II. Measurement
- Measure at 0.04 sec (1 mm) after the J-Point
- Compare to baseline (line drawn from P start to T end)
III. Causes: General
- Acute Myocardial Infarction
- See Electrocardiogram in Myocardial Infarction
- Type A Aortic Dissection may also cause Coronary Artery dissection (esp. right Coronary Artery)
-
Pericarditis
- Diffuse ST Elevation
-
Left Bundle Branch Block
- Findings
- Left Bundle Branch Block in lead V1
- QRS Duration > 120 ms
- QRS Complex negative (down) in V1
- Left ventricular activation delay
- Hides ST Segment Elevation
- Evaluate new LBBB as Acute Coronary Syndrome
- Findings
-
Pacemaker with paced beats from right ventricle
- Left Bundle Branch Block in V1 with pacer spike
- Not possible to diagnose Acute MI
-
Left Ventricular Hypertrophy
- Increased QRS Complex amplitude
- ST Segment Elevation/depression in precordial leads
- T Wave direction opposite to QRS Complex
- Not possible to diagnose Acute MI
-
Early Repolarization
- More common in black men, young and athletes
- Concave upwards (smiley) elevation
- Other causes
- Prinzmetal's Angina
- Hyperkalemia
- See Hyperkalemia Related EKG Changes
- ST Depression is more common
- Associated with Wide QRS, Bradycardia, Peaked T Waves
- Neurologic catastrophe (e.g. Subarachnoid Hemorrhage)
- Pulmonary Embolism
- Wolff-Parkinson-White Syndrome (WPW Syndrome)
- Tricyclic Antidepressant Overdose
- Brugada Syndrome
- Global Myocardial Ischemia
- Left Ventricular aneurysm
- LV Aneurysm is a complication following Myocardial Infarction
- Diffuse ST Elevation without reciprocal changes
IV. Causes: Diffuse ST Elevation
- Large acute Myocardial Infarction
-
Acute Pericarditis
- See EKG in Pericarditis
- Other findings include PR Segment Depression and downsloping
- Benign Early Repolarization
-
Left Ventricular Hypertrophy
- See Left Ventricular Hypertrophy Related EKG Changes to calculate voltage criteria
V. Causes: aVR ST Elevation with Diffuse ST Depression
-
Acute Coronary Syndrome (ACS)
- Major Coronary Vessel insufficiency (esp. AVR ST Elevation > V1)
- Left Main Coronary Artery (LMCA)
- Proximal Left Anterior Descending Artery (LAD)
- Triple Vessel Disease
- Global Cardiac Ischemia
- Prinzmetal Angina
- Major Coronary Vessel insufficiency (esp. AVR ST Elevation > V1)
- Other Non-ACS Causes
- Severe Anemia
- Aortic Dissection
- Left Bundle Branch Block or ventricular Pacemaker
- Left Ventricular Hypertrophy with strain
- Pulmonary Embolism
- Return of Spontaneous Circulation (ROSC) after Cardiac Arrest
- Severe Potassium disorder (Hypokalemia, Hyperkalemia)
- Sodium channel blockade
- Supraventricular Tachycardia (esp. very rapid rates)
- References
- Berberian, Brady and Mattu (2023) Crit Dec Emerg Med 37(1): 10-11
VI. References
- DeMeester and Swaminathan in Swadron (2022) EM:Rap 22(8): 9-10
- Mattu (2022) Crit Dec Emerg Med 36(8): 13
- Wang (2003) N Engl J Med 349:2128-35 [PubMed]