Ventricular septal defects (VSDs) may be classified as perimembranous, inlet, outlet, or trabecular. Echocardiography is quite useful for the detection and classification of VSDs.569-571 The defect itself is sometimes visible with 2D imaging alone (B-nSi Fig. 13-113/1), but smaller VSDs are easily missed. Complete absence of the interventricular septum (single ventricle) is quite rare (Q*-B; Fig. 13-113,5). Pulsed- or continuous-wave Doppler interrogation often reveals discrete areas of high-velocity flow across the interventricular septum. Measurement of the peak CW velocity through the shunt allows calculation of the interventricular pressure gradient (via the modified Bernoulli equation); subtraction of this gradient from the systolic blood pressure (in the absence of aortic valve disease) approximates the RV systolic pressure.
Overall, color-flow imaging is the most useful Doppler technique for the diagnosis of VSDs.571 Typically, a high-velocity systolic color jet is seen traversing the interventricular septum, although the velocity is lower with large defects and in the presence of pulmonary hypertension (&H0; Fig. 13-114, Plate 70). The appearance of the color jet in the standard imaging planes can be used to determine the type of VSD. Intravenous contrast injection may reveal a negative contrast jet in the right ventricle, and contrast may cross the defect and partially opacify the left ventricle. In the absence of MR, contrast will not enter the left atrium, distinguishing an isolated VSD from an ASD. Doppler echocardiography can also be used to detect abnormalities associated with VSDs, such as ventricular septal aneurysm, MR and TR, ASD (especially with inlet VSDs), aortic insufficiency-with outlet (supracristal) VSDs-and "straddling" of the defect by the mitral or tricuspid valve.572,573 Accurate detection of such lesions is especially critical before surgical intervention.
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...