Canine dilated cardiomyopathy. Part 1: screening, diagnosis and management of preclinical DCM

Background: Canine dilated cardiomyopathy (DCM) is a disease of the myocardium classically characterised by progressive eccentric hypertrophy (dilation) and systolic dysfunction of typically the left ventricle; however, DCM can also manifest as electrical abnormalities resulting in arrhythmic forms of the disease. The aetiology is idiopathic and there is often a genetic basis, which explains its over-representation in certain breeds. Preclinical DCM describes the usually protracted period where an individual dog experiences structural changes over several years, or an arrhythmia (in specific breeds) that meet criteria for diagnosis without outward clinical signs of disease. Detection of this phase is crucial to facilitate early intervention with medical treatment, close monitoring and prognostication. Clinical DCM describes progression to congestive heart failure; the management of this will be discussed in the second part of this series, to be published in a subsequent issue of In Practice.

Aim of the article: This article discusses case selection for DCM screening, including the utility of cardiac biomarkers. It outlines the echocardiographic diagnostic criteria for preclinical DCM, as well as the identification of arrhythmias that may be primary in nature or associated with the presence of cardiac remodelling. The medical management of preclinical DCM and associated arrhythmias is also discussed.