New onset atrial fibrillation is rarely the sole manifestation of myocardial infarction. In other words, in the absence of accompanying chest pressure, dyspnea, diaphoresis, or other anginal equivalents, a rule-out ACS workup in not supported by the literature and is not cost-effective.

The two exceptions to the statement above are elderly and diabetic patients, in whom subtle presentations of ACS are common with or without atrial fibrillation.