CONGRESS ABSTRACT

A 56-year-old man was referred to our cardiomyopathy clinic by his primary care physician due to persistently low heart rate and suspected left ventricular hypertrophy (LVH) detected on a coronary CT scan performed for nonspecific chest pain. His cardiac history was otherwise unremarkable, except for a family history of sudden cardiac death in his father at the age of 50 under unclear circumstances.Holter ECG showed rare ventricular ectopic beats (VEBs) with a generally low heart rate. His resting 12-lead ECG revealed low QRS voltages and negative T waves in precordial leads V1-V4 and . Transthoracic echocardiography confirmed LVH, with a maximum septal thickness of approximately 14 mm. Coronary CT ruled out significant coronary artery stenosis.Given these findings, cardiac magnetic resonance imaging (CMR) was performed, confirming LVH and revealing mid-wall late gadolinium enhancement (LGE) in the basal septum and the inferolateral wall of the left ventricle. These findings raised suspicion of an infiltrative or genetically determined cardiomyopathy (“scarring” cardiomyopathy).Genetic testing identified a pathogenic mutation in the desmoplakin (DSP) gene. Given the autosomal dominant inheritance pattern of DSP mutations, family screening was initiated. The patient’s daughter was also found to carry the same mutation. Although her resting ECG showed a similar pattern of low QRS voltages and negative T waves, echocardiography did not reveal LVH. However, CMR detected right ventricular (RV) bulging and mid-wall LGE in the basal septum, suggestive of early-stage arrhythmogenic cardiomyopathy (ACM).This case illustrates an atypical presentation of arrhythmogenic cardiomyopathy (ACM) associated with a DSP gene mutation, characterized by left ventricular hypertrophy and low heart rate. The coexistence of LVH, negative T waves, and mid-wall LGE strongly suggested the possibility of a non-classic cardiomyopathy.The identification of the same mutation in the patient’s daughter, who exhibited a more typical ACM phenotype (RV bulging and septal LGE), highlights the wide phenotypic variability associated with DSP mutations. This variability underscores the importance of considering ACM even in patients presenting with LVH and low voltage on ECG, features more commonly associated with infiltrative or hypertrophic cardiomyopathies.