Intraventricular conduction abnormalities in patients with clinically suspected myocarditis are associated with myocardial necrosis.

Twenty-nine patients with suspected myocarditis, either with or without intraventricular conduction abnormalities, were investigated for degree of myocardial necrosis by antimyosin scintigraphy. Among those 29 patients, 16 had intraventricular conduction abnormalities. Antimyosin scans were analyzed for heart/lung ratios and semiquantitative visual uptake scores (0 to 4+ scale). Of the 16 patients with conduction abnormalities, 15 (94%) demonstrated visual antimyosin uptake versus 7 (54%) of 13 cases without conduction abnormalities (p < 0.03). In addition, the heart/lung ratios and uptake scores were significantly higher in the group with conduction abnormalities than in the group without (1.64 +/- 0.31 vs 1.39 +/- 0.20, p < 0.03; and 2.3 +/- 0.7 vs 1.4 +/- 0.7, p < 0.005; respectively). In conclusion, intraventricular conduction abnormalities in patients with suspected myocarditis were more strongly associated with active and more severe myocardial necrosis as judged by antimyosin imaging than patients with normal electrocardiograms.