LETTERS TO THE EDITOR
F u r t h e r study will determine whether or not right atrial pacing results in lower morbidity and fewer episodes of ventricutar tachycardia at normal sinus rates during catheterization as compared with atropine administered before catheterization. K e n n e t h B. D e s s e r , MD, F A C C A l b e r t o B e n c h i m o l , MD, F A C C G o o d S a m a r i t a n Hospital Phoenix, Arizona
THE FOURTH HEART S O U N D m A NORMAL FINDING?
In a series of publications over the past 3 years dealing with the fourth heart sound and coronary revascularization, David Spodick has been quite effective in exposing the "emperor's new clothes. ''i-3 In a recent article 4 comparing the prevalence of the fourth heart sound (St) in normal subjects and hypertensive middle-aged men, he and his colleagues demonstrated t h a t a fourth heart sound could be recorded in 70 percent of subjects in both groups. Spodick has previously shown that older subjects, considered to be normal, also have a prevalence rote of recordable fourth h e a r t sounds of approximately 70 to 75 percent. 3,5 Experienced cardiologists have taken great exception to the meaning of these findings. 6 9 Wilbert Aronow and colleagues 1°,11 have also demons t r a t e d t h a t one can record a fourth h e a r t sound in a significant number of normal persons, although their incidence rate is far lower than t h a t of Spodick's normal subjects. These studies have certainly done much to make all auscultators listen more carefully, and to t r y to document with greater objectivity what it is we are calling fourth heart sounds. It has been aptly emphasized t h a t in the presence of palpable presystolic distension, one is very likely to be correct in verifying an abnormal $4, s,g,12 and also t h a t m a n y times the so-called $4 is in reality splitting of the first h e a r t sound, s,9,13 The question of audibility versus recordability is crucial. This has been clearly stressed by Noble Fowler, Robert Adolph and Morton Tavel. 6-9,14 There is little doubt t h a t low frequency vibrations of $4 can be recorded with high quality microphones in most normal persons, as Spodick and others have demonstrated. Spodick 13 has previously shown t h a t " b l i n d e d " observers hear S4's with the same frequency t h a t they are recorded but, of course, one cannot tell whether his observers were really hearing a split $1, and calling it an $4; there were more t h a n 50 percent false positive responses in t h a t study. In m y experience, a n d t h a t of virtually every clinical cardiologist t h a t I know, it is most unusual to hear a definite fourth h e a r t sound in middle-aged or older persons who are a p p a r e n t l y free from cardiac disease. We occasionally hear what we think is an $4 in a "normal" subject, b u t nowhere near the reported incidence rate of 70 to 75 percent. 3-5 Spodick deplores matching one's "experience" over "an appropriately designed study," 1~ but serious questions have been raised a b o u t the design of his " b l i n d e d " study. 9 Spodick himself has inadvertently weakened his position in a recent study from his group demonstrating that chronic alcoholics have abnormal systolic time intervals, thus indicating subclinical myocardial dysfunction. 16 T h a t study, in conjunction with several other recent investigations, 1%19 clearly indicates t h a t acute and chronic alcoholism is frequently associated with impaired myocardial function, even when there are no symptoms or signs of cardiac disease. In the study of Spodick et al., 16 26 normal control
534
O c t o b e r 6, 1 9 7 5
The A m e r i c a n Journal of C A R D I O L O G Y
subjects and 26 a m b u l a t o r y chronic alcoholics clinically free from heart disease were carefully evaluated by systolic time intervals. The mean age in both groups was approximately 45 years; thus many of these persons are in the same age group as in Spodick's recent publication. 4 The group of chronic alcoholics Clearly had abnormal systolic time intervals, with prolonged preejection periods, and decreased left ventricular ejection times, highly suggestive of latent cardiac malfunction; apparently, however, normal fourth heart sounds or "atrial gallops" were not heard. "All s u b j e c t s - both alcoholic patients and screening-clinic normal pers o n s - - w e r e free of h e a r t a b n o r m a l i t y . . . . there were no m u r m u r s or abnormal heart sounds . . . . ,, 16 Two of the authors, Spodick and Pigott, participated in the phonocardiographic studies in normal subjects, 3,5,13 and m u s t have been well aware o f the importance of listening for a fourth h e a r t sound. The best explanation for the m a r k e d discrepancy in hearing an $4 in Spodick's two studies, 13,16 is t h a t fourth heart sounds were simply inaudible in the s t u d y of alcoholics. Presumably, the middle-aged control subjects and alcoholics would have had a 70 to 75 percent incidence rate of fourth heart sounds recordable with specialized recording equipment. T h e high incidence rate of false positive S4's (56 percent) in his " b l i n d e d " study 13 makes it even more a p p a r e n t t h a t auscultator expectation and experience of the auscultator play a large b u t poorly defined role in this controversy. While the arguments are sure to continue, it is i m p o r t a n t to emphasize t h a t auscultation of a definite atrial sound in a middle-aged or older person is not likely to be a normal event, in the experience of m a n y practicing cardiologists. 6,s,2°,21 On the contrary, there are considerable d a t a to substantiate the view t h a t an audible fourth heart sound is, in fact, an indication of decreased left ventricular compliance, if not a definite elevation of left ventricular diastolic pressure, 12'21'22 and is not simply a hallmark of aging. Jonathan Abrams Division of Cardiology The University of New Mexico School of Medicine Albuquerque, New Mexico References 1. Spodick DH; Revascularization of the heart: numerators in search of denominators. Am Heart J 81:149-157, 1971 2. Spodick DH: Fourth heart sound gallop or first heart sound? Am J Cardiol 41:530531, 1973 3. Spodlck DH, Quarry-Pigott VM: Fourth heart sound as a normal finding in older per= sons. N EnglJ Med 288:140-141, t973 4. Swistak M, Mushlin H, Spodick DH: Comparative prevalence of the fourth heart sound in hypertensive and matched normal persons. Am J Cardiol 33:614-616, 1974 5. Spodick DH, Quarry VM: Prevalence of the fourth heart sound by phonocardiography in the absence of cardiac disease. Am Heart J 87:11-14, 1974 6. Fowler NO, Adolph RJ: Fourth sound gallop or sp!it first sound? Am J Cardiol 30: 441-444, 1972 7, Adolph RJ, Fowler NO: Hearing a fourth heart sound. N Engl J Med 288:688, 1973 8. Tavel ME: The fourth heart sound--a premature requiem? Circulation 44:4-6, 1974 9. "ravel MEt The fourth heart sound. Circulation 44:1264-1266, 1974 lO. Aronow WS, Cassidy J, Uyeyama RR: Effect of position on the resting and postexercise phonocardiogram, Chest 61:439-442, 1972 11. Aronow WS Cassidy J, Uyeyama RR: The resting and postexerblse phonocardiogram and electrocardiogram in asymptomatic women. Ca~'diology 55:333-339, 1970 12. Bethell HJN, Nixon PGF: Understanding the atrial sound. Br Heart J 35:229-235, 1973 13. Rectra EH, Khan AH, Pigolt VM, et al: Audibility of the fourth heart sound. A prospective, "blind" ausoultatory and polygraphic investigation. JAMA 221:36-41, 1972 14. Fowler NO Adolph RJ: Fourth heart sound gallop or first heart sound? Am J Cardiol 31:531, 1973 15. Spodlck DH: The fourth heart sound. Circulation 44:1263-1264, 1974 16. Spodick DH, Pigott VM, Chirife R: Preclinical cardiac malfunction in chronic alcoholism. ComparisOn with matched normal controls and w th alcoholic cardiomyopathy. N Engl J Med 287:677-680, 1972
Volume 36
LETTERS TO THE EDITOR
17. Asokan SK, Frank MJ, Witham AC: Cardiomyopathy without cardiomegaly in alcoholics. Am Heart J 84:13-18, 1972 18. Gould L, Reddy n, Goswami K, et al: Cardiac effects of two cocktails in normal man. Chest 63:943-947, 1973 19. Turner PP, Hunter J: The atrial sound in i~chemic heart disease. Br Heart J 35: 657-662, 1973 2t. Getzee JH, Dimond EG: Saga of the fourth heart sound. Am J Cardio122:609-613, 1968 22. Shah PM! Yu PN: Gallop rhythm. Hemodynamic and clinical correlation. Am Heart J 78:823-828, 1969
REPLY: THE FOURTH H E A R T SOUND: Q U A T EL Y INVESTIGATED S U B J E C T
AN
INADE-
The $4 problem is a specific case of a more general question: unexamined acceptance of traditional wisdom. I am grateful to Abrams for the o p p o r t u n i t y to continue the dialogue on significance of fourth heart sounds. In citing our work, he has read widely b u t not always deeply. While acknowledging the validity of particular disagreements (especially some paraphrasing TaveP), I deplore the a t t e m p t to make certain points by selective citations, and by posing questions about our work t h a t we ourselves have repeatedly raised. A b r a m s ' assertion t h a t " m a n y times the so-called $4 is in reality splitting of the first heart sound" is a reasonable auscultatory generalization, b u t has he investigated t h i s - t h a t is, how m a n y times? Moreover, he ignores the reverse possibility: How many times is a so-called split $1 "in reality" an $4? How do we decide which is "in reality" which? Indeed, his reference 13 on this point does not s u p p o r t his reasoning since t h a t reference was our report, 2 which concludes t h a t "false audibility (of $4) was not related to the low-frequency component of $1 or to split $1." In fact, t h a t was so precisely among our 56 percent of subjects with false positive results. This figure is only a p p a r e n t l y a b a d result, since it is a fraction of the small total without a recordable $4. It represents only 19 of 122 patients. Curiously, Abrams omits the 25 false negative results. Yet, the false positive results weakened our auscultators' performance, possibly because of zealous belief in " S 4 " - - t h e exact counterpart of supplying nonexistent "split $1" because of zeal for the traditional belief. In this context, Abrams correctly cites "auscultator expectation." But in the absence of investigations designed to minimize biases, this factor cuts two ways. For example, "auscuttator expectation" held for many years t h a t the second heart sounds were unitary events with "A2" and "P2" on respective sides of the upper sternum. Generations of physicians and voluminous studies reported them in this way. Now we hear and report $2 as a binary event in terms of its splitting dynamics. We are listening to the same sound, but now we hear it differently. Similarly, the conventional wisdom regarding "split $1" might also provide a misleading "auscultatory expectation." To the extent t h a t our studies prove to be flawed, I will be equally guilty. Our studies have not yet provoked formal reinvestigation of $4. Although our phonocardiographic results by themselves m u s t be totally objective for the e q u i p m e n t used (that is, we recorded undeniable S4's in normal subjects and patients), the crucial question of auscultation remains. Our auscultatory study, while electronically simplistic (and currently the subject of an improved protocol), utilized the only "scoring system" possible in clinical c a r d i o l o g y ~ t h e phonocardiogram. We recognize t h a t it is impossible at present to determine exactly which vibrations are audible in a train of vibrations occurring within milliseconds of each other, such as the $4 + $1, (o-a-b-c) complex, 7 among which we usually hear only two discrete sounds. Intricate
questions of frequency-audibility thresholds, masking and reverse masking are involved. Moreover, the logarithmic response of the ear to pure audiometric tones m a y not have a direct counterpart in the vibratory complexities of actual h e a r t sounds. These formidable obstacles confront us, b u t t h e y confront our critics equally. We a t t e m p t e d to minimize t h e m by elaborate blinding p r o c e d u r e s - - a d m i t t e d l y imperfect, b u t aimed a t reducing those biases inherent in preliminary knowledge of patients' clinical d a t a and prejudices inherent in the traditional b u t unexamined concepts of $4. Abrams cites the work of Bethell and Nixon (his reference 12) to substantiate the view t h a t an audible $4 is ipso facto abnormal. Curiously, he omits the same authors' citation of work by us and others substantiating an age-related increased incidence of $4 and including their s t a t e m e n t t h a t "it m a y be a physiological event in m a n y cases" 3 (my emphasis). He further cites Fowler, Adolph and Tavel as stressing "the question of audibility versus recordability." H e does not cite the very paper by us t h a t precipitated his letter, which states: "Registration by phonocardiogram does not prove its audibility." Also not cited was our own extensive section raising caveats and questions about our own work (Abrams' reference 5), in which we declare: " T h e audibility study served to raise more questions about current concepts of $4 than it answered . . . . We believe it has not completely settled any of these issues . . . . It would be desirable to have confirmation or refutation by other controlled studies . . . . since the results of auscultation for a frequently subtle phenomenon remain highly subjective." 5 Abrams states t h a t I have " i n a d v e r t e n t l y weakened" m y position on $4 in our report of preclinical cardiac malfunction in apparently normal alcoholics. 6 He deduces that, despite poor functional indexes in the alcoholics, "normal fourth heart sounds or atrial gallops were not heard" (his emphasis). He has no evidence for this. Actually they were disregarded. I have always considered abnormal any p a l p a ble and subjectively loud $4. 2,4,5,7 In the alcoholic study any subjectively loud atrial sounds thus had to be excluded. Indeed, since our $4 studies point to the mere presence of $4 as possibly physiologic, the question could not properly arise either by auscultation or by phonocardiography. It could only have arisen if we shared the traditional view of $4. Moreover, since we cannot yet tell the pathologic from the nonpathologic, we could not consider any recorded $4. T h u s we did maintain fidelity to our $4 results, and it is Abrams who falls victim to his own view. Finally, this was a systolic interval study and here Abrams also overlooked Table I of our auscultatory study, 2 which showed a group t r e n d toward better values for systolic intervals in all those with $4 by phonocardiogram. In conclusion, let me acknowledge again t h a t our investigations have been at best imperfect and at worst invalid. B u t we tackled the $4 problem by a t t e m p t i n g to minimize subjective and objective bias. Examination of our illustrations 2,4,5 will show t h a t the phonocardiographic prevalence of $4 cannot be d e n i e d - - a t least using Maas and Weber filters (discussed elsewhereS). Our results with Hewlett-Packa r d filters do conform more closely to those of most others, s Which phonocardiographic result is "right"? Which auscult a t o r y result is "right"? This remains a problem in observer performance. In a meticulous investigation, observer performance among experienced auscultators varied astonishingly when they were "blinded" to everything else about the patient. 9 Who among t h e m was "right"? The problem m u s t be dealt with by appropriately designed studies. Evaluation of $4 is more complex t h a n the recently c o r -
October 6, 1975
The American Journal of CARDIOLOGY
Volume 36
535
F u r t h e r study will determine whether or not right atrial pacing results in lower morbidity and fewer episodes of ventricutar tachycardia at normal sinus rates during catheterization as compared with atropine administered before catheterization. K e n n e t h B. D e s s e r , MD, F A C C A l b e r t o B e n c h i m o l , MD, F A C C G o o d S a m a r i t a n Hospital Phoenix, Arizona
THE FOURTH HEART S O U N D m A NORMAL FINDING?
In a series of publications over the past 3 years dealing with the fourth heart sound and coronary revascularization, David Spodick has been quite effective in exposing the "emperor's new clothes. ''i-3 In a recent article 4 comparing the prevalence of the fourth heart sound (St) in normal subjects and hypertensive middle-aged men, he and his colleagues demonstrated t h a t a fourth heart sound could be recorded in 70 percent of subjects in both groups. Spodick has previously shown that older subjects, considered to be normal, also have a prevalence rote of recordable fourth h e a r t sounds of approximately 70 to 75 percent. 3,5 Experienced cardiologists have taken great exception to the meaning of these findings. 6 9 Wilbert Aronow and colleagues 1°,11 have also demons t r a t e d t h a t one can record a fourth h e a r t sound in a significant number of normal persons, although their incidence rate is far lower than t h a t of Spodick's normal subjects. These studies have certainly done much to make all auscultators listen more carefully, and to t r y to document with greater objectivity what it is we are calling fourth heart sounds. It has been aptly emphasized t h a t in the presence of palpable presystolic distension, one is very likely to be correct in verifying an abnormal $4, s,g,12 and also t h a t m a n y times the so-called $4 is in reality splitting of the first h e a r t sound, s,9,13 The question of audibility versus recordability is crucial. This has been clearly stressed by Noble Fowler, Robert Adolph and Morton Tavel. 6-9,14 There is little doubt t h a t low frequency vibrations of $4 can be recorded with high quality microphones in most normal persons, as Spodick and others have demonstrated. Spodick 13 has previously shown t h a t " b l i n d e d " observers hear S4's with the same frequency t h a t they are recorded but, of course, one cannot tell whether his observers were really hearing a split $1, and calling it an $4; there were more t h a n 50 percent false positive responses in t h a t study. In m y experience, a n d t h a t of virtually every clinical cardiologist t h a t I know, it is most unusual to hear a definite fourth h e a r t sound in middle-aged or older persons who are a p p a r e n t l y free from cardiac disease. We occasionally hear what we think is an $4 in a "normal" subject, b u t nowhere near the reported incidence rate of 70 to 75 percent. 3-5 Spodick deplores matching one's "experience" over "an appropriately designed study," 1~ but serious questions have been raised a b o u t the design of his " b l i n d e d " study. 9 Spodick himself has inadvertently weakened his position in a recent study from his group demonstrating that chronic alcoholics have abnormal systolic time intervals, thus indicating subclinical myocardial dysfunction. 16 T h a t study, in conjunction with several other recent investigations, 1%19 clearly indicates t h a t acute and chronic alcoholism is frequently associated with impaired myocardial function, even when there are no symptoms or signs of cardiac disease. In the study of Spodick et al., 16 26 normal control
534
O c t o b e r 6, 1 9 7 5
The A m e r i c a n Journal of C A R D I O L O G Y
subjects and 26 a m b u l a t o r y chronic alcoholics clinically free from heart disease were carefully evaluated by systolic time intervals. The mean age in both groups was approximately 45 years; thus many of these persons are in the same age group as in Spodick's recent publication. 4 The group of chronic alcoholics Clearly had abnormal systolic time intervals, with prolonged preejection periods, and decreased left ventricular ejection times, highly suggestive of latent cardiac malfunction; apparently, however, normal fourth heart sounds or "atrial gallops" were not heard. "All s u b j e c t s - both alcoholic patients and screening-clinic normal pers o n s - - w e r e free of h e a r t a b n o r m a l i t y . . . . there were no m u r m u r s or abnormal heart sounds . . . . ,, 16 Two of the authors, Spodick and Pigott, participated in the phonocardiographic studies in normal subjects, 3,5,13 and m u s t have been well aware o f the importance of listening for a fourth h e a r t sound. The best explanation for the m a r k e d discrepancy in hearing an $4 in Spodick's two studies, 13,16 is t h a t fourth heart sounds were simply inaudible in the s t u d y of alcoholics. Presumably, the middle-aged control subjects and alcoholics would have had a 70 to 75 percent incidence rate of fourth heart sounds recordable with specialized recording equipment. T h e high incidence rate of false positive S4's (56 percent) in his " b l i n d e d " study 13 makes it even more a p p a r e n t t h a t auscultator expectation and experience of the auscultator play a large b u t poorly defined role in this controversy. While the arguments are sure to continue, it is i m p o r t a n t to emphasize t h a t auscultation of a definite atrial sound in a middle-aged or older person is not likely to be a normal event, in the experience of m a n y practicing cardiologists. 6,s,2°,21 On the contrary, there are considerable d a t a to substantiate the view t h a t an audible fourth heart sound is, in fact, an indication of decreased left ventricular compliance, if not a definite elevation of left ventricular diastolic pressure, 12'21'22 and is not simply a hallmark of aging. Jonathan Abrams Division of Cardiology The University of New Mexico School of Medicine Albuquerque, New Mexico References 1. Spodick DH; Revascularization of the heart: numerators in search of denominators. Am Heart J 81:149-157, 1971 2. Spodick DH: Fourth heart sound gallop or first heart sound? Am J Cardiol 41:530531, 1973 3. Spodlck DH, Quarry-Pigott VM: Fourth heart sound as a normal finding in older per= sons. N EnglJ Med 288:140-141, t973 4. Swistak M, Mushlin H, Spodick DH: Comparative prevalence of the fourth heart sound in hypertensive and matched normal persons. Am J Cardiol 33:614-616, 1974 5. Spodick DH, Quarry VM: Prevalence of the fourth heart sound by phonocardiography in the absence of cardiac disease. Am Heart J 87:11-14, 1974 6. Fowler NO, Adolph RJ: Fourth sound gallop or sp!it first sound? Am J Cardiol 30: 441-444, 1972 7, Adolph RJ, Fowler NO: Hearing a fourth heart sound. N Engl J Med 288:688, 1973 8. Tavel ME: The fourth heart sound--a premature requiem? Circulation 44:4-6, 1974 9. "ravel MEt The fourth heart sound. Circulation 44:1264-1266, 1974 lO. Aronow WS, Cassidy J, Uyeyama RR: Effect of position on the resting and postexercise phonocardiogram, Chest 61:439-442, 1972 11. Aronow WS Cassidy J, Uyeyama RR: The resting and postexerblse phonocardiogram and electrocardiogram in asymptomatic women. Ca~'diology 55:333-339, 1970 12. Bethell HJN, Nixon PGF: Understanding the atrial sound. Br Heart J 35:229-235, 1973 13. Rectra EH, Khan AH, Pigolt VM, et al: Audibility of the fourth heart sound. A prospective, "blind" ausoultatory and polygraphic investigation. JAMA 221:36-41, 1972 14. Fowler NO Adolph RJ: Fourth heart sound gallop or first heart sound? Am J Cardiol 31:531, 1973 15. Spodlck DH: The fourth heart sound. Circulation 44:1263-1264, 1974 16. Spodick DH, Pigott VM, Chirife R: Preclinical cardiac malfunction in chronic alcoholism. ComparisOn with matched normal controls and w th alcoholic cardiomyopathy. N Engl J Med 287:677-680, 1972
Volume 36
LETTERS TO THE EDITOR
17. Asokan SK, Frank MJ, Witham AC: Cardiomyopathy without cardiomegaly in alcoholics. Am Heart J 84:13-18, 1972 18. Gould L, Reddy n, Goswami K, et al: Cardiac effects of two cocktails in normal man. Chest 63:943-947, 1973 19. Turner PP, Hunter J: The atrial sound in i~chemic heart disease. Br Heart J 35: 657-662, 1973 2t. Getzee JH, Dimond EG: Saga of the fourth heart sound. Am J Cardio122:609-613, 1968 22. Shah PM! Yu PN: Gallop rhythm. Hemodynamic and clinical correlation. Am Heart J 78:823-828, 1969
REPLY: THE FOURTH H E A R T SOUND: Q U A T EL Y INVESTIGATED S U B J E C T
AN
INADE-
The $4 problem is a specific case of a more general question: unexamined acceptance of traditional wisdom. I am grateful to Abrams for the o p p o r t u n i t y to continue the dialogue on significance of fourth heart sounds. In citing our work, he has read widely b u t not always deeply. While acknowledging the validity of particular disagreements (especially some paraphrasing TaveP), I deplore the a t t e m p t to make certain points by selective citations, and by posing questions about our work t h a t we ourselves have repeatedly raised. A b r a m s ' assertion t h a t " m a n y times the so-called $4 is in reality splitting of the first heart sound" is a reasonable auscultatory generalization, b u t has he investigated t h i s - t h a t is, how m a n y times? Moreover, he ignores the reverse possibility: How many times is a so-called split $1 "in reality" an $4? How do we decide which is "in reality" which? Indeed, his reference 13 on this point does not s u p p o r t his reasoning since t h a t reference was our report, 2 which concludes t h a t "false audibility (of $4) was not related to the low-frequency component of $1 or to split $1." In fact, t h a t was so precisely among our 56 percent of subjects with false positive results. This figure is only a p p a r e n t l y a b a d result, since it is a fraction of the small total without a recordable $4. It represents only 19 of 122 patients. Curiously, Abrams omits the 25 false negative results. Yet, the false positive results weakened our auscultators' performance, possibly because of zealous belief in " S 4 " - - t h e exact counterpart of supplying nonexistent "split $1" because of zeal for the traditional belief. In this context, Abrams correctly cites "auscultator expectation." But in the absence of investigations designed to minimize biases, this factor cuts two ways. For example, "auscuttator expectation" held for many years t h a t the second heart sounds were unitary events with "A2" and "P2" on respective sides of the upper sternum. Generations of physicians and voluminous studies reported them in this way. Now we hear and report $2 as a binary event in terms of its splitting dynamics. We are listening to the same sound, but now we hear it differently. Similarly, the conventional wisdom regarding "split $1" might also provide a misleading "auscultatory expectation." To the extent t h a t our studies prove to be flawed, I will be equally guilty. Our studies have not yet provoked formal reinvestigation of $4. Although our phonocardiographic results by themselves m u s t be totally objective for the e q u i p m e n t used (that is, we recorded undeniable S4's in normal subjects and patients), the crucial question of auscultation remains. Our auscultatory study, while electronically simplistic (and currently the subject of an improved protocol), utilized the only "scoring system" possible in clinical c a r d i o l o g y ~ t h e phonocardiogram. We recognize t h a t it is impossible at present to determine exactly which vibrations are audible in a train of vibrations occurring within milliseconds of each other, such as the $4 + $1, (o-a-b-c) complex, 7 among which we usually hear only two discrete sounds. Intricate
questions of frequency-audibility thresholds, masking and reverse masking are involved. Moreover, the logarithmic response of the ear to pure audiometric tones m a y not have a direct counterpart in the vibratory complexities of actual h e a r t sounds. These formidable obstacles confront us, b u t t h e y confront our critics equally. We a t t e m p t e d to minimize t h e m by elaborate blinding p r o c e d u r e s - - a d m i t t e d l y imperfect, b u t aimed a t reducing those biases inherent in preliminary knowledge of patients' clinical d a t a and prejudices inherent in the traditional b u t unexamined concepts of $4. Abrams cites the work of Bethell and Nixon (his reference 12) to substantiate the view t h a t an audible $4 is ipso facto abnormal. Curiously, he omits the same authors' citation of work by us and others substantiating an age-related increased incidence of $4 and including their s t a t e m e n t t h a t "it m a y be a physiological event in m a n y cases" 3 (my emphasis). He further cites Fowler, Adolph and Tavel as stressing "the question of audibility versus recordability." H e does not cite the very paper by us t h a t precipitated his letter, which states: "Registration by phonocardiogram does not prove its audibility." Also not cited was our own extensive section raising caveats and questions about our own work (Abrams' reference 5), in which we declare: " T h e audibility study served to raise more questions about current concepts of $4 than it answered . . . . We believe it has not completely settled any of these issues . . . . It would be desirable to have confirmation or refutation by other controlled studies . . . . since the results of auscultation for a frequently subtle phenomenon remain highly subjective." 5 Abrams states t h a t I have " i n a d v e r t e n t l y weakened" m y position on $4 in our report of preclinical cardiac malfunction in apparently normal alcoholics. 6 He deduces that, despite poor functional indexes in the alcoholics, "normal fourth heart sounds or atrial gallops were not heard" (his emphasis). He has no evidence for this. Actually they were disregarded. I have always considered abnormal any p a l p a ble and subjectively loud $4. 2,4,5,7 In the alcoholic study any subjectively loud atrial sounds thus had to be excluded. Indeed, since our $4 studies point to the mere presence of $4 as possibly physiologic, the question could not properly arise either by auscultation or by phonocardiography. It could only have arisen if we shared the traditional view of $4. Moreover, since we cannot yet tell the pathologic from the nonpathologic, we could not consider any recorded $4. T h u s we did maintain fidelity to our $4 results, and it is Abrams who falls victim to his own view. Finally, this was a systolic interval study and here Abrams also overlooked Table I of our auscultatory study, 2 which showed a group t r e n d toward better values for systolic intervals in all those with $4 by phonocardiogram. In conclusion, let me acknowledge again t h a t our investigations have been at best imperfect and at worst invalid. B u t we tackled the $4 problem by a t t e m p t i n g to minimize subjective and objective bias. Examination of our illustrations 2,4,5 will show t h a t the phonocardiographic prevalence of $4 cannot be d e n i e d - - a t least using Maas and Weber filters (discussed elsewhereS). Our results with Hewlett-Packa r d filters do conform more closely to those of most others, s Which phonocardiographic result is "right"? Which auscult a t o r y result is "right"? This remains a problem in observer performance. In a meticulous investigation, observer performance among experienced auscultators varied astonishingly when they were "blinded" to everything else about the patient. 9 Who among t h e m was "right"? The problem m u s t be dealt with by appropriately designed studies. Evaluation of $4 is more complex t h a n the recently c o r -
October 6, 1975
The American Journal of CARDIOLOGY
Volume 36
535
