Altitude and the Heart: Is Going High Safe for Your Cardiac Patient?

John P. Higgins, MD, MPhil; Troy Tuttle, MS; Johanna A. Higgins, MD


Am Heart J 

In This Article

Congenital Heart Disease

In simple uncomplicated congenital heart disease including atrial septal defect, restrictive ventricular septal defects, and patent ductus arteriosus, there is usually a net shunting of blood from the higher pressure left side to the lower pressure right side of the heart, with little, if any, right-to-left shunting. Upon short-term exposure to hypobaric hypoxia, right-sided pressures may increase, resulting in an increase in the right-to-left shunting with resultant arterial oxygen desaturation as more of the deoxygenated right-sided blood is bypassing oxygenation in the lungs.[47,56]

This has been confirmed via cardiac catheterization. One group has shown that in a patient with an atrial septal defect and a resting left-to-right shunt, there was a significant increase in pulmonary artery pressure on hypoxic exposure resulting in reversal of the shunt.[57] Interestingly, most studies of individuals who were born at and lived at high altitude reveal an increase in prevalence of patent foramen ovale and patent ductus arteriosus, likely due to a persistence of the fetal pattern of pulmonary vasculature, that is, thick smooth muscle cells, narrow lumen, small pulmonary vessels, and increased pulmonary and right ventricular pressures.[58,59,60]

Because of the potential catastrophic effects of an acute increase in right-to-left shunting and/or pulmonary artery pressures in patients with congenital heart disease with shunts, exposure to high altitude should be avoided.[56] However, exposure to moderate altitude has been reported to be safe even in adults with cyanotic congenital heart disease.[61]