Late‐onset lethal arrhythmia after catheter ablation
A 73‐year‐old man with drug‐resistant paroxysmal common atrial flutter (AFL) and atrial fibrillation (AF) was referred to our center for catheter ablation. He had no structural heart disease or any history of angina. The initial rhythm was common AFL, and the procedure was performed under moderate sedation with dexmedetomidine. Coronary angiography prior to the ablation showed normal coronary arteries. A cavotricuspid isthmus (CTI) linear ablation was performed using an irrigated‐tip catheter (SmartTouch, Biosense Webster, Diamond Bar, CA, USA), and sinus rhythm was restored. Subsequently, a pulmonary vein antrum isolation was performed. No complications were observed during the procedure, and the patient returned to the ward. Two hours after the procedure, ventricular fibrillation (VF) occurred suddenly. The patient was successfully resuscitated by external cardioversion and an additional intravenous nitroglycerin injection. The bedside continuous single‐lead electrocardiogram (ECG) monitoring disclosed progressive ST‐segment elevation and subsequent atrioventricular block, followed by VF 10 minutes after the start of the ST elevation (Figure 1). The patient was discharged on the fifth day after the procedure, and had no recurrent angina without vasodilators or antiplatelet drugs during 12 months of follow‐up.
ST‐segment elevation suggested a coronary occlusion due to vasospasms or an embolism; however, the former was most likely given so that he had normal coronaries just before the ablation procedure, prompt ST‐segment recovery with a nitroglycerine injection, and no recurrence during the follow‐up. Coronary spasms are a rare but important complication of catheter ablation. Both the CTI and left atrial ablation could provoke coronary spasms regardless of the energy source. The mechanisms of coronary spasms are still under debate; however, direct thermal injury and an autonomic nerve activity imbalance via ganglionated plexi are the proposed mechanisms. Generally, they occur in the right coronary artery during the procedure, and a late onset is rare. Along with the progression of the technologies and because of economical reasons, recently hospital stays have become shorter and day surgery is proposed. The present case highlighted the importance of careful bedside continuous ECG monitoring not only during the procedure, but also presumably at least for one night after the CTI and/or AF ablation.