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

Abstract

Background: 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.

Objective: 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.

Methods: The distribution of mapping confirmed VTs within the RV body, ECG characteristics, and results of radiofrequency (RF) ablation were analyzed.

Results: 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).

Conclusion: 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.