Influence of prior atrial arrhythmias on the effects of innovative programming in reducing inappropriate therapy and death in MADIT-RIT

Abstract

Background: The impact of prior atrial arrhythmias on the effects of innovative programming and subsequent outcome has not yet been evaluated. Methods: The MADIT-RIT trial randomized ICD patients to three programming arms: conventional programming with a VT zone ≥170 bpm (Arm A), high-rate cut-off with a VT zone ≥200 bpm (Arm B), or 60-sec delayed therapy in the VT zone 170-199 bpm (Arm C). The effects of programming on inappropriate therapy and death were assessed in multivariate Cox models stratified by prior atrial arrhythmias (atrial arrhythmia prior to enrollment). Results: In patients with prior atrial arrhythmias (n=203, 14%) there was a significantly higher risk of inappropriate therapy (HR=2.10, 95% CI: 1.38-3.20, p 0.10) (Figure). High-rate cut-off programming (Arm B) was associated with a significant reduction in the risk of all-cause mortality in patients without prior atrial arrhythmias (HR=0.48, 95% CI: 0.25-0.93, p=0.03), and similar, but not significant reduction in those with prior atrial arrhythmias (HR=0.33, 95% CI: 0.08-1.34, p=0.12, interaction p-value=0.645). ![Figure][1] Figure Conclusion: Novel ICD programming reduces inappropriate therapy in those with or without prior atrial arrhythmias. There was a beneficial reduction in all-cause mortality in those programmed to high-rate therapy (Arm B), particularly in those with a history of prior atrial arrhythmias. [1]: pending:yes