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[Effects of Coxsackie B-2 virus infection on electrophysiologic properties of beating cultured rat heart cells].

Beating rat heart cell cultures were prepared in vitro and infected with Coxsackie B-2 virus. The cells were evaluated in the post infected period for changes in beating frequency, percentage of active cells and cytopathic effect (CPE), and for alterations of the electrical activity by standard intracellular microelectrode techniques. The beating frequency and percentage of active cells began to decrease in infected group at 24 h, and the beating percentage was less than 30% at 96 h after virus challenge. Meanwhile the CPE appeared rapidly from 1+ to 3+. In contrast, the beating percentage was 95% and no CPE was shown in the control group. Decrease of maximum diastolic potential (MDP), maximum upstroke rate (Vmax) and overshoot (os) and amplitude (APA) of action potential, and shortened action potential duration (APD50 and APD100) were found 24 h after infection. Multiform arrhythmias occurred commonly during the experiment. Complete loss of cardiac electrical activities and maximal CPE occurred at 96 h post-infection. Our findings may be useful for the study of pathogenesis and treatment of viral myocarditis in human being.