Atrial Fibrillation and Myocardial Infarction: A Systematic Review and Appraisal of Pathophysiologic Mechanisms

Abstract

Background: A growing body of evidence suggests that atrial fibrillation (AF) is associated with myocardial infarction (MI). However, incidence and management of MI in AF is still undefined.

Methods and results: We searched MEDLINE via PubMed and Cochrane database between 1965 and 2015. All observational clinical studies and interventional trials reporting 1-year incidence of MI in AF were included. We also discussed pathophysiological mechanisms, predictors, and therapeutic approaches to reduce the risk of MI in AF. Twenty-one observational studies and 10 clinical trials were included. The annual rate of MI in observational studies including AF patients ranged from 0.4% to 2.5%. Higher rates of MI were reported in AF patients with stable coronary artery disease (11.5%/year), vascular disease (4.47%/year), heart failure (2.9%/year), and in those undergoing coronary artery interventions (6.3%/year). However, lower annual rates have been described in AF patients from Eastern countries (0.2-0.3%/year), and in those enrolled in clinical trials (from 0.4 to 1.3%/year).

Conclusions: AF patients had a significant residual risk of MI despite anticoagulant treatment. Coexistence of atherosclerotic risk factors and platelet activation account for the increased risk of MI in AF. Identification of high-risk AF patients is a needed first step to develop cost-effective approaches for prevention. A new score, the 2MACE score, has been recently developed to stratify MI risk in AF, and may help not only in allocating resources to high-risk groups, but also in design of studies examining novel therapies for prevention of MI in AF.

Keywords: atherosclerosis; atrial fibrillation; myocardial infarction.

Figure 1

Flow diagram of search strategy. AF indicates atrial fibrillation; MI, myocardial infarction; RCTs, randomized controlled trials.

Figure 2

Mechanisms of thromboembolism and atherothrombosis in atrial fibrillation (AF).

Figure 3

Holistic antithrombotic approach for the management of AF patients starting oral anticoagulation. AF indicates atrial fibrillation; CHF, congestive heart failure; EF, ejection fraction; INR, international normalized ratio; MI, myocardial infarction; TIA, transient ischemic attack; TTR, time in therapeutic range.