From the Guidelines
Presyncope with elevated troponin is most likely caused by conditions that lead to myocardial injury, such as acute coronary syndromes, cardiac arrhythmias, or severe pulmonary embolism, which can reduce blood flow to the brain and cause cardiac damage. The etiology of presyncope and elevated troponin can be multifactorial, but it is crucial to consider cardiac and non-cardiac causes that may lead to myocardial injury. According to the European Society of Cardiology guidelines 1, possible non-acute coronary syndrome causes of troponin elevation include chronic or acute renal dysfunction, severe congestive heart failure, hypertensive crisis, tachy- or bradyarrhythmias, pulmonary embolism, and inflammatory diseases.
When evaluating a patient with presyncope and elevated troponin, it is essential to consider the following potential causes:
- Cardiac conditions: acute coronary syndromes, cardiac arrhythmias, aortic stenosis, hypertrophic cardiomyopathy, pulmonary embolism, and cardiac tamponade
- Non-cardiac causes: severe anemia, dehydration, vasovagal reactions, orthostatic hypotension, and medication side effects
- Other life-threatening conditions: dissecting aortic aneurysm, severe pulmonary hypertension, and acute neurological disease
The management of presyncope with elevated troponin depends on the underlying cause, but it may include:
- Immediate assessment: vital signs, ECG, troponin levels, complete blood count, basic metabolic panel, and cardiac monitoring
- Treatment: antiplatelet therapy, anticoagulation, rate or rhythm control medications for arrhythmias, and fluid resuscitation if hypovolemia is present
- Prompt identification of the specific cause is essential, as treatment approaches vary significantly based on etiology. The elevated troponin indicates myocardial injury, which can result from direct ischemia due to coronary artery disease or from increased oxygen demand or decreased supply in conditions like tachyarrhythmias, hypotension, or severe anemia, as noted in the ESC guidelines 1.
From the Research
Etiology of Presyncope
- Presyncope refers to a feeling of lightheadedness or a sensation of impending faint [@\4@]
- The etiology of presyncope can be varied, including cardiac, neurological, and other causes
Elevated Troponin
- Elevated troponin levels are often associated with acute coronary syndrome (ACS) [@\1@, @\2@]
- However, elevated troponin levels can also be seen in other conditions, such as critically ill patients without ACS [@\3@]
- The prognostic value of initial elevation in cardiac troponin I level in critically ill patients without ACS is significant, with higher mortality and more intubations [@\3@]
Relationship between Presyncope and Elevated Troponin
- There is limited direct evidence on the relationship between presyncope and elevated troponin
- However, it is possible that presyncope may be a symptom of underlying cardiac conditions, such as ACS, which can cause elevated troponin levels [@\1@, @\4@]
- The electrocardiogram (ECG) is an important diagnostic tool in evaluating patients with syncope, and can help identify underlying cardiac conditions [@\4@]
Diagnostic Evaluation
- The diagnostic evaluation of patients with presyncope and elevated troponin should include an ECG, troponin levels, and other tests to rule out ACS and other underlying conditions [@\1@, @\4@, @\5@]
- The use of rapid troponin T tests can be useful in cardiac emergency triage and therapeutic decision making [@\5@]