Functional consequences of interventricular septal involvement in right ventricular infarction: echocardiographic, clinical, and hemodynamic observations.

Although ischemic involvement of the interventricular septum (IVS) may occur in patients with right ventricular infarction (RVI), the potential functional significance of such involvement has not been explored. In 10 patients with hemodynamically evident RVI, ischemic involvement of the IVS was assessed by measuring IVS systolic thickening on M-mode echocardiography. Six patients (group I) had decreased IVS systolic thickening, an echocardiographic indicator of ischemia, or infarction, while four (group II) did not. Group I had significantly higher right ventricular filling pressures (19 +/- 3 vs 12 +/- 5 mm Hg, p = 0.04) and right ventricular end-diastolic echocardiographic dimensions (32 +/- 8 vs 20 +/- 3 mm; p = 0.02) than group II. Paradoxic septal motion was noted only in group I patients (p = 0.01). Left ventricular filling pressures, left ventricular end-diastolic dimensions, and systolic thickening of the left ventricular posterior wall (LVPW) were not significantly different between the groups. Three group I patients died; all had decreased systolic thickening of both the IVS and LVPW. In each, autopsy confirmed infarction of the right ventricular free wall, IVS, and LVPW. In patients with right ventricular infarction, ischemic involvement of the interventricular septum may have important consequences for both right and left ventricular function.