The Normal Systolic Murmurs in the Japanese- The Normal Phonocardiogram. II.

Transcription

1 The Normal Systolic Murmurs in the Japanese- The Normal Phonocardiogram. II. Hideo UEDA, M. D., Zen'ichiro UOZUMI, M. D., and Tsuguya SAKAMOTO, M. D. Using a multi-filter system phonoeardiograph and a dynamic microphone, 200 phonocardiograms of the normal Japanese were analysed. The systolic murmur was recorded in almost all normal subjects. The normal systolic murmur showed a graphic configuration of the ejection systolic murmur irrespective of the area of maximal intensity. The pulmonic systolic murmur was the most common type of the normal systolic murmurs, except cases aged above 60. The apical systolic murmur of aortic origin was frequently observed among elderly subjects, and the normal systolic murmur was rarely maximal in intensity at the aortic area. The musical normal systolic murmur was not infrequently observed in adult life. IN the previous paper,1) the phonocardiographic study on the normal heart sounds was reported, showing their ranges and variations with age. As the consecutive studies on the normal heart, another attempt was also made in a similar way to evaluate the murmur in the normal condition. We prefer to apply a term "normal systolic murmur"2),3) to the murmur observed in the normal subjects. In a review of literatures there described various names for this category of murmur, such as functional,4),5) physiological,6) innocent,7) non-pathological,8) accidental,9) etc. Though each of these expressions implies that the murmur arises in subjects with normal heart, the murmur originating from some extra-cardiac pathological conditions (i. e. thyrotoxicosis, anemia, pregnancy, chest deformity, pericardial lesion, etc.) is not always excluded from this category. However, the term "normal systolic murmur" seemed to indicate more clearly the murmur observed in subjects who are free of any disease, general or cardiac. From the Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Tokyo. 207

2 208 UEDA, UOZUMI, AND SAKAMOTO Jap, Heart J. May, METHODS AND MATERIALS As was in the previous paper, the same 200 normal subjects aged from 4 to 72 were studied with the multi-filter system phonocardiograph and the dynamic microphone. The analysis of the phonocardiograms is concerned with the murmur and the items are as follows: I. Incidence of the murmur. II. Features of the murmur. a) Locations of maximal intensity. b) Graphic configurations. c) Timings and durations compared with the other cardiac events. These were measured in the Medium-Low PCG. d) Frequencies calculated from number of vibrations in 0.1 sec. e) Loudness including the intensity ratio estimated by the calibration method (the ratio of the maximal amplitude of the murmur to the height of calibration wave) and the relative intensity determined by the comparison to the heart sounds (the ratios of the maximal amplitude of the murmur to that of the 1st or 2nd heart sounds). Both intensity ratios were measured in the Medium PCC, which may give graphically a similar impression to the auscultatory findings. I. Incidence of the murmur RESULTS Systolic murmur was recorded in 97% of 200 subjects. The remaining 6 cases were not the cases without murmur, but the cases with too slight murmur to be recorded by routine procedures. In the tracings of such cases rudimentary vibrations in systole were observed without exception. The diastolic murmur was recorded in no case. II. Features of the normal systolic murmur The normal systolic murmur was classified into 2 groups, the musical variety and the non-musical one, by its graphic appearances. The musical variety of the normal systolic murmur was composed of uniform vibrations of a constant frequency, resembling in general a damped sine-wave form. The non-musical variety was composed of vibrations in a range of degree of irregularity, having some similarity to the musical variety, but showing more or less distorted wave form. One hundred and seventy-four out of 194 cases with the normal systolic murmur had only one murmur, and the remaining 20 cases had 2 different murmurs. Thus a total of 214 murmurs was recorded in 194 cases. Among these murmurs it was musical in 28 and non-musical in 186. a) Locations of maximal intensity: Table I shows the incidence of the normal systolic murmur in regard

3 Vol.3 No.3 NORMAL SYSTOLIC MURMURS IN JAPANESE 209 Table I. Incidence of Normal Systolic Murmurs in Each Age Group Cases with one murmur (174 cases) to its area of maximal intensity in each age group. The musical systolic murmur was maximal in intensity at the apex in 14 cases and at the pulmonic area in 14. The non-musical systolic murmur was maximal in intensity at the apex in 50 cases, at the pulmonic in 131 and at the aortic in only 5. Among the cases with 2 different murmurs there were 9 cases with musical murmur and pulmonic one, 10 with apical and pulmonic murmurs and 1 with apical and aortic murmurs. These were frequently found among the cases below 39 years of age. Fig.1 shows the variation of incidences of normal systolic murmurs with age. Musical murmur was observed with high incidence among young subjects, but not infrequently among elderly persons. Pulmonic murmur was the most frequent type of the normal systolic murmurs except the cases aged above 60. Apical murmur became more frequent with increase of age, especially among the cases aged above 40. b) Graphic configurations: Two hundreds and fourteen normal systolic murmurs were divided by graphic configurations into 3 types, crescendo-decrescendo (spindle or

4 210 UEDA, UOZUMI, AND SAKAMOTO Jap. Heart J. M ay, 1962 Fig.1. Variation of incidences of normal systolic murmur with age. = musical systolic murmur (M. M.); --- non-musical apical systolic murmur (Ap. M.); - non-musical pulmonic systolic murmur (P. M.). diamond shape), decrescendo, and atypical figures. The decrescendo figure, in which the murmur started with the 1st sound and decreased in intensity during systole and disappeared before the 2nd sound, was found in only one apical murmur. The atypical figure, in which the murmur was variable in shape and intensity from one heart cycle to another, was observed in 3 apical and 6 pulmonic murmurs. The remainder, all of 28 musical murmurs and 176 non-musical systolic murmurs, showed the crescendo-decrescendo configuration. The atypical figure was considered as a variant form of the crescendo-decrescendo figure because the former was separated from the 1st sound by a brief interval and ended before the 2nd sound, like the latter configuration, in spite of inconstant maximum of intensity. Therefore, almost all of the normal systolic murmurs showed the crescendo-decrescendo configuration. c) Timings and durations: Tabe II shows the timings and durations of the normal systolic murmurs, except the cases of the decrescendo and atypical figures. Both musical and non-musical systolic murmurs, including the cases maximal in intensity at the apical area, started during the 3rd phase of the 1st sound complex or shortly after that time. The murmurs were increasing in amplitude and the maximum fell usually during the middle third of systole.

5 Vol.3 No.3 NORMAL SYSTOLIC MURMURS IN,JAPANESE 211 Table II. Timings and Durations of Normal Systolic Murmurs (1/100sec.) top: average below: range Thereafter they were decreasing in amplitude and disappeared before the 2nd sound. In summary, the normal systolic murmur showed a graphic configuration of the ejection systolic murmur, which starts with the beginning of ventricular ejection and is increasing and then decreasing in amplitude and ends before the 2nd sound. The durations of the murmurs were in a range from 0.05 to 0.25 sec. and from 17 to 61% of the total length of systole. The duration of the murmurs varied with the length of systole, and possibly with the grade of amplification if the murmur was of low intensity. d) Frequencies: The distribution of the frequencies of the normal systolic murmurs is shown in Fig.2. The frequency of musical murmur varied from 90 to 130 c. p. s. with a mean of 108 c. p. s. That of apical murmur was in a range of 90 to 150 c. p. s. with a mean of 124 c. p. s. There was some difference of its frequency between the cases aged below 39 and those above 40. It was in higher frequency among the latter groups than those among the former. The frequency of pulmonic murmur varied from 100 to 160 c. p. s. with a mean of 125 c. p. s. In contrast with the apical murmur there was little difference of its frequency between age groups. That of aortic murmur, which was found in only 5 cases, was in a range between 110 and 150 c. p. s. with a mean of 128 c. p. s. e) Loudness: The normal systolic murmurs could be heard by a careful ausculta-

6 212 UEDA, UOZUMI, AND SAKAMOTO Jap. Heart J. May, 1962 Fig.2. Distribution of frequencies of normal systolic murmurs. tion, especially in the sound-proof room. Most of them were of low intensity, Grade I or II, and a few of moderate intensity, Grade III. Table III shows the intensity ratio and the relative intensity to the heart sounds of the normal systolic murmurs, and Fig.3 shows the variation of the intensity ratios with age. The musical systolic murmur was usually of greater intensity than the non-musical one. The intensity ratios of musical murmur and pulmonic murmur had a trend to decrease with age. On the other hand, the intensity ratio of apical murmur had a tendency to decrease with the age up to the 5th decade and thereafter to increase with age. The variation Fig.3. Variation of intensity ratios of normal systolic murmurs with age. The line means the average intensity ratios in each age group.

7 Vol.3 No.3 NORMAL SYSTOLIC MURMURS IN JAPANESE 213 Table III. Intensity Ratio and Relative Intensity to Heart Sounds of Normal Systolic Murmurs top: average below: range of the relative intensities to the heart sounds was perplexing because the intensity of the heart sounds also varied with age. DISCUSSION By many authors, much attention has been given to the functional murmur in children and young adults. The frequency of this murmur estimated by ordinary stethoscopic examination was in a wide range between 10 and 60%.10)-26) It has been usually said that the murmur is more frequent (from 40 to 60%) among children,10)-16),20),22) and become infrequent (from 10 to 35%) among young adults.23)-26) With phonocardiographic examination higher incidences were reported.2),27)-36) McKee27) found that the murmur was recorded in 90% of 105 children and also that the low amplitude waves were observed in the remainders. Mannheimer28) stated that the murmur was observed in 75% of 135 children, and later Paulin and Mannheimer33) stressed that slight murmur could be recorded in 100% of children, if the ideal phonocardiographic technique was used. There has been few reports dealing with functional murmur in adult life.2),30)-32),34) Recently, Groom and his co-workers2) reported that with a high sensitivity pickup and in a sound-proof room 100% of normal adults showed readily discernible murmurs, which were subaudible on ordinary stethoscope. Similar result was obtained in our study. With a multi-filter system phonocardiograph and a dynamic microphone, the normal systolic murmur was clearly recorded in almost all of 200 subjects aged from 4 to 72. If the murmur can be recorded in all normal persons, it will be of less

8 214 UEDA, UOZUMI, AND SAKAMOTO.lap. Heart J. M ay, 1962 importance to estimate its incidence with stethoscope, because the audibility of the normal systolic murmur may depend to a great degree on the acuity of examiners and the condition of observation rather than the intensity of the murmur. It is more important to analyse what kind of the murmur is observed in the normal subjects. A) The musical variety of the normal systolic murmur: The musical variety of the normal systolic murmur was first described by Still") as the twanging-string murmur, and later designated by Harris and his co-workers, 8),38)-40) as the precordial vibratory murmur. The murmur is buzzing,8) groaning,'s) or squeaky") in quality, and the area of its maximal intensity is usually in the mid-precordium. In the phonocardiogram, the murmur has musical characteristics of vibrations and shows a diamond-shaped wave form. It is of a short duration, occupying the first one-third or one-half of systole, and is separated by a slight gap from the 1st sound. This variety of the murmur is the most frequent type of the murmurs observed among children, and it decreases in intensity in adolescence and disannears in adult life. The frequency is estimated in a range between 30 and 857o' of the functional murmur.2),13),10,17),20,22),3: 35),41),42) There was some difference of its occurrence in our result of study. The musical normal systolic murmur was frequently observed among young subjects, but not the most common type of the normal systolic murmurs. And it was not infrequently observed among adult individuales. The incidence of the murmur may vary with the age distribution of the subjects studied and with the methods of study selected, either with stethoscopic examination or with phonocardiographic technique. In fact, Fogel22) reported with stethoscopic examination that the parasternal-precordial murmur," which he named, appeared most often in children and its incidence was more than 85% of the so-called functional murmurs. However, the musical normal systolic murmur may be easily heard on auscultation because of its characteristic quality and of greater intensity than the other normal systolic murmurs. Moreover, the non-musical apical systolic murmur may be misjudged on auscultation as the musical one, because the former in young subjects showed less distorted wave form in the phonocardiogram and will be of similar acoustic quality to the latter. From the reasons mentioned above, we believe that the musical normal systolic murmur is frequently observed among young subjects but is not so high in incidence as stated by Fogel. A reasonable mechanism for the production of this murmur, as suggested by McKusick'43) is the trigon.oidation44) of the pulmonary cusps, resulting in 3 relatively taut flaps which are incited into vibration. It is quite consistent with this assumption that the murmur starts during

9 Vol, 3 No. 3 NORMAL SYSTOLIC MURMURS IN JAPANESE 215 the beginning of ventricular ejection and shows a crescendo-decrescendo configuration and ends before the 2nd sound like the ejection systolic murmur,45> and that its area of maximal intensity is frequently observed in the 2nd or 3rd intercostal space on the left sternal border, beneath which the pulmonary cusps situate. The frequent occurrence of the murmur in the area between the left lower sternal border and the apex may be accounted for the characteristic transmission of the musical murmur downward to the apex like Gallavardin46> phenomenon in aortic stenosis. A number of cases with the musical normal systolic murmur has another non-musical pulmonic systolic murmur. B) The non-musical variety of the normal systolic murmur: a. The pulmonic systolic murmur: One of the frequent type of the so-called functional murmurs is the pulmonic systolic murmur, which has been a well known finding among young subjects.') -1),44) It is heard in a range of degree of rough or harshness, and the area of its maximal intensity is in the 2nd or 3rd intercostal space on the left sternal border. In the phonocardiogram'>' 34), 39),40) the murmur consists of relatively irregular vibrations, which begin during early systole and which shows a rising and then falling amplitude with a spindle or diamond envelop and disappears before the 2nd sound. The frequency of its occurrence is estimated in a range between 10 and 80% of the so-called functional murmurs."), 13), 16) -26), 3 35) It is usually in low incidence among children")' 16), 22>, 33) and it trends to become more prevalent in adolescence")' 15) and thereafter it is the most common type of the functinal murmurs.2l)-26) In our study, the pulmonic systolic murmur was the most frequent type of the normal systolic murmurs throughout whole age groups except the cases aged above 60. Available data dealing with the pulmonic systolic murmur in adult life have been scarcely written in the literature. Spitzbarth30>' 32> reported that the accidental basal systolic murmur was found in 68% of clinical patients, aged from 14 to 56 or 57. On the other hand, Groom and his co-workers') demonstrated that among the normal systolic murmurs of subaudible intensity, which could be recorded in 100% of normal adults, 25%% were of diamond-shaped pattern, being registered near the base of the heart, and 58% showed a decrescendo figure, being registered along the left lower sternal border or near the apex. The latter report is quite different from our result of study. The mechanism of origin for this murmur is the rapid flow through the outflow tract of the right ventricle, which at this site is relatively superficial, and in addition the trigonoidation of the pulmonary cusps.43> It has been emphasized, especially in young subjects, that the outflow tract of the right ventricle, which is often narrow and irregular walled,32>' 33>

10 216 UEDA, UOZUMI, AND SAKAMOTO Jap. Heart J. May, 1962 and the pulmonary artery, which is relatively well developed33) or dilated as normal limits of variation,35),42),44) give origin to the turbulence. Low peripheral resistance of minor circulation is considered as another factor of the production of this type of murmur.30)-33) In the phonocardiogram, the basic wave of the pulmonic systolic murmur consists of lower frequency and of less distortion than that of pathological murmurs, and rather shows some similarity to the musical normal systolic murmur. This fact suggests that the trigonoidation of the pulmonary cusps plays a role in the production of this murmur. And the distortion in its wave form may be produced by the turbulence arising in the outflow tract of the right ventricle and in the pulmonary artery. b. The apical systolic murmur: The apical systolic murmur of the non-musical variety becomes a problem of discussion. Relatively high incidence of the so-called functional murmur at the apical area observed among young subjects is mainly due to the high incidence of the musical variety. The rate of real occurrence of the non-musical apical systolic murmur is estimated to be less than 15% of the functional murmurs.16),34) The mechanism of origin for this murmur has remained to be solved. Groom and his co-workers2) described that the normal systolic murmur, which showed frequently a decrescendo configuration, was not analogous to the pathological murmur, but understandably it might be generated from the normal flow of blood through the irregular contours of the heart and great vessels though the site of origin was uncertain. However, in our phonocardiographic study, the normal systolic murmur of maximal intensity in either the apical area or the base of the heart showed a graphic configuration of the ejection systolic murmur. This fact suggests that the apical systolic murmur may be generated from the flow of blood through great vessels during ventricular ejection. Whether the apical systolic murmur is of pulmonic or aortic origins? We think that at least in elderly subjects it is more likely of aortic origin. The evidence in favour of this assumption rests on the variation of the incidence of the normal systolic murmur with age and on the relationship between the murmur and the heart sounds. With increasing of age the pulmonic systolic murmur decreases in intensity and then decreases in incidence, as the apical systolic murmur increases in incidence and becomes relatively great intensity. The apical systolic murmur in elderly subjects has higher frequency range of vibrations than the other systolic murmurs. The 3rd phase of the 1st sound complex increases in duration, and from this fact aging process in the aorta may be suspected. The area of maximal intensity of the 2nd sound (aortic component) is frequently found in the apical area, and in the majority of cases with the apical systolic murmur

11 Vol,3 No. 3 NORMAL SYSTOLIC MURMURS IN JAPANESE 217 the 2nd sound is maximal in intensity at the same area. This fact indicates that the events arising in the aortic valve or in the aorta are well transmitted downward to the apex among normal elderly subjects. In young subjects, the non-musical apical systolic murmur is in low incidence. In contrast with the murmur in elderly subjects it consists of lower frequency of vibrations and is of less distorted wave form, showing some similarity to the musical systolic murmur. This murmur may be considered as an abortive or equivalent form of the musical one, which is due to the trigonoidation of the pulmonary cusps and which is frequently maximal in intensity at the apical area. c. The aortic systolic murmur: The normal systolic murmur with the maximal intensity at the aortic area is much less frequent in the normal subjects, even in the elderly, than previously reported.47)-49) The normal systolic murmur of aortic origin is usually observed in the area downward to the apex of the heart. SUMMARY AND CONCLUSION Using a multi-filter system phonocardiograph and a dynamic microphone, 200 phonocardiograms of the normal Japanese were analysed. (1) The systolic murmur was recorded in almost all normal subjects. (2) The normal systolic murmur showed a graphic configuration of the ejection systolic murmur irrespective of the area of maximal intensity, and it was less in frequency and intensity than the pathological murmur. a) The musical systolic murmur was observed in high incidence among young subjects, but not infrequently in adult life. b) The non-musical pulmonic systolic murmur was the most freqeunt type of the normal systolic murmurs, except cases aged above 60. c) The non-musical apical systolic murmur of aortic origin was frequently observed among elderly subjects. d) The normal systolic murmur was rarely maximal in intensity at the aortic area. (3) The above-mentioned phonocardiographic findings and their significances were discussed. (This report was presented by H. Ueda at the 24th Annual Meeting of Japanese Circulation Society on April 1, 1960, in Osaka). ACKNOWLEDGEMENT We are much obliged to Dr. J. Takeuchi and Dr. G. Kaito for their advice and encouragement. We are also indebted to Drs. H. Watanabe and T. Kobayashi for their collaboration in this study.

12 218 UEDA, UOZUMI, AND SAKAMOTO J ap. Heart J. May, 1962 REFERENCES 1. Ueda, H., Uozumi, Z., and Sakamoto, T.: Jap. Heart J. 2:426, a. Groom, D., Sihvonen, Y. T., Francis, W. W., and Sprouse, J. H.: Am. Heart J. 54: 592, b. Groom, D.: Circulation 18:1044, c. Groom. D., Chapman, W., Francis, W. W., Bass, A., and Sihvonen, Y. T.: Ann. Int. Med. 52:134, a. Lewis, D. H., Deitz, G. W., Wallace, J. D., and Brown, J. R., Jr.: Circulation 16: 764, b. Lewis, D. H, Ertugrul, A., Deitz, G. W., Wallace, J. D., and Brown, J. R., Jr.: Pediatrics 23:837, Potain, C.: Clinique medicale de la Charite, Masson, Paris, 1894 (cited by Major, R. H.: Physical Diagnosis, 2nd ed., W. B. Saunders, Philadelphia and London, 1940.). 5. Freeman, A. R. and Levine, S. A.: Ann. Int. Med. 6:1371, White, P. D., Adams, F. D., and Craib, D.: Am. J. Med. Sc. 203:52, Evans, W.: Brit. Heart J. 9:1, Harris, T. N., Friedman, S., and Haub, C. F.: Pediatrics 3:845, Schmidt-Voigt, J.: Atlas der Klinischen Phonocardiographie, Urban and Schwarzenberg, Munchen and Berlin, Thayer, W. S.: Am. J. Med. Sc. 169:313, Schwartzman, J.: Arch. Pediat. 58:443, Epstein, N.: J. Pediat. 32:39, Friedman, S., Robie, W., and Harris, T. N.: Pediatrics 4:782, Gardner, J. H. and Keith, J. D.: Pediatrics 7:713, Maresh, G. J., Dodge, H. J., and Lichty, J. A.: J. A. M. A. 148:802, Lynxwilder, C. P. and Donahoe, J. L.: South M. J. 48:164, Stuckey, D.: M. J. Australia 2:841, Stuckey, D., Dowa, B., and Walch, H.: M. J. Australia 1:36, Lessof, M. and Brigden, W.: Lancet 2:673, Fogel, D. H.: Pediatrics 19:793, Mainzer, W., Pincovici, R., and Heymann, G.: Arch. Dis. Child 34:131, Fogel, D. H.: Am. Heart J. 59:844, King, J. T., Jr.: Arch. Int. Med. 24:89, Bock, A. V.: cited by White (6). 25. Contratto, A. W.: New Engl. J. Med. 228:499, Stewart, I. M. G.: Brit. Heart J. 13:561, McKee, M. H.: Am. Heart J. 16:79, Mannheimer E.: Acta paediat. 28 (suppl. II) 1: Rappaport, M. B. and Sprague, H. B.: Am. Heart J. 23:591, Spitzbarth, H.: Verb. Dtsch. Ges. Kreislaufforsch. 20:384, Spitzbarth, H.: Arch. Kreislaufforsch. 22:1, Spitzbarth, H.: Dtsch. med. Wschr. 82:947, Paulin, S. and Mannheimer, E.: Acta paediat. 46:438, Wells, B.: Brit. Heart J. 19:129, Luisada, A. A., Haring, C. M., Aravanis, C., Cardi, L., Jona, E., and Zilli, A. B.: Ann. Int. Med. 48:597, Heidel, W.: Z. Kreislaufforsch. 50:66, Still, G. H.: Common Disorders and Diseases of Childhood, 3rd ed., Oxford Univ. Press, London, Harris, T. N. and Friedman, S.: Am. Heart J. 43:707, 1952.

13 Vol.3 No.3 NORMAL SYSTOLIC MURMURS IN JAPANESE Harris, T. N.: Am. Heart J. 50:805, Harris, T. N. and Needleman, H. L.: Am. Heart J. 52:887, Messeloff, C. R.: Am. J. Med. Sc. 217:71, Stuckey, D.: M. J. Australia 1:38, McKusick, V. A.: Cardiovascular Sound in Health and Disease, Williams and Wilkins, Baltimore, Chisholm, D. R.: Am. Heart J. 13:362, Leatham, A.: Brit. Heart J. 17:574, Gallavardin, L. and Pauper-Ravault: cited by McKusick (43). 47. Aravanis, C. and Harris, R.: Dis. Chest 33:214, Bruns, D. L. and van der Hauwaert, L. G.: Brit. Heart J. 20:370, Spitzbarth, H. and Dermentocoglu, A.: Z. Kreislaufforsch. 48:906, 1959.