THE EFFECT OF REPETITIVE STIMULATION UPON THE DURATION OF THE ELECTRICAL RESPONSE OF VENTRICULAR MUSCLE

Abstract

The experiments reported were made on ventricular strips of turtle heart. The strength of stimulation selected was 5 to 10% above threshold at the beginning of the experiment. The chief changes seen in the electrogram as the result of continuous stimulation are a slowing of conduction and a shortening of the R-T interval. The rate of stimulation of the strip determines the rate at which these changes occur. These changes are recovered from more or less completely during resting periods. Treppe may be observed as regards conduction and duration of the sustained electrical response. Treppe is manifested by a shortening of the conduction time and a lengthening of the period of electrical response for a few beats. A short discussion of the effects of temperatures on the treppe of the R-T interval is given.