Diagnosis and Management of Type 2 NSTEMI

Diagnostic Criteria

The European Society of Cardiology recommends that Type 2 NSTEMI is diagnosed when elevated cardiac troponin (above the 99th percentile) occurs in the setting of myocardial oxygen supply-demand mismatch WITHOUT acute coronary atherothrombosis, requiring identification of a precipitating condition such as tachyarrhythmia, hypotension, anemia, hypoxemia, hypertension, coronary spasm, or coronary microvascular dysfunction 1, 2
The diagnosis requires all three of the following components: Elevated cardiac troponin, Clinical evidence of myocardial ischemia, and Absence of acute coronary atherothrombosis, as recommended by the European Society of Cardiology 1, 2

The critical distinction is identifying the underlying mechanism, with Type 2 MI resulting from supply-demand mismatch from conditions like severe hypertension, tachyarrhythmias, severe anemia, hypotension, respiratory failure, coronary artery spasm, spontaneous coronary artery dissection, coronary embolism, or coronary microvascular dysfunction, as stated by the European Society of Cardiology 1, 2

The European Society of Cardiology recommends looking specifically for high-risk features that suggest Type 2 MI, including hemodynamic instability, arrhythmias, and metabolic/systemic conditions 3, 2
Obtain 12-lead ECG within 10 minutes of presentation, as recommended by the American Heart Association 4, 5, 6

High-sensitivity cardiac troponin is the preferred biomarker, with initial measurement at presentation and repeat measurement using validated algorithm, as recommended by the European Society of Cardiology 1, 6
High-sensitivity assays are associated with a 2-fold increase in detection of Type 2 MI compared to standard assays, according to the European Heart Journal 3

Physical examination findings that increase suspicion for alternative diagnoses or precipitating conditions, such as blood pressure differences between limbs, irregular pulse, new systolic murmur, and signs of heart failure, should be considered, as stated by the European Society of Cardiology 3, 6, 1

The primary focus of treatment for Type 2 NSTEMI is to treat the underlying precipitating condition, as recommended by the European Society of Cardiology 1, 2

Fever‑induced tachycardia during influenza B infection creates a supply‑demand mismatch that can precipitate Type II NSTEMI. 7 (expert consensus)

ST‑segment depression as low as 0.05 mV (0.5 mm) on a standard 12‑lead ECG predicts adverse outcomes in NSTEMI patients. 8 (observational cohort study)

Aggressive antiviral therapy and supportive care for influenza B are advised to treat the underlying precipitating condition of Type II NSTEMI. 7 (expert consensus)
In patients with influenza infection who have mild troponin elevation (≈ 2–3 × the upper limit of normal) together with ST‑segment depression, routine coronary angiography is not required unless there are strong clinical indicators of a Type I MI (e.g., typical angina). 7 (expert consensus)
Marked troponin elevations (> 5 × the upper limit of normal) in the setting of influenza may signal severe respiratory failure, shock, or a concurrent Type I MI and should trigger further diagnostic work‑up. 7 (expert consensus)
When troponin is markedly elevated but a Type I MI is not clinically evident, echocardiography should be considered to help identify the underlying cause. 7 (expert consensus)