Ventricular Extrasystole Ablation: electrophysiological characterization according to its origin

Abstract

Introduction. Premature Ventricular Complexes (PVCs) are a frequent nonsevere cardiac condition that in some cases can be malignant, as they may result in structural cardiomyopathies or even sudden death, and need treatment. For pharmacoresistant PVCs, catheter ablation is used with a success rate between 50-90% for PVC burden reduction. The catheter used has a set of electrodes used to measure intracavitary signals. Hypothesis and objectives. Electrophysiological characteristics of the PVCs could be used to characterize the signals expected at different ventricular structures and assess the outcome of the ablation in real-time. Material and methods. Using CARTO3 (Remote Magnetic Navigation) we studied 29 PVCs (24 patients), from the Arrhythmia Unit of the Hospital Clinic of Barcelona. We characterized unipolar and bipolar electrograms by measuring amplitudes, precocities and unipolar negative deflections, and the most precocious isochrone at different cardiac points: Left ventricle (LV), Right ventricle (RV), Pulmonary artery (AP), Summit(S) and cusps (C). Results. Bipolar signals: the most precocious locations were RV and S, differences between RV-S (24.2 ms vs 43.3 p=0.0017) and C-S (26.6 vs 43.3 p=0.0104). LV showed the largest bipolar amplitude (5.65 mV), S the lowest (0.26). Areas showing largest number of unipolar negative deflections were RV (n=1.43), C (n=1.53) and AP (n=1.65), being significantly different form S (n=0.95, p= 0.0445, 0.0092, 0.00119, respectively). The steepest slope at LV (0.3 mV/ms), flattest at S (0.0297), finding significant differences LV-RV (p=0.0493). Unipolar precocities were significantly different between RV (26.9 ms) and LV (16.2, p=0.0002). Conclusion. Relations can be found between intracavitary ablation signals and ventricular structures. Differences in precocities between ventricles could be used as a marker to assess the state of intervention. More studies are needed to characterize ventricular substructures and to assess the long-term outcome of the procedure.