Po-03-006 characterization of right coronary artery vasospasm during radiofrequency ablation at the cavo-tricuspid isthmus

Pulsed field ablation (PFA) has been touted to have important safety benefits, including no esophageal damage, pulmonary vein stenosis or permanent phrenic nerve paralysis. However, recent data suggest that when PFA is performed adjacent to a coronary artery, there is a susceptibility for vasospasm. In a study of right coronary artery (RCA) angiography during PFA of the cavo-tricuspid isthmus (CTI), there was universally severe RCA spasm. While these phenomena were all subclinical, there are other reports of clinically evident vasospasm during PFA. The specificity of this vasospastic phenomenon to PFA (vs with thermal ablation) is unclear; this is particularly the case since clinically evident vasospasm has only rarely been reported during radiofrequency ablation (RFA) and has not been systematically evaluated with dedicated coronary angiography studies. To describe the incidence and severity of RCA vasospasm during RFA on the CTI. After informed consent, patients underwent AF ablation under deep sedation. Coronary angiography was performed from the right femoral artery before, during and after CTI ablation using a saline-irrigated RFA catheter (Thermocool, Boston Scientific Inc). RFA was performed using 35-50W with saline at 17-30ml/min, with careful attention to titration based on impedance drop. Intracardiac echocardiography (ICE; Acunav, Biosense Webster Inc) was employed to assure catheter tip-to-tissue contact throughout linear lesion delivery. The frequency of RCA vasospasm was identified and characterized by severity and ECG changes. A total of 13 patients underwent CTI ablation with irrigated RFA (see Table). Acute bidirectional isthmus block was achieved in all patients. Upon coronary angiography during CTI lesions, only 2 of 13 pts (15%) developed RCA spasm; neither of these events were severe (>90% stenosis), but instead were mild (<50% stenosis) and without ECG changes, ventricular wall motion changes (evaluated by ICE) or hemodynamic instability (or symptoms, albeit in sedated patients). The vasospasm self-resolved without nitroglycerin administration. On the one hand, just like subclinical spasm that has been reported with PFA, spasm may also occur with RFA. However, the frequency of vasospasm (∼100% with PFA vs 15% with RFA) and the severity (nearly 100% severe with PFA vs mild with RFA) are markedly distinct between these modalities, indicating that the difference is not just “of degree” but functionally and qualitatively unique with PFA.Tabled 1Patient CharacteristicsAge, mean±SD, y64.8±10.4Male, n (%)10 (77)Body mass index, mean±SD30.3±4.4Type of atrial fibrillationParoxysmal, n (%)1 (8)Persistent, n (%)12 (92)CHA2DS2-VASc Score, mean±SD2.2±1.6Coronary artery disease, (%)3 (23)Left ventricular ejection fraction, mean±SD, %61.8±3.2Left atrium dimension, mean±SD, mm48.0±9.3MedicationsWarfarin, n (%)9 (69)Nonwarfarin oral anticoagulant, n (%)4 (31) Open table in a new tab