Role of right ventricular asynergy and tricuspid regurgitation in hemodynamic alterations during acute inferior myocardial infarction.

To elucidate the role of right ventricular asynergy and tricuspid regurgitation (TR) in hemodynamic alterations occurring during right ventricular infarction, left and right ventriculography with pressure measurements were performed in 22 patients with acute inferior myocardial infarction. Twelve patients with a proximal right coronary artery (RCA) occlusion (Group I) had elevated right atrial pressure (16 +/- 4 vs 8 +/- 5 mmHg, p less than 0.01), low cardiac output (2.5 +/- 0.7 vs 3.5 +/- 0.6 l/min/m2, p less than 0.05) and a greater degree of TR, compared with 10 patients with a distal RCA occlusion (Group II). Inferoposterior wall asynergy of the right and left ventricles was similar in Groups I and II. In Group I, there was an additional asynergy of the anterolateral free wall of the right ventricle. Cardiac output in those patients was not related to the left ventricular ejection fraction (EF) but to the right ventricular EF. A greater degree of TR was found in association with a lower right ventricular EF. The decrease in cardiac output was closely related to the extent of TR. These results indicate that right ventricular asynergy and TR due to proximal RCA occlusion may play important roles as causes of hemodynamic alterations seen during the acute phase of inferior myocardial infarction.