Increased Incidence of VentricularArrhythmias in Patients WithAdvancedCancer and ImplantableCardioverter-Defibrillators.

Abstract

This study evaluated the incidence of ventricular arrhythmia and implantable cardioverter-defibrillator (ICD) therapies in patients with a diagnosisof cancer. Cardiac disease and cancer are prevalent conditions and share common predisposing factors. Nostudies have assessed the impact of cancer on the burden of ventricular arrhythmia in patients with cancer andICDs. Retrospective study of patients with an ICD and cancer who were followed from January 2007 to June 2015. Rates of ventricular tachycardia (VT) and ventricular fibrillation (VF) before and after patients' cancers were diagnosed were evaluated by searching device data collection systems. Rates were adjusted for length of follow-up and compared using the Wilcoxon test, and times to first therapy following diagnosis (stages I to III vs. IV) were compared using Kaplan-Meier curves and log-rank test. Among 1,598 patients with an ICD, 209 patients (13.1%) had a pathological diagnosis of malignancy; and in 102 patients (6.4%), malignancy was diagnosed following device insertion. After the diagnosis of cancer, 32% of patients experienced VT/VF over 23.2 ± 23.6 months, and the frequency of arrhythmic events was significantly increased after the diagnosis (1.19 ± 0.32 vs. 0.12 ± 0.21 episodes per month, respectively; p= 0.03). The incidence of VT/VF was markedly higher in patients with stage IV cancer than in those with earlier stages (p= 0.03). In this group, the incidence of VT/VF was 41.2%, with an average of 7.2 ± 18.5 events per patient, all of whom received ICD shocks. The rate of ICD deactivation in stage IV patients was 35.3%. Inappropriate therapies occurred in 13.7%, and atrial fibrillation was themost frequent cause. One-third of patients who had received ICDs developed ventricular arrhythmia after a diagnosis of cancer. The incidence was significantly higher in those with advanced metastatic disease. Findings underscore the need to discuss ICD management as part of end-of-life care.