Systolic time intervals (STIs) were determined in 19 diabetic patients under age 50 (mean age 35.2 years) and 24 normal control subjects (mean age 30.6 years). Preejection period (PEP), left ventricular ejection time (LVET), and PEP-LVET ratio were obtained by the conventional manner. Preejection period index (PEPI) and left ventricular ejection time index (LVETI) were derived by Weissler9s formula. 14 The isovolumic relaxation time (IVRT) was measured: (1) from the aortic component of the second heart sound of the phonocardiogram to the rapid opening anterior motion of the anterior leaflet of the mitral valve on echocardiogram (A 2 D 1 ), (2) and to the “0” point of the apexcardiogram (A 2 O). PEP, LEVT, PEPI, LVETI, and PEP/LVET ratio were statistically similar in diabetics and controls. However, the A 2 D 1 was longer in diabetics (71.2 ± 3.4 msec.) than in control subjects (59.5 ±3.1 msec.) ( p No change in STIs occurred in group 2 (controls) but the heart rate, PEPI, and PEP/LVET ratio rose in group 1 (diabetics). There were significant differences in PEPI and PEP/LVET ratio between groups 1 and 2, 30 and 60 minutes after alcohol. IVRT remained unchanged. Maximum blood alcohol levels for both groups were comparable at 60 minutes, (67.8 ± 5.2 mg./100 ml. in group 1 and 66.7 ± 7.5 mg./100 ml. in group 2). Glucose levels, although higher in group 1, remained stable throughout for both groups. Lactate levels, after alcohol ingestion, were comparable in both groups. Although the only evidence of myocardial dysfunction noted in diabetic patients in the resting state was the increase in IVRT, their response to alcohol revealed further changes in cardiac function not seen with such low doses of ethanol in normal individuals.

Noninvasive estimation of myocardial performance in patients with diabetes. Effect of alcohol administration.

Phonocardiograms and carotid pulse tracings were done on a group of 47 patients with all degrees of aortic stenosis and were compared with two groups of normals. Indices evaluated were pre-ejection period, left ventricular ejection time, maximum rate of arterial pulse rise, arterial half rise time (T time) and upstroke time, and timing of the peak intensity of the systolic murmur in relation to the electrocardiographic QRS and first heart sound. The indices most indicative of the presence of aortic stenosis and best correlated with its severity were the ejection time index, the maximal rate of rise of the carotid pulse and the timing of the peak of the systolic murmur. If, in a given case, all three of these indices fall outside of certain limits (ejection time index >0.42 sec, maximum rate of arterial pulse rise 0.19 sec), then severe aortic stenosis is almost invariably present.

Assessing the Severity of Aortic Stenosis by Phonocardiography and External Carotid Pulse Recordings

The left apex cardiogram was recorded in the dog by means of a pulse transducer with an infinite time constant. The time relation between the left apex cardiogram and left ventricular and aortic pressure tracings (recorded by means of high fidelity micromanometers) and their first time derivatives (dp/dt) was studied. Both the onset of the upstroke and the protodiastolic nadir of the left apex cardiogram and of the left ventricular pressure curve were found to occur nearly simultaneously. This close relation was preserved during various acutely induced hemodynamic changes and during right and left ventricular pacing. The E point of the left apex cardiogram occurred simultaneously with the peak dp/dt of the left ventricular pressure, or followed it with a time lag of 2 to 35 msec. Diastolic waves also occurred simultaneously. It is concluded that the left apex cardiogram provides a reliable noninvasive technique for the timing of intracardiac events.

On the value of apex cardiography for timing intracardiac events.

In 10 patients without left heart valvular disease and having normal function of the left ventricle, the left ventricular apex cardiogram with its first derivative (dA/dt), left ventricular pressure with its first derivative (dP/dt), aortic pressure, electrocardiogram, and phonocardiogram were reocrded simultaneously during cardiac catheterization. The apex cardiographic tracings were obtained by means of a transducer with infinite time constant and very high resonant frequency and the LV and aortic pressures with catheter tip-manometers. The onset of the systolic rise of apex cardiographic and LV pressures were found to occur almost simultaneously with the upstroke of LV pressure, preceding that of the apex cardiogram by only 2 +/- 4 ms (mean +/- 1 SD). The summit of the systolic upstroke of the apex cardiogram (called E-point) occurred 37 +/- 9 ms after opening of the aortic valve and 41 +/- 9 ms after peak dP/dt. The peak of dA/dt preceded peak dP/dt by 10 +/- 4 ms. The protodiastolic nadir of the apex cardiogram (called-O-point) occurred slightly earlier (19 +/- 16 ms) than the nadir of the LV pressure curve, with considerable variation. In conclusion, this study using external and internal transducers with similar characteristics gives a new definition of the time relation between the externally recorded apex cardiogram and the haemodynamic events within the left heart in human subjects with normal left ventricular function.

https://heart.bmj.com/content/heartjnl/37/12/1263.full.pdf

Time relation between apex cardiogram and left ventricular events using simultaneous high-fidelity tracings in man.

The ability of the echocardiogram to define mitral valve opening and closure was assessed by simultaneously recording the echocardiogram of the anterior leaflet (ECHO) with intracardiac pressures, aortic second sound, and ECG on 38 occasions in 14 patients undergoing cardiac catheterization. Hemodynamic opening and closure were defined by intersection of the pulmonary wedge and left ventricular pressures and the onset of left ventricular systole. The onset of the most rapid anterior motion (D9) in early diastole and termination of the last rapid posterior movement in end diastole (Co) were used as echocardiographic markers of mitral valve opening and closure. Intervals measured included: the isovolumic relaxation period (IRP) from A2 to either hemodynamic (IRPH) or echocardiographic (IRPE) opening; the Q to closure interval (QCI) from the Q wave to either hemodynamic (QCIH) or echocardiographic (QCIE) closure; and diastolic filling period (DFP), either hemodynamic (DFPH) or echocardiographic (DFPE). The following significant (P less than .01) regression equations resulted: IRPE equals (.97) IRPH plus 30 (sem plus or minus 8 msec) r equals .89; QCIE equals (.68) QCIH plus 37 (sem plus or minus 7 msec) r equals .71; DEPE equals (.98) DFPH plus 10 (sem plus or minus 18 msec) r equals .98. Thus hemodynamic markers of opening and closure systematically precede echocardiographic markers of opening (D9) and closure (Co) and the diastolic filling periods are equal within 10 msec. It is concluded that the echocardiogram of the anterior leaflet is a reliable indicator of hemodynamic markers of opening and closure of the mitral valve in man and is useful in the noninvasive determination of certain systolic and diastolic time intervals.

Robert E. Nagle

Papers

Air leaks as a source of distortion in apexcardiography.