Circadian changes in cardiac rhythm structure in decompensated chronic heart failure.
Circadian changes in heart rhythm structure were studied in rats with decompensated heart failure (experimental group) using the telemetric system for ECG recording and analysis. Analysis of many-day ECG records showed the predominance of various mechanisms of heart rhythm regulation in experimental and control rats throughout 24 h. More severe dysfunction of neuroautonomic mechanisms of regulation in experimental rats was characterized by a circadian dynamics. Many-fold increase in the number of QTc intervals longer than 220 msec and the Tpeak-Tend, most pronounced in experimental animals at night and in the morning, indicated the maximally high risk of fatal ventricular arrhythmias, leading to sudden cardiac death.
Department of Human and Animal Anatomy and Physiology, Moscow Pedagogical State University, Moscow, Russia, mamalyga_49@mail.ru.
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D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology; D002908:Chronic Disease; D057906:Circadian Clocks; D016757:Death, Sudden, Cardiac; D006333:Heart Failure / Q000503:physiopathology*; D008297:Male; D009200:Myocardial Contraction; D017208:Rats, Wistar