Relation between apex cardiographic and internal indices of left ventricular relaxation in man.
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Biomedical subjects
Publications and source records attributed to J Manolas.
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In 11 patients with nonobstructive cardiomyopathy and coronary heart disease and decreased myocardial function of the left ventricle, as well as in nine patients without left heart valvular or myocardial disease, left apexcardiograms were recorded during diagnostic heart catheterization, wherein micromanometers were used; ACG's were registered additionally in 54 healthy volunteers in order to establish the normal range of apexcardiographic parameters. In all cases the apex tracings were recorded by means of a pulse transducer with infinite time constant. The most important finding of this study was the close correlation between the duration of the systolic upstroke (SUT) of the apex tracing and some accepted isovolumic indexes of left heart function (isovolumic contraction time, time interval from the onset to peak of the first derivative of left ventricular pressure, maximal value of the first derivative of left ventricular pressure, and the peak measured velocity of shortening of the contractile elements). Further, the mean value of SUT in patients with impaired left myocardial function was significantly prolonged, compared to the control subjects; an overlap was apparent due to the fact that some of these patients showed a normal left myocardial performance at rest, having an abnormal response only to exercise tests. The apexcardiographic SUT can practically always be measured when the first derivative of apex tracing is simultaneously recorded. It showed itself to be only slightly influenced by the resting heart rate. The mentioned relationship of the systolic upstroke time of the ACG to internal isovolumic indexes of myocardial function makes this noninvasive measurable parameter an additional excellent tool for the evaluation of the left myocardial state, thus supporting a new aspect of the value of quantitative apexcardiography.
A new apexcardiographic time parameter is described which is definable as the interval between the beginning of the aortic component of the second heart sound and the protodiastolic negative peak of the first derivative of the apexcardiogram and called A2-min dA/dt. There was a significant inverse correlation between the parameter in question and the simultaneous minimal and maximal rate of rise of the first derivative of left ventricular pressure in 20 patients (r = -0.79, p less than 0.001, r = -0.60, p less than 0.01 respectively).
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.
A case of atrial parasystole is described in a 55-year-old female with multivalvular heart disease, treated with high doses of digitalis and showing first-degree av block. The left atrial origin of the parasystolic P waves was supported by their distinctive morphology, especially in lead V1, and the sequence of left and right atrial activation. Depending on the refractory state of the myocard, there was a greater shortening of the av conduction time during the parasystolic discharge than during sinus beats indicating a caudal localization of the parasystolic center.
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This study was undertaken to determine the prevalence and distribution of diastolic function abnormalities at rest and during isometric exercise in patients with systemic hypertension using the recently introduced handgrip-apexcardiographic test (HAT). It has been shown that HAT reflects left ventricular pressure changes in early (relaxation) and late (compliance) diastole. A HAT was obtained in 132 patients with systemic hypertension (duration >1 year) without history of congestive heart failure. A healthy group (n = 186) served as control subjects. Diastolic abnormalities were present at rest in 53/132 (40%) and during isometric handgrip stress in 92/132 (70%) patients. At rest the most frequent diastolic abnormality was the prolongation of relaxation time (27%) whereas an isolated increase in A wave was rare (8%). During isometric exercise, however, an elevation of A wave was the predominant abnormality (38%) whereas an isolated prolongation of relaxation time was less frequent (14%). Alternatively, an 'ischemic' pattern (abnormal prolongation of resting normal relaxation time during handgrip and/or abnormal as well as more than double increase of resting normal relative A wave to total height during or after handgrip) was observed in 29%. In 89% of these patients with an ischemic pattern of diastolic changes, a typical angina and/or positive stress ECG and/or angiographically proved coronary artery disease were present. Using HAT data the present study demonstrates for the first time that in patients with systemic hypertension: (1) diastolic abnormalities occur significantly more frequently during isometric stress than at rest, (2) the most frequently observed diastolic abnormality at rest is the relaxation time prolongation whereas during isometric stress the A wave elevation, and (3) patients with an ischemic pattern of exercise-induced diastolic abnormalities show frequently clinical or angiographic evidence of demand ischemia. Thus, HAT can become a useful additional diagnostic tool for detecting latent diastolic dysfunction and myocardial ischemia in this clinical setting.