Successful radiofrequency ablation of para-left bundle branch premature ventricular contractions: Aiming at the breakout point to spare the conduction system

Author(s): Leonor Parreira, Dinis Mesquita, Rita Marinheiro, Rita Marinheiro, Duarte Chambel, Pedro Amador, Rui Caria

Background: The origin of the arrhythmia and its breakout point may be located apart. This has been described for arrhythmias originating within the His-Purkinje system. Case presentation: We report a case of a 70-year-old man with right bundle branch block and left anterior fascicular block with idiopathic nonsustained ventricular tachycardia originating in the septal left ventricular outflow close to the proximal left bundle branch. Ablation was successfully and safely performed away from the origin of the arrhythmia near the left anterior fascicle, at the breakout point. Arrhythmias from the conduction system may have different preferential exits and meticulous activation sequence mapping is the preferable strategy to select the ablation site.