Clinical and pathologic findings in Doberman pinschers with occult cardiomyopathy that died suddenly or developed congestive heart failure: 54 cases (1984-1991).

To determine echocardiographic, electrocardiographic, and histologic abnormalities in Doberman Pinschers with occult cardiomyopathy that died suddenly and to compare findings with those of Doberman Pinschers with cardiomyopathy that died of congestive heart failure. Retrospective study. 14 Doberman Pinschers with occult cardiomyopathy that died suddenly (group 1) and 40 Doberman Pinschers with cardiomyopathy and congestive heart failure (group 2). Serial echocardiography and continuous, ambulatory electrocardiographic (Holter) monitoring were performed. Hearts of dogs that died suddenly were examined histologically. Group-2 dogs died at a significantly older age than did group-1 dogs. All dogs had echocardiographic abnormalities, but changes were more severe in group-2 than in group-1 dogs. Ventricular tachyarrhythmias were documented in all dogs. Group-1 dogs were more likely to have episodes of sustained ventricular tachycardia than were group-2 dogs. Multifocal interstitial fibrosis and replacement of muscle fibers with collagen and fat were consistently observed in hearts from dogs that died suddenly. Ten group-1 dogs had received antiarrhythmic treatment prior to death. Occult cardiomyopathy can be identified by means of echocardiography and Holter monitoring in Doberman Pinschers. Doberman Pinschers with cardiomyopathy that had episodes of sustained (> 30 seconds) ventricular tachycardia were at risk of dying suddenly.