Objective. Pressure and volume overload of cardiac chambers increase coronary flow but the magnitude of their effect is not known.
Methods. Sixty-four patients with acyanotic congenital heart diseases (CHD) were included in the study: 12 neonates with coarctation of aorta (CoA), 7 neonates with severe pulmonary valve stenosis (PS), 18 infants with ventricular septal defect (VSD), and 27 children with atrial septal defect (ASD). Coronary flow (CF) parameters were measured in the left anterior descending artery in CA and VSD and in the posterior descending artery in PS and ASD patients with transthoracic Doppler echocardiography. Age-matched healthy controls (n=49) were included. Patients were studied 1-2 days before the treatment with either surgery or interventional cardiac catheterization. Coronary flow data in each patient group are expressed as percent change from the controls.
Results. Cardiac output and fractional shortening were decreased in patients as compared with controls (p< 0.05 in all patient groups). The median of peak flow velocity was 600% in patients with CoA and 225%, 225% and 118% in patients with PS, VSD and ASD, respectively. The increase in CF was relatively larger than peak flow velocity (773% in CoA, 233 % in PS, 172 in VSD, and 185 in ASD).
Conclusions. Coronary flow and peak flow velocity appear to be markedly increased in patients with CHD. Increased preductal blood pressure, myocardial strain and ventricular hypertrophy due to CoA seem to have maximal effect on coronary flow, but volume and pressure overload of the ventricles have also significant increasing effects.