Arrhythmogenic right ventricular cardiomyopathy: a challenging disease of the intercalated disc.

A 52-year-old male patient, a former competitive athlete, was admitted to the hospital because of recurrent episodes of palpitations and presyncope, which occurred while he was running in the course of the previous 12 months. Family history was significant for a first-degree cousin who received an implantable cardioverter-defibrilla-tor (ICD) at 38 years of age because of an unclassified cardiomyopathy. An initial resting 12-lead ECG showed sinus rhythm at a heart rate of 57 beats per minute with an atypical right bundle-branch block, extensive notching of the QRS complex in leads V1 to V3, visible late potentials (resembling epsilon waves) in the inferolateral leads, T-wave inversions in leads V1 to V4, and one ventricular beat with left bundle branch block morphology and superior axis as well (Figure 1, top). Exercise testing induced a sustained ventricular tachycardia (VT) at a rate of 200 beats per minute with left bundle-branch block morphology. Ischemic heart disease was ruled out by coronary angiography. Transthoracic echocardiography (TTE), cardiac magnetic resonance (CMR), and right ventricular (RV) angiography demonstrated RV dilata-tion, a reduced RV function with wall thinning, and akinesis/dyskinesis of the RV apex, inferior wall, and the subtricuspid area (white arrows), and late gadolinium enhancement within the RV and left ventricular (LV) lateral wall, as well (Figure 2). Subsequently, an electrophysiological (EP) study including high-density electroana-tomic voltage mapping was performed with the induction of a nonsustained VT with left bundle-branch block morphology and superior axis (Figure 1, bottom) at a rate of 230 beats per minute. Electroanatomic voltage mapping demonstrated low-voltage areas and scar within the RV corresponding to the regional wall motion abnormalities (Figure 3). Endomyocardial biopsies taken from the RV septum revealed some fibrotic infiltration surrounding the myocytes. Genetic testing yielded a severe heterozygous mutation of des-moplakin at position E1181, resulting in a premature stop codon and trunca-tion of the protein desmoplakin.