Unlike left ventricular function, right ventricular (RV) function has not been widely studied after a myocardial infarction (MI). The current study describes RV function determined by tricuspid annular motion and tricuspid annular velocity after MI. Thirty-eight patients with a first acute inferior MI were prospectively compared with 33 patients with a first anterior MI and 24 age-matched healthy individuals. Association of RV infarction in inferior MI was defined as the presence of >/=1-mm ST-segment elevation at the right precordial lead, V(4)R, of the electrocardiograms. From the echocardiographic apical 4-chamber views, the systolic motion of the tricuspid annulus was recorded at the RV free wall with the use of 2-dimensional guided M-mode recordings. Peak systolic and peak early and late diastolic velocities of the tricuspid annulus at the RV free wall also were recorded with the use of pulsed-wave Doppler tissue imaging. The tricuspid annular motion was reduced in inferior MI compared with that in healthy individuals (20.5 and 25 mm, P <.001). The peak systolic velocity of the tricuspid annulus was significantly reduced in inferior MI compared with that in healthy individuals (12 vs 14.5 cm/s, P <.001) and patients with anterior MI (12 and 14.5 cm/s, P <.001). Patients with inferior MI were divided into 2 subgroups: those with and those without electrocardiographic signs of RV infarction. The tricuspid annular motion was significantly lower in patients with RV infarction than in patients without RV infarction (17 and 22.7 mm, P <.001). In addition, compared with patients without electrocardiographic signs of RV infarction, patients with RV infarction also had a significantly decreased peak systolic tricuspid annular velocity (13.3 and 10.3 cm/s, P <.001) and peak early diastolic velocity (13 and 8.2 cm/s, P <.001). These results suggest that tricuspid annular motion and tricuspid annular velocity can be used to assess RV function in association with inferior MI.