[Mechanism of post-operative abnormal septal motion: clinical and experimental studies].

In a previous report, we showed that pericardium closure is responsible for post-operative abnormal septal motion. To elucidate this hypothesis, we performed additional clinical and experimental studies. Twenty-six patients were studied during cardiac surgery. We also studied five dogs during cardiopulmonary bypass using M-mode and two-dimensional echocardiography. M-mode echograms and short-axis views of the left ventricle were obtained before and after pericardiotomy, and before and after pericardium closure. In the clinical study, the patients were divided into three groups according to pre-operative septal motion: Group 1 included six patients with atrial septal defect showing paradoxical motion, Group 2 included thirteen patients with aortic or mitral regurgitation of hyperdynamic motion, and Group 3 consisted of seven patients with ventricular septal defects or mitral stenosis showing normal systolic motion. In Group 1, septal motion became normal after closure of atrial septal defect and then, became abnormal just after pericardium closure. Again in Group 2, septal motion became normal following surgical repair, but abnormal motion appeared immediately after pericardium closure. In Group 3, normal septal motion persisted until just prior to closure of the pericardium. Abnormal septal motion in all groups persisted following chest closure. In all dogs, paradoxical septal motion resulted from pericardium closure after cardio-pulmonary bypass. We conclude that both pericardium closure and cardio-pulmonary bypass are responsible for post-operative abnormal septal motion.