From the Guidelines
Type II myocardial infarction (MI) should be managed by addressing the underlying cause of the supply-demand mismatch, such as hypertension, hypotension, tachycardia, or anemia, rather than the standard primary coronary intervention used for Type I MI. This approach is supported by the most recent guidelines, including the 2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM guideline for perioperative cardiovascular management for noncardiac surgery 1. According to this guideline, patients presenting with perioperative MI after noncardiac surgery are more likely to present with type 2 MI due to supply-demand mismatch compared with type 1 MI.
The management of Type II MI involves treating the underlying condition, such as:
- Hypotension: fluid resuscitation or vasopressors like norepinephrine (starting at 0.05-0.1 mcg/kg/min) may be needed
- Tachyarrhythmias: rate control with beta-blockers (metoprolol 5mg IV every 5 minutes up to 15mg) or calcium channel blockers might be appropriate
- Severe anemia: blood transfusion to maintain hemoglobin above 7-8 g/dL may be required Unlike Type I MI, antiplatelet therapy, anticoagulation, and coronary interventions are not routinely indicated unless concurrent coronary artery disease exists.
It is essential to monitor cardiac biomarkers like troponin and perform an echocardiogram to assess ventricular function. The prognosis depends largely on successful management of the underlying condition, with mortality rates often reflecting the severity of the primary illness rather than the cardiac injury itself, as noted in the 2020 ESC guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation 1.
From the FDA Drug Label
Myocardial Infarction Metoprolol tartrate injection is indicated in the treatment of hemodynamically stable patients with definite or suspected acute myocardial infarction to reduce cardiovascular mortality. The FDA drug label does not answer the question.
From the Research
Definition and Characteristics of Type II MI
- Type II MI is defined as myocardial infarction secondary to ischemia due to either increased oxygen demand or decreased supply 2, 3, 4.
- This type of myocardial infarction is commonly seen in hospitalized patients and is associated with increased mortality and morbidity compared to Type I MI 2, 3.
Causes and Risk Factors of Type II MI
- The main causes of Type II MI include anemia, sepsis, and arrhythmia 2.
- Patients with Type II MI tend to be older, female, and have more frequently impaired functional level and a higher GRACE risk score 2.
- These patients often have multiple comorbidities and a high-risk cardiovascular profile 2, 5.
Diagnosis and Management of Type II MI
- There is no consensus on the diagnostic criteria for Type II MI, and further investigation is urgently needed 4.
- The diagnosis of MI is reserved for patients with myocardial ischemia as the cause of myocardial injury, whether attributable to acute atherothrombosis or supply/demand mismatch without acute atherothrombosis 5.
- Optimal evaluation and treatment strategies for Type II MI have yet to be defined, but a multi-disciplinary approach including cardiology may be beneficial 3.
- Secondary prevention therapies may also play a role in decreasing adverse events from Type II MI 3.
Treatment and Outcomes of Type II MI
- Patients with Type II MI are less often referred for coronary interventions and less frequently prescribed guideline-directed medical therapy 2.
- Mortality rates are substantially higher among patients with Type II MI both at thirty-day and at one-year follow-ups 2.
- The complex medical condition of this cohort imposes a great therapeutic challenge, and specific guidelines with recommended medical treatment and invasive strategies are warranted 2.