A single report tells the story: Ventricular fibrillation caused by vasospastic angina recorded from an implantable loop recorder.

Implantable loop recorders (ILRs) are essential for diagnosing unexplained syncope, particularly when cardiogenic causes are suspected. An 80-year-old male experienced unexplained syncope following chest tightness, with no obstructive coronary findings. A comprehensive cardiac evaluation failed to identify the underlying cause, however Holter electrocardiography showed non-sustained ventricular tachycardia, suggesting cardiogenic syncope. Therefore, we proceeded with ILR implantation. Ten days post-discharge, ILR monitoring detected ventricular fibrillation (VF) preceded by ST-T elevation and triggered by a premature ventricular contraction, confirming vasospastic angina (VSA) as the cause. This is the first documented case where VF due to VSA was diagnosed via a single ILR electrogram. ILRs thus play a crucial role in managing syncope. Learning objective: Implantable loop recorder (ILR) is useful not only for diagnosing arrhythmias in unexplained syncope, but also for identifying underlying conditions causing the arrhythmias. In this case report, ventricular arrhythmias following ST-T elevation caused by vasospastic angina were detected through a single ILR report.