Although mitral valve prolapse (MVP) has shown to be associated with thromboembolic complications, the cause of thromboembolic events in those patients is still unknown. The purpose of this study was to evaluate the fibrinolytic activity in MVP patients. The study included 35 consecutive patients (25 women, mean age 25+/-11 years) with echocardiographically documented MVP and 25 age- and sex-matched subjects as a control group. Four of MVP patients have a history of transient ischemic attack (TIA). Global fibrinolytic capacity (GFC), a new technique that examines the effectiveness of the entire fibrinolytic system, was measured. Global fibrinolytic capacity was found to be nonsignificantly increased in MVP patients (3.14+/-1.42 microg/mL) compared to those in control subjects (2.36+/-1.33 microg/mL) (p>0.05). However, in four of these MVP patients who had a history of transient ischemic attack, the GFC level was significantly lower than in patients who have no history of transient ischemic attack (1.67+/-0.6 microg/mL vs 3.27+/-1.46 (microg/mL, p=0.003). Furthermore, the GFC levels of these four patients were less than those of controls (p=0.04). These results showed that global fibrinolytic activity was similar in MVP patients without a history of TIA and control subjects. However, MVP patients with a history of TIA had significantly decreased global fibrinolytic activity compared to controls and as well as MVP patients without a history of TIA.