Reassessment of cardiovascular parameters and comorbidities in implantable cardioverter-defibrillator patients at the time of first replacement.

Abstract

Guidelines provide extensive recommendations regarding implantable cardioverter-defibrillator (ICD) implantation. However, ICD replacement at the time of battery depletion is rarely studied. Our objectives were to identify patients at high-risk of death after ICD replacement, with a reassessment of changes in risk factors and comorbidities at the time of replacement, and to determine predictors for subsequent mortality. Patients undergoing ICD replacement for regular battery depletion were selected from a prospective single-center ICD registry. Both at implant and replacement, 3 demographic parameters, 9 cardiovascular parameters, 5 comorbidities, and 4 laboratory parameters were collected. Cox proportional hazard analyses were used. We included 308 patients who were predominantly male (86%) with a median age at ICD replacement of 66 years. Replacement was performed 65 months (interquartile range, 52-91) after implantation. Median follow-up after replacement was 41 months, during which 82 patients (27%) died. Multivariable analysis revealed 4 independent predictors of mortality after ICD replacement: age/year (hazard ratio [HR]: 1.05, 95% confidence interval [CI]: 1.03-1.08, P = 0.01), worsening heart failure by 1 class (HR: 1.53, 95% CI: 1.15-2.03, P = 0.003), presence of left bundle branch block (HR: 1.98, 95% CI: 1.22-3.23, P = 0.006), and ICD therapy prior to replacement (HR: 2.22, 95% CI: 1.37-3.58, P = 0.001). Incorporated into a dichotomous score, they strongly correlated with mortality at 5 years after replacement (5% with 0 parameters, 15% with 1 parameter, and 30%-55% with >2 parameters). Focused reassessment of selected patient characteristics at the time of ICD replacement correlates with subsequent mortality and can impact decision making at this point in time.