Insight from the microelectrodes in case of two different types of premature ventricular contractions originating from left ventricular summit

TL;DR

This paper shows how microelectrodes can help locate the origin of heart rhythm issues more accurately than traditional methods.

Contribution

The study demonstrates the clinical utility of microelectrodes in identifying the depth of PVC origins.

Findings

Microelectrodes showed shorter pre-PVC activation times compared to conventional electrodes in certain cases.

RF ablation was more effective at the site indicated by microelectrode data for PVC-1.

Both electrode types showed similar activation times for PVC-2, leading to successful ablation in LCC.

Abstract

Premature ventricular contraction (PVC) is usually eliminated in the earliest activation site based on the conventional electrode of ablation catheter. However, the large size electrode may contain far-field potential. The QDOT MICRO ablation catheter has three micro electrodes with 0.33 mm electrode length, in addition to the conventional electrode with 3.5 mm electrode length. The micro electrodes can reflect only near-field potential.

A 78-year-old with symptomatic frequent PVCs underwent catheter ablation. PVC-1 showed good pace-mapping in distal great cardiac vein (GCV). The local bipolar electrograms in the conventional electrode of ablation catheter preceded the PVC-QRS onset by 32 ms in distal GCV and 13 ms in left coronary cusp (LCC), but those in the micro electrodes preceded only by 13 ms both in distal GCV and LCC. PVC-1 was eliminated by radiofrequency (RF) application, not in distal GCV, but in LCC. PVC-2 showed good pace-mapping in LCC. The local bipolar electrograms in both the conventional electrode and the micro electrodes of ablation catheter preceded the PVC-QRS onset by 32 ms in LCC. PVC-2 was eliminated by RF application in LCC.

Comparing the local electrograms of micro electrodes and the conventional electrodes may be important for identifying depth of the origin of PVCs.

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