Who still remains at risk of arrhythmic death at time of implantable cardioverter-defibrillator generator replacement?: MADEIRA et al.

BACKGROUND: Implantable cardioverter-defibrillator (ICD) is associated with reduction in arrhythmic mortality. However, at the time of generator replacement (GR) some patients had not experienced therapies and had a different clinical profile. Therefore, the risk-benefit ratio of ICD may have changed. Our aim was to determine the proportion of patients with ICD implanted in primary prevention that maintain guideline-derived indications at the time of GR and assess predictors of therapies in the postreplacement period. We evaluate the long-term benefit of ICD after GR in nonischemic cardiomyopathy (NICM) versus ischemic cardiomyopathy (ICM). METHODS: We included 141 patients undergoing GR from 11/2009 to 7/2015. Patients were divided into: G1 - guideline congruent indication for ICD at the time of GR (left ventricular ejection fraction [LVEF] ≤ 35% or appropriate therapies) and G2 - guideline incongruent indication (patients without appropriate therapies and LVEF >35%). We also compared ICD benefit between ICM and NICM patients. RESULTS: Maintenance of guideline-driven indications for ICD (G1) was present in 68% of patients and 32% had recovery of LVEF and no ICD therapies at the time of GR (G2). After GR, G2 patients showed a lower rate of appropriate therapies (3% vs 33%, P < 0.01). LVEF ≤ 35% was the only independent predictor of appropriate therapies (OR 12.0, P < 0.01). In multivariate analysis, etiology of heart failure did not predict the arrhythmic risk. CONCLUSION: At the time of GR, a significant proportion of patients no longer met guideline indications for ICD and their need for therapies is reduced. The etiology of heart failure did not predict freedom from therapies.