Coronary artery spasm as a cause of ST elevation and inappropriate implantable cardioverter defibrillator intervention.

Coronary artery spasm can cause both brady- and tachyarrhythmia, through induction of AV block (usually linked to coronary spasm of the right coronary artery) or ventricular tachycardia/fibrillation linked to extensive myocardial ischemia. The electrocardiographic aspect of coronary artery spasm is an ST segment elevation. We describe the case of patient implanted with an implantable cardioverter defibrillator (ICD) for unexplained syncope which, during coronary artery spasm, received an inappropriate device firing due to ST segment elevation, leading to a double count of the QRS by the ICD.