metabolic requirements of competitive sports, one must take into account not only the athletic event, but also the training program preceding. While there is ample evidence that training will improve performance,l it is not unusual to see coaches whose training programs are so vigorous that the actual performance is a "warm-down" in comparison. When allowing participation in a competitive sport, one must take the total activities into account, rather than what one might see at the athletic event itself. It should also be remembered that strong emotional factors may be involved in athletics. Competition may bring out maximal performance, but it also allows for the suppression of the normal warnings of fatigue and pain; for the cardiac, these warnings may playa crucial role in the prevention of serious harm. An additional problem making exercise proscription difficult is that there is tremendous variability in the severity of heart problems. There are 30 or so common types of congenital heart malformations, but each may have several different distinct varieties. Each disease may place a different hemodynamic burden on the heart and each has a different natural history, prognosis, and surgical option. In addition, each of these diseases may vary in severity-for example, mild or severe valvar pulmonic stenosis or mild tetralogy of Fallot with minimal systemic hypoxemia versus severe tetralogy with incapacitating hypoxemia and "spells" leading to unconsciousness. Finally, the severity of congenital diseases frequently change over time. Some almost invariable progress like valvar aortic stenosis, which typically increases in severity during the adolescent growth spurt as the growth of the valve lags behind the somatic growth and the need for increased cardiac output. Other diseases may improve over time like ven-
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tricular septal defects, that often get smaller and may even close during childhood. Another, perhaps insurmountable, problem, at least at present, is that, for some diseases, symptoms on severe exercise may be the presenting symptom. In children with myocarditis, cardiomyopathy, or certain anomalies of the coronary arteries, the pediatrician or even the pediatric cardiologist may be unaware of potentially serious disease present until syncope upon effort occurs. In spite of the rather formidable set of problems outlined above, it is important to attempt to outline the "state of the art" and attempt some meaningful recommendations that are neither too strict, so as not to eliminate those who could safely exercise if they were so inclined, nor too loose, so that children with heart disease but with an otherwise good prognosis will not be put in jeopardy.
CARDIOVASCULAR ADAPTATION TO EXERCISE: NORMAL AND IN CHILDREN WITH HEART DISEASE Physical activity, one of the essentials of life, may also be one of the most stressful to the cardiovascular system. Strenuous activity calls on a complex system of hormonal, neural, biochemical, respiratory, and circulatory adaptations acting in concert to deliver oxygen to metabolizing tissues as well as removing waste products. In this section I would like to review the normal circulatory adjustments to strenuous activity and the additional burdens placed by congenital or acquired heart disease. The review of normal hemodynamics on exercise will necessarily be short; those desiring a more in-depth review are encouraged to consult one of the current reviews'!, 27 During rigorous upright exercise the tissue demand for oxygen, and therefore the overall body oxygen consumption, increases. The cardiac output increases almost linearly with oxygen consumption and may be four or five times normal with peak exercise. Since the stroke volume increases only 25 to 50 per cent, most of the increase in cardiac output is due to increased heart rate. The increased flow is directed toward the involved skeletal muscle and the heart, with blood flow to the nonexercising tissues (brain, kidney, splanchnic bed, nonexercising muscles) normal or reduced slightly secondary to increased sympathetic tone and the concomitant vasoconstriction. On the systemic side of the circulation, the vascular resistance falls dramatically because of vasodilation of the exercising muscles, so that in spite of the markedly increased flow, the mean arterial pressure rises only slightly with the systolic pressure rising, accompanied by a drop in diastolic pressure. Pulmonary vasodilation is more limited, with pulmonary arterial pressure typically rising about 50 per cent from 12 mmHg to 18 mmHg with the fourfold increase in pulmonary flow. In the normal ventricle, the increase in output comes with little increase in end-diastolic pressure, the increased efficiency in part due to the beta-adrenergic system. At rest, there are normally no gradients across the
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four heart valves, but on maximal exercise small gradients have been observed, as four or five times the normal flow must traverse a fixed orifice valve. Obstructive Lesions Children with semilunar valve obstruction usually have loud murmurs and may have difficulty at peak exertion, although they may be asymptomatic at rest. As cardiac output increases with exercise, the stroke volume also increases by 20 to 25 per cent. Since the orifice of the abnormal valve is fixed, as the flow increases, the ventricular pressure and the pressure gradient across the valve increase in a parabolic fashion. At a valve area of less than 0.6 cm 2, considered moderate stenosis, the ventricle may be unable to generate a pressure that will allow normal flow during exertion. 12 In the hypertrophied heart with marginal flow to the endocardium at rest, the marked increase in heart rate with exercise reduces diastolic coronary flow and the combination of increased intraluminal pressure, increased pressure work of the heart, and diminished coronary flow may lead to ventricular ischemia. Children with pulmonic stenosis may develop increased right ventricular end-diastolic and right atrial pressures and an inability to adequately increase cardiac output that may result in shortness of breath or dyspnea,20 but in children with aortic stenosis the consequences may be even more dire, with the development of significant myocardial ischemia2 or even sudden death (Table 1). Aortic stenosis was the most common cause of sudden unexpected death in a collaborative study of children with heart disease,15 accounting for 18 per cent of all deaths. Almost 20 per cent of the children with aortic stenosis who died in this study expired during sports participation. Since the exercising muscles are usually distal to the aortic obstruction, children with coarctation of the aorta may develop very high gradients between ascending and descending aorta, as three or four times normal output must traverse the obstructed segment. This results in severe systemic hypertension in the vessels proximal to the obstruction, both subclavian and carotid arteries, and the increased pressure load on the left ventricle may lead to ischemic changes on the electrocardiogram. lO Myocardial ischemia on exertion may be even worse in children with idiopathic hypertrophic cardiomyopathy; a disease associated with a disproportionate thickness of the ventricular muscle mass, especially in the ventricular septum, with a marked disorganization of muscle cells that mayor
Table 1.
Congenital and Acquired Heart Disease Commonly Associated with Sudden Death During Exertion in Children and Adolescents
Idiopathic Hypertrophic Cardiomyopathy Aortic Stenosis Anomalous origin of the left coronary artery Cyanotic congenital heart disease Pulmonary vascular obstructive disease
Marfan·s syndrome Prolonged Q-T syndrome Coronary atherosclerosis Mitral valve prolapse
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may not be associated with left ventricular outflow obstruction (idiopathic hypertrophic sub aortic stenosis). This entity may be unsuspected clinically but is the most common cause of sudden death in young athletes, accounting for more than half the deaths in a large study by Maron et aU 8 Unfortunately this is one of the most difficult diseases to diagnose on the basis of routine sports physical examination. 17 A family history of sudden unexpected death in close relatives in the second or third decade or a history of chest pain, syncope, or dizziness on exercise that may be associated with a murmur along the left sternal border should alert the clinician to obtain an electrocardiogram or echocardiogram and to refer the child to a pediatric cardiologist. Right-To-Left Shunts
Children with cyanotic congenital heart disease usually become more hypoxic with exercise due to increased right-to-Ieft shunting. In many of these children, the ratio of pulmonary artery and aortic flow is a function of the relative ventricular outflow resistances. In children with a ventricular septal defect with pulmonary stenosis (tetralogy of Fallot) blood entering the right ventricle will exit into the pulmonary artery or through the ventricular septal defect into the aorta depending upon the relative resistances to each pathway. During strenuous exertion, the muscle arterioles dilate, lowering the systemic vascular resistance. Since the pulmonary valvar resistence is relatively fixed, more right ventricular blood will pass through the ventricular septal defect into the aorta, bypassing the lungs. This blood, lower in oxygen content, may result in severe systemic hypoxemia that may lead to myocardial hypoxemia and systemic acidosis. 29 Children with cyanosis because of pulmonary vascular obstructive disease are at risk with exercise for similar reasons. In these children the pulmonary vascular resistance is fixed secondary to obliterative changes in the pulmonary arteries due to long-standing damage from high pulmonary artery flow and pressure from lesions resulting in a large left-to-right shunt-for example, ventricular septal defect, single ventricle, patent ductus arteriosus or truncus arteriosus. In these children, increased right-toleft shunting and systemic hypoxemia with exercise results from the drop in systemic vascular resistance with the fixed pulmonary resistance secondary to the obliterative changes. 19 Recent evidence suggest that the pulmonary resistance can even increase in this situation, possibly due to the systemic hypoxemia or increased left atrial pressure. 14 Children with pulmonary vascular disease without an intracardiac communication (either because it has been surgically closed or on the basis of primary pulmonary hypertension) also have a fixed pulmonary resistance but these children lack a "blow off." They usually have pulmonary artery hypertension at rest with the level of the pressure roughly correlating with the severity of the disease. As cardiac output and therefore pulmonary blood flow increases with exercise in these children, the pulmonary artery pressure rises proportionately, often to levels far in excess of the systemic arterial pressure. This may lead to acute right ventricular decompensation with dyspnea or syncope and predisposes the myocardium to ischemic dysrhythmias and even death.
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Myocardial Dysfunction Children with primary "pump" failure either due to acute myocarditis or a more chronic dilated cardiomyopathy (now seen most commonly after treatment with adriomycin for anti-cancer therapy) may also be at increased risk with strenuous exercise. While the children may do quite well at rest, they may be unable to adequately increase cardiac output with the additional hemodynamic burdens of exercise, resulting in localized ischemia that predisposes to dysrhythmias that may further compromise the circulation and even led to sudden death. 22 Abnormalities of Rate or Rhythm Since the increase in cardiac output with exercise is for the most part due to increases in heart rate, diseases that limit the heart rate response may interfere with the ability to perform maximum exercise. At low levels of exercise, children with congenital heart block usually do well by modest increases in heart rate and stroke volume. As oxygen demands increase, however, they are unable to adequately increase cardiac output and symptoms of a localized myocardial ischemia like ectopy are not uncommon. 34 Paroxysmal supraentricular tachycardia is often associated with heart rates of up to 300 beats per minute. At very rapid heart rates myocardial perfusion and cardiac output may be compromised, resulting in symptoms of dizziness and shortness of breath or syncope. This arrhythmia may be precipitated by exercise in some children but is usually independent of activity level. Atrial or ventricular ectopic beats unassociated with structural heart disease do not seem to be associated with significant risk at exercise and, in fact, usually disappear at low levels of exercise as the sinus mechanism speeds up. Premature ventricular contractions that are not abolished by increasing the heart rate to 120 to 140 or those that are multifocal or associated with structural heart disease may suggest myocardial dysfunction and probably deserve further evaluation with stress testing (see below) and examination by a pediatric cardiologist. Volume Overload Congenital or acquired heart disease that imports a volume overload to the right or left ventricle is usually well tolerated, if mild. Children with left-to-right shunts associated with an atrial septal defect, ventricular septal defect, or patent ductus arteriosus are usually asymptomatic on exercise if they do not have associated pulmonary artery hypertension. Mitral or aortic insufficiency is not usually associated with symptoms on effort if the leakage is modest, possibly because of the reduced systemic resistance secondary to vasodilation that facilitates ventricular emptying even in the presence of an increased ventricular diastolic volume. When abnormalities in systolic or diastolic function of the heart are present at rest, however, the dysfunction usually will be exacerbated with exercise. Miscellaneous Lesions A few children have structurally normal hearts but have anomalies of the coronary arteries that are inconsequential at rest but that interfere with
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myocardial blood flow during exercise when the myocardial oxygen demands are increasing because of the increased work load of the heart. In adults this almost invariably is due to atherosclerosis involving the coronary arteries. While this occasionally may be seen in some children or young adults with one of the familiar hyperlipidemias, a more common problem is anomalous origin of the left coronary artery from the anterior sinus of Valsalva. In this lesion the left coronary artery arises anteriorly and passes between the aorta and the pulmonary artery before dividing into the circumflex and anterior descending branches. While this apparently causes no problems at rest, during exercise the increasingly pulsatile aorta and pulmonary artery ensnares the left main coronary artery, compromising flow and leading to syncope and occasionally death. 3, 11, 18, 32 The most common cause of death in patients with Marfan's syndrome is aortic dissection, While some children with this syndrome have no cardiovascular manifestations, dilation of the ascending aorta is frequently seen on chest x-ray or echocardiogram, Strenuous exercise increases both the volume and the velocity of aortic flow and may dilate the already weakened aortic wall and increase the likelihood of acute dissection. Contact sports where trauma to the chest is a possibility are contradicted in these children. 21 Children with a prolonged QT interval at rest associated with hereditary deafness as in the Jervell and Lange-Nielson syndrome or without the deafness in the otherwise identical Romano-Ward syndrome also seem to be at high risk of sudden death with exertional or emotional stress. 24, 33 In these children the increased sympathetic activity associated with exertion predisposes (in a mechanism not yet worked out but probably involving the stellate ganglion) to ventricular fibrillation, syncope, and sudden death. While this syndrome is uncommon, all children with syncope on exertion should have an ECG, and, if the QT interval corrected for rate exceeds 0.48 seconds, a referral to a pediatric cardiologist for further evaluation is indicated. Systolic hypertension increases the pressure work of the heart. While the systolic pressure increases with exercise in normal children, the increases may be extreme in children or adolescents with hypertension at rest. Interestingly there is some data in adults that suggests a lowering of the blood pressure associated with cardiovascular fitness induced by a moderate exercise program. The exact level of systolic pressure that results in myocardial ischemia is unknown, but a level of 230 to 250 mmHg has been suggested. 31 Recently Strong30 has commented that there is little available data to support risk on exercise for the adolescent with mildly elevated (170/100) blood pressure at rest,
EXERCISE TESTING Given the multiplicity of problems associated with quantitating the cardiovascular demands of different recreational and sports activities, and the variable alteration qualitatively and quantitatively in cardiovascular dynamics associated with acquired or congenital heart disease, it would appear virtually impossible to decide upon the level and type of activity re-
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strictions that one should allow to an individual child. While the exact metabolic demands of strenuous exercise cannot yet be well quantitated, recent work with graded exercise testing in children may be helpful in estimating cardiac reserve and provide clues to the mechanisms that may limit physical work capacity in children with heart disease. While one cannot exactly duplicate the intensity and duration of effort of specific athletic events, nevertheless exercise testing may be useful in obtaining an objective assessment of endurance and to ascertain which serious arrhythmias or evidences of ischemia are elicited with cardiovascular stress. Testing can be performed either on a treadmill or a bicycle. Each ha~ its own proponents but, in fact, each can stress the patient to anaerobic threshold and each can be adapted easily to children older than 5 and to young adults. 9 Most protocols involve continuous graded tests with increasing workloads until exhaustion. Three leads of the electrocardiogram are continuously monitored for heart rate and to evaluate dysrhythmias, and periodically all 12 leads are reviewed looking for evidence of myocardial ischemia. The blood pressure is measured before, during, and after exercise looking either for significant hypertension or, the more ominous, hypotension, a sign of limited cardiac reserve. Some centers are able to do more sophisticated studies, including measurements of cardiac output, systolic time intervals, and radionuclide studies that further ellucidate pathophysiologic mechanisms. 9 Exercise testing has been especially useful in evaluating the severity of aortic stenosis, where the ECG usually shows ischemic changes when the resting gradient is more than 50 mmHg,2 in patients following repair of coarctation of the aorta where severe systolic hypertension and/or ischemic changes on ECG may occur with residual gradients, and in the evaluation of dysrhythmias, associated with, or independent of, coexisting congenital heart disease. The procedure has a very low risk with serious complications in a high-risk group occuring only 1.7% of the time. S No deaths have been reported during exercise testing in children. The only contraindications to exercise testing in children are acute inflammatory disease, severe systolic hypertension in the range of 200/100, uncontrolled congestive heart failure, acute renal disease, or acute febrile disease, although special consideration should be given for children with heart disease associated with sudden death on exercise (Table 1) or those with malignant ventricular arrhythmias. Certainly if complications are going to occur during severe exercise, it is better that they happen in the exercise lab under the watchful eye of the physician with the electrocardiogram and blood pressure monitored and resuscitation equipment available than on the athletic field where help may be far away.
PERSONAL RECOMMENDATIONS ON EXERCISE PRESCRIPTION In view of the difficulties listed previously, recommendations must be viewed as only recommendations. Exceptions will almost certainly need to be made based on individual circumstances, and changes are likely as our knowledge increases. In addition, my recommendations follow, but do not
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necessarily mimic, others with an interest in the field. With these important caveats, I will proceed. Recreational and competitive activities may be divided into three categories: strenuous, moderately strenuous, and nonstrenuous (Table 2). While some overlap undoubtedly exists, the categorization seems a reasonable approximation of the energy requirements and hemodynamic burdens on the heart. In addition, a distinction is made between purely recreational and competitive athletics with the tacit assumption that the former are associated with a lower energy requirement and intensity of participation. For the child with trivial heart disease-that is, mild aortic or pulmonic stenosis; small atrial, ventricular, or great vessel communications; repaired coarctation of the aorta with no Significant gradient at rest; mild aortic or mitral regurgitation; mitral valve prolapse; mild dysrhythmias that disappear with exertion or more serious dysrhythmias unrelated to effortno activity restriction is required (Table 3). In this group, which usually comprises children with normal x-ray and ECGs, there is no conclusive evidence that athletics are harmful and little to suggest that restrictions are necessary. In the child with mild heart disease, including mild pulmonic stenosis; left-to-right shunts through atrial, ventricular, or great vessel defects with mild pulmonary hypertension; adequately repaired coarctation of the aorta; mild aortic or mitral insufficiency; systemic hypertension; or premature ventricular contractions not abolished by mild exercise, the ECG and/or x-ray will usually be abnormal. In these children, recreational activities need not be restricted (Table 4). Moderately strenuous or non strenuous competitive activities should be allowed, but it must be made clear to all concerned (child, parents, gym teacher) that the child should be allowed to rest if he or she becomes unduly fatigued. Strenuous competition may be acceptable in this group, but only if yearly exercise testing shows no
Table 2. Basketballt Crew Cross country Cyclingt Fencingt Field Hockey Football Gymnasticst
Classification of Sports by Activity Level* Strenuous Ice Hockey Lacrosse Racketball Rugby Skiingt Soccer Squash Swimmingt Moderately Strenuous Badminton Baseball Curling Golf Table Tennis
Tennist Track and Fieldt Volleyballt Water Polot Weight Lifting Wrestling
Nonstrenuous Archery Bowling Riflery
*Modified from Schaffer, T. E.: The health examination for participation in sports. Pediatr. Ann., 7: 66fH375, 1978. tpossible to perform at a moderate strenuous level of activity
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Table 3.
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Trivial Heart Disease
No restrictions on recreational or competitive sports. Peak systolic gradient less than 20 mmHg Peak systolic gradient less than 40 mmHg Operated or unoperated, normal pulmonary artery pressure Operated or unoperated, normal pulmonary Ventricular Septal Defect artery pressure Operated or unoperated, normal pulmonary Patent Ductus Arteriosus artery pressure Repaired; residual resting gradient less than Coarctation of the Aorta 10 mmHg Normal x-ray, ECe, pulse pressure, echo Aortic Insufficiency Normal x-ray, ECe, echo Mitral Insufficiency Normal x-ray, ECe Mitral Valve Prolapse If disappear on mild exertion Premature atrial contractions If disappear on mild exertion Premature ventricular contractions If no dysrhythmias on exercise by history Supraventricular tachycardia If no dysrhythmias on exercise by history Wolff-Parkillson-White syndrome Aortic Stenosis Pulmonic Stenosis Atrial Septal Defect
evidence of cardiac compromise (hypotension, ischemic changes or ectopy) at maximum activity levels. Children with moderate heart disease, including those with moderate aortic stenosis or insufficiency, unrepaired or incompletely repaired coarctation of the aorta, moderate mitral insufficiency, tetralogy of Fallot, repaired cyanotic congenital heart disease, those with prosthetic valve replacement, Marfan's syndrome without aortic root dilation, prolonged Q-T syndrome, coronary heart disease, or those with multifocal or repetitive premature ventricular contractions, may be at risk with severe exericse. In this group, strenuous competitive athletics ought to be prohibited (Table 5). Strenuous recreational, moderately strenuous, or nonstrenuous competitive activities may be allowed if exercise testing performed at least yearly fails to show evidence of hemodyanamic compromise. Although the child with repaired tetrology of Fallot or transposition may be doing quite well, there is a small but frightening incidence of sudden death that has Table 4.
Mild Heart Disease
No restrictions on recreation activities; no restrictions on nonstrenuous or moderately strenuous competitive athletics. Strenuous competitive athletics prohibited without normal stress test (yearly) Pulmonic Stenosis Resting gradient 40-60 mmHg Atrial Septal Defect Repaired or unrepaired; PA pressure
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Moderate Heart Disease
No strenuous competitive athletics. Strenuous recreational activities prohibited without normal stress test yearly. Moderately strenuous or nonstrenuous competitive activities prohibited without normal stress test yearly. Moderately strenuous or nonstrenuous recreational activities allowed. Aortic Stenosis Peak gradient 20---50 mmHg Aortic Insufficiency Abnormal ECG or x-ray but no ischemic changes at rest Coarctation of the Aorta Gradient <20 mm Hg at rest Mitral Insufficiency Abnormal x-ray and ECG Tetralogy of Fallot Postoperative Cyanotic Congenital Heart Disease Postoperative Prosthetic Valve Replacement Trivial gradient across prosthetic valve Marfan's Disease Prolonged Q-T Syndrome Without aortic root dilation Coronary Artery Disease Multifocal or repetitive PVC
}
been found to correlate with the presence of ventricular ectopy that may be exacerbated with exercise. 9 Until the etiology and correlates of this sudden death are further delineated, exercise testing is probably prudent in these groups. No restrictions are placed on moderately strenuous or nonstrenuous recreational activities in these children. Finally, those with severe heart disease, including aortic stenosis with ischemic changes, obstructive or nonobstructive cardiomyopathy, pulmonary vascular disease, unrepaired cyanotic congenital heart disease, Marfan's syndrome with a dilated aortic root, anomalous origin of the left coronary artery, or those with active myocarditis or congestive heart failure, are at real risk of sudden death with exercise (Table 6). In this group all strenuous competitive or recreational activities are prohibited, although moderately strenuous or nonstrenuous recreational activity may be allowed if yearly stress test is unremarkable except those with active myocarditis or congestive heart failure who should remain sedentary.
Table 6.
Severe Heart Disease
No strenuous competitive or recreational activities. No competitive moderately strenuous activities. Moderately strenuous recreational activity allowed if yearly stress test negative. Nonstrenuous recreational activity allowed (except myocarditis, congestive heart failure with ischemic changes). Aortic Stenosis With gradient >50 mm or ischemic changes on ECG Obstructive or Nonobstructive Cardiomyopathy Pulmonary Vascular Disease Cyanotic Congenital Heart Disease Marfan's Disease Anomalous Origin of Left Coronary Artery Myocarditis Congestive Heart Failure
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As mentioned earlier, these can only be guidelines. Consultation and dialogue between child, parent, school, pediatrician, and pediatric cardiologist to develop a program that meets the needs of the individual child is the goal. ACKNOWLEDGMENT I would like to thank Dr. Alexander S. Nadas for his helpful review of this manuscript and Ms. Ileana Fishlin for assistant in its preparation.
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