ABSTRACT
STEMI is not seen in an acute posterior myocardial infarction unless an ECG is recorded using posterior leads, V7-V9, on the back of the chest. Posterior myocardial infarctions are therefore commonly overlooked, or misdiagnosed as anterior wall ischaemia. Using posterior leads helps to distinguish between the two diagnoses. • In the clinical context of acute chest pain with
ST segment depression in the anterior or anteroseptal leads, always consider the possibility of posterior myocardial infarction. • Posterior myocardial infarction is one cause of a
‘dominant’ R wave in lead V1. Other causes are: • right ventricular hypertrophy • Wolff-Parkinson-White syndrome with a
left-sided accessory pathway.
