Outcomes of High Power Application in Catheter Ablation of Paroxysmal Atrial Fibrillation Guided by Unipolar Signal Modification.

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation procedures in patients with paroxysmal atrial fibrillation (PAF) [1]. However, the incidence of atrial fibrillation (AF) recurrence remains high [2], mostly due to pulmonary vein (PV) reconnection [1], emphasizing the formation of transmural lesions to achieve complete conduction block along the ablation lines [3].

Previous studies have shown that elimination of the negative component of the unipolar electrogram (UP-EGM) during radiofrequency applications reflects transmural lesions. The persistence of such a negative component consistently corresponds to non-trans mural lesions [4].

The high-power short duration (HPSD) RF application applies to all RF energies delivered at more than 40 W [5]. Higher the power more is the resistive heating causing wider tissue injury [5]. The lesion size with HPSD is larger in width but lesser in depth compared to lower powers with longer duration [5]. In contrast, RF applications of lower power and longer duration result in larger dissipation of RF energies deep into the tissues due to conductive heating causing tissue destruction at greater depths [6]. Hence, there is a risk of collateral tissue damage [5].

HPSD ablation has been advocated as a means to minimize the risk of collateral organ damage as the lesions are smaller in depth. However, Maintaining a high power for a constant duration in the absence of a guide may not be the right strategy [5].

Unipolar waveform modification by complete elimination of the negative component may serve as a guide for HPSD ablation [5].