Characteristics of PVC group (Table 4)
The median duration between valve surgery and PVC onset was 3.4 (IQR 0.6, 8.0) years while the median duration between MVS and PVC ablation was 4.0 (IQR 1.0, 10.0) years. Twelve patients in this group had MV repair while 3 patients had MV replacement (of which 2 had mechanical valve). The median LVEF is 48(IQR 43, 53). Thirty-three percent of the PVC group had ICD in situ prior to ablation. The mean LVIDd was 55±9 mm. The mean RVSP was 27 ±8 mmHg. Thirteen patients (87%) in the PVC group had RBBB morphology with an inferiorly directed axis in 9 cases and a superior axis in 4 cases. Eleven (73%) out of the 15 patients in the PVC group had mapping of the perimitral area. Of these, signal abnormalities consistent with scar in the perimitral area were noted in 5 (45%) patients. In 9 patients with PVCs, the successful site of ablation was unrelated to the perimitral area. Rather, 20% of patients had successful ablation from the posterior papillary muscle; all of them had prior history of mitral valve repair with posterior annuloplasty ring and commissuroplasty. The remainder of PVCs were mainly of outflow tract origin. One patient had PVC originating from the septal RVOT while in another, PVC originated from the lateral RV inflow. The local ventricular activation time recorded at successful ablation targets that preceded the QRS onset was 34 ±8 millisecond. Procedural success was achieved in 93% of the PVC group. Only one patient had procedural failure. In this patient, the clinical PVC was mapped to the epicardial LV “summit” region where RF ablation was limited due to proximity to the left anterior descending coronary artery. This patient was discharged on amiodarone.
The median total procedure time for the PVC group was 255 (IQR 318.25, 191) minutes and median fluoroscopy time was 28 (IQR 46, 12.3) minutes. The median energy delivery time was 20.9 (IQR 30.6, 9.5) minutes.