Implantable Cardioverter Defibrillator for the Primary Prevention of Sudden Cardiac Death among Patients With Cancer

Data are limited regarding the characteristics and outcomes of patients with cancer who are found eligible for primary defibrillator therapy. We performed a single-center retrospective analysis of patients with preexisting cancer diagnoses who become eligible for a primary prevention implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy (CRT) defibrillator. Multicenter Automatic Defibrillator Implantation Trial-ICD (MADIT-ICD) benefit scores were calculated. The study included 75 cancer patients at a median age of 73 (interquartile range 64, 81) years at heart failure diagnosis. Active cancer was present in 51%. Overall, 55% of the cohort had coronary artery disease and 37% were CRT eligible. We found that 48%, 49%, and 3% of cohorts had low, intermediate, and high MADIT-ICD Benefit scores, respectively. Only 27% of patients underwent primary defibrillator implantation. Using multivariate analysis, indication for CRT and intermediate/high MADIT-ICD Benefit categories were found as independent predictors for implantation (odds ratio 8.42 p <0.001 and odds ratio 3.74 p = 0.040, respectively). During a median follow-up of 5.3 (interquartile range 4.5, 7.2) years, one patient (5%) with a defibrillator had appropriate shock therapy and 2 patients (10%) had bacteremia. Of 13 patients with CRT defibrillator-implants, one patient was admitted for heart failure exacerbation (8%). Using a time-varying covariate model, we did not observe statistically significant differences in the survival of patients with cancer implanted versus those not implanted with primary defibrillators (hazard ratio 0.521, p = 0.127). In conclusion, although primary defibrillator therapy is underutilized in patients with cancer, its relative benefit is limited because of competing risk of nonarrhythmic mortality. These findings highlight the need for personalized cardiologic and oncologic coevaluation.