Maximal tricuspid annular plane systolic excursion (TAPSE) correlates well with right ventricular (RV) function; however, little is known regarding the impact of left ventricular (LV) systolic function on TAPSE. Consequently, TAPSE was examined in 206 patients (105 men; mean age 56 +/- 17 years), and the data were analyzed with respect to RV (RV fractional area change 45 +/- 19%) and LV (56 +/- 17%) systolic function. The mean TAPSE for the population studied was 1.97 +/- 0.72 cm. Although a strong linear correlation was noted between RV fractional area change and TAPSE (r = 0.73, p <0.0001), relative differences with regard to TAPSE were also found. First, the greatest TAPSE was noted only when RV and LV systolic function were normal (2.46 +/- 0.50 cm). Second, patients with reduced RV systolic function had the smallest TAPSE (1.28 +/- 0.48 cm, p <0.0001). Third, patients with normal RV function but reduced LV systolic function had TAPSE (1.91 +/- 0.54 cm, p <0.0001) that was intermediate between that of patients with normal RV and LV systolic function and those with abnormal RV systolic function. Fourth, patients with reduced biventricular function had the smallest TAPSE (1.16 +/- 0.41 cm, p <0.0001). In conclusion, TAPSE is not only determined by RV systolic function but also appears to depend on LV systolic function. TAPSE <2.0 cm is associated with some degree of either RV or LV dysfunction, whereas a value >2.0 cm suggests normal biventricular systolic function.