Appropriate and Inappropriate Implantable Cardioverter Defibrillators Therapies in Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia Patients

Abstract

BackgroundArrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is an inherited cardiomyopathy characterized histologically by the replacement of ventricular myocardium with fibrous and fatty tissue, and clinically by ventricular tachycardia arrhythmias primarily of right ventricular (RV) origin. Implantable cardioverter defibrillator (ICD) is the only proven therapy to reduce mortality in ARVC/D patients. However, it has the risk of inappropriate anti-tachycardia pacing (ATP) or shocks. This study aimed to assess the occurrence of appropriate and inappropriate ICD therapies in ARVC/D patients who underwent ICD implantation in a single Cardiac Centre.MethodsRetrospective analysis of the data of patients with the diagnosis of ARVC/D based on the 2010 revised Task Force Criteria, who underwent ICD implantation in the Heart Centre, at King Faisal Specialist Hospital and Research Center (KFSH&RC), Riyadh between January 1997 and May 2016. 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).ResultsTwenty-two ARVC/D patients with ICD implantation (20 males (91%), mean age at ICD implantation: 32 ± 14 years). ICD was implanted for secondary prevention of sudden cardiac death (SCD) in 15 patients (68.2%), and for primary prevention in 7 patients (31.8%). At mean follow-up of 9.4 ± 4.8 years, 11 patients (50%) had appropriate ICD therapies, and five patients (22.7%) had inappropriate ICD therapies. Out of 950 ICD therapies, 865 (91%) were appropriate (586 episodes of VT/VF treated with ATP (61.3%), and 279 episodes treated with shocks (29.37%)) and 85 (9.4%) were inappropriate (45 episodes treated with ATP (4.73%), and 40 treated with shocks (4.21%)).ConclusionARVC/D patients are at risk of VT/VF arrhythmias. ICD therapy is the only proven life-saving therapy in those patients. Most of ICD therapies in our patient’s population are appropriate, and ATP therapy is effective in terminating most of VT episodes. Although we do not have any patient with subcutaneous ICD, the high success rate of ATP suggests that transvenous ICD would be more appropriate in ARVC/D patients.

Clinical impact of defibrillation testing in a real‐world S‐ICD population: Data from the ELISIR registry

“…This latter is estimated as the difference between the device's maximum output and the energy required to terminate VF during testing, being assumed as at least 15 J in clinical experiences available to date 13,16,18 . In TV‐ICD recipients instead, a 5‐J safety margin was demonstrated as effective as a larger one when a true defibrillation threshold is attained by a strict testing protocol, 19,20 while testing VF termination resulted hardly meaningful in the setting of a large safety margin 5,6,8 . Indeed, there is convincing evidence that S‐ICD safety margin is larger than expected, conversion rate at ≤40 J approaching 90% in three recent studies collecting about 400 patients 13,14,21 .…”

“…On the contrary, current evidence assessing the long‐term safety of a similar strategy for S‐ICDs is limited, and the current expert consensus still recommends systematic DT during implantation of S‐ICDs 7 . However, since their publication in 2015, no updates have been issued, while several real‐world experiences of patients undergoing S‐ICD implantation without DT have been reported 8–10 …”

A Low Critical Event Rate Despite a High Abnormal Event Rate in Patients with Cardiac Implantable Electric Devices Followed Up by Remote Monitoring

“…In patients with Brugada syndrome, it is reported that in addition to ICD therapy, adverse events, such as inappropriate ICD therapy, lead failure, or infection often occurred (25, 26). In patients with arrhythmogenic right ventricular cardiomyopathy, it is also reported that critical events associated with ICD are likely to occur (27, 28). However, no previous reports have compared the critical event rates among these groups.…”

Ventricular arrhythmia management in patients with genetic cardiomyopathies

“…A study of 22 ARVC patients with ICD in situ with 950 ICD therapies over follow-up of approximately 9 years found 61.3% of VA episodes were treated with ATP, with about 95% of these therapies found to be appropriate. 83 Dual-chamber transvenous systems may aid discrimination of atrial arrhythmias but are associated with a higher incidence of complications, with Task Force guidelines recommending single-chamber devices. 80…”