Arrhythmogenic right ventricular cardiomyopathy in boxers.

Arrhythmogenic right ventricular cardiomyopathy, formerly termed boxer cardiomyopathy, is a familial primary myocardial disease that is prevalent in boxers. Unique histopathologic changes in the myocardium lead to conduction abnormalities that typically manifest as ventricular tachyarrhythmias with left bundle branch block morphology. Affected dogs can be asymptomatic or may have syncope and/or exercise intolerance. Diagnosis can be difficult, and indications for antiarrhythmic therapy are not always clear. A small number of dogs present with systolic dysfunction and/or congestive heart failure. Screening in asymptomatic breeding dogs was difficult until the recent development of genetic testing.