Phenotypic characteristics of patients with arrhythmogenic left ventricular cardiomyopathy and sustained ventricular tachycardias

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The Padua criteria proposed for the diagnostic approach to Arrhythmogenic Cardiomyopathy (AMC) introduced new diagnostic criteria to recognize patients with a phenotype of the left ventricular variants of AMC (ALVC). Unlike ARVC, the arrhythmogenicity of this left phenotype has not yet been established. Objectives This study aims to analyze the phenotypic characteristics in a group of patients with ALVC and ventricular arrhythmias (VA). Methods Thirty-seven related patients with ALVC and VA were included and these were evaluated at the Inherited Cardiac Disease Unit of a Tertiary Hospital. Results Between 2000 and 2021, a total of 207 patients were diagnosed with ALVC. Thirty-seven patients (18%) presented VA; 25 ( 67%) sustained ventricular tachycardia (SVT), 10 ( 27 %) non sustained ventricular tachycardia (NSVT) and 2 ventricular fibrillation (VF). Eighteen 18/37 (49%) biventricular and 19/37 (51%) dominant . Twenty-five, 67 % male, aged 41.8 ± 13.4 years. A genetic study was performed in 36 ( 97%), and the pathogenic mutations were identified in desmoplakin in eighteen, plakophilin-2, desmoglein-2 and phospholamb in three, titin and filamine in two; desmin, plakoglobin and lamin A in one. There was one variant of uncertain significance in desmocollin-2, desmoplakin and titin. A low amplitude QRS voltages (LAQRS) in limb leads was present in 14/33 patients . Inverted T waves in right (V1-V3) in 4/33 patients and in left precordial (V4-V6) were present in 9/33 patients. The average left ventricular ejection fraction (LVEF) was 41%± 14 and myocardial fibrosis evidenced by contrast-enhanced CMR as LGE was presented in 22 patients. Ventricular arrhythmias with a right bundle branch block (RBBB) morphology were most frequent (7/12 ), denoting the origin from LV. All VT with LBBB morphology appeared in biventricular cases (5/12). Reverse pattern break was present in three patients. EAM showed bipolar or unipolar endocardial scar left ventricle in 6/10 and bipolar or unipolar endocardial scar right ventricle in 3/10 patients. Epicardial scar was present in 4 patients ( 3 LV, 2 RV). An implantable cardioverted defibrillator (ICD) therapy was performed in 25 patients for primary or secondary prevention of sudden death. Heart transplantation was carried out for three patients. Conclusions A substancial number of patients with ALVC have presented ventricular arrhythmias. Ventricular arrhythmias with a right bundle branch block (RBBB) morphology were the most frequent. All of VT with LBBB morphology appeared in biventricular cases. The mutation in DSP was the most prevalent in patients with ALVC and VT. Patients with ALVC and VA are characterized by a ventricular function that is not significantly impaired; however, fibrosis in LGE is widespread.