According to the international registry ICOPER, right ventricular (RV) dysfunction is the most significant predictor of mortality in patients with pulmonary embolism (PE). To identify the most informative indicators of gated blood pool single photon emission computer tomography (GBP-SPECT) for evaluation of RV function in patients with PE. A total of 52 patients were included in the study. The main group (n=37) comprised patients with PE, and the comparison group (n=15) patients suffering from coronary heart disease (NYHA class I-II). All patients received GBP-SPECT, and assessment of plasma levels of endothelin-1, stable nitric oxide (NO) metabolites, and 6-keto-PG F1α. In patients with PE, RV end-systolic volume, stroke volume, ejection fraction, peak ejection rate, peak filling rate, and mean filling rate were significantly lower in comparison with patients without PE. In patients with PE, the levels of endothelin-1, 6-keto-PG F1α, and stable NO metabolites were increased in comparison with patients without PE. GBP-SPECT facilitates verification of RV dysfunction in patients without massive PE or severe pulmonary hypertension. Dissociation between the volume of PE and degree of RV dysfunction may be caused by an unbalance between humoral vasoactive factors.