The mechanism of abnormal septal motion in atrial septal defect: pre- and postoperative study by radionuclide ventriculography in adults.

Abstract

SUMMARY The mechanism of abnormal interventricular septal wall (IVS) motion in atrial septal defect (ASD) was studied by radionuclide cineventriculography before and within 2 weeks of ASD closure in 11 adult patients. Pre-and postoperative right ventricular/left ventricular volume ratio (RV/LV volume), LV peak filling rate (PFR) and LV ejection fraction (EF) were measured and compared with measurements in 13 normal adults.In normal subjects the configuration of the left ventricle was ovoid in diastole and the IVS curvature was convex toward the right ventricle. In all 11 ASD patients increased RV volume caused the IVS either to flatten during diastole or reverse its normal direction of curvature, becoming convex toward the left ventricle and resulting in a crescentic LV configuration. In early systole the IVS bulged anteriorly as the left ventricle reassumed its normal ovoid configuration and thereafter contracted normally. Postoperatively, RV volume decreased and both diastolic LV configuration and diastolic IVS curvature returned to normal in nine of the 11 patients. Postoperatively, mean RV/LV volume (± SD) decreased (3.6 ± 0.5:1 preop vs 2.1 ± 0.8:1 postop, p < 0.001; normal subjects 1.3 ± 0.1:1), PFR increased (2.13 ± 0.57/sec vs 3.16 1.19/sec,p < 0.01; normal subjects 2.92 ± 1.28/sec) and EF was unchanged (0.62 ± 0.12 vs 0.69 ± 0.09; NS; normal subjects 0.66 ± 0.08). In three older patients a low LV EF returned to normal postoperatively.Systolic anterior IVS motion in ASD is caused by an initial abnormal curvature of the IVS during diastole to accommodate increased RV volume, and the IVS curvature returns to normal when this is relieved. The increased RV/LV volume ratio decreases and indexes of LV filling and ejection may improve early after ASD closure in adults.ALTHOUGH paradoxical systolic anterior motion of the interventricular septal wall (IVS) is an echocardiographic finding in atrial septal defect (ASD),' its cause is uncertain.3-6 It has been reported to be caused by exaggerated systolic anterior motion of the Received July 23, 1979; revision accepted May 30, 1980. Circulation 63, No 1, 1981 entire heart,3 posterior displacement of the septum from right ventricular (RV) overload7 or anterior septal displacement at the onset of systole.' Weyman et al.,7 using short-axis cross-sectional echocardiography, suggested the abnormal septal motion was due to a change in the diastolic shape of the left ventricle caused by RV volume overload. Contrast left ventriculography in the left anterior oblique (LAO) projection has not shown these changes,6' 8 but foreshortening of the left ventricular (LV) cavity is imaged in this view, and changes in IVS and LV shape may be obscured.9 Equilibrium-gated radionuclide cineventriculography using a slant-hole collimator allows sufficient

The Interventricular Septum: Structure, Function, Dysfunction, and Diseases

“…PSM may also occur after uncomplicated cardiac surgery resulting from an increase in RV transverse shortening (free wall to septal fibers), in order to compensate for the reduced RV longitudinal shortening [ 33 ], atrial septal defect (ASD) to accommodate the increased RV volume [ 34 ], and mitral stenosis reflecting an abnormal transseptal gradient [ 35 ].…”

P wave dispersion in assessment of dysrhythmia risk in patients with secundum type atrial septal defect and the effect of transcatheter or surgical closure

“…10 Increased right ventricular volume affects the movements of interventricular septum and causes paradoxical motion. 23 In this study, while all of surgical group had right heart dilatation, 61.76% of patients in transcatheter group had right heart dilatation (p < 0.001). While there was no septal paradoxical movement in transcatheter group, 14.81% of patients in surgical group had septal paradoxical movement (p = 0.020).…”