Ventricular Arrhythmia Ablation in Inherited Cardiomyopathy: Phenotype Variability and Outcomes Based on Functional Genotypes

Background Inherited cardiomyopathies cause ventricular tachycardia (VT) and heart failure, yet genotype‐based substrate characterization is limited. Methods Patients with inherited cardiomyopathy undergoing VT (n=80) or premature ventricular complex (n=25) ablation between 2010 and 2024 were evaluated for arrhythmia substrate, ablation, and heart failure outcomes. Results Among 105 patients, the median age was 51 years, 72% were men, and the cohort comprised desmosomal (desmoplakin [DSP], 11%; non‐DSP, 24%), titin (22%), lamin A/C (LMNA; 20%), sarcomeric (14%), ion‐channel (5%), and cytoskeletal/Z‐disk (4%) genotype groups. In the VT cohort, low‐voltage substrate was predominantly septal in the LMNA (55%), titin (67%), and sarcomeric (75%) groups; both septal (75%) and lateral left ventricle (75%) in the cytoskeletal/Z‐disk group; perimitral (71%) and lateral left ventricle (57%) in the DSP desmosomal group; and right ventricular free wall (91%) in the non‐DSP desmosomal group. Ablation eliminated clinical VT in 90%, with noninducibility of any VT in 52 of 80 (65%) cases. VT‐free survival was 51% during 3 years (1.8–6.3 years). Among recurrences, 11 of 39 (28%) patients had a single VT episode. VT‐free survival was highest in the non‐DSP desmosomal group and lowest in the LMNA group (66% versus 20%, P =0.03). Residual VT inducibility (hazard ratio [HR], 2 [95% CI, 1.05–3.77]) and LMNA variant (HR, 2.25 [95% CI, 1.1–4.57]) predicted recurrence. In the premature ventricular complex cohort, the burden decreased from 12% (interquartile range [IQR]=Q3–Q1, 21–8) to 3.75% (IQR 3–1, 6–1), and 17 of 25 (68%) had ≤5% burden. End‐stage heart failure outcome (left ventricular assist device, transplant, or death) occurred in 29% overall and 52% in the LMNA group. Conclusions Genotype correlates with VT substrate. Ablation successfully reduced VT and premature ventricular complex burden; however, long‐term VT recurrence was common except in non‐DSP desmosomal variants. LMNA variants portend worse outcomes.