['To evaluate the release of cardiac troponin I in normotensive patients with acute pulmonary embolism in relation to the duration of symptoms.', 'Fifty-seven normotensive patients with acute pulmonary embolism were included in the study. Patients were divided into two groups based on the duration of symptoms at presentation: symptoms of < or =72 h, group A; symptoms of >72 h, group B. Serum cardiac troponin I levels were measured at presentation.', 'Mean age was 63+/-18 years and 23 (40%) patients were males. Thirty-three (58%) patients had symptoms of < or =72 h (group A) and 24 (42%) had symptoms of >72 h (group B). Both groups had similar prevalence of right ventricular dysfunction on echocardiography (55% [n=18] in group A vs. 42% [n=10] in group B, p=NS). Sixteen patients had elevated serum cardiac troponin I (mean+/-S.D. 3.3+/-2.3 ng/ml, range 0.6-8.3 ng/ml). Elevated serum cardiac troponin I was strongly associated with right ventricular dysfunction (p=0.015). All patients with elevated serum cardiac troponin I (n=16) were in group A (p<0.0001). Twelve of 18 (67%) patients with (p=0.0005) and 4 of 15 (27%) patients without (p=NS) right ventricular dysfunction had elevated serum cardiac troponin I. Thirteen of 16 (81%) patients with elevated serum cardiac troponin I had duration of symptoms < or =24 h at presentation.'] Do cardiac troponin I release in acute pulmonary embolism in relation to the duration of symptoms?