cardiovascular disorders
Arrhythmogenic Right Ventricular Cardiomyopathy
Diagnosis of ARVC
ECG and signal-averaged ECG Cardiac imaging (eg, echocardiography, cardiac magnetic resonance imaging, right ventricular angiography) Sometimes right ventricular biopsy Genetic testing Screening of first-degree family members Diagnosis of arrhythmogenic right ventricular cardiomyopathy is difficult in the absence of advanced right ventricular systolic dysfunction, leading to historic under-recognition of the disorder. ARVC should be suspected particularly in young patients with palpitations, cardiac syncope, documented ventricular tachyarrhythmias, or resuscitation from unexplained cardiac arrest in the absence of clinically evident structural heart disease. The diagnosis of ARVC is often first suspected when it is recognized that the patient's ventricular arrhythmias are of right ventricular origin, typically indicated by a left bundle branch block–shaped QRS complex with a superior frontal plane axis (the latter helping to differentiate ARVC from the more benign idiopathic right ventricular outflow tract ventricular tachycardia, which usually has an inferior frontal plane QRS axis). Patients should have ECG, signal-averaged ECG, echocardiography, and cardiac MRI. If no spontaneous ventricular arrhythmia has been demonstrated, exercise testing, ambulatory ECG monitoring, and/or electrophysiologic testing may be required. Right ventricular angiography is not routine but, if done, may reveal characteristic structural abnormalities and also allow biopsy of the right ventricle; however, biopsy findings are often nonspecific. Because no single test is diagnostic, major and minor diagnostic criteria have been proposed by an international task force ( Diagnosis reference ). The criteria include Evidence of right ventricular disease on imaging studies Right ventricular biopsy showing replacement of myocytes by fibrous tissue, fatty tissue, or both ECG repolarization changes including right precordial T-wave inversion ECG depolarization changes including right precordial epsilon waves Signal-averaged ECG showing late potentials Documented ventricular arrhythmias originating from the right ventricle Family history of ARVC or sudden death Identification of a gene mutation associated with ARVC Genetic testing is usually done in patients suspected of having ARVC. The yield of testing is about 60% when task force criteria are met. First-degree family members of patients have a significant risk of disease. Starting at age 10 to 12 years and every 1 to 3 years thereafter, they should have clinical evaluation (ie, to detect symptoms suggestive of arrhythmia), ECG, ambulatory ECG monitoring, and echocardiography. Genetic testing is done if the index case has a mutation identified. Family members without the index mutation are then freed of follow-up investigations. 1.Marcus FI, McKenna WJ, Sherrill D, et al: Diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia: proposed modification of the task force criteria.Eur Heart J31;806–814, 2010. doi: 10.1093/eurheartj/ehq025 