Paroxysmal Tachycardia and Its Treatment in Young Infants

Abstract

The following 9 case reports are presented to call attention to the clinical features of paroxysmal tachycardia as it occurs in infants less than 1 year of age. This study has been limited to this age group because in older children paroxysmal tachycardia is more readily recognized, has been described more often and seems to be similar to the form of the disorder that occurs in adults in that it sometimes appears in short attacks of no consequence and occasionally continues or recurs in persistent fashion and is more or less resistant to the various forms of treatment used. On the other hand, in young infants, especially during the early weeks of life, there appears to be a somewhat different and distinctive clinical entity, readily diagnosed if kept in mind, which responds satisfactorily to proper treatment. Failure to detect paroxysmal tachycardia in the young infant may lead to such faulty diagnoses as congenital idiopathic hypertrophy of the heart or pneumonia and may be of serious consequence to the patient.In considering tachycardia in infancy, it is important to remember certain differences between the infant and the adult. In the first place, the pulse rate during the early weeks of life is rapid and unstable, vary¬ ing normally between 110 and 140. Excitement or illness may readily elevate the rate to 180 or more. One who is unaccustomed to examin¬ ing infants might be led to make a diagnosis of paroxysmal tachycardia on the basis of a pulse rate of 180 which is due, for example, to pneu¬ monia with simple sinoauricular tachycardia. On the other hand, it is easy to make the mistake of paying too little attention to a rapid rate in a sick infant. It takes considerable skill and experience to count pulse rates of 200 or more, and yet it is important to do so in order to avoid overlooking the possibility that abnormal tachycardia is the true cause of the illness.In the second place, the conduction of impulses within the heart of the infant appears to differ in certain respects from that in the heart of the adult. The commonly accepted definition of paroxysmal tachy¬ cardia in the adult is a condition marked by a pulse rate of usually 150

Concealed pre-excitation causing paroxysmal reciprocating atrioventricular tachycardia in infancy.

“…Accurate counting of the heart rate in infants is difficult and it is mandatory to record an ECG in any sick infant with an unmodifiable rapid heart rate. The severity of symptoms in paroxysmal tachycardia in infants relates more closely to duration of the episode than to the rate (Hubbard, 1941) which again emphasises the necessity ofhaving an index ofsuspicion of the underlying problem. Fortunately one of our patients (Case 2) was resuscitated after cardiac arrest but infant deaths have been reported directly referable to the tachycardia (Werley, 1925;Kimball and Burch, 1947;Silverman and Werner, 1950;Engle, 1952) and it is conceivable that paroxysmal tachycardia may be a cause of sudden death in a seemingly healthy infant .…”

“…Although pre-excitation is recognised as being a major cause of supraventricular tachycardia in infants and children, case reports of infants are comparatively few. Long-term follow-up studies have shown a good prognosis for children and adults (Hubbard, 1941;Nadas et al, 1952;Lundberg, 1963;Giardina et al, 1972) and have confirmed that the serious clinical problem relates to the young infant. In recent years electrophysiological studies in adults, Received 7 February 1978 children, and infants (Goldreyer and Bigger, 1971;Wellens, 1971;Kaye et al, 1975;Gillete, 1976) have greatly increased the understanding ofthe mechanism of supraventricular tachycardia in all age groups and have stimulated interest in the tachycardias and the natural history of pre-excitation, the diagnosis of which is customarily based on the classical electrocardiographic finding of the Wolff-Parkinson-White (WPW) syndrome.…”

Congenital paroxysmal atrial tachycardia.

“…Atrial flutter and paroxysmal supraventricular tachycardia in infancy have been well documented (Hubbard, 1941;Nadas et al, 1952;Apley, Corner, and Gibson, 1955;Moller, Davachi, and Anderson, 1969;Jacobsen et al, 1975) and the greater likelihood of initial attacks during the first few months after birth has been recognized. Such arrhythmias in utero are usually considered rare (Schaffer and Avery, 1971), though many case reports have been published.…”

Paroxysmal Tachycardia in the Newborn

“…Treatment with mechanical methods, such as pressure on the eyeballs or induction of vomiting, is rarely effective and potentially dangerous in infants. 5,9 Digitalis is the drug of choice,5'9,15 which fulfills the double task of terminating the rhythm disorder and acting on congestive failure, when present.…”