Causes of ST Segment Elevation - Differential Diagnosis Framework



STEMI:

 • Upsloping convex STE: "Pardee's sign" + PPD

 • Opposing leads ST depression



Pericarditis/Myocarditis:

 • Diffuse ST-segment elevation (concave morphology)

 • Reciprocal ST-segment depression in aVR, not in aVL

 • PR-segment depression



Takotsubo Cardiomyopathy:

 • STE mainly in anteroseptal leads (V2-V4)

 • These disappear in a few days and are replaced by T wave inversion and a prolonged QT interval



J Wave Syndromes

 • Early Repolarization:

	- Early-repolarization pattern, with a notch at the J point in V4

	- The ST segment is concave, and the T waves are relatively tall

	- Reciprocal ST depression in aVR, not in aVL, when limb leads are involved

 • Brugada Syndrome:

	- rSR' in V1 and V2

	- ST-segment elevation in V1 and V2 typically downsloping

	- Coving ST



Secondary Repolarization Abnormalities

 • Left Bundle Branch Block:

	- QRS duration > 120ms

	- Dominant S wave in V1

	- Broad monophasic R wave in lateral leads (I, aVL, V5-6)

	- Absence of Q waves in lateral leads

	- Prolonged R wave peak time > 60ms in leads V5-6

 • Left Ventricular Hypertrophy:

	- Concave ST elevation with prominent T waves

 • Ventricular Pacing:

	- Pacing spike precedes the QRS complex

	- Right ventricle pacing lead placement results in a QRS morphology similar to LBBB

	- ST segments and T waves should be discordant with the QRS complex



Pulmonary Embolism:

 • T-wave inversion in the right precordial leads

 • ST-segment elevation, or both in the anteroseptal and inferior leads

 • S1Q3T3 pattern; complete or in-complete right bundle-branch block; and sinus tachycardia



Electrolyte Disorders:

 • Hyperkalemia:

	- ST-segment elevation

	- Widened QRS complexes; tall, pointed, tented T waves (Eiffel Tower sign) and low-amplitude or no P waves

 • Hypercalcemia:

	- J wave/Osborne waves

	- Short QT



LV Aneurysm:

 • ST elevation seen > 2 weeks following an acute myocardial infarction

 • Seen in the precordial leads

 • May exhibit concave or convex morphology



Prinzmetal's Angina:

 • Epicardial artery is episodically "pinched off" as a result of spasm, the ST segment becomes elevated in the leads facing the affected area



ST Elevation of Normal Variant:

 • Seen in V3 through V5 with inverted T waves

 • Short QT, high QRS voltage



Other Causes - STE can be seen in:

 • Hypothermia (Osborn waves)

 • Intracranial pathologies: (Cerebral T waves) Deep T-wave inversions (especially in subarachnoid or intraparenchymal hemorrhage)

 • Wolff-Parkinson-White syndrome

 • Post-cardioversion

 • Acute aortic dissection

 • Sodium-channel blocking drugs



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