Aim of the Present Investigation

John P. Hubbard was the first to “call attention to the clinical features of paroxysmal tachycardia as it occurs in infants lless than 1 year of age”, up to then comparatively oftten unrecognized. When reporting 9 personal cases in 1941, Hubbard particularly stressed the difference between paroxysmal kachycardia in ol’d’er chilldren and in infants. In the former, it is more easily detected, and its course resembles that in adults, since it mmetimes appears in short bouts of little importance, but may recur or persist for long periods, k i n g markedly resistant to therapy. Hubbard stated that this difference is especially distinct during the first weeks of life. Failure to detect paroxysmal tachycardia in the infant may lead to a fauky diagnosis, with serious or even fatal cons2quences. On the other hand, paroxysmal ,tachycardia in the youngest infants responds highly satisfactorily to adequate therapy. Hubbard’s views have subsequently been conf,irmed by other authors, among them Nadas et al., whose detailed analysis was published in 1952. Certain fundamental problems nevertheless remain. A contrisbutory factor may be that, hitherto, relatively small series have been available for consistent analyses of all the features of the disorder. Thus, uniform diagnostic criteria are lacking, and no systematic study has been made of t!:e aetiologic aspects. Insufficient regard seems to have been paid to the appearance of the ECG during and afber a paroxysm, as well as its relation to the clinical picture as a whole. A search of the literature discloses no systematic foll’ow-up studies. After studying a few personal cases, I circularized all the pediatric departments in Sweden, requesting informatlion about every hospitalized case of suspected paroxysmal tachycardia in infancy. Through the courtesy of the directors of clinics and physicians-in-chief, I was able in this way to collect a series of 54 infants from the period 1944-1961. This series the largest of the kind published up to now was then analyzed, with the main object of elucidating the problems that have not hitherto been systematically invesliigated. The scope of the inves:igsLion was briefly as follows. Diagnostic criteria applicable in this special age group were formulated. Consi’derabk attention was paid to the aetiologic aspects, which were analyzed against the background of among other matters ,the parents’ former and current physical and mental health, and studies of the prenatal conditions.