Idiopathic right ventricular arrhythmias requiring additional ablation from the left‐sided outflow tract: ECG characteristics and efficacy of an anatomical approach

Abstract

Introduction: Despite the characteristic electrocardiogram (ECG) findings of early activation during ventricular tachyarrhythmias (VAs) and/or excellent pacemapping in the right ventricular outflow tract (RVOT), some VAs may require additional, left-sided ablation for a cure. Methods and Results: This study included five patients with idiopathic VAs whose QRS morphologies were highly suggestive of an RVOT origin. The ECG characteristics and intracardiac electrocardiograms during catheter ablation were assessed. In all patients, the clinical VAs had an LBBB QRS morphology and inferior axis with a precordial R/S transition through leads V3-V5, and negative components in lead I. The earliest activation during the VAs (local electrogram-QRS interval = −34 ± 6.8 ms) and excellent pacemapping were obtained at the posterior portion of the RVOT just beneath the pulmonary valve. However, ablation at those sites failed, and the QRS morphology of the VAs changed. During left-sided OT mapping, the earliest activation was found at sites just contralateral to the initially ablated sites of the RVOT (junction of the left and right coronary cusps = 2, left coronary cusp = 3). In spite of the late activation time and poor pacemapping scores, catheter ablation at those sites cured the VAs. Those successful sites were also near the transitional zone from the great cardiac vein to the anterior interventricular vein (GCV-AIV). Conclusions: Some VAs, highly suggestive of having RVOT origins, require catheter ablation in the left-sided OT near the initially ablated RVOT site. Those VAs have the same ECG characteristics and might have intramural origins in the superobasal LV surrounded by the RVOT, LVOT, and GCV-AIV.

Coronary arterial injury during right ventricular outflow tract ablation: Know your neighbors

“…Many of these ECG features are reminiscent of arrhythmias successfully ablated in the anterior interventricular or intraseptal veins. 3,4 Consider next the extent of ablation performed in these patients. We have relatively complete ablation data from only three patients, and the total radiofrequency ablation duration was 40 and 26 minutes in patients 1 and 3 respectively.…”

Coronary arterial injury during right ventricular outflow tract ablation: Know your neighbors

“…Many of these ECG features are reminiscent of arrhythmias successfully ablated in the anterior interventricular or intraseptal veins. 3,4 Consider next the extent of ablation performed in these patients. We have relatively complete ablation data from only three patients, and the total radiofrequency ablation duration was 40 and 26 min in patients 1 and 3, respectively.…”

“…Also note the lack of initial r wave in V1, coupled with a relatively slurred QRS onset in these patients. Many of these ECG features are reminiscent of arrhythmias successfully ablated in the anterior interventricular or intraseptal veins 3,4 …”