ECG findings of acute myocardial infarction and atrioventricular block during a transseptal procedure for left atrial ablation.

We report on a patient with transient atrioventricular block and ST-segment elevation mimicking the ECG of myocardial infarction during transseptal puncture for radiofrequency catheter ablation of atrial fibrillation. Symptoms and EGG findings resolved spontaneously. A neurally-mediated mechanism, activated by the mechanical effects of the transseptal puncture on the interatrial septum and leading to coronary artery spasm, may be considered as a possible explanation of this phenomenon. Coronary artery embolism following the transseptal procedure represents an alternative mechanism. The above mechanisms could also explain the atrioventricular block.