BACKGROUND Myocardial rupture is an important and catastrophic complication of acute myocardial infarction. A dramatic form of this complication is a left ventricular free wall rupture (LVFWR). METHODS A 70-year-old man with acute inferoposterolateral myocardial infarction and single-vessel coronary artery disease underwent emergency percutaneous coronary intervention (PCI). The circumflex coronary artery was successfully stented with a drug-eluting stent. Fifty days after PCI the patient experienced progressive fatigue and chest pain with haemodynamic instability. Transthoracic echocardiography showed a covered LVFWR of the lateral wall. The patient underwent successful emergent surgical repair of the LVFWR. CONCLUSIONS In the current era of swift PCI, mechanical complications of acute myocardial infarction, such as LVFWR, are rare. The consequences, however, are haemodynamic deterioration and imminent death. This rare diagnosis should always be considered when new cardiovascular symptoms or haemodynamic instability develop after myocardial infarction, even beyond one month after the initial event. Timely diagnosis and emergency surgery are required for successful treatment of this devastating complication.