Idiopathic ventricular arrhythmias arising from the pulmonary artery: Prevalence, characteristics, and topography of the arrhythmia origin

BackgroundThe characteristics of idiopathic ventricular tachycardias (VTs) or idiopathic premature ventricular contractions (PVCs) arising from the pulmonary artery (PA) have not been sufficiently clarified.ObjectiveThe purpose of this study was to clarify the prevalence, characteristics, and preferential sites of idiopathic VT/PVCs arising from the PA (PA-VT/PVCs).MethodsData obtained from 276 patients with idiopathic VT/PVCs who underwent radiofrequency (RF) catheter ablation were analyzed.ResultsTwelve VT/PVCs (4%) were PA-VT/PVCs, and their onset (34 ± 14 years) was the youngest among all subgroups. Because those QRS morphologies were similar to VT/PVCs arising from the right ventricular outflow tract (RVOT-VT/PVC) and the earliest ventricular activation was from the RVOT, an initial ablation was performed in the RVOT in all patients. However, RF catheter ablation at the RVOT resulted in a QRS morphology change in all patients, so thereafter PA mapping and ablation was performed. A characteristic potential during sinus rhythm and/or the arrhythmia was recorded at the successful PA ablation site in all patients. A perfect or good pace map was obtained in 7 (70%) of 10 patients. The successful ablation site was the septal side of the PA close to the posterolateral attachment in 9 patients (75%) and the septal side close to the anterior attachment in the remaining 3 (25%). No PA-VT/PVCs recurred during follow-up of 27 ± 13 months.ConclusionPA-VT/PVCs should always be considered when the ECG suggests RVOT-VT/PVCs and RF catheter ablation in the RVOT results in both a failed ablation and a change in QRS morphology. PA-VT/PVCs often originate from the septal side of the PA.