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The Sick Sinus Syndrome
Dillon et al. Also, echocardiographic studies have been shown to be extremely useful in the setting of acute aortic regurgitation due to fenestrations of the valvular leaflets where the left ventricle is forced to operate on a steep portion of its pressure-volume curve, where middle and late diastolic pressures are severely elevated and exceed the left atrial pressure, and where the mitral valve thereby closes relatively early in diastole. This abbreviation of diastolic filling of the left ventricle can be readily detected by ech0cardiographic recordings of the motion of the anterior and posterior leaflets of the mitral valve and their temporal relationship to the surface electrocardiogram. Premature closure correlates with a severe volume overload that is marginally compensated and thus serves as a relatively objective marker of the need for emergency replacement of the aortic valve. 7 Serial echocardiograms (weekly) also may be useful in patients with fevers of unknown origin and where bacterial endocarditis is suspected but cannot be proven by cultures of blood and other clinical characteristics. In one patient in my experience, serial echocardiograms defined the gradual development over a six-week period of a large obstructive vegetation on the mitral valve due to infection with Hemophilw parain'fluem:ae. There is hope on the horizon for further improved modes for early precise detection of infectious end0carditis. Imaging of valvular vegetations may become feasible using either computerized axial tomographic studies or phase-array two-dimensional echocardiographic studies. Range-gated Doppler's ultrasound may provide a further noninvasive means of detecting subtle derangements of patterns of intracardiac flow produced by otherwise clinically silent vegetations. Improved bioprostheses for valvular replacement may be found which will be considerably more resistant to harboring the bacteria and fungi that cause infectious endocarditis. These potential· advances hopefully will minimize the controversy that presently surrounds the diagnosis and management of this difficult clinical problem. Kirk L. Petef'son, M.D.•
San Diego, Cal.if •Associate Professor of Medicine, University of California Medical Center, University Hospital. Reprint requem: Df'. Petenon, 225 W ut Dicldnaon. San Diego 9S013
fu:FERENCES 1 GrifBn FM, Jones G, Cobbs CC: Aortic insufllciency in bacterial endocarditis. Ann Intem Med 76:23, 1972 2 Black S, O'Rourke RA, Karliner JA: Role of surgery in the treabnent of primary infective endocarditis. Am J Med 56:357-369, 1974 3 ColUns NP, Braunwald E, Morrow AG: Detection of
554 EDITORIALS
4 5
6 7
pulmonic and tricuspid valvular regurgitation by me~ of indicator solutions. Circulation 20:561-568, 1959 Pazin J, Peterson KL, Griff FW, et al: Determination of site of infection in endocarditis. Ann Intem Med 82:746750, 1975 Arbulu A, Thomas NW, Wilson RF: Valvulectomy without prosthetic replacement. J. Thorac Cardiovasc Surg 64:103-107, 1972 Dillon JC Feigenbaum H, Konecke LL, et al: Echocardiographic manifestations of valvular vegetations. Am Heart J 86:698-704, 1973 Mann T, McLaurin L, Grossman et al: Acute aortic regurgitation due to infective endocarditis. N Engl J Med 293:108-113, 1975
The Sick Sinus Syndrome Its Status aHer Ten Years the ten years since its original description, the I nsick sinus syndrome bas generated much clinical 1
interest and electrophysiologic investigation. This syndrome is now recognized not to be rare, and in its full-blown state, criteria2 for its diagnosis appear to be relatively adequate. There are, nevertheless, some outstanding de:8ciencies in our knowledge of the sick sinus syndrome, and it is salutary to review some of these. The incidence of the dysfunction is as yet uncertain, although statistics on pacemakers suggest that patients with the sick sinus syndrome may even exceed in number those with atrioventricular or intraventricular block. The great difficulty in early diagnosis of the syndrome of dysfunction of the sinoatrial node remains and has stimulated much excellent electrophysiologic study. w The de:8ciency of knowledge regarding the basic natural history of the sick sinus syndrome is gradually being diminished. The splendid report in this issue (see page 628) by Lien et al from the Republic of China on the longitudinal survey of 52 patients provides important data in this sector, showing duration of the disease as long as 29 years and stressing the intermittency of the dysfunctions in many subjects. Boal and Kleinfeld8 also have noted long durations (up to 33 years) of the syndrome; however, adequate prediction of the stage of the dysfunction has eluded us to date. Especially weak in the young or middle-aged patient, the ability to tag the danger zone of malfunction in any one person is perhaps best now in the elderly patient, where the dysfunction usually is more rapidly progressive. The correct timing of insertion of a pacemaker depends on the prediction of dangerous symptoms, and this problem of timing remains dif:8cult to solve until the natural history of the syndrome is better known.
CHEST, 72: 5, NOVEMBER, 1977
At present, the diagnostic criteria for full-blown failure of the sinoatrial node are still to be found in the clinical electrocardiogram; however, provocative testing by atrial pacing methods can uncover less definite dysfunction. In a study of 51 patients with sinus bradycardia, Reiffel and Bigger7 searched for the electrocardiographic criteria of spontaneously occurring sinoatrial nodal dysfunction using continuous electrocardiographic monitOring (Holter) coupled to functional testing (by atrial pacing) of the sinoatrial node; these two methods -together represent our best means of finding the patient with the sick sinus syndrome. Neither test alone was as effective in sorting out the subjects with basically disturbed sinoatrial nodes from the physiologic ( nonpathologic) variants. A new approach to testing the function of the sinoatrial node has been initiated by Cramer et al8 and represents the only additional recent physiologic information, since direct action potentials from the sinoatrial node have not been secured as yet in man. It has been an unfortunate side effect of the great interest in the sick sinus syndrome that some subjects with sinus bradycardia alone are incorrectly designated as having disordered behavior of the sinoatrial· node and even have been offered pacemakers. It is urgent to disseminate knowledge concerning the normal effects of the autonomic nervous system upon the sinoatrial node, effects which may be extreme and produce the slow rate, sinus arrest, and exit block. Vagotonia is common, and its production springs from many areas, eg, gastrointestinal causes, emotional causes, pain, and the mechanical effects of pregnancy and labor. Again, continuous electrocardiographic monitoring (for 24 hours) and possibly functional testing should precede any diagnosis of the sick sinus syndrome, especially if the diagnosis is based solely on the presence of sinus bradycardia. By the same token, primary dysfunction of the autonomic system, in contrast to physiologic (or normal) effects, can produce all the characteristics of the sick sinus syndromes and autonomic activity should be tested by mechanical or pharmacologic means.• Finally, the sinoatrial node may become unresponsive to appropriate autonomic activity or hypersensitive to vagal stimuli, as Jordan et al• have stressed, and this is a form of dysfunction of the sinoatrial node. Continuing interest in sinoatrial nodal dysfunction, alone and as part of other pathologic states, appears certain from an overveiw of the progress in the past ten years. In the next decade, basic anatomic data (now scanty), physiologic investigation, and careful, meticulous clinical information should generate helpful knowledge for the subjects
CHEST, 72: 5, NOVEMBER, 19n
with the sick sinus syndrome. M. Irene Ferrer, M.D. • New York •Department of Medicine, College of Physicians and Surgeous, Columbia University, and·the Presbyterian Hospital of the Columbia-Presbyterian Medical Center.
fu:nm:NCES 1 Ferrer MI: The sick sinus syndrome in atrial disease. JAMA 206:645-646, 1968 2 New York Heart Association: N()lllenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels (7th ed). Boston, Little, Brown, and Co, 1973 3 Dhingra RC, Amat-y-Leon F, Wyndham C, et al: Electrophysiologic effects of atropine on sinus node and abium in patients with sinus nodal dysfunction. Am J Cardiol 38:848-855, 1976 4 Jordan JL, Yamaguchi I, Mandel WJ: The sick sinus syndrome. JAMA 237 :682, 1977 5 Strauss HC, Prystowsky EN, Scheinman MM: Sino-atrial and atrial electrogenesis. Prog Cardiovasc Dis 19:385-404, 1977 6 Boal BH, Kleinfeld MJ: Long-term follow-up of patients with the sick sinus syndrome. J Chronic Dis, to be published 7 Reiffel JA, Bigger JT Jr: The ability of Holter ECG recording and atrial stimulation to detect sinus node dysfunction. Am J Cardiol, to be published 8 Cramer M, Siegal M, Bigger JT, et al: Characteristics of extracellular potentials recorded from the sinoatrial Pacemaker of the rabbit. Circ Res, to be published
Are Medical Journals Obsolete 7* The world of multimedia engulfs us. The medical profession has been particularly receptive to innovations in communications, including audio tapes and video tapes. Physicians eagerly embrace newer educational techniques, such as the use of the computer as an integral element of workshops and lecture programs. The teacher and the practitioner are beguiled daily by advertisements extolling the virtues of multimedia packages with self-assessment features. These packages range from elaborate motion pictures and filmstrip programs to relatively unsophisticated devices such as handheld viewers and workbooks with exotic self-quiz techniques. Many of these innovations are positive contributions to the physician's learning process. However, in the current national explosion of educational programs, technique rather than content threatens to assume a primary role rather than a subsidiary status. Participants in national symposia have suggested that audio tapes and video tapes have made the position of the medical periodical untenable. Were we to believe some enthusiasts, the traditional role of medical periodicals has been dramatically altered. How very refreshing, therefore, to read Reprinted by permiuion f1'0m JAMA 238:1402-1403, 1971, Association.
© American Medical
EDITORIALS 555
San Diego, Cal.if •Associate Professor of Medicine, University of California Medical Center, University Hospital. Reprint requem: Df'. Petenon, 225 W ut Dicldnaon. San Diego 9S013
fu:FERENCES 1 GrifBn FM, Jones G, Cobbs CC: Aortic insufllciency in bacterial endocarditis. Ann Intem Med 76:23, 1972 2 Black S, O'Rourke RA, Karliner JA: Role of surgery in the treabnent of primary infective endocarditis. Am J Med 56:357-369, 1974 3 ColUns NP, Braunwald E, Morrow AG: Detection of
554 EDITORIALS
4 5
6 7
pulmonic and tricuspid valvular regurgitation by me~ of indicator solutions. Circulation 20:561-568, 1959 Pazin J, Peterson KL, Griff FW, et al: Determination of site of infection in endocarditis. Ann Intem Med 82:746750, 1975 Arbulu A, Thomas NW, Wilson RF: Valvulectomy without prosthetic replacement. J. Thorac Cardiovasc Surg 64:103-107, 1972 Dillon JC Feigenbaum H, Konecke LL, et al: Echocardiographic manifestations of valvular vegetations. Am Heart J 86:698-704, 1973 Mann T, McLaurin L, Grossman et al: Acute aortic regurgitation due to infective endocarditis. N Engl J Med 293:108-113, 1975
The Sick Sinus Syndrome Its Status aHer Ten Years the ten years since its original description, the I nsick sinus syndrome bas generated much clinical 1
interest and electrophysiologic investigation. This syndrome is now recognized not to be rare, and in its full-blown state, criteria2 for its diagnosis appear to be relatively adequate. There are, nevertheless, some outstanding de:8ciencies in our knowledge of the sick sinus syndrome, and it is salutary to review some of these. The incidence of the dysfunction is as yet uncertain, although statistics on pacemakers suggest that patients with the sick sinus syndrome may even exceed in number those with atrioventricular or intraventricular block. The great difficulty in early diagnosis of the syndrome of dysfunction of the sinoatrial node remains and has stimulated much excellent electrophysiologic study. w The de:8ciency of knowledge regarding the basic natural history of the sick sinus syndrome is gradually being diminished. The splendid report in this issue (see page 628) by Lien et al from the Republic of China on the longitudinal survey of 52 patients provides important data in this sector, showing duration of the disease as long as 29 years and stressing the intermittency of the dysfunctions in many subjects. Boal and Kleinfeld8 also have noted long durations (up to 33 years) of the syndrome; however, adequate prediction of the stage of the dysfunction has eluded us to date. Especially weak in the young or middle-aged patient, the ability to tag the danger zone of malfunction in any one person is perhaps best now in the elderly patient, where the dysfunction usually is more rapidly progressive. The correct timing of insertion of a pacemaker depends on the prediction of dangerous symptoms, and this problem of timing remains dif:8cult to solve until the natural history of the syndrome is better known.
CHEST, 72: 5, NOVEMBER, 1977
At present, the diagnostic criteria for full-blown failure of the sinoatrial node are still to be found in the clinical electrocardiogram; however, provocative testing by atrial pacing methods can uncover less definite dysfunction. In a study of 51 patients with sinus bradycardia, Reiffel and Bigger7 searched for the electrocardiographic criteria of spontaneously occurring sinoatrial nodal dysfunction using continuous electrocardiographic monitOring (Holter) coupled to functional testing (by atrial pacing) of the sinoatrial node; these two methods -together represent our best means of finding the patient with the sick sinus syndrome. Neither test alone was as effective in sorting out the subjects with basically disturbed sinoatrial nodes from the physiologic ( nonpathologic) variants. A new approach to testing the function of the sinoatrial node has been initiated by Cramer et al8 and represents the only additional recent physiologic information, since direct action potentials from the sinoatrial node have not been secured as yet in man. It has been an unfortunate side effect of the great interest in the sick sinus syndrome that some subjects with sinus bradycardia alone are incorrectly designated as having disordered behavior of the sinoatrial· node and even have been offered pacemakers. It is urgent to disseminate knowledge concerning the normal effects of the autonomic nervous system upon the sinoatrial node, effects which may be extreme and produce the slow rate, sinus arrest, and exit block. Vagotonia is common, and its production springs from many areas, eg, gastrointestinal causes, emotional causes, pain, and the mechanical effects of pregnancy and labor. Again, continuous electrocardiographic monitoring (for 24 hours) and possibly functional testing should precede any diagnosis of the sick sinus syndrome, especially if the diagnosis is based solely on the presence of sinus bradycardia. By the same token, primary dysfunction of the autonomic system, in contrast to physiologic (or normal) effects, can produce all the characteristics of the sick sinus syndromes and autonomic activity should be tested by mechanical or pharmacologic means.• Finally, the sinoatrial node may become unresponsive to appropriate autonomic activity or hypersensitive to vagal stimuli, as Jordan et al• have stressed, and this is a form of dysfunction of the sinoatrial node. Continuing interest in sinoatrial nodal dysfunction, alone and as part of other pathologic states, appears certain from an overveiw of the progress in the past ten years. In the next decade, basic anatomic data (now scanty), physiologic investigation, and careful, meticulous clinical information should generate helpful knowledge for the subjects
CHEST, 72: 5, NOVEMBER, 19n
with the sick sinus syndrome. M. Irene Ferrer, M.D. • New York •Department of Medicine, College of Physicians and Surgeous, Columbia University, and·the Presbyterian Hospital of the Columbia-Presbyterian Medical Center.
fu:nm:NCES 1 Ferrer MI: The sick sinus syndrome in atrial disease. JAMA 206:645-646, 1968 2 New York Heart Association: N()lllenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels (7th ed). Boston, Little, Brown, and Co, 1973 3 Dhingra RC, Amat-y-Leon F, Wyndham C, et al: Electrophysiologic effects of atropine on sinus node and abium in patients with sinus nodal dysfunction. Am J Cardiol 38:848-855, 1976 4 Jordan JL, Yamaguchi I, Mandel WJ: The sick sinus syndrome. JAMA 237 :682, 1977 5 Strauss HC, Prystowsky EN, Scheinman MM: Sino-atrial and atrial electrogenesis. Prog Cardiovasc Dis 19:385-404, 1977 6 Boal BH, Kleinfeld MJ: Long-term follow-up of patients with the sick sinus syndrome. J Chronic Dis, to be published 7 Reiffel JA, Bigger JT Jr: The ability of Holter ECG recording and atrial stimulation to detect sinus node dysfunction. Am J Cardiol, to be published 8 Cramer M, Siegal M, Bigger JT, et al: Characteristics of extracellular potentials recorded from the sinoatrial Pacemaker of the rabbit. Circ Res, to be published
Are Medical Journals Obsolete 7* The world of multimedia engulfs us. The medical profession has been particularly receptive to innovations in communications, including audio tapes and video tapes. Physicians eagerly embrace newer educational techniques, such as the use of the computer as an integral element of workshops and lecture programs. The teacher and the practitioner are beguiled daily by advertisements extolling the virtues of multimedia packages with self-assessment features. These packages range from elaborate motion pictures and filmstrip programs to relatively unsophisticated devices such as handheld viewers and workbooks with exotic self-quiz techniques. Many of these innovations are positive contributions to the physician's learning process. However, in the current national explosion of educational programs, technique rather than content threatens to assume a primary role rather than a subsidiary status. Participants in national symposia have suggested that audio tapes and video tapes have made the position of the medical periodical untenable. Were we to believe some enthusiasts, the traditional role of medical periodicals has been dramatically altered. How very refreshing, therefore, to read Reprinted by permiuion f1'0m JAMA 238:1402-1403, 1971, Association.
© American Medical
EDITORIALS 555