Supraventricular tachycardia in infants: use of the "diving reflex"

Management of Supraventricular Tachycardia in Infants

Supraventricular tachycardia is the most common tachyarrhythmia encountered in infants. In older children and adults, definitive treatment of the supraventricular tachycardia substrate with catheter ablation is a common approach to management. However, in infants, the risks of catheter ablation are significantly higher, and the patients often outgrow the potential to experience episodes. Therefore, antiarrhythmic medications are often utilized to minimize the likelihood of experiencing episodes. This article reviews the common arrhythmia mechanisms encountered in infants and the medications used to treat these patients.

The diving reflex in healthy infants in the first year of life

A cohort study was conducted with a random sample of 33 healthy infants evaluated at birth and at 1, 2, 3, 4, 5, 6, 9, and 12 months to determine the frequency of respiratory rate changes in response to air blown over the face (diving reflex) in the first year of life, and to standardize the description of diving reflex occurrence. All 33 infants remained neurologically normal throughout follow-up. Diving reflex was observed in 95.3% of newborns and in 100% of infants between 2 and 6 months of age. At 6 months, it started to decrease but persisted in 90% of the infants up to 12 months. The diving reflex is highly prevalent in the first year of life and can be easily elicited by applying a flow of air over the infant's face, particularly during crying.

Emergency department management of the pediatric patient with supraventricular tachycardia

Supraventricular tachycardia (SVT) is the most common tachyarrhythmia that necessitates treatment in children. It is characterized by a rapid and regular heart rate, which generally exceeds 180 beats per minute in children and 220 beats per minute in adolescents. Supraventricular tachycardia results from conduction of electrical impulses along an accessory connection from the atrium to the ventricle (atrioventricular reentry tachycardias: orthodromic or antidromic) or conduction within the atrioventricular node (atrioventricular node reentry tachycardia). Emergency department management of SVT depends on the patient's clinical status. Treatment of a stable patient with SVT includes vagal maneuvers and adenosine, whereas treatment of an unstable patient requires synchronized cardioversion. This article presents an overview of the etiology, pathophysiology, and clinical presentation of SVT and discusses the emergency department management of an infant or child with SVT.

Supraventricular tachycardia: diagnosis and current acute management

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Supraventricular tachycardia in infants: response to initial treatment

All patients with supraventricular tachycardia during the first 12 months of life who presented between 1977 and 1988 were identified by a retrospective survey of records in this hospital and by a questionnaire sent to paediatricians in the Northern region. Twenty two of 29 patients (76%) were in heart failure and seven (24%) had cardiogenic shock. Seven patients (24%) were free of symptoms. All had narrow QRS tachycardia at 215-315 beats/minute (mean (SD) 292 (21)). Initial treatment included digoxin (effective in seven of 14 patients, with overdose in three), verapamil (effective in three of three but fatal in one), cardioversion (effective in all 10 who were treated in this way), iced water applied to the face (effective in all 16 patients on 53 of 59 occasions, 90%). Initial treatment in local hospitals was less effective and associated with more complications than that given in the regional referral centre. Digoxin is often ineffective, return to sinus rhythm is delayed, and overdosing is common. Cardioversion is effective but tachycardia often recurs. Iced water is safe and effective, and should become the treatment of choice for termination of supraventricular tachycardia in neonates and young infants.

Relative efficacy of various physical manoeuvres in the termination of junctional tachycardia

The ability of four vagotonic physical manoeuvres to terminate paroxysmal junctional tachycardias was tested in 35 patients with inducible and sustained arrhythmia. Each manoeuvre was used up to three times in an attempt to terminate an induced tachycardia and was judged to be effective if it terminated two out of the three induced episodes. The Valsalva manoeuvre in the supine position was effective in 19 (54%), right carotid sinus massage in 6 (17%), left carotid sinus massage in 2 (5%), and the diving reflex in 6 (17%) cases. 4 of the 6 patients who responded to right carotid sinus massage and all patients who responded to the diving reflex also responded to the Valsalva manoeuvre. The Valsalva manoeuvre while standing was effective in 9 (20%) patients only. Patients in whom the manoeuvres terminated the tachycardias were significantly younger than those who did not respond (median age: 30 vs 45 years, p less than 0.01). Physical manoeuvres were much more successful in terminating atrioventricular re-entry tachycardias (19/24) than atrioventricular nodal re-entry tachycardias (3/11, p less than 0.01). Efficacy of the manoeuvres was related to their bradycardic effect in sinus rhythm.

Refractory supraventricular tachycardia in the neonate: treatment with temporary antitachycardial pacing

Although intracardiac antitachycardial pacing techniques are frequently used to terminate reentrant supraventricular tachycardia in adults, this approach has rarely been used in neonates. We describe two neonates, both of whom were in circulatory shock due to recurrent paroxysmal supraventricular tachycardia, who were treated with temporary antiatachycardial pacing. This approach allows repeated termination of the tachycardia at the bedside until an adequate therapeutic concentration of an effective drug regimen is achieved and obviates repeated direct-current cardioversion.