Brian P. Delisle, Circadian Regulation of Cardiac Electrophysiology

Abstract: Circadian rhythms in physiology and behavior are regulated by circadian clocks, ubiquitous molecular transcriptional-translational feedback loops that cycle with a periodicity of ~24 hours. Circadian clocks serve as cellular timekeepers regulating important cell-type specific functions. The phase of circadian rhythms and circadian clocks throughout the body are entrained to the light cycle by signals originating in the suprachiasmatic nucleus of the hypothalamus. The functional importance of circadian clocks in cardiomyocytes is underscored by the observation that genetic disruption of the circadian clock mechanism in mouse hearts alters the electrocardiogram (ECG), cardiac action potential, and size of individual ionic currents. This presentation discusses recent basic science studies showing how daily environmental, behavioral, and circadian rhythms impact cardiac electrophysiology and cardiac arrhythmogenesis at the systems, tissue, and molecular levels. These studies provide new insights into how daily environmental, behavioral, and circadian rhythms affect the timing of cardiovascular events, and they are starting to identify chronotherapeutic strategies that may mitigate the risk for cardiac arrhythmias.