The absence of chest pain in no way excludes the diagnosis of ACS. Around 33-50% of the patients with ACS present to the hospital without chest pain. Close to 20% of patients diagnosed with acute MI present with symptoms other than chest pain. Risk factors associated with the absence of chest pain included age, female gender, non-white race, diabetes mellitus, and a prior history of congestive heart failure or stroke. Over the age of 85, 60–70% of patients with acute MI present without chest pain; shortness of breath is the most frequent anginal equivalent in this population.
Patients experiencing an acute MI without chest pain are more likely to suffer delays in their care. They were also more likely to die in the hospital compared to patients who presented with chest pain. Over the age of 85, 60–70% of patients with acute MI present without chest pain.
A normal ECG and normal cardiac enzymes rule out ACS
Cardiac markers provide a non-invasive means of determining whether myocardial damage has occurred. When ischemia gives way to infarction, the myocardial cell membrane is disrupted and various chemical markers are released into the systemic circulation.
Cardiac Troponins (I or T) are now the preferred cardiac markers for identifying myocardial damage. It is important to remember that troponin can only detect myocardial cell death but not ischemia.
- Do not exclude the diagnosis of acute cardiac ischemia or MI based on the absence of pain, especially when evaluating dia- betic patients, the elderly, and women.
- Never use reproducible chest wall tenderness to exclude the diagnosis of acute MI.
- Neither a single normal ECG nor a single negative set of cardiac enzymes should be used to rule out acute cardiac schema.
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