The present report demonstrates two cases of transient inferior ST-segment elevation accompanied by profound hypotension and bradycardia immediately after transseptal puncture for catheter ablation of atrial fibrillation.This rare complication of transseptal puncture was resolved quickly within several minutes.The most likely mechanism of this phenomenon is coronary vasospasm,although coronary embolism can not be ruled out completely.This complication is characterized as follows:(1) The right coronary artery might be the most likely involved vessel and therefore myocardial ischemia usually occurs in the inferior wall of left ventricular; (2) Reflex hypotension and bradycardia by the Bezold-Jarisch reflex secondary to inferior ischemia often occur at the same time.Though it appears to be a transient and completely reversible phenomenon,there are still potential life-threatening risks because of myocardial ischemia and profound haemodynamic instability.Clinical cardiologists should be aware of this rare complication and properly deal with it.