<prompt> Posterior wall MI not presentST elevation in V1-V3 leadsTall and broad R wavesTall T wavesSignificant R waves  <response>: A ST elevation in V1-V3 leads As the posterior myocardium is not directly visualised by the standard 12-lead ECG, reciprocal changes of STEMI are souht in the anteroseptal leads V1-3. Posterior Mi is suggested by the following changes in V1-3: Horizontal ST depression Tall, broad R waves 30ms Upright T waves Dominant R wave RS ratio 1 in V2. In patients presenting with ischaemic symptoms, horizontal ST depression in the anteroseptal leads V1-3 should raise the suspicion of posterior Ml. Typical appearance of posterior infarction in V2. 