Abnormal postoperative septal motion appears directly related to cardiopulmonary bypass events, characterized by medial hypokinesis (4.9%) and lateral hyperkinesis (65.2%, p<0.0001).
Observational (n=21)
What is the mechanism underlying altered interventricular septal motion during cardiac surgery in patients undergoing their first cardiac operation?
Abnormal postoperative septal motion is caused by cardiac translation related to cardiopulmonary bypass events, rather than the removal of pericardial or mediastinal restraining forces.
p-value: p=<0.0001
Abnormal motion of the interventricular septum is frequently observed after uncomplicated cardiac surgery. We sought to elucidate the mechanism underlying this phenomenon by using continuous echocardiographic imaging of the heart from a constant transesophageal location in 21 patients undergoing their first cardiac operation. Quantitative global and regional functional analyses were performed in each patient at baseline (stage 1), after median sternotomy (stage 2), after sternal retraction (stage 3), after pericardiotomy (stage 4), after completion of cardiopulmonary bypass (stage 5), and after chest closure (stage 6). During the first four surgical stages, mean left ventricular fractional shortening varied little among regions with a fixed reference system (maximum range, 31.6-39.2%; p = NS) but changed dramatically after the discontinuation of cardiopulmonary bypass (stage 5). The apparent medial hypokinesis that was observed (4.9 +/- 4.7% SD) was accompanied by lateral hyperkinesis (65.2 +/- 4.1%, p less than 0.0001). These regional differences were completely eliminated with a floating reference system (33.6 +/- 2.7% for medial, and 34.8 +/- 1.7% for lateral; p = NS), suggesting cardiac translation. Quantitative curvature analysis supported this conclusion, with preservation of baseline regional curvature seen throughout the procedure. The mean length of individual translational vectors (reflecting systolic movement of the endocardial centroid) remained minimal (less than or equal to 1.0 mm) through stage 4 but increased more than fourfold at stage 5, continuing in a medial direction after chest closure (5.2 +/- 3.0 mm and 271 +/- 6 degrees from anterior). Thus, abnormal postoperative septal motion is not caused by removal of restraining forces of the pericardium or anterior mediastinum but rather appears to be directly related to events occurring during cardiopulmonary bypass.
Lehmann et al. (Mon,) conducted a observational in Patients undergoing their first cardiac operation (n=21). Continuous intraoperative transesophageal echocardiography vs. Baseline and various surgical stages was evaluated on Left ventricular fractional shortening and regional functional changes across surgical stages (p=<0.0001). Abnormal postoperative septal motion appears directly related to cardiopulmonary bypass events, characterized by medial hypokinesis (4.9%) and lateral hyperkinesis (65.2%, p<0.0001).