Reversible pulsed-field mapping: feasibility of clinical applications beyond atrial flutter

Background

Reversible electroporation (PFREV) has recently been described as a useful tool for mapping macroreentrant atrial tachycardias, allowing identification of the critical isthmus before delivering definitive lesions.

Purpose

This study aimed to expand the clinical application of PFREV mapping to other arrhythmias and electrophysiological substrates.

Methods

All procedures were performed using a 9mm lattice-tip catheter. Single trains of up to 32 pulses (pulse duration <10 μs) were used. We evaluated the feasibility of PFREV mapping in different clinical scenarios:

•Ventricular tachycardia (VT)

•Discrete gaps

•AVNRT

For VT PFREV mapping, the critical isthmus was identified using electroanatomical mapping (EAM) and entrainment. Non-synchronized PFREV pulses were delivered at the presumed isthmus.

For discrete gaps, conventional EAM identified the suspected target area, and PFREV pulses were delivered to test suitability for definitive ablation, assessing both efficacy and functional impact (e.g., potential left atrial appendage -LAA- isolation after anterior mitral line block).

For AVNRT, PFREV pulses were delivered at the slow pathway to rule out PR prolongation before creating definitive lesions.

Results

•VT mapping: Five cases were performed (four ARVC and one ischemic VT) with 19 PFREV pulses delivered at the critical isthmus. Four PFREV pulses (21%) induced local capture based on surface ECG and intracardiac electrogram analysis. Three were applied epicardially. Overall, 7 PFREV pulses (36.8%) terminated VT, 1 (5.3%) converted to a second stable VT, 1 (5.3%) caused transient TCL prolongation and 10 (52.6%) showed no effect.

•Discrete gap mapping: Five PFREV pulses were delivered to 3 patients at discrete gaps for PVI. A single PFREV pulse achieved acute conduction block in all cases. Left atrium-pulmonary vein (LA-PV) conduction was recovered within 25 to 67 seconds (with prolonged LA-PV interval in sinus or reduced LA-PV conduction ratio during AF), showing progressive return to baseline after 65 to 319 seconds. One additional patient received a single PFREV pulse at a discrete gap in the anterior mitral line, which demonstrated effective line block without LAA isolation, supporting the safety of definitive ablation.

•AVNRT mapping: Two patients received one PFREV pulse each at the slow pathway to test PR prolongation. None induced PR changes, and definitive radiofrequency lesions at the same sites eliminated AVNRT without affecting AV conduction.

Some illustrative cases are shown in Figure 1.

Conclusion

PFREV mapping is a promising electrophysiological tool applicable not only to atrial flutter but also to other arrhythmias, including ventricular reentry and discrete gap assessment. Beyond mapping, it may act as a predictive marker for the functional impact of ablation, such as unintended isolation or iatrogenic block, thus enhancing safety and procedural precision.Illustrative cases