Complex Rhythms Resulting From Overdrive Suppression in Electrically Stimulated Heart Cell Aggregates

Authors


  • This work was supported by Canadian Heart and Stroke Foundation, and the Natural Sciences Engineering and Research Council of Canada. Zeng Wanzhen is a recipient of a postdoctoral fellowship from the Canadian Heart and Stroke Foundation.

2 Department of Physiology, McGill University, 3655 Drummond Street, Montreal, Quebec, Canada, H3A 1Y6

Abstract

WANZHEN, Z., ET AL.: Complex Rhythms Resulting From Overdrive Suppression in Electrically Stimulated Heart Cell Aggregates. Spontaneously beating embryonic chick heart cell aggregates were stimulated with current pulses delivered either as periodic trains, or at a fixed delay after each action potential. Following Stimulation at fixed rates faster than the intrinsic rate, there was a transient slowing of the spontaneous rhythm. This response, called overdrive suppression, can lead to a complex evolution of rhythms. During periodic stimulation there is a continuum of dropped beat patterns, and during fixed delay stimulation bursting activity appears. This study provides a conceptual basis for understanding analogous rhythms in the intact heart.

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