The degree of scooping of the interventricular septum influences electrocardiographic findings in atrioventricular septal defect

Abstract

AbstractThe aim of this study was to clarify those morphological features and hemodynamic stress factors which influence the electrocardiographic findings in atrioventricular septal defect. In 64 patients with the incomplete form of atrioventricular septal defect (separate valvar orifices) with usual atrial arrangement, the length from the left ventricular apex to the aortic valve (outlet dimension), to the so-called cleft (scoop dimension), and to the lowest point of the left atrioventricular valve (inlet dimension) were measured by biplanar cineangiography. The size of the ostium primum defect, the ventricular pressure ratio, and the pulmonary/systemic flow ratio were also evaluated. The results showed that the lower the scoop/outlet ratio (r=0.60, p<0.001), or the higher the ventricular pressure ratio (r= −0.55, p<0.001), the more deviated to the left and superior was the mean frontal QRS axis. These factors also had significant correlation with the QRS patterns in the Frank vectorcardiogram. We conclude that the scoop/outlet ratio, supposedly reflecting the degree of scooping of the interventricular septum, is one of the most significant factors which influence the electrocardiographic findings in atrioventricular septal defect.