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Clinical Manifestations and Diagnosis of Coronary Artery Disease
CORONARY ARTERY DISEASE IN THE ELDERLY
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CLINICAL MANIFESTATIONS AND DIAGNOSIS OF CORONARY ARTERY DISEASE Donald D. Tresch, MD, and Wilbert S. Aronow, MD
Coronary atherosclerosis is very common in the elderly population, with autopsy studies demonstrating a prevalence of at least 70% in persons over age 70.37,38 These autopsy findings may be coincidental, with the disease clinically silent throughout the person's life; however, 20% to 30% of persons over age 65 show clinical manifestations of coronary heart disease (CHD). In most elderly persons, the disease has manifested itself much earlier in life, but in others the disease is entirely silent until the person's seventh or eighth decade. Unfortunately, even though CHD is so prevalent in elderly persons, the disease is often undiagnosed or misdiagnosed in this age group. In certain elderly persons the disease may not be diagnosed until death, which in a percent of elderly persons will be sudden. Failure to correctly diagnose the disease in the elderly may be due to the difference in clinical manifestation in this age group compared to that of younger patients. Such differences may reflect a difference in the disease process between older and younger patients or it may be related to the superimposition of normal aging changes with the presence of concomitant diseases that may mask the usual clinical manifestations. MYOCARDIAL ISCHEMIA
Typical exertional angina pectoris is commonly the first manifestation of CHD in young and middle-aged persons, and it is usually easily recognized. In elderly persons, however, this may not be the case. Due to limited physical activity, many elderly persons with CHD may not experience exertional angina. Even when
From the Medical College of Wisconsin, Milwaukee, Wisconsin (DDT); and the Mount Sinai School of Medicine and Hebrew Hospital Home, Bronx, New York (WSA)
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angina does occur, it is often attributed to causes other than CHD. For example, myocardial ischemia, appearing as shoulder or back pain, may be misdiagnosed as degenerative joint disease, or, if the pain is located in the epigastric area, may be ascribed to peptic ulcer disease. Nocturnal or postprandial epigastric discomfort that is burning in quality is often attributed to hiatus hernia or esophageal reflux instead of coronary artery disease. In addition, the pain of myocardial ischemia in elderly persons may be described as less severe and less distressing than in younger patients, further obscuring the diagnosis. Instead of typical angina, myocardial ischemia in elderly patients is commonly manifested as dyspnea. In many elderly persons the dyspnea may be exertional and is thought to be related to a rise in left ventricular end-diastolic pressure caused by ischemia superimposed on diminished ventricular compliance, occurring either as a result of normal aging changes or because of the presence of other cardiac diseases (such as hypertension or myocardial infiltration diseases) that commonly cause ventricular diastolic dysfunction. In other elderly patients myocardial ischemia is manifested as acute pulmonary edema. Siege1 and associates47reported on a group of elderly patients (mean age 69 years) with CHD in whom the disease manifested as acute pulmonary edema. The majority of patients were without angina and many were without a prior history of CHD. Ninety percent, however, had a past history of hypertension. Angiographically, the majority of patients had three-vessel CHD though left ventricular systolic function was only moderately depressed with a mean ejection fraction of 43%. Over 60% of these patients were treated with interventional therapy (coronary bypass surgery or percutaneous transluminal angioplasty), and long-term prognosis was excellent. Similar findings have been reported in other studies of acute pulmonary edema caused by CHD.l8, 19,32,33 The majority of patients are usually elderly, have a past history of hypertension, and show multi-vessel coronary disease with usually only moderate impairment of systolic left ventricular function. In another study of elderly patients with CAD, Tresch and associate^^^ studied the initial manifestations of CHD in a group of elderly patients who underwent coronary angiography. The mean age of the group was 71 years with some of the patients over the age of 80 before the onset of symptoms. The initial manifestation in the majority of patients was ischemic chest pain, with 34% of the patients sustaining an acute myocardial infarction. In 8% of these elderly patients the initial manifestation was acute heart failure unassociated with an acute myocardial infarction. Upon cardiac catheterization, multivessel disease was common, though left ventricular systolic function was good. Only 9% of the patients had an ejection fraction of less than 35%. Comparing these findings to those of patients younger than 65 years, younger patients more commonly sustained an acute myocardial infarction as the initial manifestation of CHD, were less likely to present with heart failure, and have less multivessel coronary disease. Cardiac arrhythmia may be a manifestation of myocardial ischemia and is a common problem in elderly patients with CHD. Sudden death as an initial of 66 elderly manifestation of CHD increases with In Tresch's s t ~ d y , 95 ~ nstipntc, h,?d ~ r r h o t h m i . ? ,?s~ thp initi?! m?nifpc.t.?tion . of TFTT), .?nr! ---?T? of - - thn ---~
~~
patients experienced out-of-hospital cardiac arrest. Silent or asymptomatic ischemia, as noted in younger patients, is a common problem in elderly patients with CHD. Approximately 15%of the elderly patients in Tresch's study2 were asymptomatic, and myocardial ischemia was detected by exercise stress testing during a preoperative evaluation. In a study of 185 very elderly (mean age 83 years) nursing-home residents, Aronow and associates8 demonstrated silent myocardial ischemia by Holter monitoring in 34% of the residents. Similar findings were reported by Hedblad and associatesz7in a study
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91
of 53 elderly Swedish patients (mean age 68 years). Holter monitoring findings of silent ischemia were evident in 36% of the patients. MYOCARDIAL INFARCTION
As with myocardial ischemia, some patients with myocardial infarction may be completely asymptomatic or the symptoms may be so vague that they are unrecognized by the patient or physician as an acute myocardial infarction. The Framingham Heart found that in the general population approximately 25% of myocardial infarctions diagnosed by pathologic Q waves on electrocardiography were clinically unrecognized, and of these, 48% were truly silent. The incidence increased with age, with 42% of infarctions being clinically silent in males aged 75 to 84 years. In women, the proportion of unrecognized myocardial infarctions was greater than in men, but the incidence was unaffected by increasing age. Other studies4,15, 39, 40,", 51, 55 have also reported a high prevalence of silent or unrecognized myocardial infarction in elderly persons, with some studies reporting as many as 60% of infarctions being unrecognized or silent in the very elderly ~ , ~ ~ that the incidence of new coronary (Table 1).Importantly, most s t ~ d i e sindicate events, including recurrent infarction, ventricular fibrillation, and sudden death, is similar in elderly patients with either recognized or unrecognized infarction. The reason for the frequent absence of chest pain in elderly patients with CAD is unclear. Various speculations have included (1)mental deterioration with inability to verbalize a sensation of pain, (2)better myocardial collateral circulation related to gradual progressive coronary artery narrowing, and (3) a decreased sensitivity to pain because of aging changes. Another theory has suggested that the increase in silent myocardial ischemia and infarction in elderly patients with CAD is related to increased levels of, or receptor sensitivity to, endogenous opi~ids.~O This explanation does not appear likely, because studies have demonstrated a similar increase in response of P-endorphin levels to exercise in both elderly and younger s~bjects,2~ and animal studies show a decrease in opiod receptor responsivGy with' advancing age.38 Symptoms when present in elderly patients with an acute myocardial infarction may be extremely vague, and, as with myocardial ischemia, the diagnosis
Table 1. PREVALENCE OF INCIDENCE OF SILENT OR UNRECOGNIZED Q-WAVE MYOCARDIAL INFARCTION IN ELDERLY PATIENTS Study Rod~tein~~ Aronow et all5 Aronow4 Vokonas et aIs3 Muller et aP9 Nadelmann et aI4O
Number of Patients
Age (years)
Unrecognized (Number)
52 115 110 199 (men) 162 (women) 46 (men) 67 (women) 115
>60 >64 >62 >65 >65 >65 >65 >75
16 78 23 65 58 14 34 50
or
Painless MI (Percent) 31 68 21 33 36 30 51 43
MI = myocardial infarction Adapted from Tresch DD, Aronow WS: Recognition and diagnosis of coronary artery disease. In Tresch DD, Aronow WS (eds): Cardiovascular Disease in The Elderly. New York, Marcel Dekker, Inc., 1994, pp 285-304; with permission.
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may be easily missed. Numerous studies4,16, 35, 47, 41, 44, 49, 54 have demonstrated the atypical features and wide varability of symptoms in elderly patients with acute ~ ~ that approximyocardial infarction (Table 2). In an early study, R ~ d s t e i nfound mately 30% of elderly nurisng home residents who sustained an acute myocardial infarction were without any symptoms referable to heart disease. In 40% of the patients, classic chest o r neck pain was absent, but symptoms such as dyspnea, syncope, vertigo, or abdominal pain were common. In the 1960s, PathqP' reported similar findings. Patients older than 80 years who sustained an acute myocardial infarction commonly showed dyspnea or neurologic symptoms such as acute confusion, stroke, or vertigo rather than typical chest pain. Both Rodstein and Pathy emphasized the importance of suspecting an acute myocardial infarction in elderly persons who experience unexplained behavior changes, acute signs of cerebral insufficiency, or dyspnea. More recent studiesI6,48,54 have also stressed the importance of atypical presentations in elderly patients with acute myocardial infarction, and some studies have suggested that dyspnea may be more common than chest pain as the presenting symptom. In the Multicenter Chest Pain the clinical presentation of acute myocardial infarction was compared in 1615 patients older than 65 years and 5109 patients younger than 65 years. Due to the decreased prevalence of some typical features (such as pressure-like pain), the initial symptoms and signs had a lower predictive value for diagnosing acute myocardial infarction i n elderly patients compared to younger patients. In another recent prospective study, Wroblewski and associates54reported that only 20% of elderly patients in a Swedish geriatric hospital showed chest pain at the onset of acute myocardial infarction, whereas 70% complained of dyspnea. DIAGNOSTIC TECHNIQUES Resting Electrocardiogram
The resting electrocardiogram may be used in elderly patients to diagnose acute or old myocardial infarction, whether silent or symptomatic. Ischemic ST-T wave changes, as well as arrhythmias and conduction defects that may occur secondary to CHD, can be diagnosed with the resting electrocardiogram.
Table 2. PREVALENCE OF CHEST PAIN, DYSPNEA, AND NEUROLOGIC SYMPTOMS ASSOCIATED WITH ACUTE MYOCARDIAL INFARCTION IN ELDERLY PATIENTS.
Study
Neurologic Number Chest Pain Dyspnea Symptoms of Age Patients (years) number percent number percent number percent
R ~ d s t e i n ~ ~ 52 path^^^ 387 TinkePY 87 Bayer et all6 777 Aronow4 110 W r ~ b l e w s k i ~ ~96 *
= symptom
t mean age
>60 >65 74t 76t >62 84t
15 75 51 515 24 19
29 19 59 66 22 20
77 19 329 38 57
20 22 42 35 59
126 14 232 20 14
33 16 30 18 15
present but number and percentage not stated
Adapted from Tresch DD, Aronow WS: Recognition and diagnosis of coronary artery disease. In Tresch DD, Aronow WS (eds): Cardiovascular Disease in The Elderly. New York, Marcell Dekker, Inc., 1994, pp 285-304; with permission.
CLINICAL MANIFESTATIONS AND DIAGNOSIS OF CORONARY ARTERY DISEASE
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In addition to being beneficial in diagnosing CHD, electrocardiogram findings may be predictive of future coronary artery events, including death. In a study of elderly nursing home patients in whom resting electrocardiographic findings were assessed as predictors of mortality and new coronary events, Aronow and associates2 found that at 37 months mean follow-up elderly patients (mean age 82 2 8 years, range 62 to 103 years) with ischemic ST segment depression greater than 1.0 mm on the resting electrocardiogram were 3.1 times more likely to develop new coronary events (myocardial infarction, primary ventricular fibrillation, or sudden cardiac death) than were elderly patients with no significant ST segment depression. Elderly patients with an ischemic ST segment depression of 0.5 to 0.9 mm on resting elcetrocardiography were 1.9 times more likely to develop new coronary events than were elderly patients with no significant ST segment depression. In another study of elderly nursing home patients, Aronow and associates' found that resting electrocardiographic findings of electronic pacemaker rhythm, atrial fibrillation, premature ventricular complexes, left bundle-branch block, nonspecific intraventricular conduction defect, and type I1 second-degree atrioventricular block were also associated with a higher incidence of new coronary events in elderly patients with CHD. Numerous studies have documented that elderly patients with electrocardiographic left ventricular hypertrophy have an increased incidence of new cardiovascular events. Men and women 65 to 94 years of age participating in the Framingham Heart Studyz9who showed electrocardiographic left ventricular hypertrophy had an increased incidence of coronary events, atherothrombotic brain infarction, congestive heart failure, and peripheral arterial disease compared to participants without left ventricular hypertrophy. Similar results were reported by Aronow and associates.13 Elderly nursing home patients with hypertension or CHD and electrocardiographic left ventricular hypertrophy had an increased incidence of new coronary events and atherothrombotic brain infarctions at 37 months mean follow-up. The increased incidence of cardiovascular morbidity was not different between black and white elderly nursing home patients who had hypertension and electrocardiographic signs of left ventricular hypertrophy. Exercise and Pharmacologic Stress Testing
Exercise stress testing using electrocardiography, isotope perfusion scintigraphy, radionuclide ventriculography, or echocardiography may be used to diagnose CHD in both asymptomatic and symptomatic elderly patients. Stress test findings may also be useful as prognostic markers of future coronary events. In elderly patients who because of musculoskeletal disorders or general debilitation are unable to perform exercise, intravenous dipyridamole-thallium has high sensitivity and specificity in diagnosing CHD in this subset of elderly patients.34Recently, the pharmacologic dobutamine-echocardiographic stress test has been shown to be an alternative to dipyridamole-thallium in diagnosing CHD in elderly patients who cannot exercise. The sensitivity and specificity of dobutamine-echocardiography stress testing is similar to other types of stress testing and it is as safe in elderly patients as in younger patients. Recent studies17have found dobutamineechocardiography stress testing to be useful in stratifying elderly patients into high and low risk groups after myocardial infarction. Ambulatory Electrocardiography (Holter Monitoring)
Ambulatory electrocardiographic monitoring (AEM)is useful in the detection of transient cardiac arrhythmias and myocardial ischemia. Such applications are
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TRESCH & ARONOW
practically applicable in elderly patients in whom CHD is prevalent and for whom resultant arrhythmias and myocardial ischemia are major clinical problems. The presence of underlying heart disease is the most important consideration of patient evaluation i n reference to the significance of arrhythmias as a predictor of future cardiac events. Numerous have shown ventricular arrhythmia to be an independent predictor of future cardiac events, including sudden death, in elderly patients with underlying heart disease (Table 3). The risk of future cardiac events increases when ventricular arrhythmia occurs in combination with left ventricular dysfunction or left ventricular hypertrophy. In contrast, most studies'0-'2~22~31~50 have failed to show a correlation between arrhythmias and future cardiac events in healthy elderly patients without underlying heart disease (see Table 3). Ischemic electrocardiographic ST-T changes demonstrated on AEM correlate with transient abnormalities in myocardial perfusion and ventricular dysfunction. The changes may be associated with symptoms, or symptoms may be completely absent, which is referred to as silent ischemia. Silent ischemia is a frequent occurrence and is predictive of future cardiac events including mortality in patients with CHD. Such findings have been reported in both middle-aged and older patients7-9,23-25,27,50 (Table 4). A 21% prevalence of silent ischemia as detected by AEM was reported by Aronow and Epstein8in a study of elderly nursing home patients (mean age 82 years) who had documented underlying heart disease; this compared with only a 5% prevalence in nursing home patients without heart disease. Nursing home patients with CHD had a prevalence of silent ischemia twice that found in patients with other forms of heart disease. Over a 26-month follow-up, 65% of patients with CHD and 33% of patients with other forms of heart disease who showed signs of silent ischemia on AEM had new cardiac events, compared with 32% and 18% patients, respectively, without silent ischemia. In another study of elderly nursing home patients9 the prevalence of silent ischemia increased significantly in patients with a left ventricular ejection fraction of less than 50%, compared with patients with a normal ejection fraction (250%):abnormal ejection fraction, as well as silent ischemia, was an independent predictor of new cardiac events. When both variables were present, the incidence of future coronary events markedly increased; 94% of nursing home patients with both silent ischemia and abnormal ejection fraction had new cardiac events during a 40-month mean follow-up period. The combination of silent myocardial ischemia and ventricular arrhythmias as a predictor of future coronary events has also been studied by Aronow and associates7in their elderly nursing home population. As expected, silent ischemia, ventricular tachycardia, and complex ventricular arrhythmias were all more prevalent in patients with coronary artery disease, and ventricular arrhythmias were common in patients with silent ischemia. In regard to predicting cardiac events, 84% of patients with the combination of silent ischemia and complex ventricular arrhythmias had a cardiac event at a mean follow-up of 37 months, compared with only 21% of the patients with neither silent ischemia nor complex ventricu!?r .?rrhvthm;.?g
As ;n Aronow's studies, Hedblad and associatesz7found ischemia detected on AEM to be highly predictive of cardiac events in older Scandinavian men, age 68 years. A 4.4-fold increased risk of coronary events occurred in men without documented coronary artery disease who showed myocardial ischemia on AEM. The relative risk of coronary events increased 16-fold in the men with coronary in a study of healthy elderly subjects who artery disease. Fleg and did not show a correlation between arrhythmias and future cardiac events, did find approximately a 4-fold increase in cardiac events in elderly persons with
Table 3. RELATIONSHIP O F VENTRICULAR ARRHYTHMIAS TO FUTURE CARDIAC EVENTS IN OLDER PATIENTS -
-
Study
Number of Patients
Age (years)
69
Aronow"
76 468
Cardiac Status
Variable
79 82t
Healthy* Healthy* Heart disease
VPCs, VT VPCs Complex VA
82t
No heart disease Heart disease
Complex VA Complex VA, VT, & LVEF
82t
No heart disease Heart disease
Complex VA, VT & LVEF Complex VA, VT & LVH
No heart disease
Complex VA
Mean Follow-up Period (months)
Incidence of Cardiac Events No correlation No correlation Approximately 2x incidence in patients with complex VA No correlation Greater than 2x incidence in patients with complex VA or VT. 3x incidence in patients with abnormal LVEF. Greater than 7x incidence in patients with abnormal LVEF and complex VA or VT No correlation 3x incidence of SCD or VF in patients with complex VA, VT, or LVH. 7x incidence of SCD or VF in patients with LVH and complex VA or VT No correlation
* See text for definition of healthy
t Age of total patients, including patients without heart disease VT
LVEF = left ventricular ejection fraction; LVH = left ventricular hypertrophy; SCD = sudden cardiac death; VA = ventricular arrhythmias; VPC = ventricular premature beat; ventricular tachycardia; VF = ventricular fibrillation. Adapted from Tresch DD: Diagnostic and prognostic value of ambulatory electrocardiography monitoring in older patients. J Am Geriatr Soc 43: 66-70, 1995; with permission.
=
Table 4. RELATIONSHIP OF SILENT ISCHEMIA TO FUTURE CARDIAC EVENTS IN OLDER PATIENTS Study
Number of Patients
Cardiac Status
69 82t
Aronowg
98 534 92 393
No heart disease Heart disease No heart disease CAD or systemic hypertension
SI* SI SI SI & LVEF
Aronow7
404
82
CAD or systemic hypertension
Sl, complex VA & VT
37
Hedbladz7
394
68
CAD or no CAD
SI
43
FlegZz Aronow8
82
Variable
Mean Follow-up Period (months)
Age (years)
120 26 26 40
Incidence of Cardiac Events Approximately 4x incidence in patients with SI Greater than 2x incidence in patients with SI No correlation 2x incidence in patients with SI. Greater than 2x incidence in patients with abnormal LVEF. Greater than 3x incidence in patients with SI and abnormal LVEF 2x incidence in patients with SI or complex VA. 4x incidence in patients with SI and complex VA. 1.7~ incidence in patients with VT. 2 . 5 ~incidence in patients with SI and VT 4 . 4 ~greater risk of MI in patients with SI. Risk increased 16x in patients with SI and CAD
* Included patients witti 2 1 mm upsloping ST-segment depression.
t Age of total patients, including patients without heart disease
CAD = coronary arterj disease; LVEF = left ventricular ejection fraction; MI = myocardial infarction; SI = silent ischemia; VA = ventricular arrhythmias; VT = ventricular tachycardia Adapted from Tresch [ID: Diagnostic and prognostic value of ambulatory electrocardiography monitoring in older patients. J Am Geriatr Soc 43:66-70, 1995; with permission.
CLINICAL MANIFESTATIONS AND DIAGNOSIS OF CORONARY ARTERY DISEASE
97
signs of silent ischemia on AEM; two of the three patients in their study who died suddenly had signs of silent ischemia and ventricular tachycardia on AEM. Such findings suggest, as in Aronow's study: that the combination of silent ischemia and ventricular arrhythmias in elderly patients may be a potent indicator of increased cardiac risk. Silent ischemia detected by AEM has been used in the assessment of patients undergoing noncardiac surgery. Such use of AEM may be especially beneficial in older patients, who frequently are at high surgical risk and may not be able to undergo preoperative exercise stress testing because of concomitant illness. Raby and associates43studied 176 patients who underwent 24-hour AEM before noncardiac surgery. Eighteen percent of the patients had signs of ischemia on preoperative AEM, with the ischemia asymptomatic in the majority of patients; and the preoperative ischemia was highly predictive of postoperative cardiac events. The sensitivity of preoperative ischemia for postoperative cardiac events in these patients was 92%, the specificity 88%, the predictive value of a positive result 38%,and the predictive value of a negative result 99%. Multivariate analyses demonstrated preoperative ischemia to be the most significant correlative of postoperative cardiac events. The authors concluded that the absence of preoperative ischemia on AEM indicates a very low risk for postoperative cardiac events. Thirty-eight percent of the patients in this study were older than 69 years, and preoperative ischemia was more prevalent in these elderly patients compared with the younger patients. In a follow-up study, Raby and associates4' assessed the significance of intraoperative and postoperative ischemia, in addition to preoperative ischemia, detected on AEM in relationship to postoperative cardiac events in patients undergoing peripheral vascular surgery. The mean age of the patients was 67 years, and 37% were 70 years or older. As in their previous study, the authors found preoperative ischemia to be the most important predictor of postoperative cardiac events. Preoperative ischemia also strongly correlated with intraoperative and postoperative ischemia, and perioperative ischemia commonly preceded clinical cardiac events. Echocardiography
Echocardiography can be a useful procedure in the assessment of elderly patients with CHD. Detection of regional wall abnormalities, acute myocardial ischemia, left ventricular aneurysm, cardiac thrombus, left main coronary artery disease, left ventricular hypertrophy, left ventricular function, and cardiac chamber size is possible with echocardiography. Such findings are useful in diagnosing CHD, and may also be useful in predicting future cardiac events and long-term prognosis in elderly patient^.^,'^,",^' Aronow and associates5in studies of elderly nursing home patients found left ventricular ejection fraction to be the most important prognostic variable for mortality in elderly patients with heart failure associated with CHD. Patients with heart failure and depressed systolic left ventricular ejection fraction had a worse prognosis than did patients with heart failure and normal systolic ejection fractions. Echocardiographic left ventricular hypertrophy is a predictor of future cardiac events in both middle-aged and The Framingham Heart Study3*found echocarelderly patients with CHD.6,'0,'3,'4,34 diographic left ventricular hypertrophy to be predictive of coronary events independently of standard risk factors in elderly patients with CHD. Echocardigraphic left ventricular hypertrophy was 15.3 times more sensitive in predicting coronary events in elderly men and 4.3 times more sensitive in predicting coronary events in elderly women than was electrocardiographic ventricular hypertrophy. In stud-
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TRESCH & ARONOW
ies of very elderly nursing home patients with CHD, Aronow and associate^'^,", l 3 , l 4 reported similar findings. Elderly nursing home patients with echocardiographic left ventricular hypertrophy had at least a 2 times higher incidence of new coronary events at follow-up than did patients without echocardiographicleft ventricular hypertrophy. The incidence of new atherothrombotic brain infarction, heart failure, and sudden death was also higher in elderly nursing home patients with CHD or hypertension and echocardiographic left ventricular hypertrophy than it was in patients without left ventricular hypertrophy regardless of whether CHD or hypertension were present. Even though CAD is prevalent in elderly persons, it is often undiagnosed or misdiagnosed, which may be related to its atypical presentation in this age group. Instead of typical chest pain, myocardial ischemia or infarction may commonly be manifested as dyspnea or acute heart failure. In other elderly persons myocardial ischemia or infarction will be silent, with the patient completely asymptomatic, even though electrocardiographic findings of ischemia or infarction are present. Some elderly patients with acute myocardial infarction will show new neurologic symptoms such as mental confusion or cerebral vascular accidents. Because of these atypical presentations and the wide variability of symptoms, physicians must be highly suspicious of the presence of myocardial ischemia or acute infarction in elderly patients who have an unexplained acute change in physical condition. Diagnostic procedures such as resting electrocardiography, stress testing, ambulatory electrocardiographic monitoring, and echocardiography can be beneficial in diagnosing CAD in elderly patients as well as in predicting future coronary events in these patients. The use of these diagnostic techniques should be considered in the evaluation of elderly patients in whom$CHDis suspected.
References 1. Aronow WS: Correlation of arrhythmias and conduction defects on the resting electrocardiogram with new cardiac events in 1,153 elderly patients. Am J Noninvas Cardiol 5:88-90, 1991 2. Aronow WS: Correlation of ischemic ST-segmentdepression on the resting electrocardiogram with new cardiac events in 1,106 patients over 62 years of age. Am J Cardiol 64:232-233,1989 3. Aronow WS: New coronary events of four-year follow-up in elderly patients with recognized or unrecognized myocardial infarction. Am J Cardiol63:621-622, 1989 4. Aronow WS: Prevalence of presenting symptoms of recognized acute myocardial infarction and of unrecognized healed myocardial infarction in elderly patients. Am J Cardiol 60:1182, 1987 5. Aronow WS, Ahn C, Kronzon I: Prognosis of congestive heart failure in elderly patients with normal versus abnormal left ventricular systolic function associated with coronary artery disease. Am J Cardiol 66:1257-1259, 1990 6. Aronow WS, Ahn C, Kronzon I, et al: Congestive heart failure, coronary events, and atherothrombotic brain infarction in elderly blacks and whites with systemic hyperten-
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left ventricular hypertrophy. Am J Cardiol 67:295-299, 1991 7. Aronow WS, Epstein S: Usefulness of silent ischemia, ventricular tachycardia, and complex ventricular arrhythmias in predicting new coronary events in elderly patients with coronary artery disease or systemic hypertension. Am J Cardiol65:511-512, 1990 8. Aronow WS, Epstein S: Usefulness of silent myocardial ischemia detected by ambulatory electrocardiographic monitoring in predicting new coronary events in elderly patients. Am J Cardiol 62:1295-1296, 1988 9. Aronow WS, Epstein S, Koenigsberg M: Usefulness of echocardiographic left ventricular ejection fraction and silent myocardial ischemia in predicting new coronary events in
CLINICAL MANIFESTATIONS AND DIAGNOSIS OF CORONARY ARTERY DISEASE
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elderlv patients with coronary artery disease or systemic hypertension. Am J Cardiol 65:81i-g12, 1990 10. Aronow WS, Epstein S, Koenigsberg M, et al: Usefulness of echocardiographic abnormal left ventricular ejection fraction, paroxysmal ventricular tachycardia and complex venover 62 of age. tricular arrhythmias in predicting newucoronaryevents in Am J Cardiol 61:1349-1351, 1988 11. Aronow WS, Epstein S, Koenigsberg M, et al: Usefulness of echocardiographic left ventricular hypertrophy, ventricular tachycardia and complex ventricular arrhythmias in predicting ventricular fibrillation or sudden cardiac death in elderly patients. Am J Cardiol 62:1124-1125, 1988 12. Aronow WS, Epstein S, Mercando AD: Usefulness of complex ventricular arrhythmias detected by 24-hour ambulatory electrocardiogram and by electrocardiograms with oneminute rhythm strips in predicting new coronary events in elderly patients with and without heart disease. J Cardiovasc Techno1 10:21-25,1991 13. Aronow WS, Koenigsberg M, Schwartz KS: Usefulness of echocardiographic and electrocardiographic left ventricular hypertrophy in predicting new cardiac events and atherothrombotic brain infarction in elderly patients with systemic hypertension or coronary artery disease. Am J Noninvas Cardiol 3:367-370, 1989 14. Aronow WS, Koenigsberg M, Schwartz KS: Usefulness of echocardiographic left ventricular hypertrophy in predicting new coronary events and atherothrombotic brain infarction in patients over 62 years of age. Am J Cardiol 61:1130-1132, 1988 15. Aronow WS, Starling L, Etienne F, et al: Unrecognized Q-wave myocardial infarction in patients older than 64 years in a long-term health-care facility. Am J Cardiol56:483,1985 16. Bayer AJ, Chadha JS, Farag RR, et al: Changing presentation of myocardial infarction with increasing old age. J Am Geriatr Soc 23:263-266, 1986 17. Carlos ME, Smart SC, Tresch DD: Benefits and safety of dobutamine stress echocardiography in the elderly. Clin Res 42:357A, 1994 18. Clark LT, Garfein OB, Dwyer EM: Acute pulmonary edema due to ischemic heart disease without accompanying myocardial infarction. Am J Med 75:332-336, 1983 19. Dodek A, Kassebaum DG, Bristow JD: Pulmonary edema in coronary artery disease without cardiomegaly: Paradox of the stiff heart. N Engl J Med 286:1347-1350, 1972 20. Ellestad MH, Kaun P: Naloxone and asymptomatic ischemia: Failure to induce angina during exercise testing. Am J Cardiol 54:982-984, 1984 21. Elveback LR, Connelly DC, Kurland LT: Coronary heart disease in residents of Rochester, Minnesota, 11:Mortality, incidence, and survivorship. 1950-1975. Mayo Clin Proc 56:665672, 1981 22. Fleg JL, Kennedy HL: Long-term prognostic significance of ambulatory electrocardiographic findings in apparently healthy subjects >60 years of age. Am J Cardiol70:748751, 1992 23. Gottlieb SO, Weisfeldt ML, Ouyang P, et al: Silent ischemia as a marker for early unfavorable outcomes in patients with unstable angina. N Engl J Med 314:1214-1219, 1986 24. Gottlieb SO, Gottlieb SH, Achuff SC, et al: Silent ischemia on holter monitoring predicts mortality in high-risk postinfarction patients. JAMA 259:1030-1035, 1988 25. Gottlieb SO, Weisfeldt ML, Ouyang P, et al: Silent ischemia predicts infarction and death during 2 year follow-up of unstable angina. J Am Coll Cardiol 10:756-760,1987 26. Hatfield BD, Goldfarb AH, Sporzo GA, et al: Serum beta-endorphin and affective response to graded exercise in young and elderly men. J Gerontol42:429-431, 1987 27. Hedblad B, Juul-Moller S, Svensson K, et al: Increased moratality in men with ST segment depression during 24h ambulatory long-term ECG recording: Results from prospective population study "Men born in 1914," from Malmo Sweden. Eur Heart J 10:149-158,1989 28. Kannel WB, Abbott RD: Incidence and prognosis of unrecognized myocardial infarction: An update on the Framingham study. N Engl J Med 311:1144-1147, 1984 29. Kannel WB, Dannenberg AL, Levy D: Population implications of electrocardiographic left ventricular hypertrophy. Am J Cardiol 60:851-931, 1987 30. Kannel WB, Schatzkin A: Sudden death: Lesions from subsets in population studies. J Am Coll Cardiol 5:141B-149B, 1985 31. Kirkland JL, Lye M, Faragher EB, et al: A longitudinal study of the prognostic significance of ventricular ectopic beats in the elderly. Gerontology 29:199-201, 1983 <
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32. Kunis R, Greenberg H, Yeoh CB, et al: Coronary revascularization of recurrent pulmonary edema in elderly patients with ischemic heart disease and preserved ventricular function. N Engl J Med 313:1207-1210,1985 33. Lam JYT, Chaitman BR, Glaenzer M, et al: Safety and diagnostic accuracy of dipyridamole-thallium imaging in the elderly. J Am Coll Cardiol 11:585-589, 1988 34. Levy D, Garrison RJ, Savage DD, et al: Left ventricular mass incidence of coronary heart disease in an elderly cohort: The Framinnham heart study. Ann Intern Med 11O:lOl-107, 1989 35. MacDonald TB: Presentation of acute mvocardial infarction in the elderlv: A review. Age Ageing '13:196-204,1980 36. McKeown F: Pathology of the Aged. London, Butterworths, 1965, pp 44-45 37. Monroe RT: Diseases in Old Age. Cambridge, MA, Harvard University Press, 1951 38. Morley JE: Neuropeptides, behavior and aging. J Am Geriatr Soc 3452-61,1986 39. Muller RT, Gould LA, Betzu R, et al: Painless myocardial infarction in the elderly. Am Heart J 119:202-204, 1990 40. Nadelmann J, Frishman WH, Ooi W1, et al: Prevalence, incidence, and prognosis of recognized and unrecognized myocardial infarction in persons aged 75 years or older: The Bronx aging study. Am J Cardiol66:533-537,1990 41. Pathv MS: Clinical presentation of mvocardial infarction in the elderly. Br Heart T 29:1$0-199, 1967 * 42. Rabv Creager MA, et al: Detection and significance of intraoperative and , KE., Barrv , ,1, , postoperative myocardyal ischemia in peripheral vaGular surgery. J&A 268:222227, 1992 43. Raby KE, Goldman L, Creager MA, et al: Correlation between preoperative ischemia and major cardiac events after peripheral vascular surgery. N Engl J Med 321:1296-1300,1989 44. Rodstein M: The characteristics of non-fatal myocardial infarction in the aned. Arch Intern Med 98234-90, 1956 45. Ruderman W, Weinblatt E, Goldberg ID, et al: Ventricular premature beats and mortalitv after myocardial infarction. N E ~ & J~ e 297750-757, d i977 46. Setaro JF, Soufer R, Remetz MS, et al: Long-term outcome in patients with congestive heart failure and intact systolic left ventricular performance. Am J Cardiol 69:12121216,1992 47. Siege1R, Clemens T, Wingo M, et al: Acute heart failure in elderly: Another manifestation of unstable "angina." J Am Coll Cardiol 17:149A, 1991 48. Solomon CG, Lee TH, Cook EF, et al: Comparison of clinical presentation of acute myocardial infarction in patients older than 65 years of age to younger patients: The Multicenter Chest Pain Study experience. Am J Cardiol63:772-776, 1989 49. Tinker GM: Clinical presentation of myocardial infarction in the elderly. Age Aging 10:237-240,1981 50. Tresch DD: Diagnostic and prognostic value of ambulatory electrocardiography monitoring in older patients. J Am Geriatr Soc 43:66-70, 1995 51. Tresch DD, Aronow WS: Recognization and diagnosis of coronary artery disease in elderly. In Tresch DD, Aronow WS (eds): Cardiovascular Disease in Elderly. Marcel Dekker, New York, 1994, pp 285-304 52. Tresch DD, Saeian K, Hoffman R: Elderly patients with late onset of coronary artery disease: Clinical and angiographic findings. American Journal of Geriatric Cardiology 1:14-25, 1992 53. Vokanas PS, Kannel WB, Cupples LA: Incidence and prognosis of unrecognized myocardial infarction in elderly: The Framingham Study (abstract). J Am Coll Cardiol ll:51A, 1988 - , St.??.S7r-rtc-c -,.= ~ .n .f--~, -vnc?rd!-.! ~ . . :-czrrticr . i- c!d zgn. E.1 -. !h?r.~F.!~~,~.ml-~ . . - - - - . . - - .-h.l .. , ?.,
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CLINICAL MANIFESTATIONS AND DIAGNOSIS OF CORONARY ARTERY DISEASE Donald D. Tresch, MD, and Wilbert S. Aronow, MD
Coronary atherosclerosis is very common in the elderly population, with autopsy studies demonstrating a prevalence of at least 70% in persons over age 70.37,38 These autopsy findings may be coincidental, with the disease clinically silent throughout the person's life; however, 20% to 30% of persons over age 65 show clinical manifestations of coronary heart disease (CHD). In most elderly persons, the disease has manifested itself much earlier in life, but in others the disease is entirely silent until the person's seventh or eighth decade. Unfortunately, even though CHD is so prevalent in elderly persons, the disease is often undiagnosed or misdiagnosed in this age group. In certain elderly persons the disease may not be diagnosed until death, which in a percent of elderly persons will be sudden. Failure to correctly diagnose the disease in the elderly may be due to the difference in clinical manifestation in this age group compared to that of younger patients. Such differences may reflect a difference in the disease process between older and younger patients or it may be related to the superimposition of normal aging changes with the presence of concomitant diseases that may mask the usual clinical manifestations. MYOCARDIAL ISCHEMIA
Typical exertional angina pectoris is commonly the first manifestation of CHD in young and middle-aged persons, and it is usually easily recognized. In elderly persons, however, this may not be the case. Due to limited physical activity, many elderly persons with CHD may not experience exertional angina. Even when
From the Medical College of Wisconsin, Milwaukee, Wisconsin (DDT); and the Mount Sinai School of Medicine and Hebrew Hospital Home, Bronx, New York (WSA)
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TRESCH & ARONOW
angina does occur, it is often attributed to causes other than CHD. For example, myocardial ischemia, appearing as shoulder or back pain, may be misdiagnosed as degenerative joint disease, or, if the pain is located in the epigastric area, may be ascribed to peptic ulcer disease. Nocturnal or postprandial epigastric discomfort that is burning in quality is often attributed to hiatus hernia or esophageal reflux instead of coronary artery disease. In addition, the pain of myocardial ischemia in elderly persons may be described as less severe and less distressing than in younger patients, further obscuring the diagnosis. Instead of typical angina, myocardial ischemia in elderly patients is commonly manifested as dyspnea. In many elderly persons the dyspnea may be exertional and is thought to be related to a rise in left ventricular end-diastolic pressure caused by ischemia superimposed on diminished ventricular compliance, occurring either as a result of normal aging changes or because of the presence of other cardiac diseases (such as hypertension or myocardial infiltration diseases) that commonly cause ventricular diastolic dysfunction. In other elderly patients myocardial ischemia is manifested as acute pulmonary edema. Siege1 and associates47reported on a group of elderly patients (mean age 69 years) with CHD in whom the disease manifested as acute pulmonary edema. The majority of patients were without angina and many were without a prior history of CHD. Ninety percent, however, had a past history of hypertension. Angiographically, the majority of patients had three-vessel CHD though left ventricular systolic function was only moderately depressed with a mean ejection fraction of 43%. Over 60% of these patients were treated with interventional therapy (coronary bypass surgery or percutaneous transluminal angioplasty), and long-term prognosis was excellent. Similar findings have been reported in other studies of acute pulmonary edema caused by CHD.l8, 19,32,33 The majority of patients are usually elderly, have a past history of hypertension, and show multi-vessel coronary disease with usually only moderate impairment of systolic left ventricular function. In another study of elderly patients with CAD, Tresch and associate^^^ studied the initial manifestations of CHD in a group of elderly patients who underwent coronary angiography. The mean age of the group was 71 years with some of the patients over the age of 80 before the onset of symptoms. The initial manifestation in the majority of patients was ischemic chest pain, with 34% of the patients sustaining an acute myocardial infarction. In 8% of these elderly patients the initial manifestation was acute heart failure unassociated with an acute myocardial infarction. Upon cardiac catheterization, multivessel disease was common, though left ventricular systolic function was good. Only 9% of the patients had an ejection fraction of less than 35%. Comparing these findings to those of patients younger than 65 years, younger patients more commonly sustained an acute myocardial infarction as the initial manifestation of CHD, were less likely to present with heart failure, and have less multivessel coronary disease. Cardiac arrhythmia may be a manifestation of myocardial ischemia and is a common problem in elderly patients with CHD. Sudden death as an initial of 66 elderly manifestation of CHD increases with In Tresch's s t ~ d y , 95 ~ nstipntc, h,?d ~ r r h o t h m i . ? ,?s~ thp initi?! m?nifpc.t.?tion . of TFTT), .?nr! ---?T? of - - thn ---~
~~
patients experienced out-of-hospital cardiac arrest. Silent or asymptomatic ischemia, as noted in younger patients, is a common problem in elderly patients with CHD. Approximately 15%of the elderly patients in Tresch's study2 were asymptomatic, and myocardial ischemia was detected by exercise stress testing during a preoperative evaluation. In a study of 185 very elderly (mean age 83 years) nursing-home residents, Aronow and associates8 demonstrated silent myocardial ischemia by Holter monitoring in 34% of the residents. Similar findings were reported by Hedblad and associatesz7in a study
CLINICAL MANIFESTATIONS AND DIAGNOSIS OF CORONARY ARTERY DISEASE
91
of 53 elderly Swedish patients (mean age 68 years). Holter monitoring findings of silent ischemia were evident in 36% of the patients. MYOCARDIAL INFARCTION
As with myocardial ischemia, some patients with myocardial infarction may be completely asymptomatic or the symptoms may be so vague that they are unrecognized by the patient or physician as an acute myocardial infarction. The Framingham Heart found that in the general population approximately 25% of myocardial infarctions diagnosed by pathologic Q waves on electrocardiography were clinically unrecognized, and of these, 48% were truly silent. The incidence increased with age, with 42% of infarctions being clinically silent in males aged 75 to 84 years. In women, the proportion of unrecognized myocardial infarctions was greater than in men, but the incidence was unaffected by increasing age. Other studies4,15, 39, 40,", 51, 55 have also reported a high prevalence of silent or unrecognized myocardial infarction in elderly persons, with some studies reporting as many as 60% of infarctions being unrecognized or silent in the very elderly ~ , ~ ~ that the incidence of new coronary (Table 1).Importantly, most s t ~ d i e sindicate events, including recurrent infarction, ventricular fibrillation, and sudden death, is similar in elderly patients with either recognized or unrecognized infarction. The reason for the frequent absence of chest pain in elderly patients with CAD is unclear. Various speculations have included (1)mental deterioration with inability to verbalize a sensation of pain, (2)better myocardial collateral circulation related to gradual progressive coronary artery narrowing, and (3) a decreased sensitivity to pain because of aging changes. Another theory has suggested that the increase in silent myocardial ischemia and infarction in elderly patients with CAD is related to increased levels of, or receptor sensitivity to, endogenous opi~ids.~O This explanation does not appear likely, because studies have demonstrated a similar increase in response of P-endorphin levels to exercise in both elderly and younger s~bjects,2~ and animal studies show a decrease in opiod receptor responsivGy with' advancing age.38 Symptoms when present in elderly patients with an acute myocardial infarction may be extremely vague, and, as with myocardial ischemia, the diagnosis
Table 1. PREVALENCE OF INCIDENCE OF SILENT OR UNRECOGNIZED Q-WAVE MYOCARDIAL INFARCTION IN ELDERLY PATIENTS Study Rod~tein~~ Aronow et all5 Aronow4 Vokonas et aIs3 Muller et aP9 Nadelmann et aI4O
Number of Patients
Age (years)
Unrecognized (Number)
52 115 110 199 (men) 162 (women) 46 (men) 67 (women) 115
>60 >64 >62 >65 >65 >65 >65 >75
16 78 23 65 58 14 34 50
or
Painless MI (Percent) 31 68 21 33 36 30 51 43
MI = myocardial infarction Adapted from Tresch DD, Aronow WS: Recognition and diagnosis of coronary artery disease. In Tresch DD, Aronow WS (eds): Cardiovascular Disease in The Elderly. New York, Marcel Dekker, Inc., 1994, pp 285-304; with permission.
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TRESCH & ARONOW
may be easily missed. Numerous studies4,16, 35, 47, 41, 44, 49, 54 have demonstrated the atypical features and wide varability of symptoms in elderly patients with acute ~ ~ that approximyocardial infarction (Table 2). In an early study, R ~ d s t e i nfound mately 30% of elderly nurisng home residents who sustained an acute myocardial infarction were without any symptoms referable to heart disease. In 40% of the patients, classic chest o r neck pain was absent, but symptoms such as dyspnea, syncope, vertigo, or abdominal pain were common. In the 1960s, PathqP' reported similar findings. Patients older than 80 years who sustained an acute myocardial infarction commonly showed dyspnea or neurologic symptoms such as acute confusion, stroke, or vertigo rather than typical chest pain. Both Rodstein and Pathy emphasized the importance of suspecting an acute myocardial infarction in elderly persons who experience unexplained behavior changes, acute signs of cerebral insufficiency, or dyspnea. More recent studiesI6,48,54 have also stressed the importance of atypical presentations in elderly patients with acute myocardial infarction, and some studies have suggested that dyspnea may be more common than chest pain as the presenting symptom. In the Multicenter Chest Pain the clinical presentation of acute myocardial infarction was compared in 1615 patients older than 65 years and 5109 patients younger than 65 years. Due to the decreased prevalence of some typical features (such as pressure-like pain), the initial symptoms and signs had a lower predictive value for diagnosing acute myocardial infarction i n elderly patients compared to younger patients. In another recent prospective study, Wroblewski and associates54reported that only 20% of elderly patients in a Swedish geriatric hospital showed chest pain at the onset of acute myocardial infarction, whereas 70% complained of dyspnea. DIAGNOSTIC TECHNIQUES Resting Electrocardiogram
The resting electrocardiogram may be used in elderly patients to diagnose acute or old myocardial infarction, whether silent or symptomatic. Ischemic ST-T wave changes, as well as arrhythmias and conduction defects that may occur secondary to CHD, can be diagnosed with the resting electrocardiogram.
Table 2. PREVALENCE OF CHEST PAIN, DYSPNEA, AND NEUROLOGIC SYMPTOMS ASSOCIATED WITH ACUTE MYOCARDIAL INFARCTION IN ELDERLY PATIENTS.
Study
Neurologic Number Chest Pain Dyspnea Symptoms of Age Patients (years) number percent number percent number percent
R ~ d s t e i n ~ ~ 52 path^^^ 387 TinkePY 87 Bayer et all6 777 Aronow4 110 W r ~ b l e w s k i ~ ~96 *
= symptom
t mean age
>60 >65 74t 76t >62 84t
15 75 51 515 24 19
29 19 59 66 22 20
77 19 329 38 57
20 22 42 35 59
126 14 232 20 14
33 16 30 18 15
present but number and percentage not stated
Adapted from Tresch DD, Aronow WS: Recognition and diagnosis of coronary artery disease. In Tresch DD, Aronow WS (eds): Cardiovascular Disease in The Elderly. New York, Marcell Dekker, Inc., 1994, pp 285-304; with permission.
CLINICAL MANIFESTATIONS AND DIAGNOSIS OF CORONARY ARTERY DISEASE
93
In addition to being beneficial in diagnosing CHD, electrocardiogram findings may be predictive of future coronary artery events, including death. In a study of elderly nursing home patients in whom resting electrocardiographic findings were assessed as predictors of mortality and new coronary events, Aronow and associates2 found that at 37 months mean follow-up elderly patients (mean age 82 2 8 years, range 62 to 103 years) with ischemic ST segment depression greater than 1.0 mm on the resting electrocardiogram were 3.1 times more likely to develop new coronary events (myocardial infarction, primary ventricular fibrillation, or sudden cardiac death) than were elderly patients with no significant ST segment depression. Elderly patients with an ischemic ST segment depression of 0.5 to 0.9 mm on resting elcetrocardiography were 1.9 times more likely to develop new coronary events than were elderly patients with no significant ST segment depression. In another study of elderly nursing home patients, Aronow and associates' found that resting electrocardiographic findings of electronic pacemaker rhythm, atrial fibrillation, premature ventricular complexes, left bundle-branch block, nonspecific intraventricular conduction defect, and type I1 second-degree atrioventricular block were also associated with a higher incidence of new coronary events in elderly patients with CHD. Numerous studies have documented that elderly patients with electrocardiographic left ventricular hypertrophy have an increased incidence of new cardiovascular events. Men and women 65 to 94 years of age participating in the Framingham Heart Studyz9who showed electrocardiographic left ventricular hypertrophy had an increased incidence of coronary events, atherothrombotic brain infarction, congestive heart failure, and peripheral arterial disease compared to participants without left ventricular hypertrophy. Similar results were reported by Aronow and associates.13 Elderly nursing home patients with hypertension or CHD and electrocardiographic left ventricular hypertrophy had an increased incidence of new coronary events and atherothrombotic brain infarctions at 37 months mean follow-up. The increased incidence of cardiovascular morbidity was not different between black and white elderly nursing home patients who had hypertension and electrocardiographic signs of left ventricular hypertrophy. Exercise and Pharmacologic Stress Testing
Exercise stress testing using electrocardiography, isotope perfusion scintigraphy, radionuclide ventriculography, or echocardiography may be used to diagnose CHD in both asymptomatic and symptomatic elderly patients. Stress test findings may also be useful as prognostic markers of future coronary events. In elderly patients who because of musculoskeletal disorders or general debilitation are unable to perform exercise, intravenous dipyridamole-thallium has high sensitivity and specificity in diagnosing CHD in this subset of elderly patients.34Recently, the pharmacologic dobutamine-echocardiographic stress test has been shown to be an alternative to dipyridamole-thallium in diagnosing CHD in elderly patients who cannot exercise. The sensitivity and specificity of dobutamine-echocardiography stress testing is similar to other types of stress testing and it is as safe in elderly patients as in younger patients. Recent studies17have found dobutamineechocardiography stress testing to be useful in stratifying elderly patients into high and low risk groups after myocardial infarction. Ambulatory Electrocardiography (Holter Monitoring)
Ambulatory electrocardiographic monitoring (AEM)is useful in the detection of transient cardiac arrhythmias and myocardial ischemia. Such applications are
94
TRESCH & ARONOW
practically applicable in elderly patients in whom CHD is prevalent and for whom resultant arrhythmias and myocardial ischemia are major clinical problems. The presence of underlying heart disease is the most important consideration of patient evaluation i n reference to the significance of arrhythmias as a predictor of future cardiac events. Numerous have shown ventricular arrhythmia to be an independent predictor of future cardiac events, including sudden death, in elderly patients with underlying heart disease (Table 3). The risk of future cardiac events increases when ventricular arrhythmia occurs in combination with left ventricular dysfunction or left ventricular hypertrophy. In contrast, most studies'0-'2~22~31~50 have failed to show a correlation between arrhythmias and future cardiac events in healthy elderly patients without underlying heart disease (see Table 3). Ischemic electrocardiographic ST-T changes demonstrated on AEM correlate with transient abnormalities in myocardial perfusion and ventricular dysfunction. The changes may be associated with symptoms, or symptoms may be completely absent, which is referred to as silent ischemia. Silent ischemia is a frequent occurrence and is predictive of future cardiac events including mortality in patients with CHD. Such findings have been reported in both middle-aged and older patients7-9,23-25,27,50 (Table 4). A 21% prevalence of silent ischemia as detected by AEM was reported by Aronow and Epstein8in a study of elderly nursing home patients (mean age 82 years) who had documented underlying heart disease; this compared with only a 5% prevalence in nursing home patients without heart disease. Nursing home patients with CHD had a prevalence of silent ischemia twice that found in patients with other forms of heart disease. Over a 26-month follow-up, 65% of patients with CHD and 33% of patients with other forms of heart disease who showed signs of silent ischemia on AEM had new cardiac events, compared with 32% and 18% patients, respectively, without silent ischemia. In another study of elderly nursing home patients9 the prevalence of silent ischemia increased significantly in patients with a left ventricular ejection fraction of less than 50%, compared with patients with a normal ejection fraction (250%):abnormal ejection fraction, as well as silent ischemia, was an independent predictor of new cardiac events. When both variables were present, the incidence of future coronary events markedly increased; 94% of nursing home patients with both silent ischemia and abnormal ejection fraction had new cardiac events during a 40-month mean follow-up period. The combination of silent myocardial ischemia and ventricular arrhythmias as a predictor of future coronary events has also been studied by Aronow and associates7in their elderly nursing home population. As expected, silent ischemia, ventricular tachycardia, and complex ventricular arrhythmias were all more prevalent in patients with coronary artery disease, and ventricular arrhythmias were common in patients with silent ischemia. In regard to predicting cardiac events, 84% of patients with the combination of silent ischemia and complex ventricular arrhythmias had a cardiac event at a mean follow-up of 37 months, compared with only 21% of the patients with neither silent ischemia nor complex ventricu!?r .?rrhvthm;.?g
As ;n Aronow's studies, Hedblad and associatesz7found ischemia detected on AEM to be highly predictive of cardiac events in older Scandinavian men, age 68 years. A 4.4-fold increased risk of coronary events occurred in men without documented coronary artery disease who showed myocardial ischemia on AEM. The relative risk of coronary events increased 16-fold in the men with coronary in a study of healthy elderly subjects who artery disease. Fleg and did not show a correlation between arrhythmias and future cardiac events, did find approximately a 4-fold increase in cardiac events in elderly persons with
Table 3. RELATIONSHIP O F VENTRICULAR ARRHYTHMIAS TO FUTURE CARDIAC EVENTS IN OLDER PATIENTS -
-
Study
Number of Patients
Age (years)
69
Aronow"
76 468
Cardiac Status
Variable
79 82t
Healthy* Healthy* Heart disease
VPCs, VT VPCs Complex VA
82t
No heart disease Heart disease
Complex VA Complex VA, VT, & LVEF
82t
No heart disease Heart disease
Complex VA, VT & LVEF Complex VA, VT & LVH
No heart disease
Complex VA
Mean Follow-up Period (months)
Incidence of Cardiac Events No correlation No correlation Approximately 2x incidence in patients with complex VA No correlation Greater than 2x incidence in patients with complex VA or VT. 3x incidence in patients with abnormal LVEF. Greater than 7x incidence in patients with abnormal LVEF and complex VA or VT No correlation 3x incidence of SCD or VF in patients with complex VA, VT, or LVH. 7x incidence of SCD or VF in patients with LVH and complex VA or VT No correlation
* See text for definition of healthy
t Age of total patients, including patients without heart disease VT
LVEF = left ventricular ejection fraction; LVH = left ventricular hypertrophy; SCD = sudden cardiac death; VA = ventricular arrhythmias; VPC = ventricular premature beat; ventricular tachycardia; VF = ventricular fibrillation. Adapted from Tresch DD: Diagnostic and prognostic value of ambulatory electrocardiography monitoring in older patients. J Am Geriatr Soc 43: 66-70, 1995; with permission.
=
Table 4. RELATIONSHIP OF SILENT ISCHEMIA TO FUTURE CARDIAC EVENTS IN OLDER PATIENTS Study
Number of Patients
Cardiac Status
69 82t
Aronowg
98 534 92 393
No heart disease Heart disease No heart disease CAD or systemic hypertension
SI* SI SI SI & LVEF
Aronow7
404
82
CAD or systemic hypertension
Sl, complex VA & VT
37
Hedbladz7
394
68
CAD or no CAD
SI
43
FlegZz Aronow8
82
Variable
Mean Follow-up Period (months)
Age (years)
120 26 26 40
Incidence of Cardiac Events Approximately 4x incidence in patients with SI Greater than 2x incidence in patients with SI No correlation 2x incidence in patients with SI. Greater than 2x incidence in patients with abnormal LVEF. Greater than 3x incidence in patients with SI and abnormal LVEF 2x incidence in patients with SI or complex VA. 4x incidence in patients with SI and complex VA. 1.7~ incidence in patients with VT. 2 . 5 ~incidence in patients with SI and VT 4 . 4 ~greater risk of MI in patients with SI. Risk increased 16x in patients with SI and CAD
* Included patients witti 2 1 mm upsloping ST-segment depression.
t Age of total patients, including patients without heart disease
CAD = coronary arterj disease; LVEF = left ventricular ejection fraction; MI = myocardial infarction; SI = silent ischemia; VA = ventricular arrhythmias; VT = ventricular tachycardia Adapted from Tresch [ID: Diagnostic and prognostic value of ambulatory electrocardiography monitoring in older patients. J Am Geriatr Soc 43:66-70, 1995; with permission.
CLINICAL MANIFESTATIONS AND DIAGNOSIS OF CORONARY ARTERY DISEASE
97
signs of silent ischemia on AEM; two of the three patients in their study who died suddenly had signs of silent ischemia and ventricular tachycardia on AEM. Such findings suggest, as in Aronow's study: that the combination of silent ischemia and ventricular arrhythmias in elderly patients may be a potent indicator of increased cardiac risk. Silent ischemia detected by AEM has been used in the assessment of patients undergoing noncardiac surgery. Such use of AEM may be especially beneficial in older patients, who frequently are at high surgical risk and may not be able to undergo preoperative exercise stress testing because of concomitant illness. Raby and associates43studied 176 patients who underwent 24-hour AEM before noncardiac surgery. Eighteen percent of the patients had signs of ischemia on preoperative AEM, with the ischemia asymptomatic in the majority of patients; and the preoperative ischemia was highly predictive of postoperative cardiac events. The sensitivity of preoperative ischemia for postoperative cardiac events in these patients was 92%, the specificity 88%, the predictive value of a positive result 38%,and the predictive value of a negative result 99%. Multivariate analyses demonstrated preoperative ischemia to be the most significant correlative of postoperative cardiac events. The authors concluded that the absence of preoperative ischemia on AEM indicates a very low risk for postoperative cardiac events. Thirty-eight percent of the patients in this study were older than 69 years, and preoperative ischemia was more prevalent in these elderly patients compared with the younger patients. In a follow-up study, Raby and associates4' assessed the significance of intraoperative and postoperative ischemia, in addition to preoperative ischemia, detected on AEM in relationship to postoperative cardiac events in patients undergoing peripheral vascular surgery. The mean age of the patients was 67 years, and 37% were 70 years or older. As in their previous study, the authors found preoperative ischemia to be the most important predictor of postoperative cardiac events. Preoperative ischemia also strongly correlated with intraoperative and postoperative ischemia, and perioperative ischemia commonly preceded clinical cardiac events. Echocardiography
Echocardiography can be a useful procedure in the assessment of elderly patients with CHD. Detection of regional wall abnormalities, acute myocardial ischemia, left ventricular aneurysm, cardiac thrombus, left main coronary artery disease, left ventricular hypertrophy, left ventricular function, and cardiac chamber size is possible with echocardiography. Such findings are useful in diagnosing CHD, and may also be useful in predicting future cardiac events and long-term prognosis in elderly patient^.^,'^,",^' Aronow and associates5in studies of elderly nursing home patients found left ventricular ejection fraction to be the most important prognostic variable for mortality in elderly patients with heart failure associated with CHD. Patients with heart failure and depressed systolic left ventricular ejection fraction had a worse prognosis than did patients with heart failure and normal systolic ejection fractions. Echocardiographic left ventricular hypertrophy is a predictor of future cardiac events in both middle-aged and The Framingham Heart Study3*found echocarelderly patients with CHD.6,'0,'3,'4,34 diographic left ventricular hypertrophy to be predictive of coronary events independently of standard risk factors in elderly patients with CHD. Echocardigraphic left ventricular hypertrophy was 15.3 times more sensitive in predicting coronary events in elderly men and 4.3 times more sensitive in predicting coronary events in elderly women than was electrocardiographic ventricular hypertrophy. In stud-
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TRESCH & ARONOW
ies of very elderly nursing home patients with CHD, Aronow and associate^'^,", l 3 , l 4 reported similar findings. Elderly nursing home patients with echocardiographic left ventricular hypertrophy had at least a 2 times higher incidence of new coronary events at follow-up than did patients without echocardiographicleft ventricular hypertrophy. The incidence of new atherothrombotic brain infarction, heart failure, and sudden death was also higher in elderly nursing home patients with CHD or hypertension and echocardiographic left ventricular hypertrophy than it was in patients without left ventricular hypertrophy regardless of whether CHD or hypertension were present. Even though CAD is prevalent in elderly persons, it is often undiagnosed or misdiagnosed, which may be related to its atypical presentation in this age group. Instead of typical chest pain, myocardial ischemia or infarction may commonly be manifested as dyspnea or acute heart failure. In other elderly persons myocardial ischemia or infarction will be silent, with the patient completely asymptomatic, even though electrocardiographic findings of ischemia or infarction are present. Some elderly patients with acute myocardial infarction will show new neurologic symptoms such as mental confusion or cerebral vascular accidents. Because of these atypical presentations and the wide variability of symptoms, physicians must be highly suspicious of the presence of myocardial ischemia or acute infarction in elderly patients who have an unexplained acute change in physical condition. Diagnostic procedures such as resting electrocardiography, stress testing, ambulatory electrocardiographic monitoring, and echocardiography can be beneficial in diagnosing CAD in elderly patients as well as in predicting future coronary events in these patients. The use of these diagnostic techniques should be considered in the evaluation of elderly patients in whom$CHDis suspected.
References 1. Aronow WS: Correlation of arrhythmias and conduction defects on the resting electrocardiogram with new cardiac events in 1,153 elderly patients. Am J Noninvas Cardiol 5:88-90, 1991 2. Aronow WS: Correlation of ischemic ST-segmentdepression on the resting electrocardiogram with new cardiac events in 1,106 patients over 62 years of age. Am J Cardiol 64:232-233,1989 3. Aronow WS: New coronary events of four-year follow-up in elderly patients with recognized or unrecognized myocardial infarction. Am J Cardiol63:621-622, 1989 4. Aronow WS: Prevalence of presenting symptoms of recognized acute myocardial infarction and of unrecognized healed myocardial infarction in elderly patients. Am J Cardiol 60:1182, 1987 5. Aronow WS, Ahn C, Kronzon I: Prognosis of congestive heart failure in elderly patients with normal versus abnormal left ventricular systolic function associated with coronary artery disease. Am J Cardiol 66:1257-1259, 1990 6. Aronow WS, Ahn C, Kronzon I, et al: Congestive heart failure, coronary events, and atherothrombotic brain infarction in elderly blacks and whites with systemic hyperten-
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left ventricular hypertrophy. Am J Cardiol 67:295-299, 1991 7. Aronow WS, Epstein S: Usefulness of silent ischemia, ventricular tachycardia, and complex ventricular arrhythmias in predicting new coronary events in elderly patients with coronary artery disease or systemic hypertension. Am J Cardiol65:511-512, 1990 8. Aronow WS, Epstein S: Usefulness of silent myocardial ischemia detected by ambulatory electrocardiographic monitoring in predicting new coronary events in elderly patients. Am J Cardiol 62:1295-1296, 1988 9. Aronow WS, Epstein S, Koenigsberg M: Usefulness of echocardiographic left ventricular ejection fraction and silent myocardial ischemia in predicting new coronary events in
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Address reprint requests to Donald D. Tresch, MD Medical College of Wisconsin 8700 Wisconsin Avenue Milwaukee. WI 53226