ECG Manifestations of Lateral Myocardial Ischemia
Lateral myocardial ischemia typically produces ischemic ST-T abnormalities in the lateral precordial and high lateral limb leads. [1] The lateral territory corresponds to leads I and aVL and leads V5 and V6. [1]
Typical ECG Changes
Lateral ischemia is commonly reflected by ST-segment depression and/or T-wave inversion in lateral leads. [1] Subendocardial ischemia can produce ST-segment depression with upright or positive T waves, depending on the pattern and severity of ischemia. [1]
Acute STEMI-Pattern Implications
If lateral ischemia is extensive enough to produce ST-segment elevation in lateral leads, this pattern is consistent with acute lateral ST-elevation myocardial infarction (STEMI). [1] Lateral STEMI commonly involves ST-segment elevation in leads I (and aVL) and V5–V6. [1]
Reciprocal ECG Changes
When lateral zone involvement is predominant, reciprocal ST-segment depression can be observed in leads V1–V3. [1] Reciprocal change supports an acute ischemic process in the setting of compatible symptoms and serial ECG evolution. [1]
Anatomic and Vascular Localization Implications
Lateral ECG ischemic or infarct patterns localize myocardial injury to the lateral wall rather than the septal or inferior wall distribution. [1] Different culprit lesion locations can produce lateral patterns, including circumflex-related territory or diagonal-related territory depending on the exact lead distribution. [1]
Practical Interpretation Considerations
Ischemic-appearing lateral ST-T changes should be interpreted in clinical context due to overlap with nonischemic ST-T abnormalities. [1] Serial ECGs and troponin testing are required to distinguish ischemia from infarction and to determine acuity. [1]
Clinical Severity Correlation
More severe ischemia tends to produce more prominent and widespread ST-T abnormalities across the lateral leads. [1] Severe ischemia is associated with regional wall-motion abnormalities detectable by imaging when clinically indicated. [0]