Hypothermia for the treatment of postsurgical greatly accelerated junctional ectopic tachycardia

Abstract

Three infants developed greatly accelerated junctional ectopic tachycardia with a heart rate greater than 200 beats/min after open heart surgery. When the heart rate exceeded 200 beats/min for 5 hours, all the infants had congestive heart failure and clinical signs of low cardiac output. Conventional therapy (cardioversion, lidocaine, verapamil, digoxin and ice to face) has been shown in the past to be unsuccessful in controlling the heart rate. Because hypothermia is known to decrease automaticity of the heart, these patients were treated with induced hypothermia. The goal was to arbitrarily decrease the junctional ectopic rate to less than 180 beats/min to increase cardiac filling time. The duration of the junctional ectopic tachycardia greater than 180 beats/min ranged from 0.5 to 17 hours after cooling began. The duration of the hypothermia ranged from 4 to 24 hours. Spontaneous reversion to sinus rhythm occurred either during the hypothermia or shortly thereafter in all three patients. The blood pressure and urinary output remained stable during hypothermia. Hypothermia is an effective means of controlling the rate of greatly accelerated junctional ectopic tachycardia after open heart surgery in infants. Although hypothermia does not convert junctional ectopic tachycardia to sinus rhythm, it slows the rate to a more acceptable level, allowing the infants' survival and eventual recovery of sinus rhythm.

Nonpharmacologic Control of Postoperative Supraventricular Arrhythmias Using AV Nodal Fat Pad Stimulation in a Young Animal Open Heart Surgical Model

“…In newborns and infants, the prevalence of supraventricular arrhythmias was similar (supraventricular tachycardia, 12.7%; accelerated junctional rhythm, 16.7%; JET, 5.4%). Medical treatment of these atrial arrhythmias can result in significant morbidity, such as excessive bradycardia and hypotension, 2 and require prolonged intubation with neuromuscular paralysis if cooling is used, 3 therefore, the need to develop alternative nonpharmacological therapies. Management of intractable arrhythmias may require the use of emergent extracorporeal membrane oxygenation support or need catheter-based ablation.…”

Therapeutic hypothermia for out-of-hospital cardiac arrest

“…Fortunately, these arrhythmias are not usually seen unless the temperature drops below 30 °C, 25 as mild hypothermia improves membrane stability and decreases the likelihood of arrhythmias. 49,50 Arrhythmias resulting from severe hypothermia are difficult to treat, as the myocardium becomes less responsive to many antiarrhythmic drugs and more difficult to defibrillate. 51,52 Efficacy data for specific antiarrhythmic agents for the treatment or prophylaxis of VF during hypothermia are limited to animal models and observations in humans.…”

Moderate hypothermia in the management of resistant automatic tachycardias in children.

“…One patient (patient 2) had pulmonary hypertensive crises on rewarming. He did not have pulmonary hypertensive episodes before Figure 5 Effect of hypothermia on the heart rate and urine output in patient 3. Heart rate fell to 150 beats per minute when the core temperature reached 32°C.…”

“…Results-Hypothermia led to a reduction in heart rate in all patients (from 211 (28) (mean (SD)) to 146 (5) beats/ minute, p < 0 001), with rises in systolic blood pressure (from 74 (14) mm Hg to 97 (10) mm Hg, p < 0 01) and hourly urine output (from 0 5 (0 4) mlikg to 4.6 (2 8) ml/kg, p < 0 02). No direct adverse effects were noted.…”