ST Depression Indicates ischemia; seen in subendocardial ischemia or as reciprocal changes in STEMI.
ST Elevation Indicates acute myocardial infarction (STEMI); caused by complete occlusion of a coronary artery.
Left Bundle Branch Block (LBBB) - Bunny Ears in V6 Widened QRS complex (>120 ms), broad or notched R wave in V6; can mask STEMI changes.
Right Bundle Branch Block (RBBB) - Bunny Ears in V1 Widened QRS complex (>120 ms), rsR' pattern ("bunny ears") in V1; commonly benign but may indicate strain on the right heart.
Reciprocal Changes ST depression seen in leads opposite the area of ST elevation; confirms STEMI diagnosis.
Lateral MI - Artery Affected by the Left Circumflex (LCx) or Diagonal branches of LAD.
Lateral MI - Leads ST Elevation in I, aVL, V5, V6; Reciprocal ST Depression in III and aVF.
Inferior MI - Artery Affected by the Right Coronary Artery (RCA) or Left Circumflex (LCx).
Inferior MI - Leads ST Elevation in II, III, aVF; Reciprocal ST Depression in I and aVL.
Anterior MI - Artery Affected by the Left Anterior Descending (LAD) artery.
Anterior MI - Leads ST Elevation in V1-V4; Reciprocal ST Depression in inferior leads (II, III, aVF).
Septal MI - Artery Affected by the Left Anterior Descending (LAD) artery.
Septal MI - Leads ST Elevation in V1-V2.
Posterior MI - Artery Affected by the Posterior Descending Artery (PDA) from RCA or LCx.
Posterior MI - Leads ST Depression in V1-V3 (posterior changes are viewed in reverse); confirmed with ST Elevation in V7-V9.
Right Ventricular MI - Artery Affected by the Right Coronary Artery (RCA).
Right Ventricular MI - Leads ST Elevation in V4R; often accompanies an inferior MI.