Heart failure severity, inappropriate ICD therapy, and novel ICD programming: a MADIT‐RIT substudy

Background The effects of heart failure (HF) severity on risk of inappropriate implantable cardioverter‐defibrillator (ICD) therapy have not been thoroughly investigated. We aimed to study the association between HF severity and inappropriate ICD therapy in MADIT‐RIT. Methods MADIT‐RIT randomized 1,500 patients to three ICD programming arms: conventional (Arm A), high‐rate cut‐off (Arm B: ≥200 beats/min), and delayed therapy (Arm C: 60‐second delay for ≥170 beats/min). We evaluated the association between New York Heart Association (NYHA) class III (n = 256) versus class I–II (n = 251) and inappropriate ICD therapy in Arm A patients with ICD‐only and cardiac resynchronization therapy with defibrillator (CRT‐D). We additionally assessed benefit of novel ICD programming in Arms B and C versus Arm A by NYHA classification. Results In Arm A, the risk of inappropriate therapy was significantly higher in those with NYHA III versus NYHA I–II for both ICD (hazard ratio [HR] = 2.55, confidence interval [CI]: 1.51–4.30, P