Electrocardiographic changes following rabbit coronavirus-induced myocarditis and dilated cardiomyopathy.

Rabbit Coronavirus (RbCV) infection was divided into two phases based upon day of death and pathologic findings. During the acute phase (days 2-5) heart weights (HW) and heart weight-to-body weight (HW/BW) ratios were increased with striking dilation of the right ventricle. These changes as well as increased dilation of the left ventricle were especially pronounced during the subacute phase (days 6-12). Myocytolysis, pulmonary edema, and degeneration and necrosis of myocytes, were seen during both phases. Myocarditis, pleural effusion, calcification of myocytes, and congestion in the liver and lungs were seen in the subacute phase. Electrocardiograms (ECGs) exhibited low voltage, nonspecific ST-T wave changes, sinus tachycardia, occasional ventricular and supraventricular premature complexes and 2(0) AV block consistent with myocarditis and heart failure. Forty-one percent of the survivors exhibited increased HW and HW/BW ratios, biventricular dilation, interstitial and replacement fibrosis, myocyte hypertrophy and myocarditis. ECGs exhibited nonspecific ST-T wave changes, sinus arrhythmia, occasional ventricular and supraventricular premature complexes and 2(0) AV block. These data suggest that RbCV infection may result in viral myocarditis and heart failure with a proportion of survivors progressing into DCM.