SUMMARY Beta adrenergic blocking drugs in hypertrophic cardiomyopathy provide symptomatic relief but their effect on long-term prognosis is uncertain.Thirty patients were studied non-invasively by simultaneous recordings of echocardiogram, apexcardiogram, phonocardiogram, and electrocardiogram in order to assess diastolic abnormalities on and off oral beta adrenergic blocking drugs. While on treatment these patients had a mean dose of propranolol 200 mg/day. The treatment was stopped for one week and then non-invasive assessment was repeated.The following diastolic time intervals were studied: isovolumic relaxation period (A2-mitral valve opening); rapid relaxation period (A2-O point of the apexcardiogram), and the period from mitral valve opening to the 0 point of the apexcardiogram (Mo-0) when most of the filling of the left ventricle occurs. The prolongation of the rapid relaxation period reflects a reduced rate of fall of the left ventricular pressure when the pressure differential does not change between A2 and the 0 point of the apexcardiogram, and in this study this period was prolonged in 19, shortened in eight, and remained the same in three patients after beta blockade. The Mo-O point was prolonged in 22, shortened in seven, and was unchanged in one patient after beta adrenergic blocking drugs. All these results were independent of heart rate.In conclusion the response of diastolic time intervals to beta blocking drugs in hypertrophic cardiomyopathy was variable but there was a significant number of patients in whom the time available for filling of the left ventricle was prolonged, suggesting better filling possibly because of improved distensibility of the left ventricle after beta adrenergic blocking drugs.

Previous reports have demonstrated that patients with hypertrophic cardiomyopathy have a prolonged isovolumic relaxation period as a result of a delay in mitral valve opening, reflecting a reduced rate of fall of left ventricular pressure. This period as measured from the aortic closure sound (A2 on phonocardiogram) to the opening of the mitral valve (on echocardiogram) was determined in 84 patients with hypertrophic cardiomyopathy and compared with findings in 31 normal volunteers. The duration of the isovolumic relaxation period in the 84 patients had a wide range from 0 to 160 ms (mean 71 +/- 32) that was not significantly different from that in normal subjects (63 +/- 11 ms). However, it was possible to identify a group of 15 patients with an extremely short isovolumic relaxation period, 2 standard deviations below the normal range. This shortening was due to a marked delay in aortic closure sound (A2) due to late left ventricular-aortic pressure crossover, as well as early opening of the mitral valve secondary to elevated left atrial pressure, which was confirmed by hemodynamic correlations and digitized echocardiographic data. In this subset of patients, A2 is a poor marker of the onset of rapid left ventricular pressure decline and, thus, the interval from A2 to mitral valve opening is not a valid reflection of left ventricular relaxation. It is concluded that in hypertrophic cardiomyopathy, both the timing and sequence of relaxation are abnormal, as is the rate of relaxation. Furthermore, the isovolumic relaxation period is multifactorially determined and depends not only on the rate of left ventricular pressure decline, but also on the magnitude of the pressure drop from A2 to mitral valve opening. All of these determinants must be kept in mind when the isovolumic relaxation period is used as a measure of left ventricular relaxation.

Summary:The salient phonoechocardiographic features of patients having hypertrophic cardiomyopathy (HCM) with or without left ventricular outflow tract (LVOT) gradients are reviewed.Intracardiac sound and pressure recordings from high fidelity catheter-tipped micromanometers have documented that the precordial murmur is the summation of both the systolic ejection murmur (SEM) arising from the LVOT, as well as the mitral regurgitant murmur recorded from the left atrium. The intensity of the precordial murmur varies directly with the LVOT gradient, which in turn is determined primarily by the contractility and loading conditions of the left ventricle.Reversed splitting of the second heart sound (S2) with paradoxical respiratory movement is a common finding in HCM, and when present, almost always denotes a significant LVOT gradient. It is due to marked lengthening of the left ventricular ejection time secondary to prolongation of the contraction and relaxation phases of left ventricular systole. The presence of a fourth heart sound (S4) is the rule in HCM when normal sinus rhythm is present, and is a reflection of a forceful left atrial contraction into a hypertrophied noncompliant left ventricle. A third heart sound (S3) is also common in HCM, and often the initial vibrations occur before the 0 point of the apexcardiogram (ACG) and continue giving the auscultatory impression of a diastolic rumble. When associated with a loud SI, which is frequently present, the clinical presentation may mimic mitral stenosis. This-is particularly true when the patient has chronic atrial fibrillation. Careful attention to evidence of marked left ventricular hypertrophy as well as the typical echocardiographic findings of HCM preclude this diagnosis.In conclusion, phonoechocardiography is a simple non-invasive technique which almost always makes the definitive diagnosis of HCM.Phonocardiography is the graphic representation of the bedside cardiovascular examination. It includes not only the recording of the auscultatory phenomena of the precordium, but also the carotid, venous, and cardiac apical pulsations simultaneously with the electrocardiogram (Shaver, 1981). When coupled with the M-mode echocardiogram, the diagnostic capabilities of this technique are further enhanced by correlating the sound and pressure tracings of the cardiac cycle with dynamic valvular and ventricular wall motion. Probably no disease lends itself so well to evaluation by these techniques as hypertrophic cardiomyopathy (HCM), because of its unique physical and anatomical findings. In this report, the salient features of patients with HCM will be described as recorded by phonoechocardiography. Furthermore, new insights into the mechanisms of the auscultatory findings in this entity will be provided by utilizing intracardiac recordings of sound and pressure obtained from high fidelity catheter-tipped micromanometers.The phonocardiogram of a 54 year old patient with HCM is shown in Figure 1, and is typical of patients with this disease having a significant l...

The early diastolic filling characteristics and pressure (as measured at the chest wall) were studied in 17 normal subjects with a physiologic third heart sound (Phy S(3)) and were compared in 13 normal subjects without this sound (controls; C). Simultaneous M-mode echocardiogram, apex phonocardiogram, calibrated apexcardiogram (ACG), and its first derivative were recorded. The maximum rate of change of ventricular dimension (max dD/dt) was derived by computer and normalized (max dD/dt/D). The Phy S(3) occurred during the early E-F slope of the mitral valve echocardiogram, followed max dD/dt, and was recorded between the O and F points of the calibrated ACG in all 17 subjects. In 14 of 17 subjects, the Phy S(3) was associated with an inflection on septum, posterior wall, or mitral valve apparatus. Compared to C, there was no significant difference in the subjects’ age, systolic or diastolic dimensions, ejection fraction, or diastolic time intervals. However, both pre-ejection period and the ratio preejection period/left ventricular ejection time were significantly shortened in subjects with the Phy S(3). There was no significant difference in any of the computer-derived indices of diastolic filling, including max dD/dt, max dD/dt/D, the interval from mitral valve opening to 20% max dD/dt, and the percent diastolic dimension change at the O point of the ACG. There was also no significant difference in any of the indices of mitral valve velocity. However, the maximal rate of change of pressure during the rapid filling wave of the calibrated ACG was markedly increased in the subjects with the Phy S3 compared to C (787 ± 296 vs. 296 ± 98 mm Hg/s; p < 0.001). These data are consistent with the thesis that the genesis of the Phy S(3) is due to the dynamic impact of the heart on the chest wall. The force of this impact and the resultant intensity of the Phy S(3) are determined by both chest wall configuration and motion of the heart within the thorax.

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