Type 2 myocardial infarction
Type 2 myocardial infarction is myocardial necrosis from an oxygen supply-demand mismatch rather than acute plaque rupture, triggered by conditions such as tachyarrhythmia, hypotension, anemia, hypoxemia, or severe hypertension. Diagnosis requires a rising troponin with ischemia in the absence of acute atherothrombosis, and management centers on treating the underlying trigger rather than urgent antithrombotic and reperfusion therapy.
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What this article covers
- Overview
Definition: type 2 myocardial infarction is myocardial necrosis resulting from a mismatch between myocardial oxygen supply and demand, without acute atherothrombotic plaque rupture.
- Epidemiology
Increasingly recognized with high-sensitivity troponin, common among hospitalized and critically ill patients.
- Risk factors
Conditions causing demand-supply mismatch: tachyarrhythmia, hypotension or shock, severe anemia, hypoxemia, and severe hypertension.
- Pathophysiology
Supply-demand imbalance: increased demand (tachycardia, hypertension) or reduced supply (hypotension, anemia, hypoxemia) causes ischemia exceeding coronary reserve.
- Clinical features
Often overshadowed by the precipitating illness: symptoms of the trigger (arrhythmia, sepsis, bleeding) may dominate.
- Differential diagnosis
Type 1 MI: acute plaque rupture with occlusive coronary thrombosis requiring reperfusion, distinguished from type 2 by an acute culprit lesion on angiography, not a supply-demand mismatch (NSTEMI, STEMI).
- Diagnosis
Establish with the Fourth Universal Definition type 2 criteria: a rise and/or fall of troponin above the 99th-percentile upper reference limit with evidence of ischemia attributable to an oxygen…
- Management
First-line, treat the underlying trigger: control tachyarrhythmia (rate or rhythm control), restore blood pressure and perfusion, transfuse for severe anemia, correct hypoxemia, and lower severely…
- Complications
Death from the precipitating illness: the dominant driver of outcome.
- Prognosis
Determined by the underlying illness: overall mortality is high, largely reflecting the precipitant and comorbidity.
- Prevention
Prevent and promptly treat precipitating conditions: rate control of arrhythmias, avoidance of hypotension and severe anemia, and correction of hypoxemia.
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Related articles
- Non-ST-elevation myocardial infarction (NSTEMI)
Non-ST-elevation myocardial infarction is acute myocardial injury from partial or intermittent coronary occlusion, diagnosed by ischemic symptoms and a rising troponin without diagnostic ST elevation. Management is antiplatelet and anticoagulant therapy with risk stratification (TIMI or GRACE) guiding the timing of an invasive coronary strategy.
- ST-elevation myocardial infarction (STEMI)
ST-elevation myocardial infarction is acute transmural myocardial ischemia from complete coronary occlusion, diagnosed by ischemic symptoms with diagnostic ST-segment elevation and a rising troponin. It is a time-critical emergency in which immediate reperfusion, primary PCI within 90 minutes or fibrinolysis when PCI is unavailable, plus antiplatelet and anticoagulant therapy, determines survival.
- Pulmonary embolism
Pulmonary embolism is thrombus, usually from a lower-extremity deep vein thrombosis, obstructing the pulmonary arterial circulation and causing V/Q mismatch, right ventricular strain, and hypoxemia. Diagnosis follows Wells criteria (with PERC in low-risk patients) to sequence D-dimer, CT pulmonary angiography, and V/Q scanning, and management is risk-stratified anticoagulation escalating to thrombolysis or embolectomy for hemodynamic instability.
- Myocarditis
Myocarditis is inflammation of the myocardium, most often postviral or immune-mediated, presenting across a spectrum from a mild chest-pain syndrome mimicking myocardial infarction to fulminant heart failure and arrhythmia. Diagnosis relies on cardiac MRI (or biopsy for severe or refractory cases), and treatment is supportive heart-failure care, with cause-specific immunosuppression for giant cell, checkpoint-inhibitor, and autoimmune myocarditis.
- Aortic dissection
Aortic dissection is a tear in the aortic intima allowing blood to split the media, creating a false lumen, and is a surgical emergency. Type A (ascending) dissection needs emergency surgery, while type B (descending) is usually managed medically with rapid heart-rate and blood-pressure control; the priority is impulse control with a beta-blocker first.