Introduction: Athletes, at risk for sudden cardiac death and who have implantable cardioverter defibrillators (ICDs), represent a unique group, for whom, optimal ICD programming remains uncertain. Purpose: To assess the association of ICD programming characteristics with occurrence and outcomes of ICD shocks, syncope, and death in athletes with ICDs.
Methods: A subanalysis of a prospective, observational, international registry of 440 athletes with ICDs followed over a median of 44 months was performed in 384 subjects, in whom, programming was documented (detection duration documented in 178). Programming including high (≥200) vs low (<200) rate cutoff and long (>nominal) vs nominal detection duration were analyzed separately. Endpoints included total, appropriate and inappropriate shocks, syncope and mortality.
Results: 62% were programmed with high-rate cutoff (38% low). 30% were programmed with long detection times (70% nominal). No athlete died from an arrhythmia related to sports (one arrhythmic death occurred at rest). Three subjects had sustained ventricular tachycardia below programmed detection rates (all in the high rate group), and presented with palpitations and/or dizziness. 98 athletes received ICD shocks, of which, 64 received appropriate, 32 received inappropriate and 2 received both. High rate cutoff was associated with fewer total (30% vs 19%, p=0.01) and inappropriate (11% vs 5%, p=0.04) shocks, with similar findings during competition or practice. Long detection duration was associated with fewer total shocks (32% vs 15%, p =0.02). Single vs dual chamber devices and number of tachycardia zones were not related to risk of shocks. Syncope, which occurred with 27 appropriate shocks, was not related to programming characteristics.
Conclusion: High-rate cut off and long detection duration programming of ICDs in athletes can reduce total and inappropriate ICD shocks without impacting survival or incidence of syncope.