ABC | Volume 110, Nº2, February 2018

Anatomopathological Correlation Favarato & Benvenuti Cardiomyopathy with arrhythmia and syncope Arq Bras Cardiol. 2018; 110(2):195-200 Figure 1 – External view of the anterior face of the explanted heart. The epicardial fat is abundant, and a collapsed aneurysmal formation can be seen in the right ventricular outflow tract (asterisks). infiltration of the compacted portion of the right ventricular free wall in its inlet, apex and outflow tract was seen (Figure 2). The left ventricle showed moderate dilation and hypertrophy, with isolated foci of subepicardial fibrofatty infiltration (Figure 3). The microscopic exam confirmed the gross aspect of myocardial fatty infiltration, in addition to fibrosis (Figure 4). The most preserved areas of the myocardium showed hypertrophic cardiomyocytes, fibrosis foci, and interstitial mild lymphohistiocytic inflammatory infiltrate. The endocardium was thickened and whitish in the region of the aneurysmal formation of the right ventricular outflow tract. The heart valves and epicardial coronary arteries showed no abnormality. No cavitary thrombus was seen. (Luiz Alberto Benvenuti, MD) Anatomopathological diagnosis: arrhythmogenic right ventricular cardiomyopathy. (Luiz Alberto Benvenuti, MD) Comments The patient is a 36-year-old male with heart disease characterized by syncope episodes since the age of 20 years, cardiomegaly and ventricular dysfunction. He underwent cardioverter defibrillator implantation in 2001. His electrophysiological study evidenced scars and late potentials in several regions of the right ventricle, ventricular tachycardia being triggered during the exam in 2015. Because of progression of the ventricular dysfunction and heart failure, the patient underwent cardiac transplantation in 2016. The anatomopathological exam of the explanted heart revealed arrhythmogenic right ventricular cardiomyopathy, with marked fatty infiltration of the compacted portion of that ventricle, with aneurysmal formation in the outflow tract. In addition, there was impairment of the left ventricle, which showed foci of subepicardial fibrofatty infiltration. Arrhythmogenic right ventricular cardiomyopathy, also known as arrhythmogenic dysplasia, is a primary genetic cardiomyopathy, most commonly of dominant autosomal inheritance. Several mutations related to the disease have been identified, usually in genes encoding desmosomal proteins, the most known being the genes of desmoplakin and plakoglobin. It can be associated with Carvajal syndrome or Naxos disease (palmoplantar keratoderma/wooly hair). Arrhythmogenic right ventricular cardiomyopathy is a frequent cause of sudden death in young individuals, being the major cause of sudden death associated with sports activity in Italy. 8 The disease can be restricted to the right ventricle, with severe arrhythmias, but, in the forms of progressive heart failure, as the present case, the left ventricle is commonly affected. Because both ventricles can be affected, many people advocate the use of the term ‘arrhythmogenic cardiomyopathy’. The diagnosis of the disease is complex and multifactorial, and several elements should be considered, such as electrocardiographic changes, presence and type of arrhythmias, echocardiographic and magnetic resonance imaging changes, family history and even histological changes of the ventricular wall. Since 1994, and modified in 2010, there has been consensus about the diagnostic criteria, some considered major and others, minor. 9 Although invasive, endomyocardial biopsy is indicated in selected cases to assess myocardial histology, and myocardial fibrofatty infiltration is considered a major criterion when the residual myocardium corresponds to less than 60%, and a minor criterion when the residual myocardium corresponds to 60% to 75% of the sample. 10 (Luiz Alberto Benvenuti, MD) 198