ECG Findings Suggestive of Lateral Wall Ischemia with Possible Inferior Involvement

Interpretation of Lead aVL Changes

Q waves with T wave inversion in lead aVL indicate lateral wall myocardial infarction or ischemia, according to the American College of Cardiology 1
Lead aVL reflects the high lateral wall of the left ventricle, and abnormal Q waves in this lead indicate mid-anterior wall MI according to newer cardiac MRI correlation studies from the American Heart Association 2, 3

When left circumflex (LCx) artery is occluded, the ST segment spatial vector is directed leftward, causing ST elevation that may be greater in lead II than lead III, and can show isoelectric or elevated ST segments in leads I and aVL, as noted by the American College of Cardiology 4, 5, 6
The trace upsloping ST elevation in inferior leads, combined with the aVL changes, suggests possible LCx involvement affecting both lateral and inferior territories, according to the American Heart Association 7

The AHA/ACCF guidelines note that what was traditionally called "posterior" MI actually represents lateral wall involvement based on cardiac MRI studies from the American Heart Association and the American College of Cardiology 4, 5, 7
Posterior chest leads (V7-V9) should be obtained if LCx occlusion is suspected, as approximately 4% of acute MIs show ST elevation isolated to these posterior leads that are "hidden" from standard 12-lead ECG, as recommended by the American College of Cardiology and the American Heart Association 2, 3, 1

The prolonged QT segment is concerning: deeply inverted T waves with QT prolongation in precordial leads indicate severe stenosis of the proximal left anterior descending artery and represent a pre-infarction state (Wellens syndrome), according to the American College of Cardiology and the American Heart Association 4, 5, 7
Patients with this ECG pattern should be considered high-risk NSTE-ACS requiring urgent coronary angiography and revascularization, as recommended by the American College of Cardiology 8

Obtain posterior leads (V7-V9) immediately to assess for hidden ST elevation from LCx occlusion, as recommended by the American Heart Association and the American College of Cardiology 2, 3, 1
Perform serial ECGs at 15-30 minute intervals or continuous 12-lead monitoring, as dynamic changes are common and a single ECG provides only a snapshot, according to the American College of Cardiology 1
Initiate immediate management, including aspirin 162-325 mg if no contraindications, ECG monitoring for arrhythmias, and nitroglycerin for symptom relief if present, as recommended by the American College of Cardiology 8
Urgent cardiology consultation and coronary angiography within 120 minutes, as recommended by the American College of Cardiology 8
Check cardiac biomarkers (troponin), though ECG changes alone warrant urgent intervention in this high-risk pattern, according to the American Heart Association and the American College of Cardiology 3, 1

Do not dismiss subtle ECG findings: misinterpretation occurs in a significant percentage of missed myocardial infarctions, as noted by the American Heart Association 2, 3
The presence of high-risk ECG features (Q waves in aVL, QT prolongation) mandates urgent evaluation even if currently asymptomatic, as recommended by the American College of Cardiology 8
Comparing to a prior ECG is valuable: an unchanged ECG reduces risk, but new changes significantly increase risk, according to the American Heart Association 2

Based on the ECG description, the most likely culprit is the left circumflex artery, given lateral wall involvement (aVL changes), inferior ST elevation with leftward vector orientation, and LCx occlusions frequently presenting with non-diagnostic standard 12-lead ECGs, requiring posterior leads for diagnosis, as noted by the American College of Cardiology and the American Heart Association 4, 5, 6, 2, 3