Incidence and clinical implication of ST-segment elevation during pulsed field ablation for atrial fibrillation

Background Despite the excellent safety profile of pulsed field ablation (PFA), coronary vasospasm remains a clinical concern. Purpose To evaluate the incidence, timing, and clinical consequences of transient ST-segment elevation during pulsed field ablation for atrial fibrillation Methods We analyzed consecutive patients undergoing PFA, with either the lattice-tip and pentaspline catheter, for atrial fibrillation at two centers between February 2024 and August 2025. ST-segment elevation (STE) was defined as ≥1 mm in ≥2 contiguous leads. Upon recognition of STE, a bolus of phenylephrine was administered, followed by 3 mg of intravenous nitroglycerin. Time to STE was defined as the interval between STE onset and nitroglycerin administration. Echocardiographic and arrhythmic follow-up assessments were performed during office visits. Results Among 411 PFA procedures, 19(0.44%) STE events (mean age 63 ± 11 years, 42.1% female, LVEF 61.3 ± 7.8%, 57.9% with coronary artery disease) occurred during ablation in coronary sinus (n = 11), mitral isthmus (n = 3) ablation, CTI (n=4) and LAA (N=1). In 17 patients time to STE was < 2 (1.1±0.3) minutes and no complication occurred. In 2 patients time to STEs was 8 and 11 minutes respectively and led to acute complications: one ventricular fibrillation requiring DC shock and one complete AV block requiring transient pacing. All STEs resolved within 2 minutes after 3 mg nitroglycerine. All patients were discharged the day after the procedure. No ventricular arrhythmias, conduction disturbances and new regional abnormalities were seen at follow-up. Conclusions Transient ST elevation during PFA is uncommon but can happen while ablating in area close to coronary artery. Prompt identification and immediate nitrate administration result in rapid resolution and prevention of major complications.