Introduction
Approximately one million people in the United States experience an acute myocardial infarction (heart attack) each year.
Therapy
In the early 1980's several large-scale research studies were performed showing that beta-blocker therapy after a heart attack improved survival. The American College of Cardiology and the American Heart Association (ACC/AHA) guidelines suggest that all patients following a heart attack should be treated indefinitely with beta-blockers, unless there is a specific reason (contraindication) not to use this therapy.
Bradycardia
Despite the tremendous benefit associated with beta-blocker therapy, many patients are not treated with a beta-blocker. This is due in part to a condition called bradycardia, which is a slow heart beat rate, usually less than 60 beats per minute or other electrical conduction disease. Bradycardia or risk for bradycardia may occur when the heart's electrical system ages or gets damaged by heart disease. Patients with bradycardia may experience symptoms such as dizziness, shortness of breath or fatigue. Some patients may feel normal, without any of these symptoms.
Pacemaker
A pacemaker is a small, battery-operated device that helps prevent the heart from beating too slowly. Pacemaker implantation has very low risk even in elderly populations.
Why should I participate in this study?
Because you have recently had a heart attack and have been identified as a patient at risk for bradycardia, you are being asked to participate in this study. This study is evaluating patients who are unable to take beta-blockers or who develop bradycardia problems on beta-blocker therapy. It will examine if these patients with risk for bradycardia can benefit from beta-blocker therapy if a pacemaker is implanted to prevent the bradycardia. The study will evaluate survival rates and incidence of any new cardiac events.
