Alternation in the electrocardiogram is only occasionally seen in patients with pulsus alternans. Furthermore, it may occur without alternation in the peripheral pulse.1
In children alternation in the electrocardiogram has rarely been reported. In 1917, Windle2 recorded alternation in a boy 13 years of age following treatment with digitalis. In a series of 16 patients Kalter and Grishman3 reported alternation in 3 children under 13 years of age, the youngest being 5 years old. In these 3 children only alternation of the QRS complex was reported. Unfortunately, none of the tracings were reproduced in their paper.
Nádrai4 mentioned alternation in the electrocardiogram (his fig. 24) in a child 9 months old with situs inversus and truncus arteriosus communis. The child died soon afterward. As far as we know, this is the earliest age at which alternation has been observed.
Alternation in the electrocardiogram, especially in patients
KISCH B, RICHMAN B. ALTERNATION IN THE ELECTROCARDIOGRAM OF A THREE AND ONE-HALF MONTH OLD INFANT. Am J Dis Child. 1950;79(2):326-328. doi:10.1001/archpedi.1950.04040010337010