Case Report: Efficacy of Oral Carnitine Therapy for Dilated Cardiomyopathy in Boxer Dogs

Abstract

This paper investigates the role of carnitine in the etiology and treatment of dilated cardiomyopathy in boxers. Two boxers were diagnosed as having dilated cardiomyopathy on the basis of clinical presentation, chest radiographs, electrocardiography and echocardiography. In one dog, carnitine was administered at 6.0 g (or ∼250 mg/kg live weight (LW) daily per os, and this dog remained asymptomatic for 4 mo until it presented for anorexia, coughing and weakness. Necropsy and histologic findings were consistent with boxer cardiomyopathy in both dogs. Cardiac carnitine concentration was 567 nmol/g wet weight in the unsupplemented dog, which is below the normal mean ± SD concentration of 1493 ± 141 nmol/g wet weight. Low cardiac carnitine concentrations appear to be a consistent finding for dilated cardiomyopathy in boxers. However, in the dog that received carnitine therapy, cardiac carnitine was 2802 nmol/g wet weight, and all tissues assayed in the supplemented dog had higher carnitine concentrations than normal dogs. Elevation of tissue carnitine failed to ameliorate dilated cardiomyopathy in this dog. Oral carnitine supplementation in these therapeutic doses appears not to resolve dilated cardiomyopathy in all boxers.