Cardiac cycle-dependent gray-level variation is not distorted by abnormal septal motion after cardiac surgery: A transesophageal videodensitometric study in humans

Variation in cyclic (systolic-to-diastolic) echodensity has been demonstrated to be areliable index of preserved myocardial function. Paradoxic septal motion can be observed frequently after cardiac surgery in the absence of any functional impairment. The aim of the study was to evaluate whether regional cycle-dependent gray-level variation in the septum is affected by abnormal septal motion after cardiac surgery. Ten patients undergoing cardiac surgery for coronary artery bypass grafting were evaluated by continuous transesophageal echocardiographic monitoring from the transgastric approach, both before and after surgery. In each patient septal motion was assessed qualitatively as normal or paradoxic. Images were digitized off-line and cyclic gray-level variation was measured in each patient by means of dedicated software. By selection, all patients exhibited normal septal motion and thickening at baseline. After surgery, five patients showed a paradoxic septal motion (group I), whereas in the remaining five patients (group II) septal motion remained normal. Percent area change, measured with the floating center-of-mass reference system, was similar in the two groups both before (I=42%+/-7% versus II=44%+/-13%; difference not significant) and after surgery (I=39%+/-8% versus II=40%+/-1%; difference not significant). Cyclic gray-level variation was also similar in the two groups, both at baseline (group I=61%+/-16% versus group II=68%+/-18%; difference not significant) and after surgery (50%+/-13% versus 57%+/-16%; difference not significant). In conclusion, cardiac cycle-dependent gray-level variation provides an objective method, independent of cardiac motion, to assess regional function in paradoxic septal motion after cardiac surgery. Cyclic gray-level variation is not distorted by altered regional wall motion, consistent with the evidence that it reflects intrinsic contractile function.