Differentiating Between Demand Ischemia and Type II MI
Demand Ischemia
Represents symptoms consistent with myocardial ischemia primarily due to oxygen supply-demand imbalance WITHOUT ELEVATED TROPONINS above the 99th percentile.
Demand Ischemia Etiologies
- Brady of tachy-arrythmia
- Aortic dissection
- Severe aortic valve disease
- Hypertrophic cardiomyopathy
- Shock (septic, cardiogenic, ect.)
- Coronary spasm
- Coronary embolism
- Coronary vasculitis/arteritis/endarteritis
- Coronary endothelial dysfunction
- Hypertensive crisis
- Anemia
Example: 66 year old male presents with paroxysmal atrial tachycardia and substernal chest pressure with ventricular rate of 180. Troponins were 0.01/0.03/0.02. PAT and a troponin leak were documented.
This clinically supports Demand Ischemia since the troponins were present but not above the criteria with evidence of acute ischemia (chest pressure).
Type II MI
Type II MI is evidenced by an acute myocardial ischemia without acute coronary atherothrombotic injury. It is caused by an oxygen supply-demand imbalance WITH ELEVATED TROPONINS from the same demand ischemia etiologies.
Type II Criteria
- Detection of a rise and/or fall of cTn values with at least 1 value above the 99th percentile requiring at least one of the following symptoms or test findings:
- Symptoms of acute myocardial ischemia
- New ischemic ECG changes
- Development of pathological Q waves
- Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality in a pattern consistent with ischemia etiology
Example: 82 year old male admits with B/P 250/135, neck and shoulder pain and SOB. EKG show non-specific ST and T wave changes. Troponin were 0.08/1.5/1.8. #1 HTN emergency and #2 NSTEMI probably due to #1-probably demand ischemia is documented.
This clinically supports a Type II MI based on elevated troponins with findings and symptoms of ischemia (EKG changes, neck and shoulder pain and SOB).