Effect of cardiac surgery on ventricular septal motion: assessment by intraoperative echocardiography and cross-sectional two-dimensional echocardiography.

Echocardiographic evidence of paradoxical septal motion frequently occurs after cardiac surgery. To assess possible etiologic factors 17 patients were studied preoperatively, intraoperatively, and 7 days after surgery. Preoperative septal motion was normal in 14 and paradoxical in three (two with previous cardiac surgery, one with atrial septal defect [ASD]). Intraoperative septal motion prior to surgical procedure was normal in 16 and paradoxical in one (ASD). Septal motion (excursion and thickening fraction) was normal in all patients prior to chest closure. Echocardiograms of adequate quality were obtained at 7 days post surgery in 15 patients; septal motion was paradoxical in nine (group A) and normal in six (group B). No significant differences were seen between the two groups in ischemic time or in the preoperative to postoperative change in left ventricular (LV) and right ventricular diastolic dimension, shortening fraction, or septal and posterior wall thickening fraction. A significant postoperative decrease in septal excursion was seen in group A but not in group B; significant postoperative increases in posterior wall excursion were seen in both groups. Cross-sectional two-dimensional echocardiograms performed in 20 patients (8 normal, 12 postoperative paradoxical septal motion) were analyzed. In normal controls no significant change was detected in the LV centroid position during systole. In contrast, the 12 postoperative patients showed significant anterior displacement of the LV centroid and right septum during systole. Thus, paradoxical septal motion after cardiac surgery appears to relate to excessive anterior cardiac mobility due to pericardiotomy rather than to myocardial ischemia resulting from cardiopulmonary bypass.