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Biomedical subjects

A M Weissler

Publications and source records attributed to A M Weissler.

At least 37 records · Page 2Linked to original sources
PubMed1982

Value of positive myocardial technetium-99m-pyrophosphate scintigraphy in the noninvasive diagnosis of cardiac amyloidosis.

Ten consecutive patients with tissue-proven amyloidosis, seven of whom presented with congestive heart failure, were found to exhibit intense diffuse uptake of technetium-99m-pyrophosphate (Tc-99m-PYP) on cardiac radionuclide imaging. The patients exhibited echocardiographic and systolic time interval abnormalities suggesting combined restrictive and congestive cardiomyopathic changes. On M-mode echocardiograms, there was symmetrically increased thickness of the interventricular septum and left ventricular (LV) posterior wall in diastole (10 of 10), decreased fractional shortening of the LV minor axis diameter in systole (eight of nine), and decreased percent thickening of the LV minor axis diameter in systole (eight of nine) and LV posterior wall (10 of 10) in systole. Three patients demonstrated enlarged LV end-diastolic diameter. All 10 patients had abnormal PEP/LVET and eight had shortened LVETI. When combined with noninvasive tests of LV performance, positive myocardial pyrophosphate (PYP) scanning provides a new and useful adjunct in the diagnosis of amyloid heart disease.

Aged↗
PubMed1982

The QT greater than QS2 syndrome: a new mortality risk indicator in coronary artery disease.

In the normal population the duration of electrical systole (QT) is shorter (mean -26 +/- 13 ms, 1 standard deviation) than that of electromechanical systole (QS2), which it closely parallels throughout the range of resting heart rate. This close association prompted the hypothesis that the duration of QT may be more closely linked physiologically to QS2 than to the heart rate and hence may provide a more potent prognostic indicator than the relation of QT to heart rate. The present study was designed to test this hypothesis. On hundred stable patients 14 months after myocardial infarction were followed up an average of 43 months. Twenty patients had prolongation of QT relative to QS2 (QT greater than QS2) and 13 patients had long QT corrected for heart rate (QTc). There were 20 deaths (16 sudden). The cumulative 5 year survival rate was 35% in patients with QT greater than QS2 and 91% in patients with QT greater than or equal to QS2 (p less than 0.001). There was no significant difference in survival in patients with long QTc compared with patients with normal QTc (69 versus 82%). Univariate and multivariate analysis for the association of QT greater than QS2 with known risk factors, clinical descriptors, drug therapy, systolic time intervals (preejection period/left ventricular ejection time), and frequency of 1, 2 and 3 vessel coronary occlusive artery disease revealed that only the presence of abnormal preejection period/left ventricular ejection time added significantly to the presence of QT greater than QS2 in stratifying 5-year survival into high and low risk groups. Thus, in patients with coronary artery disease, the presence of QT greater than QS2 provides a new risk indicator that is more potent than QT corrected for heart rate.

Aged↗
PubMed1981

Natural history of electrical interventricular septal force in the course of left ventricular hypertrophy in man.

Initial electrical forces emanating from interventricular septal depolarization, being directed to the right and anteriorly, normally produce an initial negative deflection or Q wave in leads I, aVL and V6 and an initial positive deflection or R wave in leads V1 and V2. The observations of hypertrophied interventricular septum, an integral part of the left ventricle, in patients with left ventricular hypertrophy would predict an increase in these septal electrical forces similar to the total left ventricular (QRS) forces in these subjects. Contrary to this expectation, several studies document an actual decrease or absence of the normally oriented initial forces in ECGs of patients with the criteria of left ventricular hypertrophy. In order to clarify the nature of this paradox, this study was initiated. Our observations suggest that the normal initial septal forces indeed increase as expected, during the initial four to six years, and subsequently show a progressive decline in patients with left ventricular hypertrophy. Although the precise mechanism for the bimodal change in the septal forces during the period of the constancy of the total QRS forces is not clear, a hypothesis based on the current knowledge is advanced to explain these observations.

Adult↗
PubMed1981

Common cardiac arrhythmias: recognition and treatment.

Cardiac arrhythmias are commonly seen in the everyday practice of medicine by the physician. Although certain arrhythmias may be suspected clinically, precise diagnosis is made by electrocardiographic recording of the abnormal rhythm. Once the arrhythmia has been recorded, the next steps are proper electrocardiographic diagnosis and selection of proper treatment. The specific mode of therapy and the speed with which it is delivered will depend not only on the type of arrhythmia, but also on the hemodynamic consequences of the rhythm abnormality on the patient's cardiovascular system. The purpose of this paper is to discuss the electrocardiographic criteria of common cardiac arrhythmias as well as current concepts regarding therapy.

Arrhythmias, Cardiac↗
PubMed1979

Changes in diastolic time with various pharmacologic agents: implication for myocardial perfusion.

Diastolic time (DT) is calculated as the cycle length (RR) minus electromechanical systole (QS2). The ratio of DT (RR-QS2) to RR interval times 100, or the percent diastole (%D), varies nonlinearly with heart rate (HR), increasing rapidly with decreasing HR. The effect of commonly used cardioactive agents on %D was studied in five groups of normal subjects. In group 1 (n = 12), propranolol (160 mg daily) increased %D from 55.9 +/- 1.7 to 64.7 +/- 1.3 (p less than 0.001) by slowing HR. In group 2 (n = 12), dobutamine (2.5 micrograms/kg/min) increased %D from 56.4 +/- 1.4 to 61.8 +/- 1.3 (p less than 0.005) by shortening the QS2. In group 3 (n = 10), Cedilanid-D (1.6 mg i.v.) increased %D from 55.5 +/- 1 to 63.2 +/- 0.7 (p less than 0.001), both by slowing the HR and shortening the QS2. In group 4 (n = 12), isoproterenol (2 micrograms/min) increased HR and shortened the QS2 significantly. The net result was a significant reduction of %D from 56.1 +/- 1.4 to 53.5 +/- 1.1, (p less than 0.05). In group 5 (n = 15), a 100-mg bolus of i.v. lidocaine did not have a significant effect on %D. This study indicates that cardiovascular drugs may have significant effects on the relative duration of diastole either by affecting HR or the duration of systole. This may have clinical implications for patients with coronary artery disease and patients with left ventricular hypertrophy, since in both cases coronary flow in mostly diastolic.

Administration, Oral↗
PubMed1978

Atrial pacing for cardioversion of atrial flutter in digitalized patients.

To test the safety and reliability of atrial pacing as a conversion technique in patients with atrial flutter who are receiving digitalis therapy, atrial pacing conversion was attempted for 49 episodes of atrial flutter in 32 consecutive patients. All patients except one were receiving digitalis. To control ventricular rates most patients had received larger than usual therapeutic doses of digitalis glycoside before pacing. Fourteen of the 25 patients whose serum levels were measured had glycoside concentrations greater than 2 ng/ml. Before atrial pacing the mean atrial and ventricular rates were, respectively, 290 +/- 20.6 and 134 +/- 27.9/min (mean +/- standard deviation). Successful rhythm conversion was achieved on 48 occasions (98%) in 31 patients. One patient required transthoracic direct current synchronized countershock cardioversion. With atrial pacing, the atrial flutter rhythm reverted immediately to sinus mechanism in 23 instances, and there were 25 episodes of atrial fibrillation. Among those who experienced atrial fibrillation, the rhythm spontaneously reverted to sinus mechanism within 24 hours on 14 occasions; on 11 occasions; the rhythm reverted to atrial flutter and repeat pacing was required. Sinus mechanism was eventually established in all 31 patients.

Adult↗
PubMed1977

Comparative pharmacodynamics of betamethyl digoxin and digoxin in man.

The positive inotropic effects and serum glycoside levels following intravenous and oral administration of betamethyl digoxin (BMD) were measured and compared with those of digoxin in normal adults. The cardiac inotropy was assessed noninvasively in the abbreviation of the electromechanical systolic index (QS2I) obtained by serial measurements of systolic time intervals. Following 0.8 mg BMD intravenously, the QS2I abbreviation occurred within 3 min and reached a maximum at 4 hr. The time-course and the magnitude of the response were essentially the same as those obtained with 0.8 mg digoxin given intravenously in the same subjects. The serum glycoside levels were also similar for both drugs. When administered orally the QS2I abbreviation to 0.8 mg BMD appeared at 40 min and reached a maximum at 4 hr. The time-course and the magnitude of the effects were similar to those observed following oral digoxin. The blood digitalis levels following the drug ingestion, however, were significantly higher for BMD than for digoxin which suggests greater gastrointestinal absorption of BMD. Based on our observations, the inotropic effects of BMD are similar to those of digoxin. Our results, however, do not demonstrate greater cardiac activity after oral administration of BMD despite higher blood levels.

Administration, Oral↗
PubMed1977

Echocardiographic manifestations of ruptured aortic valvular leaflets in the absence of valvular vegetations.

The diagnosis of ruptured (perforated or torn) aortic valvular leaflets due to various causes has been made primarily at surgery or postmortem examination. Although angiocardiographic studies readily reveal aortic regurgitation, they rarely establish the presence of a ruptured aortic cusp as the cause of the aortic leak. Recent echocardiographic experience has brought to our attention seven patients with ruptured aortic valvular leaflets in whom the absenc of valvular vegetations was confirmed at surgery in six and at autopsy in one. The echocardiogram of the aortic root in these subjects revealed little or no increment in the diameter of the aortic root. In systole the usual box-like configuration of the leaflets, similar to that observed in normal subjects, was seen; however, in diastole the normal thin midaortic linear echoes were replaced by a thick band of echoes which often revealed high-frequency oscillations. In addition, high-frequency fibrations of the anterior mitral leaflet in diastole and increased systolic excursion of the interventricular septum and left ventricular posterior wall were observed.

Adult↗
PubMed1976

Left ventricular performance in coronary artery disease evaluated with systolic time intervals and echocardiography.

Simultaneous determinations of systolic time intervals (preejection period index [PEPI], left ventricular ejection time index [LVETI] and ratio of preejection period to left ventricular ejection time [PEP/LVET]) and echographic measures of left ventricular performance (percent change in minor axis diameter [%delta D], circumferential shortening rate [Vcf] and end-diastolic diameter [Dd]) were obtained in 25 normal subjects and 37 patients with previously documented transmural myocardial infarction. The group with previous infarction demonstrated significant (P less than 0.001) differences from the normal group in each of the noninvasive measures. PEP/LVET and %deltaD were the most sensitive measures of left ventricular dysfunction. Deviation from the normal range in these measures occurred, respectively, in 70 and 65 percent of patients without dyspnea or fatigability (20 patients) and 85 percent of those without angina pectoris (13 patients). Abnormalities in systolic time interval and echocardiographic measures were related to the severity of dyspnea and fatigability but not to that of angina. Neither the presence of phonocardiographically documented third or fourth sound gallops nor an abnormal cardiothoracic ratio by chest roentgenogram reliably detected patients with abnormal left ventricular performance. The range of abnormality in left ventricular performance did not differ between patients with prior anterior or diaphragmatic myocardial infarction. The frequency of abnormal performance was greatest among patients with combined sites of prior infarction. Among 26 patients studied by coronary arteriography, abnormal left ventricular performance as determined by values for PEP/LVET and %deltaD occurred in fewer than 30 percent of those with 70 percent or greater obstruction of one coronary artery and in more than 80 percent of those with two or three vessel involvement. There was a high correlation between systolic time intervals, %delta D and Vcf, the closest correlation occurring between PEP/LVET and %deltaD (r = -0.93). These data document the sensitivity of the noninvasive systolic time intervals and echographic measures and their superiority over current clinical bedside methods in evaluating left ventricular performance in patients with prior myocardial infarction.

Adult↗