Reducing Unnecessary Implantable Cardioverter-Defibrillator Therapy With ENHANCED Programming: Long-Term Outcomes of the ENHANCED-ICD Study

BACKGROUND: Advances in implantable cardioverter-defibrillator (ICD) programming strategies have achieved significant reductions in inappropriate shocks. However, further refinement is needed to minimize appropriate but unnecessary therapies. The ENHANCED-ICD study initially demonstrated the short-term safety and efficacy of programming a number of intervals to detect (NID) of 60/80 over a median follow-up of 1.3 years. A decade later, this study presents the long-term impacts of this programming strategy.

OBJECTIVE: To assess the long-term impact of programming NID 60/80 for ventricular tachycardia (VT)/ventricular fibrillation (VF) detection on adverse events related to shocks and arrhythmias, as well as on ICD therapies-both delivered and avoided.

METHODS: A retrospective analysis was conducted on 60 patients from the ENHANCED-ICD study, a prospective, single-center trial. The median age was 60 years, 78% were men, and 53% had a primary prevention ICD indication. A prolonged detection interval of NID 60/80 was programmed for VT/VF detection. The cycle lengths for VT/fast VT/VF were set at 360/330/240 ms, respectively.

RESULTS: After a median follow-up of 9.4 years, Enhanced programming prevented unnecessary ICD therapies in 16.7% of patients and reduced the overall therapy rate by 25.9%. A total of 26.7% of patients received ICD therapy, with appropriate therapy delivered in 23.3% and inappropriate therapy occurring in 3.3% of patients. No arrhythmic deaths were observed, while syncope was reported in 10.0% of patients (1.63 per 100 patient-years).

CONCLUSION: Prolonging the ICD detection interval to an NID of 60/80 successfully prevented appropriate but unnecessary therapy, while maintaining safety during long-term follow-up.

TRIAL REGISTRATION: The ENHANCED-ICD study registered on http://ClinicalTrials.gov under study ID NCT01715116.