Two distinct stages and mechanisms of ST-elevation during cryothermal cavotricuspid isthmus ablation guided by intracardiac echocardiography: A case report

Radiofrequency (RF) catheter ablation is the primary treatment for cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL), with cryothermal energy as an alternative. While cryoablation offers comparable effectiveness and safety to RF ablation, it poses a risk of coronary artery spasm leading to ST-elevation. This case report presents a 65-year-old man with drug-refractory atrial fibrillation (AF) and AFL undergoing cryothermal CTI ablation guided by intracardiac echocardiography (ICE). During the procedure, two distinct ST-elevation episodes were observed. The first episode coincided with the pull-down of the cryoablation catheter, potentially resulting in coronary compression, as indicated by ICE, and was rapidly resolved by discontinuing the freezing process. The second episode, occurring without active freezing, was attributed to coronary artery spasm and resolved with intracoronary nitroglycerin administration. During the second episode, emergent right coronary angiography confirmed total occlusion in the segment 4 AV adjacent to the region where cryoablation was performed, which fully resolved post-nitroglycerin. This report underscores the dual mechanisms of ST-elevation-coronary artery compression and spasm-during cryothermal CTI ablation, highlighting the critical role of ICE in enhancing procedural safety.