[Echocardiographic anomaly of septal contraction after open heart surgery]

The function of the interventricular septum (IVS) was studied by M mode echocardiography one month after open-heart surgery in 256 patients with valvular heart disease and without any accepted mechanism of abnormal septal motion. Systolic anterior motion of the IVS was observed in 44% of all the patients and was found to be more common in patients undergoing corrective aortic procedures (64%) than in patients undergoing corrective mitral (36%, p less than 0,01) or mitro-aortic (45% , p less than 0,01) procedures. In technically very adequate studies of 43 patients (33 with systolic anterior motion of the IVS) and 10 normal controls, the following observations were made: - the systolic anterior motion of the IVS was greater after aortic procedures than after mitral ones (-5,64 +/- 1,44 mm, and -2,14 +/- 2,66 mm, p less than 0,005); - patients with systolic anterior motion of the IVS had reduced percentage systolic septal thickening (30,9 +/- 19,0%, p less than 0,02) and normal controls (56,1 +/- 21,0%, p less than 0,005); -the systolic anterior motion of the posterior epicardial echo was more pronounced in post-operative patients, both with abnormal (7,9 +/- 1,8 mm) and normal (7,8+/- 2,2 mm) septal motion, than in normal controls (4,8 +/- 0,7 mm p less than 0,001 and p less than 0,005, respectively); - no other known cause of systolic anterior septal motion were present in the post-operative patients. In conclusion, patients undergoing cardio-pulmonary bypass demonstrated increased systolic anterior motion of the whole heart, which was thought to be related to the partial removal and/or the non-closure of the pericardium. However, this feature was not the only mechanism for the abnormal post-operative motion of the IVS, as reduced contraction of the IVS was always found in these patients. This finding could be ascribed to myocardial per-operative injury, the exact nature of which remains unknown.