| Abstract: | The prevalence of congenital heart disease (CHD7at high altitude was determined by st.trveying 1116children at 4 study sites, ranging from sea level to4 300 M. Children were screened by physical exami-nation, and echocardiogram and electrocardiogramwere done on those suspected of having CHD. Ahigh prevalence of patent ductus arteriosus (PDA)and atrial septal defect (ASD) was found at highaltitude sites and the effect of altitude was progres-sivc. At 4300 M, a combined prevalence of 5.2%was found. PDA is thought to result from failureof low atmospheric p02 to constrict ductal muscle.We speculate that the persistence of high pulmonaryvascular resistance and right heart pressure inhibits early closure of the patent foramen ovale (PFO) andthat the flap becomes incompetent with growth, re-sulting in ASD. The high prevalence of ASD/PFOin tetralogy of Fallot may be analogous and related to high right ventricular pressurc present from birth. |
