Manifestation of J wave induced by acetylcholine applied for a coronary spasm provocation test in a patient with aborted sudden cardiac death.

A 51-year-old man with a resuscitation episode was referred to our hospital. Coronary angiography revealed a focal spasm overlapped with organic stenosis where a bare metal stent was implanted. Acetylcholine (ACh) provocation test did not induce chest pain. It revealed no discernible ST-T changes but unmasked a J wave at the end of the QRS complex, which was associated with short-coupled repetitive premature ventricular beats. A J wave reportedly appears immediately before the onset of ventricular fibrillation caused by vasospastic angina. However, a J wave observed newly after a coronary spasm provocation test using ACh without ST-T changes is informative when considering the mechanisms of the J wave.