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]
