We recommend beta-blockers as initial therapy for rate control of AF or AFL in patients with myocardial infarction or left ventricular systolic dysfunction. (Recommendation Strong, Quality High)<br /><br /><b>Values and preferences: </b>This recommendation places a high value on the results of multiple randomized clinical trials reporting the benefit of beta-blockers to improve survival and decrease the risk of recurrent myocardial infarction and prevent new-onset heart failure following myocardial infarction, as well as the adverse effects of calcium channel blockers in the setting of heart failure.