Dilated heart disease screening in UK Great Danes

Abstract

BACKGROUND: Great Danes (GD) are predisposed to dilated cardiomyopathy (DCM), but little is known about progression, clinical manifestations, or inheritance in dogs in the UK. For echocardiographic screening, breed-specific reference intervals (RI) are required. OBJECTIVES: To document the prevalence, clinical manifestations, and inheritance of DCM in UK GD. To establish RI for Doppler echocardiography (ECHO) in GD. ANIMALS: One hundred and seven client-owned GDs. METHODS: Echocardiographic screening study. Dogs were scored on ECHO and ECG variables and classified as normal (NORM), equivocal (EQUIV), or affected (AFX). Forty NORM dogs were used to determine RI for ECHO. Pedigrees from all dogs were examined for mode of inheritance. RESULTS: The prevalence of DCM in this population, based on score, was 35.6%. Significant differences in M mode left ventricular dimensions (MMLVD) were identified between male and female dogs (P < .011). RI for MMLVD and transformed MMLVD (allometric scaling) were lower than previously suggested. When dogs were reclassified using amended RI for MMLVD, prevalence increased to 47%. End-systolic volume index more reliably identified AFX dogs than other systolic function indices. Ventricular arrhythmias (VA) were commonly identified, with the highest prevalence in AFX dogs (54%). Pedigree analysis suggested an autosomal dominant mode of inheritance. CONCLUSIONS AND CLINICAL IMPORTANCE: The prevalence of DCM in UK GD is higher than previously reported and autosomal dominant inheritance is likely. Sex or body weight-dependent RI should be used for ECHO in GD and current RI might underestimate ESVI in GD. VA might play an important role in GD with DCM.