Paradoxical septal motion after cardiac surgery: a review of 3,292 cases

Paradoxical septal motion (PSM) is the systolic movement of the interventricular septum toward the right ventricle despite normal thickening. The PSM is a frequent echocardiographic finding after cardiac surgery. Although it is universally recognized, there has been no large-scale study to correlate PSM with the type of surgical procedure. The cause of PSM is unknown; prevailing theories include: (1) operation on the heart alters the degree to which it is restrained by the pericardium and the chest wall and (2) transient ischemia alters septal motion.

The PSM is related to type of surgery and surgical approach.

Between 1996 and 2002, 3,292 patients underwent a first cardiac operation and had a postoperative echocardiogram; 313 were excluded due to other explanations for PSM (severe tricuspid regurgitation [TR] cardiac pacing), leaving a study group of 2,979 patients. Univariate and multivariate analyses were performed to determine which surgical characteristics were correlated with postoperative PSM. Septal thickening was assessed in a subset.

On multivariate analysis, aortic (p = 0.02) and mitral valve surgery (p < 0.001) and longer cardiopulmonary bypass time (p < 0.001) were independently associated with PSM. Coronary artery bypass grafting (CABG) was less likely to cause PSM than non-CABG surgery (p = 0.003) and off-pump coronary artery bypass (OPCAB) caused less PSM than did on-pump CABG.

1. Valve surgery is more likely to cause PSM than CABG. 2. Among patients with CABG, OPCAB causes less PSM. 3. Cardiopulmonary bypass time is associated with the development of PSM. 4. The cause of PSM is likely to be multifactorial.