What EKG change indicates a lateral myocardial infarction?

The indication of a lateral myocardial infarction on an electrocardiogram (EKG) is characterized by elevation in leads I and aVL. These leads are positioned over the left lateral aspect of the heart; therefore, they provide direct insight into the electrical activity and blood supply of the lateral wall of the left ventricle.

When a lateral myocardial infarction occurs, it typically results from an occlusion of vessels such as the circumflex artery, which supplies that region. As the infarcted myocardial tissue becomes ischemic, it manifests as ST segment elevation in these specific leads.

The other options reflect different areas of myocardial injury or physiological states. Elevation in leads II, III, and aVF would suggest an inferior wall MI. Depression in leads V1-V3 may indicate anterior ischemia or possible non-ST elevation myocardial infarction, but it does not specifically pinpoint lateral involvement. Normal sinus rhythm indicates absence of acute myocardial ischemia or infarction, making it inconsistent with any infarction diagnosis.

Understanding the specific lead changes is crucial not only for diagnosis but also for guiding further management and intervention for patients experiencing myocardial infarction.