Localizing the Infarct by Lead Groups
Flashcards mapping EKG lead groups to myocardial walls, culprit coronary arteries, and reciprocal change patterns.
Keyboard Shortcuts
💡 Pro tip: Use keyboard shortcuts for faster studying!
Study Smart Tips for Localizing the Infarct by Lead Groups
Master these concepts using proven study techniques that actually work:
Active Recall
Test yourself before flipping each card to strengthen memory retention
Spaced Repetition
Review difficult cards more frequently than easy ones
Multiple Sessions
Break study time into shorter, focused sessions
Explain Aloud
Verbalize answers to reinforce understanding
Questions Covered in This Set
10 cards to master
Which leads view the septal wall, and what artery feeds it?
V1–V2; the LAD via its proximal septal perforator branches.
Which leads view the anterior wall, and what is the usual culprit artery?
V3–V4; the LAD.
Which leads represent the high lateral wall and their usual culprit vessel?
I and aVL; the left circumflex (LCx) or first diagonal branch.
Which leads represent the inferior wall, and which artery is responsible ~80–85% of the time?
II, III, aVF; the RCA (LCx in about 15–20%).
How does a posterior STEMI appear on a standard 12-lead?
As a mirror image in V1–V3: ST depression, tall broad R waves, and upright T waves. Confirm with V7–V9 (≥0.5 mm elevation is diagnostic).
How do you distinguish RCA from LCx as the culprit in an inferior MI?
RCA: ST elevation in III > II with ST depression in I and aVL. LCx: II ≥ III, often with elevation in I, aVL, V5–V6.
What finding confirms right ventricular infarction, and why does it matter?
ST elevation in V4R (from proximal RCA occlusion). These patients are preload-dependent — avoid nitroglycerin, give fluids.
What EKG features suggest a proximal LAD occlusion?
ST elevation V1–V4 plus aVL, reciprocal inferior ST depression, often new RBBB or left anterior fascicular block; large territory, high mortality.
What pattern suggests left main or proximal triple-vessel disease?
Widespread ST depression in 6+ leads with ST elevation in aVR (and often V1) — a red-alert finding, not a classic STEMI.
Why should a perfectly normal aVL make you doubt an inferior STEMI?
Inferior injury almost always produces reciprocal ST depression in aVL; without it, consider pericarditis instead.
