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The assessment of failure in aortic stenosis from the diastolic movements of the left ventricle
The assessment the
diastolic
of failure movements
James 5’. Fleming, M.D., London, England
M.R.C.P.,
uring palpation of the cardiac apex in many patients with aortic stenosis, a small outward movement may be detected preceding the forceful systolic thrust of the hypertrophied left ventricle. Occasionally, when the patient is in severe cardiac failure, an outward movement of the apex beat in early diastole, coinciding in timing with a third heart sound, is palpable. In the present study, the abnormalities of the diastolic movements of the cardiac apex in aortic stenosis are analyzed and an attempt is made to relate the findings to the intracardiac pressures obtained during left heart catheterization. For detailed analysis of the movements of the cardiac apex, the apexcardiogram was recorded in each patient using a displacement transducer held against the chest wall over the apex beat. The instrument used provides an accurate recording of the displacement of the cardiac apex relative to the thoracic wall and considerably extends the information obtained from clinical palpation of the apex beat. Methods
The apexcardiogram was recorded from 20 patients with aortic valve stenosis. There were 15 male and 5 female patients, all over the age of 25, and all in sinus rhythm when the recording was made. Patients having From the Cardiac Department. Keceived for publication Sept.
Vol. 76, No. 2, pp. 235-241
St. Bartholomew’s 8, 1967.
August, 1968
in aortic of the
stenosis
left
from
ventricle
M.R.C.P.E.
evidence of mitral valve disease, either on clinical examination or at cardiac catheterization, were excluded. A total of 21 subjects without evidence of heart disease, ages ranging from 14 to 56 years, were also studied to establish normal values for the apexcardiogram using the present technique. The apexcardiogram was recorded using a Philips inductive displacement transducer, type PR9310, described as suitable for this work by Nixon and associates,” and this instrument provided signals for direct application to an oscilloscope display and a galvanometer recorder. The transducer has a metal base and a protruding probe that is sensitive to movement along its long axis, the frequency response being flat from 0 to 50 c.p.s. The transducer was adapted for recording the apexcardiogram by placing an adjustable perspex cylinder over the base of the instrument so that the probe was nearly level with the open end of the cylindere2 The apexcardiogram was recorded with the patient lying on the left side and the breath held at the end of a normal expiration. An electrocardiogram (EGG) and a phonocardiogram from the left sternal edge were obtained simultaneously with the apexcardiogram and the tracings were recorded photographically using a multiHospital,
London.
E.C.
1, England.
American Heart Journal
235
Fig. 1. Simultaneous recording of the “a” wave and the third
of the apexcardiogram, sound point are shown,
ECG,
and phonocardiogram.
The
measurements
~~lade
, / I
I
/
i;ig. 2. Left ventricular wave measured from
diastolic pressure Z Point to -4.
recorded
from
catheter
iI> the left ventricle.
I,elt atria1 s)-stolic
pressrr i-e
Assessn~e&
chan1~1 photographic recorder (New Electronics Products) at a paper speed of 80 mm. per second. The presystolic wave of the apexcardiogram, referred to as the *‘a” wave, was identified in each tracing as the positive deflection following the onset of the P wave of the ECG by an average of 0.11 sec.,3and its height was measured from onset to peak (Fig. 1). The third sound point, when present, appears as the peak of the rapid filling wave in early ventricular diastole and the height of this point was expressed as the vertical distance between this point and the lowest point of the apexcardiogram, the 0 point (Fig. 1). The heights of the “a” wave and of the third sound point have been expressed as a percentage of the total amplitude of the tracing, measured from the 0 point to the highest point during ventricular systole, thus allowing for differences in the amplitude of the apexcardiogram from one patient to another.4 All reported ratios and measurements
Table I. The normal
apexcardiogram
in 21 subjects
01‘ fa’ailztyein aovtic stenosis
represent the 111eal1of three consecutive cardiac cycles. Pressure measurements were obtained from the left atrium and the left ventricle by trans-septal catheterization within five days of recording the apexcardiogram in all patients with aortic stenosis. For comparison with the apexcardiogram, the left atria1 systolic pressure wave and the left ventricular end-diastolic pressure were measured from recordings taken at a paper speed of 80 mm. per second, the left atria1 systolic pressure wave being measured from the “2” point to the peak of the left atria1 “a” wave, and the left ventricular end-diastolic pressure was taken at the point where the pressure rises abruptly at the onset of left ventricular systole (Fig. 2). The measurements reported are the average measurements over one complete respiratory cycle. Differences between the apexcardiogram in the normal group and the patients with aortic stenosis have been tested for significance by the “t” test, and
with
no evidence of heart disease ‘iarr wave
Subject
Age
Sex
Diagnosis
--__ Total amplitude (per rent)
F. S. D. D. 4. c. K. c. D. 8. 1). J. M. J. J. T. P. w. I<. P. n. c. J. I. G. F. H. I’. A. B. D. E. w. w. M. Y. K. W. J. H. D. M. Mean S.D.
41 19 56 56 35 25 20 35 28 26 34 26 28 5.5 43 29 26 14 51 28 22
M M M M M M M M M M M M M M M F F F F M M
237
Cervical spondylosis Glandular fever Urethral fistula Duodenal ulcer Ulcerative colitis Normal Normal Normal Normal Normal Normal Normal Normal Cirrhosis of the liver Colloid goiter Psoriasis Tonsillectomy Tonsillectomy Peptic ulcer Thyroidectomy Tonsillectomy
4.5 3.5 9.0 7.0 7.0 7.0 7.5 7.0 4.0 3.5 6.0 6.0 6.5 9.0 7.0 6.5 3.5 6.5 6.5 8.0 3.0 6.12 1.8
238
Am. Newt 1. Augmt., 1968
Fleming
the relationship between diastolic pressures and the diastolic waves of the apexcardiogram has been expressed as the correlation co-efficient. Results
For the 21 subjects without evidence of heart disease, the mean height of the presystolic wave of the apexcardiogram expressed as a percentage of the total amplitude of deflection was 6 per cent (S.D. 2 per cent). The presystolic wave was not greater than 9 per cent in any patient (Table I). 45
. .
40
5 s 30 cl a ;: LX mi-25 9 Iz ;
-l
20 15
. .
.
. .
. .
.
.
l 0
l
.
5 10 15 LEFT ATRIAL ‘a’ WAVE
20
25
(mm Hg)
Fig. 3. No significant correlation between the presystolic wave of the apexcardiogram and the left atria1 systolic pressurewave.
LEFT
VENTRICULAR
Fig. 4. Regression line for best estimate of left ventricular rupted lines at two standard errors of estimate.
Iii the group of 20 patierrts with aortic stenosis, a large presystolic wave exceeding 10 per cent of the total deflection was present in 18 (90 per cent of the patients studied). The mean height of the presystolic wave for the group was 21 per cent (SD. 10 per cent), and this wave was less than 10 per cent in only two patients. The difference between the mean of 6 per cent for the subjects without heart disease and the mean of 21 per cent for the patients with aortic stenosis is highly significant (“t” = 16.35 p < 0.01). The left atria1 systolic pressure wave was measured in 19 patients; the onset of atria1 fibrillation during cardiac catheterization preventing the measurement in the remaining patient. The average height for the 19 patients was 11 mm. Hg (range 6 to 22 mm. Hg). A third sound point was identified on the apexcardiogram in 16 patients, 80 per cent of the patients with aortic stenosis, and the height of this point was measured in each case, the mean value for the group being 10 per cent (SD. 9 per cent). The average left ventricular end-diastolic pressure for the 20 patients was 12 mm. Hg, with a range from -5 to 30 mm. Hg. Comparison of apexcardiogram zvith intracardiac pressures. In Fig. 3, the height of the presystolic wave in the apexcardiogram has been compared with the left atria
END DIASTOLIC end-diastolic
PRESSURE pressure
(mm Hg)
(continuous
line)
with
inter-
Assessment
systolic pressure. X0 significant correlation is demonstrable (r = 0.39 p > 0.05). When the height of the third sound point is compared with the left ventricular enddiastolic pressure in each patient (Fig. 4), a highly significant correlation is found, r = 0.8 p < 0.001. The regression equation for the prediction of left ventricular enddiastolic pressure (x) from the height of the third sound point (y) is x = 0.97~ + 3. In Table II, the heights of the third sound points on the apexcardiogram have been used in the regression equation to predict left ventricular end-diastolic pressures, and the predicted values are compared with those measured during catheterization. Discussion
Precordial vibrations have a frequency range from 0 to 1,500 c.p.s. and only a small proportion of these vibrations are below the audible range. The amplitude of these infrasonic vibrations is large and they have usually been recorded by means
Table II. Prediction of left ventricular enddiastolic $ressure (LVEDP) in 20 patients with aortic stenosis L VEDP
22 9 16 12 3 5 12 15 1.5 32 27 13 8 16 12 7 3 3 18 3
30 10 25 10 6 -5 10 12 10 22 30 25 5 22 18 8 3 0 7 0
8 1 9 -2 3 -10 -2 -3 -5 -10 3 12 -3 6 6 1 0 -3 -11 -3
of ;faillLre in ao&c stenosis
239
of an air tube connected to a crystal pickup.596Roberts and Sherwood-Jones’ point out, however, that the low frequency response of the widely used crystal microphone may introduce serious distortions of the apexcardiogram. The instrument used in the present study has a satisfactory frequency response from 0 to 50 c.p.s. and the apexcardiogram obtained is an accurate record of the movements of the apex beat relative to the rib cage. The presystolic wave of the apexcardiogram. The presystolic wave of the apexcardiogram represents active filling of the left ventricle due to left atria1 contraction.8 The presystolic wave is closely related to the P wave of the ECG, the onset of the P wave preceding the onset of this wave by 0.11 sec., and in the presence of complete atrioventricular dissociation the presystolic wave continues to follow this close relationship with the P wave. Furthermore, in the presence of atria1 fibrillation the presystolic wave is no longer seen. From a study of 52 normal subjects, Benchimol and Dimond* determined a mean height for the presystolic wave of the apexcardiogram of 7.8 per cent and this is in reasonable agreement with the mean of 6 per cent for subjects without heart disease in the present investigation. The presystolic wave of the apexcardiogram has been shown to be abnormally large in aortic stenosis by Braunwald and associatesg and Goldblatt and co-workers”’ and a significant difference has also been demonstrated here. An abnormally large presystolic wave implies greater filling of the left ventricle than normal during atria1 systole and may be the result of an increased force of atria1 contraction or of an altered distensibility of the ventricle. Both of these factors will be considered. Force of the left atria1 systole. The average pulse pressure of left atria1 systole for normal subjects is 3.4 mm. Hg with a range of 1 to 7 mm. Hg.11The “a” wave in the left atria1 pressure pulse is therefore abnormally high in most of the patients with aortic stenosis in the present study, but this cannot be the sole factor determining the abnormally large presystolic wave in the apexcardiogram as there is no significant correlation between the pressure wave
240
Fleming
10
20
30
40
50
AORTIC VALVE
60
AREA
70
80
90
100
(mm/M21
Fig. 5. The height of the presystolic wave apexcardiogram is not related to the severity aortic stenosis.
of the of the
and the apexcardiogram presystolic wave in individual patients. Most catheter studies were performed without any premedication and there was no obvious change in the clinical state of the patient between recording the apexcardiogram and obtaining left atria1 pressure, so the lack of correlation cannot be ascribed to the interval between the measurements. Altered distensibility of the left ventricle. Gorlin and associates12 have shown that the increase in volume of the left ventricle for a given increase in pressure may be abnormally small in aortic stenosis, i.e., the distensibility of the ventricle is reduced. Under these circumstances, filling of the ventricle during early and mid-diastole might be less complete and the contribution of left atria1 systole to left ventricular filling augmented producing a large presystolic filling wave in the apexcardiogram. The lack of correlation between the presystolic wave in the apexcardiogram and the left atria1 pressure wave is explained by this hypothesis, for large variations in the distensibility of the left ventricle will occur in individual patients in response to varying degrees of left ventricular hypertrophy and myocardial fibrosis. It appears that the distensibility of the left ventricle is influenced by factors other than the left ventricular hypertrophy in response to aortic valve stenosis, for when the height of the presystolic wave in the apexcardiogram is compared with the sever-
ity of rhe obstructiou to left ventricular outflow no significant corre!ation is found (Fig. 5). The height of the “a” wave in the apexcardiogram cannot be used to assess the severity of the stenosis. Third sound point of the apexcardiogram. The rapid filling wave of the apexcardiogram often terminates at a peak which has been termed the third sound point. Dock13 comments that this peak coincides in timing with the third heart sound and is probably a record of the sharp arrest of the outward motion of the left ventricle when the papillary muscles, chordae tendineae, and mitral valve cusps suddenly limit further expansion of the chamber. When the height of the third sound point is plotted against the left ventricular, enddiastolic pressure in the patients with aortic stenosis (Fig. 4) a relationship is apparent. A loud third heart sound in adults is a well accepted sign of heart failurei and it might therefore be expected that some correlation would exist between left ventricular end-diastolic pressure, which is usually very high in the presence of left ventricular failure and the height of the third sound point. From the present findings, it appears that the presence of a high third sound point on the apexcardiogram in adults with aortic stenosis implies a high left ventricular enddiastolic pressure. Possibly the properties of the left ventricle during the early rapid filling phase of diastole are different in children, for a third sound and a third sound point are normally present in young people. The apexcardiogram cannot be expected to give the same indication of the left ventricular diastolic pressure in children as is found in adults with aortic stenosis. Conclusions
The presystolic thrust of the cardiac apex beat caused by left atria1 systole is abnormally large in many patients with aortic stenosis. The size of this presystolic wave does not reflect the severity of the obstruction to left ventricular outflow in the individual case, nor does it correlate well with the magnitude of the left atria1 pressure wave. It is believed that the lack of correlation between the size of the presystolic apical impulse and the left atria1
pressure wave indicates variations in compliance of the left ventricle in aortic stenosis. The height of the third sound point in the apexcardiogram in adults with aortic stenosis correlates well with the left ventricular end-diastolic pressure, an elevated end-diastolic pressure, and a high third sound point being found together in left ventricular failure. REFERENCES Nixon, P. G. F., Hepburn, F., and lkram, H.: Simultaneous recording of heart pulses and sounds, Brit. M. J. 1:1169, 1964. 2. Fleming, J., and Hamer, J.: Effect of propan0101 on left atria1 systole in ischaemic and hypertensive heart disease, Brit. Heart J. 29:257, 1967. 3. Tafur, E., Cohen, L. S., and Levine, H. D.: The normal apexcardiogram, Circulation 30: 381, 1964. 4. Benchimol, A., and Dimond, E. G.: The apex cardiogram in ischaemic heart disease, Brit. Heart J. 24:581, 1962. 5. Rappaport, M. B., and Sprague, H. B.: The graphic registration of the normal heart sounds, An{. HEART J. 23:591, 1942. 6. Luisada, A. A., and Magri, G.: The low fre-
7.
8.
9.
10.
1.
11.
12.
13. 14.
quency tracings of the precordium and epigastrium in normal subjects and cardiac patients, AM. HEART J. 44:545, 1952. Roberts, D. V., and Sherwood-Jones, E.: A new system for recording the apex-beat, Lancet X:1193, 1963. Coulshed, N., and Epstein, E. J.: The apexcardiogram; its normal features explained by those found in heart disease. Brit. Heart T. 25: 697, 1963. Braunwald, E., Goldblatt, ,4., Aygen, M. M., Rockoff. S. D., and Morrow. A. G.: Conpenital aortic stenosis,’ Circulation 27:426, 1963.O Goldblatt, A., Aygen, M. M., and Braunwaid, E.: Haemodynamic-phonocardiographic correlations of the fourth heart sound in aortic stenosis, Circulation 26:92, 1962. Braunwald, E., Brockenbrough, E. C., Frahm, C. J., and Ross, J., Jr.: Left atria1 and left ventricular pressure in subjects without cardiovascular disease, Circulation 24:267, 1961. Goriin, R., Rolett, E. L., Yurchak, P. M., and Elliott, W. C.: Left ventricular volume in man measured by thermodilution, J. Clin. Invest. 43:1203, 1964. Dock, W.: Heart sounds from Starr-Edwards valves, Circulation 31:801, 1965. Wood, P.: Diseases of the heart and circulation, 2nd ed., London, 1956, Eyre & Spottiswoode, Ltd.
diastolic
of failure movements
James 5’. Fleming, M.D., London, England
M.R.C.P.,
uring palpation of the cardiac apex in many patients with aortic stenosis, a small outward movement may be detected preceding the forceful systolic thrust of the hypertrophied left ventricle. Occasionally, when the patient is in severe cardiac failure, an outward movement of the apex beat in early diastole, coinciding in timing with a third heart sound, is palpable. In the present study, the abnormalities of the diastolic movements of the cardiac apex in aortic stenosis are analyzed and an attempt is made to relate the findings to the intracardiac pressures obtained during left heart catheterization. For detailed analysis of the movements of the cardiac apex, the apexcardiogram was recorded in each patient using a displacement transducer held against the chest wall over the apex beat. The instrument used provides an accurate recording of the displacement of the cardiac apex relative to the thoracic wall and considerably extends the information obtained from clinical palpation of the apex beat. Methods
The apexcardiogram was recorded from 20 patients with aortic valve stenosis. There were 15 male and 5 female patients, all over the age of 25, and all in sinus rhythm when the recording was made. Patients having From the Cardiac Department. Keceived for publication Sept.
Vol. 76, No. 2, pp. 235-241
St. Bartholomew’s 8, 1967.
August, 1968
in aortic of the
stenosis
left
from
ventricle
M.R.C.P.E.
evidence of mitral valve disease, either on clinical examination or at cardiac catheterization, were excluded. A total of 21 subjects without evidence of heart disease, ages ranging from 14 to 56 years, were also studied to establish normal values for the apexcardiogram using the present technique. The apexcardiogram was recorded using a Philips inductive displacement transducer, type PR9310, described as suitable for this work by Nixon and associates,” and this instrument provided signals for direct application to an oscilloscope display and a galvanometer recorder. The transducer has a metal base and a protruding probe that is sensitive to movement along its long axis, the frequency response being flat from 0 to 50 c.p.s. The transducer was adapted for recording the apexcardiogram by placing an adjustable perspex cylinder over the base of the instrument so that the probe was nearly level with the open end of the cylindere2 The apexcardiogram was recorded with the patient lying on the left side and the breath held at the end of a normal expiration. An electrocardiogram (EGG) and a phonocardiogram from the left sternal edge were obtained simultaneously with the apexcardiogram and the tracings were recorded photographically using a multiHospital,
London.
E.C.
1, England.
American Heart Journal
235
Fig. 1. Simultaneous recording of the “a” wave and the third
of the apexcardiogram, sound point are shown,
ECG,
and phonocardiogram.
The
measurements
~~lade
, / I
I
/
i;ig. 2. Left ventricular wave measured from
diastolic pressure Z Point to -4.
recorded
from
catheter
iI> the left ventricle.
I,elt atria1 s)-stolic
pressrr i-e
Assessn~e&
chan1~1 photographic recorder (New Electronics Products) at a paper speed of 80 mm. per second. The presystolic wave of the apexcardiogram, referred to as the *‘a” wave, was identified in each tracing as the positive deflection following the onset of the P wave of the ECG by an average of 0.11 sec.,3and its height was measured from onset to peak (Fig. 1). The third sound point, when present, appears as the peak of the rapid filling wave in early ventricular diastole and the height of this point was expressed as the vertical distance between this point and the lowest point of the apexcardiogram, the 0 point (Fig. 1). The heights of the “a” wave and of the third sound point have been expressed as a percentage of the total amplitude of the tracing, measured from the 0 point to the highest point during ventricular systole, thus allowing for differences in the amplitude of the apexcardiogram from one patient to another.4 All reported ratios and measurements
Table I. The normal
apexcardiogram
in 21 subjects
01‘ fa’ailztyein aovtic stenosis
represent the 111eal1of three consecutive cardiac cycles. Pressure measurements were obtained from the left atrium and the left ventricle by trans-septal catheterization within five days of recording the apexcardiogram in all patients with aortic stenosis. For comparison with the apexcardiogram, the left atria1 systolic pressure wave and the left ventricular end-diastolic pressure were measured from recordings taken at a paper speed of 80 mm. per second, the left atria1 systolic pressure wave being measured from the “2” point to the peak of the left atria1 “a” wave, and the left ventricular end-diastolic pressure was taken at the point where the pressure rises abruptly at the onset of left ventricular systole (Fig. 2). The measurements reported are the average measurements over one complete respiratory cycle. Differences between the apexcardiogram in the normal group and the patients with aortic stenosis have been tested for significance by the “t” test, and
with
no evidence of heart disease ‘iarr wave
Subject
Age
Sex
Diagnosis
--__ Total amplitude (per rent)
F. S. D. D. 4. c. K. c. D. 8. 1). J. M. J. J. T. P. w. I<. P. n. c. J. I. G. F. H. I’. A. B. D. E. w. w. M. Y. K. W. J. H. D. M. Mean S.D.
41 19 56 56 35 25 20 35 28 26 34 26 28 5.5 43 29 26 14 51 28 22
M M M M M M M M M M M M M M M F F F F M M
237
Cervical spondylosis Glandular fever Urethral fistula Duodenal ulcer Ulcerative colitis Normal Normal Normal Normal Normal Normal Normal Normal Cirrhosis of the liver Colloid goiter Psoriasis Tonsillectomy Tonsillectomy Peptic ulcer Thyroidectomy Tonsillectomy
4.5 3.5 9.0 7.0 7.0 7.0 7.5 7.0 4.0 3.5 6.0 6.0 6.5 9.0 7.0 6.5 3.5 6.5 6.5 8.0 3.0 6.12 1.8
238
Am. Newt 1. Augmt., 1968
Fleming
the relationship between diastolic pressures and the diastolic waves of the apexcardiogram has been expressed as the correlation co-efficient. Results
For the 21 subjects without evidence of heart disease, the mean height of the presystolic wave of the apexcardiogram expressed as a percentage of the total amplitude of deflection was 6 per cent (S.D. 2 per cent). The presystolic wave was not greater than 9 per cent in any patient (Table I). 45
. .
40
5 s 30 cl a ;: LX mi-25 9 Iz ;
-l
20 15
. .
.
. .
. .
.
.
l 0
l
.
5 10 15 LEFT ATRIAL ‘a’ WAVE
20
25
(mm Hg)
Fig. 3. No significant correlation between the presystolic wave of the apexcardiogram and the left atria1 systolic pressurewave.
LEFT
VENTRICULAR
Fig. 4. Regression line for best estimate of left ventricular rupted lines at two standard errors of estimate.
Iii the group of 20 patierrts with aortic stenosis, a large presystolic wave exceeding 10 per cent of the total deflection was present in 18 (90 per cent of the patients studied). The mean height of the presystolic wave for the group was 21 per cent (SD. 10 per cent), and this wave was less than 10 per cent in only two patients. The difference between the mean of 6 per cent for the subjects without heart disease and the mean of 21 per cent for the patients with aortic stenosis is highly significant (“t” = 16.35 p < 0.01). The left atria1 systolic pressure wave was measured in 19 patients; the onset of atria1 fibrillation during cardiac catheterization preventing the measurement in the remaining patient. The average height for the 19 patients was 11 mm. Hg (range 6 to 22 mm. Hg). A third sound point was identified on the apexcardiogram in 16 patients, 80 per cent of the patients with aortic stenosis, and the height of this point was measured in each case, the mean value for the group being 10 per cent (SD. 9 per cent). The average left ventricular end-diastolic pressure for the 20 patients was 12 mm. Hg, with a range from -5 to 30 mm. Hg. Comparison of apexcardiogram zvith intracardiac pressures. In Fig. 3, the height of the presystolic wave in the apexcardiogram has been compared with the left atria
END DIASTOLIC end-diastolic
PRESSURE pressure
(mm Hg)
(continuous
line)
with
inter-
Assessment
systolic pressure. X0 significant correlation is demonstrable (r = 0.39 p > 0.05). When the height of the third sound point is compared with the left ventricular enddiastolic pressure in each patient (Fig. 4), a highly significant correlation is found, r = 0.8 p < 0.001. The regression equation for the prediction of left ventricular enddiastolic pressure (x) from the height of the third sound point (y) is x = 0.97~ + 3. In Table II, the heights of the third sound points on the apexcardiogram have been used in the regression equation to predict left ventricular end-diastolic pressures, and the predicted values are compared with those measured during catheterization. Discussion
Precordial vibrations have a frequency range from 0 to 1,500 c.p.s. and only a small proportion of these vibrations are below the audible range. The amplitude of these infrasonic vibrations is large and they have usually been recorded by means
Table II. Prediction of left ventricular enddiastolic $ressure (LVEDP) in 20 patients with aortic stenosis L VEDP
22 9 16 12 3 5 12 15 1.5 32 27 13 8 16 12 7 3 3 18 3
30 10 25 10 6 -5 10 12 10 22 30 25 5 22 18 8 3 0 7 0
8 1 9 -2 3 -10 -2 -3 -5 -10 3 12 -3 6 6 1 0 -3 -11 -3
of ;faillLre in ao&c stenosis
239
of an air tube connected to a crystal pickup.596Roberts and Sherwood-Jones’ point out, however, that the low frequency response of the widely used crystal microphone may introduce serious distortions of the apexcardiogram. The instrument used in the present study has a satisfactory frequency response from 0 to 50 c.p.s. and the apexcardiogram obtained is an accurate record of the movements of the apex beat relative to the rib cage. The presystolic wave of the apexcardiogram. The presystolic wave of the apexcardiogram represents active filling of the left ventricle due to left atria1 contraction.8 The presystolic wave is closely related to the P wave of the ECG, the onset of the P wave preceding the onset of this wave by 0.11 sec., and in the presence of complete atrioventricular dissociation the presystolic wave continues to follow this close relationship with the P wave. Furthermore, in the presence of atria1 fibrillation the presystolic wave is no longer seen. From a study of 52 normal subjects, Benchimol and Dimond* determined a mean height for the presystolic wave of the apexcardiogram of 7.8 per cent and this is in reasonable agreement with the mean of 6 per cent for subjects without heart disease in the present investigation. The presystolic wave of the apexcardiogram has been shown to be abnormally large in aortic stenosis by Braunwald and associatesg and Goldblatt and co-workers”’ and a significant difference has also been demonstrated here. An abnormally large presystolic wave implies greater filling of the left ventricle than normal during atria1 systole and may be the result of an increased force of atria1 contraction or of an altered distensibility of the ventricle. Both of these factors will be considered. Force of the left atria1 systole. The average pulse pressure of left atria1 systole for normal subjects is 3.4 mm. Hg with a range of 1 to 7 mm. Hg.11The “a” wave in the left atria1 pressure pulse is therefore abnormally high in most of the patients with aortic stenosis in the present study, but this cannot be the sole factor determining the abnormally large presystolic wave in the apexcardiogram as there is no significant correlation between the pressure wave
240
Fleming
10
20
30
40
50
AORTIC VALVE
60
AREA
70
80
90
100
(mm/M21
Fig. 5. The height of the presystolic wave apexcardiogram is not related to the severity aortic stenosis.
of the of the
and the apexcardiogram presystolic wave in individual patients. Most catheter studies were performed without any premedication and there was no obvious change in the clinical state of the patient between recording the apexcardiogram and obtaining left atria1 pressure, so the lack of correlation cannot be ascribed to the interval between the measurements. Altered distensibility of the left ventricle. Gorlin and associates12 have shown that the increase in volume of the left ventricle for a given increase in pressure may be abnormally small in aortic stenosis, i.e., the distensibility of the ventricle is reduced. Under these circumstances, filling of the ventricle during early and mid-diastole might be less complete and the contribution of left atria1 systole to left ventricular filling augmented producing a large presystolic filling wave in the apexcardiogram. The lack of correlation between the presystolic wave in the apexcardiogram and the left atria1 pressure wave is explained by this hypothesis, for large variations in the distensibility of the left ventricle will occur in individual patients in response to varying degrees of left ventricular hypertrophy and myocardial fibrosis. It appears that the distensibility of the left ventricle is influenced by factors other than the left ventricular hypertrophy in response to aortic valve stenosis, for when the height of the presystolic wave in the apexcardiogram is compared with the sever-
ity of rhe obstructiou to left ventricular outflow no significant corre!ation is found (Fig. 5). The height of the “a” wave in the apexcardiogram cannot be used to assess the severity of the stenosis. Third sound point of the apexcardiogram. The rapid filling wave of the apexcardiogram often terminates at a peak which has been termed the third sound point. Dock13 comments that this peak coincides in timing with the third heart sound and is probably a record of the sharp arrest of the outward motion of the left ventricle when the papillary muscles, chordae tendineae, and mitral valve cusps suddenly limit further expansion of the chamber. When the height of the third sound point is plotted against the left ventricular, enddiastolic pressure in the patients with aortic stenosis (Fig. 4) a relationship is apparent. A loud third heart sound in adults is a well accepted sign of heart failurei and it might therefore be expected that some correlation would exist between left ventricular end-diastolic pressure, which is usually very high in the presence of left ventricular failure and the height of the third sound point. From the present findings, it appears that the presence of a high third sound point on the apexcardiogram in adults with aortic stenosis implies a high left ventricular enddiastolic pressure. Possibly the properties of the left ventricle during the early rapid filling phase of diastole are different in children, for a third sound and a third sound point are normally present in young people. The apexcardiogram cannot be expected to give the same indication of the left ventricular diastolic pressure in children as is found in adults with aortic stenosis. Conclusions
The presystolic thrust of the cardiac apex beat caused by left atria1 systole is abnormally large in many patients with aortic stenosis. The size of this presystolic wave does not reflect the severity of the obstruction to left ventricular outflow in the individual case, nor does it correlate well with the magnitude of the left atria1 pressure wave. It is believed that the lack of correlation between the size of the presystolic apical impulse and the left atria1
pressure wave indicates variations in compliance of the left ventricle in aortic stenosis. The height of the third sound point in the apexcardiogram in adults with aortic stenosis correlates well with the left ventricular end-diastolic pressure, an elevated end-diastolic pressure, and a high third sound point being found together in left ventricular failure. REFERENCES Nixon, P. G. F., Hepburn, F., and lkram, H.: Simultaneous recording of heart pulses and sounds, Brit. M. J. 1:1169, 1964. 2. Fleming, J., and Hamer, J.: Effect of propan0101 on left atria1 systole in ischaemic and hypertensive heart disease, Brit. Heart J. 29:257, 1967. 3. Tafur, E., Cohen, L. S., and Levine, H. D.: The normal apexcardiogram, Circulation 30: 381, 1964. 4. Benchimol, A., and Dimond, E. G.: The apex cardiogram in ischaemic heart disease, Brit. Heart J. 24:581, 1962. 5. Rappaport, M. B., and Sprague, H. B.: The graphic registration of the normal heart sounds, An{. HEART J. 23:591, 1942. 6. Luisada, A. A., and Magri, G.: The low fre-
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