Sudden death is a natural death occurring within one hour after the onset of symptoms. It remains a major public health problem and accounts for 5 to 10

• of the annual total mortality ie about 300.000 in the United States. Despite community-based interventions, overall survival remains below 5%. Better understanding of the mechanisms causing sudden death could allow early identification of high risk subjects and implementation of specific prevention strategies. The cause of more than 90% of sudden deaths is cardiac with ventricular fibrillation or fast ventricular tachycardia complicating an underlying heart disease. Coronary heart disease and its consequences account for at least 80% of sudden cardiac deaths. Several risk factors associated with sudden death and not with myocardial infarction have been identified in population-based studies. However, the relationship between the occurrence of a coronary artery occlusion and the onset of arrhythmia is unclear. In particular, coronary artery occlusion can be rapidly followed by chest pain, which acts as a signal and allows identification of patients for emergency reperfusion. However, in some cases, the coronary artery occlusion is followed by a sudden onset of arrhythmia and sudden death. Recent data suggest that acute coronary occlusion is caused by plaque erosion or rupture and is followed by an intense local inflammation and rapid thrombus formation. Our hypothesis is that the speed of thrombus formation and coronary occlusion determines the clinical symptoms. Slow and progressive thrombus formation is likely to induce myocardial pre-conditioning thereby reducing the occurrence of ventricular arrhythmia. In contrast, rapid thrombus formation followed by acute coronary artery occlusion and ischemia is more likely to trigger fatal ventricular arrhythmia. During angioplasty procedures, coronary artery thrombus are aspirated, providing the opportunity for pathological studies. The aim of the TIDE study (Thrombus and Inflammation in Sudden Death) is therefore to compare the composition and age of thrombus collected at the site of coronary occlusion in patients with sudden death due to acute coronary artery occlusion and patients with an acute myocardial infarction without ventricular arrhythmia. The following hypothesis will be tested : fresh thrombus is more frequent in patients with sudden cardiac death versus patients with acute myocardial infarction without ventricular arrhythmia.