Kalman Greenspan

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Conventional intracellular recordings from the bundle of His and right bundle branch of the canine heart demonstrated that the slope of diastolic depolarization is markedly depressed by superfusion with relatively small concentrations (4—8 jug/ml) of acetylcholine. As the cells become less automatic, take-off potential increases, rise time of phase 0 is(More)
The effects of aprindine and lignocaine (lidocaine USP) were compared on intracellularly recorded potentials from normal canine conducting tisues. Only aprindine produced marked depression of the maximum rate of rise (Vmax) of action potentials elicited at normal cycle lengths (1000 ms). Both compounds, however, produced enhanced depression of Vmax at short(More)
The rate of oxygen uptake of quiescent papillary muscle of the cat heart has been determined in a flow respirometer with the use of the oxygen electrode. The apparent rate of oxygen uptake as a function of the diameter of the muscle was also determined. It was found that papillary muscles from cat hearts use oxygen at a rate of 2.84 (microliters/mg. wet(More)
• Recent observations on the isolated rabbit heart and in the intact dog have indicated that potassium (K) is antagonistic to the action of acetylcholine (ACh) on atrioventricular (A-V) transmission. Both groups of investigators reported that A-V block induced by ACh was abolished by K. Furthermore, it has been demonstrated in human subjects with varying(More)
A series of experiments were performed upon intact anesthetized dogs to determine the relevance of a variety of hemodynamic variables to the irregular ventricular performance associated with atrial fibrillation. During experimentally induced atrial fibrillation central aortic pulse pressure was measured in relation to the duration of the preceding diastolic(More)
• The mechanism of cardiac arrhythmias induced by digitalis compounds has been investigated recently by the microelectrode technique. Coraboeuf et al. found that the automaticity of the canine "tissu nodal" was enhanced by administration of digitalis. This finding was confirmed by Dudel and Trautwein for canine Purkinje fibers. Also, the action of(More)