The value of microelectrodes and microbipolar electrograms in premature ventricular complex mapping and ablation: The...

Catheter ablation is an effective treatment for premature ventricular contractions (PVCs). Mapping typically relies on bipolar (bip-EGMs) and unipolar electrograms (uni-EGMs). Recently, catheters equipped with microbipolar electrodes have become available.

This study aimed to investigate the value of microbipolar EGMs (micro-EGMs) in PVCs mapping.

We performed a multicenter retrospective study including patients who underwent successful outflow tract PVC ablation using QDOT catheters. 2 groups were identified based on the superficial or intramural origin of the PVC. EGMs-bip-, uni-, and micro-EGMs-were assessed at the successful ablation sites. The primary outcome was the ability of micro-EGM to discriminate between superficial and intramural PVCs. The secondary outcome was signal amplitude.

Among 81 patients (mean age 54 ± 11 years; 59.3% male), 51 had superficial and 30 had intramural PVCs. In superficial PVC, micro-EGM preceded both uni-EGM and bip-EGM in 90% of cases. In particular, when the earliest bip-EGM preceded the earliest micro-EGM by >10 ms (Δ_bip-micro >10 ms), there was a high probability (sensitivity 0.94; specificity 0.75) of requiring ablation in both the right ventricular outflow tract and left ventricular outflow tract for successful PVC suppression. Micro-EGMs had higher initial deflection amplitude (1.5 vs 2.8 mV; P = .025).

Micro-EGMs allow more accurate PVC mapping, improving depth estimation. Micro-EGMs seem to be valuable for local activation time annotation with important implications on automated annotation algorithms within existing electroanatomic mapping systems.