SummaryBackground: In most cases, sudden cardiac death is triggered by ischemia-related ventricular tachyarrhythmias and accounts for 50% of deaths from cardiovascular disease in developed countries. Chronic elevation of indicators of coagulation activation has been found in patients with coronary heart disease, but a role of coagulation activation as a potential risk factor for ventricular fibrillation (VF) during acute myocardial infarction (MI) has not been investigated.Methods: We enrolled 50 patients with a history of MI, of whom 26 presented with VF in the acute phase of myocardial ischemia; 24 patients had an acute MI without ventricular tachyarrhythmias. Levels of thrombin-antithrombin complexes (TAT), prothrombin fragment F1 + 2 (F1 + 2), fibrinopeptide A (FPA), plasmin-antiplasmin complexes (PAP), protein C, antithrombin, activated partial thromboplastin time (aPTT), thromboplastin time, D-Dimer, fibrinogen, and high-sensitivity C-reactive protein (hs-CRP) were measured in plasma samples of all patients. Blood collection was obtained sequentially in two separate settings. Patients were studied at a median of 351 days after the acute coronary event.