NEW INSIGHTS AND OBSERVATIONS IN 3-DIMENSIONAL ECHOCARDIOGRAPHIC VISUALIZATION OF VENTRICULAR SEPTAL-DEFECTS - EXPERIMENTAL AND CLINICAL-STUDIES

Background-The positions, sizes, and shapes of ventricular septal defe cts (VSDs) can be difficult to assess by 2-dimensional echocardiograph y (2DE). Volume-rendered 3-dimensional echocardiography (3DE) can prov ide unique views of VSDs from the left ventricular (LV) side, allowing complete assessment of their circumference and spatial orientations t o other anatomic structures. Methods and Results-Seventeen experimenta lly created defects of various locations, sizes, and shapes were image d and reconstructed in 9 explanted porcine hearts. From an en face pro jection, major and minor axis diameters of the defects were measured, and these data were compared with direct anatomic measurements. Optima l reconstructions of the VSDs were obtained in all heart specimens, ac curately depicting their positions and shapes. The correlations betwee n 3DE and anatomy for the VSD major and minor axis diameters were y = 1.0x + 0.3 (r = 0.88, P<0.001) and y= 1.0x - 1.4 (r =0.89, P<0.001), r espectively. Good agreement between the 2 methods was demonstrated for all measurements. Our experience from the in vitro model was then app lied to patient studies. Optimal LV en face reconstructions were obtai ned in 45 of 51 patients, permitting detailed assessment of the positi ons, sizes, and shapes of the VSDs. In the 25 patients with comparativ e surgical measurements, the correlations between 3DE and surgery for the VSD major and minor axis diameters were y =0.81x + 2.1 (r=0.92, P< 0.001) and y=0.73x + 2.0 (r=0.91, P<0.001), respectively. Good agreeme nt was demonstrated between measurements made by 3DE and those obtaine d at surgery. Conclusions-3DE provides excellent visualization of vari ous types of VSDs. From an LV en face projection, the positions, sizes , and shapes of VSDs can be accurately determined. Such precise imagin g will be beneficial for surgical and catheter-based closure of diffic ult perimembranous and singular or multiple muscular VSDs.