Implantable cardioverter defibrillator in arrhythmogenic cardiomyopathy: which role for antitachycardia pacing?

Abstract

Funding Acknowledgements Type of funding sources: None. Background Arrhythmogenic Cardiomyopathy (ACM) is an inherited cardiomyopathy characterized by ventricular arrhythmias and sudden cardiac death. Implantable cardioverter defibrillator (ICD) remains the only proven therapy to reduce mortality in ACM. Purpose The objective of this study was to identify characteristics of ventricular arrhythmias and treatment in patients with ACM. Method Retrospective analysis of the data of consecutives patients with confirmed diagnosis of ACM based on the proposed Padua Criteria, who underwent implantation of transvenous ICD from January 1992 and October 2021. The clinical data and information about appropriate and inappropriate ICD therapies were obtained from medical records with the review of the available intra-cardiac electrograms (EGMs). Results We enrolled 52 patients (69% males, mean age at implant 48.9 ±14.8 years), 27 (52%) were implanted for primary prevention, 25 (48%) for secondary prevention. After a median follow-up of 7.52 years [IQR: 4.37 - 12.0], 32 patients (61.5%) had 914 sustained episodes of ventricular arrhythmias (VA). 25 patients (48%) had 309 episodes of life-threatening arrhythmias (LT-VA), defined as sustained ventricular tachycardia ≥200 beats/min. In 29/32 patients (91%) ATP treated at least one episode of VA and in 14/25 (56%) at least one episode of LT-VA. Ventricular tachycardia (VT) detection was programmed at least 20 seconds, while VF detection was at least 7 seconds. Among patients with appropriate ICD activation, the first treated episode was a LT-VA in 50% of cases. Out of 914 VA episodes, 735 (80.4%) were treated with ATP and 179 (19.6%) with shocks. Considering LT-VA (cycle length 248 ± 25 ms), 201/309 (65%) and 108/309 (35%) episodes were treated with ATP and shocks, respectively. In 13 patients (25%) there was an inappropriate ICD activation, mostly caused by atrial fibrillation, while in 8 patients (15%) there was a complication needing reintervention (in 3 cases there was a loss of ventricular sensing dictating lead revision). Conclusions ACM patients are at risk of VA and LT-VA. The majority of VA at follow-up are monomorphic at rate <200 beats/minute, however the first treated VA episode is a LT-VA in half of cases. ATP is highly successful in terminating VT and even LT-VA, which questions the use of non-transvenous ICD in this young patient population. Nevertheless, transvenous ICDs are burdened by a relevant rate of lead complications which should be weighed in the choice of the ICD type.