Recent evidence that the disease is familial and that early intervention may increase survival has lead to significant
interest in screening asymptomatic dogs for signs of early disease. Annual echocardiography and ambulatory
electrocardiography (Holter monitoring) are believed to be the best predictors of early DCM. Criteria that are believed to be
indicators of early disease include a left ventricular diastolic dimension of greater than 4.6 cm and a systolic dimension of
3.8 cm even without evidence of systolic dysfunction.