Long-term outcomes of subcutaneous implantable cardioverter-defibrillators: a single-centre Australian experience.

Background: The subcutaneous implantable cardioverter-defibrillator (S-ICD) has become an established alternative to overcome conventional transvenous ICD (TV-ICD) lead-related complications.

Objective: To describe the long-term outcomes of S-ICD implantation at a single Australian institution.

Methods: We retrospectively reviewed the clinical outcomes of consecutive patients who underwent S-ICD implantation from 2015 to 2019.

Results: In total, 128 patients (median age 52.5 years, 70% male) underwent S-ICD implantation. The indication was primary prevention in 86 patients (66%), and 22 patients (17%) had a previous transvenous device. Seventy-seven patients (60%) had heart failure, and the median left ventricular ejection fraction was 36% (29%-60%). The procedure was performed under general anaesthesia in 124 patients (97%), and the median procedure time was 105 min (interquartile range (IQR) 90-120). During a median follow-up of 4.7 years (IQR 3.8-5.8), 15 patients (12%) died, none of which were due to sudden death or device-related complications. Inappropriate shocks occurred in 17 patients (13.3%), predominantly due to T-wave oversensing (4.7%) and supraventricular arrhythmias (4.7%), and 15 patients (11.7%) received appropriate shocks. During the follow-up period, the S-ICD system was revised to TV-ICD in 10 patients (8%), and 24 patients (19%) required S-ICD generator change. Four patients (3%) underwent surgical intervention due to lead (two) or pocket-related (two) complications, and two patients (1.5%) developed pocket infection without systemic sepsis.

Conclusions: In this single-centre study, S-ICDs were implanted safely with acceptable device performance and clinical outcomes over long-term follow-up.