A 12-lead electrocardiogram (ECG) demonstrating diagnostic findings of an acute inferior wall myocardial infarction (ST-elevation myocardial infarction, or STEMI). The primary findings include significant ST-segment elevation in the inferior leads (II, III, and aVF), marked with black stars. Concurrently, there is evidence of reciprocal ST-segment depression in the high lateral leads (I and aVL), indicated by yellow stars. The precordial leads (V1-V3) also exhibit prominent ST-segment depression, which can suggest posterior wall involvement or reciprocal changes from the inferior injury. The inferior leads show a 'shark fin' morphology, characterized by a fusion of the QRS complex, ST segment, and T wave, typically indicating a large area of transmural ischemia. The rhythm appears to be a junctional or sinus bradycardia/tachycardia depending on the clinical phase, with evident electrical instability. This ECG is a critical educational example for identifying acute coronary syndrome and understanding the relationship between anatomical lead groups and reciprocal changes.

This diagnostic image is a 12-lead electrocardiogram (ECG) demonstrating signs of an acute inferior wall ST-elevation myocardial infarction (STEMI). The tracing reveals significant ST-segment elevation in the inferior leads (II, III, and aVF), with the elevation being most pronounced in lead III compared to lead II. Accompanying these changes is evidence of reciprocal ST-segment depression and T-wave inversion in the high lateral leads, specifically I and aVL. The precordial leads (V1-V6) show preserved R-wave progression without significant ST-segment deviations or QRS widening. The rhythm appears to be sinus bradycardia with a regular rate. This ECG is a classic representation of acute myocardial ischemia or infarction involving the territory of the right coronary artery (RCA). It serves as an educational tool for identifying inferior STEMI patterns, understanding reciprocal changes in lateral leads, and differentiating localized ST elevations from diffuse patterns.

This diagnostic image is a 12-lead electrocardiogram (ECG) demonstrating an acute inferior myocardial infarction. The tracing shows marked ST-segment elevation in the inferior leads (II, III, and aVF), highlighted by red rectangular annotations. Concurrently, reciprocal ST-segment depression is visible in the precordial leads (V2 through V6), indicated by a blue rectangular annotation. The rhythm appears to be a sinus rhythm with a prolonged PR interval, suggestive of a first-degree atrioventricular block, and there is evident bradycardia. The ECG morphology is characteristic of an evolving ST-elevation myocardial infarction (STEMI) involving the inferior wall, often associated with right coronary artery occlusion. This visual material is intended for medical students and clinicians to learn the identification of ischemic patterns, specifically inferior wall injury and the importance of recognizing reciprocal changes in the anterior and lateral leads.