defibrillator in acute myocardial infarction trial (DINAMIT) The Question During the first year following a myocardial infarction, commonly referred to as a heart attack, there is an increased risk of sudden cardiac arrest (SCA). A myocardial infarction (heart attack) occurs when a blood clot blocks the flow of blood to the heart muscle. Sudden cardiac arrest occurs when the lower chamber of the heart beats so fast that it cannot pump effectively. This fast heart beat is called ventricular tachycardia (VT) or ventricular fibrillation (VF). The implantable cardioverter defibrillator is a device which can shock the heart back to normal and so prevent sudden death. With other recent studies suggesting the use of implantable cardioverter-defibrillator devices (ICDs) to prolong life in certain patients at risk for SCA, would ICD therapy be effective for patients who’ve just had a heart attack? This Study DINAMIT is the first study to evaluate the use of ICDs to prevent death in high-risk patients early after myocardial infarction. The study included 674 patients who’d had a heart attack within six to 40 days, had poor cardiac pumping function, and who showed irregular heart activity while being monitored. Patients were assigned to two groups: 1) medical therapy plus an ICD, and 2) medical therapy alone. While the study demonstrated a decrease in arrhythmic mortality by more than 50%, overall mortality did not decrease. Conclusion Overall, ICD therapy is not beneficial in patients with a recent myocardial infarction. While actual arrhythmic mortality was reduced, this was offset by the increase in non-arrhythmic deaths. One explanation may be that additional stabilization of the MI patient is necessary before ICD therapy becomes an effective treatment strategy. Other therapeutic strategies need to be identified and investigated to reduce non-arrhythmic mortality in these patients. Who may be affected by these findings? Of the 865,000 myocardial infarctions in the United States each year, 565,000 are new attacks and 300,000 are recurrent attacks. Within one year after having an initial recognized myocardial infarction, 25% of men and 38% of women will die. Caveats Questions remain about how to handle the early period of time after a myocardial infarction with regard to implanting an ICD. Find this Study http://www.medscape.com/viewarticle/472003 Sponsor and Presentation National Institutes of Health; St. Jude Medical. Presented at the American College of Cardiology Scientific Sessions in March of 2004.