Idiopathic right ventricular arrhythmias not arising from the outflow tract: Prevalence, electrocardiographic characteristics, and outcome of catheter ablation

Most idiopathic right ventricular (RV) ventricular tachycardias (VTs) originate from the outflow tract. Data on VT from the lower body of the RV are limited.The purpose of this study was to describe a large experience with idiopathic VT detailing the prevalence and characteristics of VT arising from the body of the RV.The distribution of mapping confirmed VTs within the RV body, ECG characteristics, and results of radiofrequency (RF) ablation were analyzed.Among 278 patients who underwent ablation for idiopathic VT or ventricular premature depolarizations (VPDs) arising from the RV, 29 (10%) had VT/VPDs from the lower RV body. Fourteen (48%) patients had VT/VPDs within 2 cm of the tricuspid valve annulus (TVA), 8 (28%) from the basal and 7 (24%) from the apical RV segments. Among the VT/VPDs from the TVA, 8 (57%) originated from the free wall and 6 (43%) from the septum. All but one RV basal or apical VT/VPDs originated from the free wall. All VT/VPDs had a left bundle branch block pattern. VT/VPDs from the free wall had longer QRS duration (P = .0032) and deeper S wave in lead V(2) (P = .042) and V(3) (P = .046) than those from the septum. Apical VT/VPDs more often had precordial R wave transition ≥V(6) (P = .0001) and smaller R wave in lead II (P = .024) and S wave in lead aVR (P = .001) compared to VT/VPDs from basal RV or TVA. RF catheter ablation eliminated VT/VPDs in 96% of patients. No complications were observed. During median follow-up of 27 months (range 4-131 months), 81% of patients had elimination of all symptomatic VT/VPDs. Nineteen percent had rare symptoms (8% without medications, 11% on beta-blocker).Idiopathic VT/VPDs from the body of RV comprise an important subgroup of idiopathic RV VTs. Although most VTs originate from the RV free wall and nearly 50% from the TVA region, septal and more apical VTs are common. ECG characteristics distinguish free-wall versus septal and more apical origin of VTs, and RF catheter ablation provides good long-term arrhythmia control.