Long-Term Performance of Subcutaneous Implantable Defibrillators in Athletes: A Multicenter, Real-World Analysis of Sport Activities from the iSUSI Registry.

Background: No data regarding subcutaneous-ICD (S-ICD) technology in patients actively engaging in sports activities is available.

Objective: To compare S-ICD performance between athletes and non-athletes.

Methods: The primary outcome of the study was the comparison of overall device-related complications between athletes and non-athletes. Appropriate shocks, inappropriate shocks, and individual device-related complications were secondary outcomes.

Results: A total of 1493 patients were extracted from the iSUSI registry, of which 152 (10.2%) were athletes, mostly engaging in dynamic sports (54.2%). Brugada syndrome, myocarditis, and ARVC were more common in athletes (11.2%vs.3.3%, p<0.001; 19.1%vs.9.0%, p<0.001; 8.6%vs.2.8%, p<0.001, respectively). During a median follow-up time of 25.5 [12.0-41.2] months, athletes were more likely to experience appropriate shocks (yearly-rate: 7.2 [4.9-10.7]% vs. 4.3 [3.6-5.1]%, p=0.028), occurring more frequently during exercise (3.9%vs.0.6%, p < 0.001). This finding lost significance when adjusting for confounders (aHR=1.440[0.909-2.281], p=0.120). No differences were found in overall device-related complications (yearly-rate: 3.3%vs.3.4%, p=0.448) and inappropriate shocks (yearly-rate: 5.3% vs. 3.7%, p=0.111). Myopotential oversensing (4.0%vs.1.3%, p=0.011) was more common in athletes, as were lead infections (3.3%vs.0.9%, p=0.008), with the latter clustering in the early post-implantation period.

Conclusion: The S-ICD is a valid therapeutic option for preventing sudden cardiac death in athletes. Sports practice was not associated with an increased risk of complications or inappropriate shocks, although athletes are exposed to a higher risk of S-ICD infections in the early post-operative period.