A young mountaineer suffered from sudden cardiac arrest at high altitude. Cardiopulmonary resuscitation was initiated immediately. After 30 min a rescue team arrived and successfully defibrillated ventricular fibrillation upon which spontaneous circulation returned. The subsequent ECG was suggestive of extensive anterior myocardial infarction. Therefore, the patient was thrombolysed and transferred for primary percutaneous coronary intervention. Echocardiography revealed severely reduced left ventricular function with antero-septo-apical akinesia. However, angiography showed unobstructed coronary arteries. The patient fully recovered and left ventricular function normalised within 2 weeks. It may be speculated that exposure to high altitude resulted in acute coronary thrombosis which dissolved by rapid thrombolysis.