Atrial Fibrillation in Acute Coronary Syndrome.

Atrial fibrillation (AF) is a common cardiac arrhythmia occurring in an estimated 2.7 to 6.1 million people in the United States. The risk factors for the development of AF are very similar to those for developing coronary artery disease, and AF is often associated with acute coronary syndrome (ACS) and acute myocardial infarction (MI). Overall, AF complicates approximately 10% of acute infarcts and the incidence rate is comparable between the thrombolytic and percutaneous coronary intervention (PCI) eras. Prior to widespread use of thrombolysis, the incidence of AF during acute MI was as high as 18%. Moreover, AF is a marker for increased long term mortality post infarct. Over the past 20 years, the relative mortality risk for patients with AF post MI has remained around 2.5 times that for patients without AF. The treatment of AF in the setting of MI and ACS is similar to without; however there is often an increased urgency to limiting rapid heart rates which may exacerbate acute ischemia. Cardioversion and IV amiodarone may be utilized more liberally in this setting than otherwise. Anticoagulation is usually required both for the treatment of MI and possible PCI, as well as for cerebral vascular accident prevention from AF-induced thromboembolism. Often patients require triple-therapy for optimal treatment of both conditions, and special considerations for bleeding risk must be analyzed.