Abstract
INTRODUCTION: Ventricular arrhythmias (VAs) have been successfully ablated from the pulmonary sinus cusps establishing pulmonary artery (PA) as a distinct site of arrhythmic foci. The aim of the present study was to determine the clinical presentation, electrocardiographic, and ablation characteristics of PA-VAs. METHODS: Thirty consecutive patients with right ventricular outflow tract (RVOT)-type VAs were included in this retrospective study. Three-dimensional electroanatomic mapping was performed in all patients. Mapping was performed initially in RVOT, and later within the PA. Mapping was performed in the PA if there was no early activation, unsatisfactory pace-map, or ablation in RVOT were unsuccessful. All PA-VAs were mapped and ablated by looping the catheter in a reverse U fashion. RESULTS: Among 30 patients, 8 (26.6%) patients VAs were successfully ablated within PA. Electrocardiography (ECG) revealed that the QRS duration was significantly wider in the PA-VAs group compared to the RVOT-VAs group (155 ± 14.14 vs 142.40 ± 8.12 ms, P < .01). Mapping by reversed U method of PA-VAs revealed earlier activation (55 ± 9.66 vs 12.00 ± 8.61 ms, P < .01) in PA compared to RVOT. An isolated discrete prepotential was present at the successful site in 50% (n = 4). CONCLUSION: Pulmonary artery-VAs are an important subset of VA originating from the outflow tract. They have a wider baseline QRS duration compared to RVOT-VAs. Presence of a prepotential aids in the identification of a successful ablation site. Mapping utilizing the reversed U method can help in localization and successful ablation of PA-VAs.