Aborted Sudden Cardiac Death Due to Radiofrequency Ablation Within the Coronary Sinus and Subsequent Total Occlusion of the Circumflex Artery

We report a case of aborted sudden cardiac death and subsequent development of malignant drug‐refractory incessant ventricular tachycardia/fibrillation in a patient with acute coronary artery occlusion following radiofrequency ablation within the CS. Catheter ablation is a well‐established therapy for treatment of atrial fibrillation (AF). In patients with longstanding persistent AF extensive left atrial ablation and ablation inside the coronary sinus (CS) is frequently performed. Perimitral flutter following AF ablation is the most common form of left atrial macroreentry, especially in patients with previous ablation of complex fractionated electrograms and incomplete linear lesion sets within the left atrium. Successful ablation of this type of tachycardia is generally difficult and in about 60–70% patients requires additional ablation within the CS to achieve termination of tachycardia or/and left atrial isthmus (LAI) block. A limited number of case reports have been published describing acute coronary artery occlusion during or immediately after LAI ablation within the CS. This case exhibits a potential lethal risk of radiofrequency ablation within the CS.