Different impact of long-detection interval and anti-tachycardia pacing in reducing unnecessary shocks: data from the ADVANCE III trial

A long-detection interval (LDI) (30/40 intervals) has been proved to be superior to a standard-detection interval (SDI) (18/24 intervals) in terms of reducing unnecessary implantable cardioverter defibrillator (ICD) therapies. To better evaluate the different impact of LDI and anti-tachycardia pacing (ATP) on reducing painful shocks, we assessed all treated episodes in the ADVANCE III trial. A total of 452 fast (200 ms < cycle length ≤ 320 ms) arrhythmic episodes were recorded: 284 in 138 patients in the SDI arm and 168 in 82 patients in the LDI arm (106/452 inappropriate detections). A total of 346 fast ventricular tachycardias (FVT) were detected in 169 patients: 208 in 105 patients with SDI and 138 in 64 patients with LDI. Setting LDI determined a significant reduction in appropriate but unnecessary therapies [208 in SDI vs. 138 in LDI; incidence rate ratio (IRR): 0.61 (95% CI 0.45-0.83), P = 0.002]. Anti-tachycardia pacing determined another 52% reduction in unnecessary shocks [208 in SDI with hypothetical shock-only programming vs. 66 in LDI with ATP; IRR: 0.37 (95% CI 0.25-0.53, P < 0.001)]. The efficacy of ATP in terminating FVT was 63% in SDI and 52% in LDI (P = 0.022). No difference in the safety profile (acceleration/degeneration and death/cardiovascular hospitalizations) was observed between the two groups. The combination of LDI and ATP during charging is extremely effective and significantly reduces appropriate but unnecessary therapies. The use of LDI alone yielded a 39% reduction in appropriate but unnecessary therapies; ATP on top of LDI determined another 52% reduction in unnecessary shocks. The strategy of associating ATP and LDI could be considered in the majority of ICD recipients.