The Achilles tendon reflex time measured with the photomotograph in 161 children with congenital heart disease was found to be within normal range. Arterial desaturation of long duration prolongs the half relaxation time but does not seem to affect the ankle reflex contraction time. In patients who have had an arteriotomy during cardiac catheterization, the ankle reflex time is shown to be normal.
Rosenthal A. The Achilles Reflex Time in Cyanotic Congenital Heart Disease. Am J Dis Child. 1970;119(3):249-251. doi:10.1001/archpedi.1970.02100050251012