102-04: Performance and Outcomes in Patients with the Subcutaneous Implantable Defibrillator Through Mid Term Follow-Up: The EFFORTLESS Study

Purpose: The S-ICD was developed to cardiovert ventricular arrhythmias without the need for intracardiac leads. EFFORTLESS is the largest S-ICD registry in the world, reporting on real-world outcomes of pts implanted with an S-ICD during a 5 yr follow-up. This is the first report on the fully enrolled EFFORTLESS cohort. Method: EFFORTLESS enrolled 985 pts at 42 sites in 10 European countries implanted from Aug 2009-Dec 2014. Pre-defined endpoints are 30 and 360 day complications, and shocks for AF/SVT. Appropriate and inappropriate episodes are reported by the site and classified by the sponsor event committee. All follow-up for at least 360 days were recorded through the last visit in Jan 2016 and at least once annually up to 60 months. Summary: Follow-up time was at least 1 yr for all pts, avg 3.1 ± 1.5 yrs, and 5 yrs in 8% of pts. Mean age was 48 yrs, 28% were female, LVEF was 44 ± 18%, and 65% of pts had a primary prevention indication. Etiology was ischemic in 31%, channelopathy 19%, HCM 12%, non-ischemic 10%, dilated cardiomyopathy 9%, idiopathic VF 6%, ARVD 3.5%, valvular disease 2.3%, congenital 2.1%, and other in 5.3% of pts. Device extraction occurred for infection in 24 (2.4%), need for ATP in 5 (0.5%), failed conversion at implant in 4 (0.4%), and bradycardia pacing need in 1 (0.1%). There have been no reports of lead failure or endocarditis to date. Complication free rate was 95.9% at 30 days, 91.7% at 360 days. From the first to the last quarter of implants, the 1 yr complication free rate improved from 88.7% (Q1), to 92.2% (Q2), 93.4% (Q3), and 92.6% (Q4) (trend test p = 0.12, Q1 vs Q2-Q4 p = 0.06). Inappropriate shocks (IAS) occurred in 11.7% of pts over the 3.1 yrs mean follow-up (annual rate 3.7%); for AF/SVT in 2.3% of pts, T wave oversensing in 4.4%, other cardiac oversensing in 3.4%, and EMI in 2.2%. 54 pts (5.5%) had >1 IAS. The 1 & 5 yr KM rate of freedom from IAS was 91.7% and 85.3%. 104 pts (10.6%, annual rate 3.4%) had 278 appropriately treated episodes including 86 storm episodes; 131 MVT in 58 pts, 147 PVT/VF in 61 pts, 22 pts (2.2%) had >1 MVT treated episode. One and 5 yr KM rate of appropriate shock was 5.8% and 13.5%. Total conversion success for discrete spontaneous episodes was 97.4% with 88.5% converting on the first shock. 99.5% of pts with testing at implant had a successful conversion and 93.5% of induced episodes converted on the first shock. Conclusion: In primary and secondary prevention patients the S-ICD provides reliable treatment for ventricular tachyarrhythmias, with an inappropriate shock rate comparable to conventional ICD. Importantly lead failure or endocarditis has not occurred, emphasizing the advantages of extravascular defibrillation. These data will provide further insight into optimization of patient selection & device utilisation.