Background: In patients with posterior wall myocardial infarction due to an occlusion of the circumflex coronary artery, a standard ECG does not show ST-elevation in half of the cases.
Case description: Two male patients aged 55 and 52 years were admitted to our hospital because of chest pain and suspected myocardial infarction. In both patients, standard electrocardiograms (ECGs) showed no signs of ischemia. Pharmacological treatment with acetylsalicylic acid, heparin, clopidogrel and nitroglycerin did not relieve their chest pain. Echocardiography and the posterior ECG leads revealed signs of ischemia in the posterior wall. Coronary angiography revealed that the circumflex coronary artery was totally occluded in both patients. They were treated successfully by percutaneous coronary intervention.
Conclusion: In approximately 50% of patients with myocardial infarction due to occlusion of the circumflex coronary artery, ST-segment elevation is limited or absent on the standard 12-lead ECG. These two cases emphasise that posterior ECG and echocardiography are valuable tools for detecting posterior wall infarction.