Implantable Cardioverter Defibrillator in Arrhythmogenic Right Ventricular Cardiomyopathies

Abstract

In the present issue of Circulation , Wichter et al1 report the largest single-center experience demonstrating the benefit of implantable cardiac defibrillators (ICDs) in the treatment of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). The patients seem well defined, and they meet the task force criteria. In addition, 50 of 60 patients have had the diagnosis confirmed by endocardial biopsy. Advances in molecular biology and genetics, however, suggest that the term ARVC encompasses a large spectrum of diseases with similar clinical presentations and histological features. This was discussed in part in a previous editorial in Circulation .2 Recent information suggests that there is an overlap in the different forms of diseases included under the general term ARVC . See p 1503 The term right ventricular cardiomyopathy , which was introduced by the World Heart Federation and World Health Organization in 1996 in the new classification of cardiomyopathies, was selected to encompass arrhythmogenic right ventricular dysplasia (ARVD) and several other clinical entities, some of them known by a different name. In the classical article by Marcus et al,3 the term right ventricular dysplasia was taken from a book chapter on reentrant arrhythmias published in 1977.4 This work reported the results of antiarrhythmic surgery in young male patients with good left ventricular function who had ventricular tachycardia (VT) originating in the right ventricle. The term dysplasia was chosen because the right ventricle of 3 operated patients was covered by fat. The remaining myocardium was present only in the subendocardium. This striking feature, which suggested the replacement of myocardium by fat, was strengthened by microscopic examination that showed strands of cardiomyocytes bordered by or sometimes embedded in fibrosis or adipose tissue. It was suspected that myocardial replacement by fat and fibrous tissue started early in life, possibly in the …