ASA administration post ischemic chest pain?

Thank you for your question. Without knowing the details of the specific patient and case, if the chest pain was thought to be ischemic in nature, it would be reasonable to treat with ASA. ASA works by inhibiting the COX-1 enzyme on platelets therefore decreasing the production of thromboxane A2, a potent platelet aggregator. This will diminish the potential platelet aggregation/thrombus formation at the site of the plaque rupture. In the case of rapid atrial fibrillation, the chest pain may be due to demand because of the tachycardia and not due to plaque rupture. This however cannot be confirmed immediately and ASA would be reasonable even if the ischemia is thought to be based on demand phenomena.