Rates and risk of arrhythmias in cancer survivors with chemotherapy-induced cardiomyopathy compared with patients with other cardiomyopathies

Objectives There is little information about arrhythmia burden in cancer survivors with chemotherapy-induced cardiomyopathy (CIC). We hypothesise that the rates and risk of arrhythmias will be similar in CIC when compared with other non-ischaemic cardiomyopathy (NICMO) aetiologies. Methods We retrospectively identified nine patients with CIC and an implantable defibrillator and 18 age and sex-matched control patients (nine patients with NICMO and nine patients with ischaemic cardiomyopathy (ICMO)). Rates and odds of arrhythmias were calculated by type of cardiomyopathy, adjusting for days since implantable cardioverter defibrillator implantation, history of atrial fibrillation and length of follow-up using logistic regression analysis. Results Compared with patients with NICMO, rates and adjusted odds were similar for patients with CIC for atrial arrhythmias (44.4% vs 33.3%; adjusted OR=1.89; 95% CI0.17 to 21.03; P=0.61), non-sustained ventricular tachycardia (NSVT) (44.4% vs 33.3%; OR=2.10; 95% CI 0.21 to 20.56; P=0.53), and the combined outcome of NSVT, sustained ventricular tachycardia and/or ventricular fibrillation (44.4% vs 44.4%; OR=2.70; 95% CI 0.25 to 29.48; P=0.42). Conversely, compared with patients with NICMO, patients with ICMO demonstrated higher rates and adjusted odds of the combined outcome (88.9% vs 44.4%; OR=28.60; 95% CI 1.26 to 648.2; P=0.04) and NSVT (77.8% vs 33.3%; OR=8.95; 95% CI 0.90 to 88.94; P=0.06). Conclusions While tentative based on sample size, rates of arrhythmias in patients with CIC appear to be similar to those experienced by patients with other forms of NICMO.