The differences in the clinical findings of patients with acute pulmonary thromboembolism (acute-PTE) and chronic pulmonary thromboembolism (chronic-PTE) were compared, and the association between the clinical findings and prognosis in the two groups was analyzed. This study included 204 patients with PTE, 139 patients with acute-PTE and 65 patients with chronic-PTE. There were significant differences between acute-PTE and chronic-PTE in the predisposing factors of post operation (19.4 versus 1.5%, p = 0.0003), and electrocardiographic signs such as sinus tachycardia (73.7 versus 50.9 %, p = 0.007), ST-depression (25.3 versus 9.4%, p = 0.03), right ventricular hypertrophy (20.0 versus 47.2%, p = 0.0007), and right axis deviation (3.2 versus 22.6%, p = 0.0003). Thirty-one of the 139 acute-PTE patients died from PTE, as did 17 of the 65 chronic-PTE patients. The prognosis was poor in patients older than 70 years old (p = 0.01), with stroke (p = 0.008), syncope (p = 0.01), shock (p = 0.0006), hypocapnia (PaCO2 < or = 25 torr; p = 0.0006) and an elevation in total pulmonary resistance (TPR >1,000 dyne-sec cm(-5) (p = 0.02)) in acute-PTE, and in those with syncope (p = 0.03), shock (p = 0.008), and right ventricular hypertrophy on electrocardiogram (p = 0.03) in chronic-PTE. The results of this study indicate a relationship between the clinical features of patients with acute-PTE and chronic-PTE, and the predictors of in-hospital mortality.