Pulsed Doppler Echocardiographic Quantification of Left-to-Right Shunts in Children with Isolated Ventricular Septal Defect

Abstract

With advancements in ultrasound technology in noninvasive cardiovascular diagnosis, Doppler quantification of blood flow velocities within the heart and great vessels has become practical. Beginning with the early experiences in Great Britain,^1,2 to the current research efforts directed at the clinical evaluation of aortic and pulmonary blood flow, Doppler echocardiography is fast becoming a promising technique in the noninvasive evaluation of blood flow. The pioneering work of Light et al.^1,2 utilizing a continuous wave Doppler demonstrated that there was a significant correlation between Doppler derived and invasively determined stroke volumes. Of historical interest to the pediatric cardiologist, these investigations observed, that in children with unequal pulmonary to systemic blood flow ratios, the velocities recorded in the pulmonary artery were higher than those in the aorta. Furthermore, these velocities equalized after corrective surgery.³ Confirmation of the value of ultrasound Doppler techniques in the estimation of stroke volume and cardiac outputs were subsequently provided by several authors in the animal laboratory, in the adult and, most recently, in children.^4–12