Introduction:
Substrate mapping is evolving as a potential strategy for atrial fibrillation ablation. Defining scar borders and functional boundaries is typically under taken with bipolar electrodes. Catheter orientation affects electrogram (EGM) signal amplitude due to an orientation dependence of bipoles. We developed orientation independent Omnipolar Technology (OT) and compared OT EGM amplitude with traditional bipolar (Bi) methods.
Methods:
Four anesthetized swine were studied in 6 sessions with a 3D mapping system and a multielectrode OT ablation catheter placed in RA and LA locations in 4 rhythms. With the OT catheter in a stable location, 30 successive atrial beats were acquired. OT electrodes provided bipole (Bi) as well as OT signals along both activation (OTa) and surface normal (OTn) directions. Peak to peak amplitudes (Vpp) of OT and Bi signals were compared for magnitude and consistency.
Results:
As shown in the table, OT signal amplitudes over all atrial locations and rhythms were greater than traditional bipole amplitudes. The coefficients of variation for signal amplitude over successive cardiac beats were substantially less for OTa and OTn (*p < 0.01 with respect to Bi) than for Bi, reflecting electrode pair orientation effects.
Conclusions:
Distinct electrogram signals were resolved by OT along physiologic (activation) and anatomic (surface normal) directions. Catheter orientation independent OT signal amplitudes were more self-consistent and reliable than those from orientation dependent bipolar electrode pairs. Omnipolar technology approaches may permit more accurate and specific definition of substrate and thus catheter ablation of arrhythmias.
Self-induced redox cycling coupled luminescence on nanopore recessed disk-multiscale bipolar electrodes
