The value of microelectrodes and microbipolar electrograms in premature ventricular complexes (PVCs) mapping and ablation: the Micropvc study

Background Catheter ablation is an effective treatment for premature ventricular contractions (PVCs). Mapping typically relies on bipolar and unipolar electrograms (EGMs) to identify the site of origin. Recently, ablation catheters equipped with microbipolar electrodes have become available. However, the value of microbipolar EGMs (MicroEGM) in PVCs mapping has not been evaluated. Methods We performed a multicenter retrospective study including patients who underwent successful outflow tract (OT) PVC ablation using QDOT catheters. Two group were identified based on the superficial or intramural origin of the PVC. EGMs — bipolar (BipEGMs), unipolar (UniEGMs) and MicroEGM —were assessed at successful ablation sites in terms of local activation time (LAT). The primary outcome was to assess the ability of MicroEGM to discriminate between superficial and intramural PVC. Secondary outcomes included size of the target ablation area and signal amplitude. Results Among 81 patients (mean age 54.6±11.9 years; 59.3% male), 51 had superficial and 30 had intramural PVCs. In superficial PVC, MicroEGM preceded both UniEGM and BipEGM in 90% of cases. DeltaLAT(Bip-Micro) >10 ms was associated with a high probability (sensitivity of 0.94 and a specificity of 0.75) of requiring ablation in both the RVOT and LVOT for successful PVC suppression. The target area identified by MicroEGM annotation was 50% smaller than with automatic annotation (1.5 vs. 3.0cm2 (p=0.02)). MicroEGMs had higher initial deflection amplitude (1.5 vs 2.8mA, p=0.025). Conclusion MicroEGMs allow more accurate PVC mapping, improving depth estimation and spatial resolution. MicroEGM appear to be valuable for LAT annotation with important implications on automated annotation algorithms within existing electroanatomic mapping systems.Figure 1Figure 2