Ventricular Tachycardia Ablation in Heart Failure: Substrate Characteristics, Outcomes of Catheter Ablation and Role of Papillary Muscle

BACKGROUND & AIMS: Ventricular tachycardia (VT) is common in heart failure (HF) with up to 20% of patients with HF experiencing VT. However, substrate characteristics and outcomes of VT ablation in a population with reduced left ventricular ejection fraction (LVEF) are not well described. This study aimed to: (i) evaluate the substrate characteristics in patients with HF with VT, in particular the role of papillary muscles (PM); and (ii) evaluate the outcomes of catheter ablation, including VT recurrence and mortality. METHODS: This is a retrospective single-centre study, including patients with LVEF <35% and sustained monomorphic VT undergoing VT ablation. Procedural characteristics, VT substrate characteristics and clinical outcomes were evaluated. Intracardiac echocardiography was used to identify abnormalities in PM. RESULTS: A total of 48 patients were included (age 68±11 years; males 93%; LVEF 27±6%; ischaemic cardiomyopathy 56%; non-ischaemic cardiomyopathy 39%; mixed cardiomyopathy 4%). The main findings were: (i) 33% of the VT exit sites were located at LV PM; (ii) 68% patients had LV PM abnormal tissue characteristics on intracardiac echocardiography; however, such characteristics were not indicative of VT exit; (iii) the presence of VT exit in the LV PM was associated with a higher rate of VT recurrence (log-rank p=0.03), and a trend towards higher mortality at 1 year (log-rank p=0.07). CONCLUSIONS: In patients with LVEF <35%, VT with endocavitary structures as exit sites is not uncommon. Patients with VT exiting at the LV PM have worse clinical outcomes with higher VT recurrence and mortality.