Magnesium Lowers the Incidence of Postoperative Junctional Ectopic Tachycardia in Congenital Heart Surgical Patients: Is There a Relationship to Surgical Procedure Complexity?

Clinical risk prediction score for post-operative accelerated junctional rhythm and junctional ectopic tachycardia in children with congenital heart disease

BACKGROUND

Accelerated junctional rhythm (AJR) and Junctional ectopic tachycardia (JET) are common post-operative arrhythmias associated with morbidity/mortality. Studies suggest that pre- or intra-operative treatment may improve outcomes, but patient selection remains a challenge.

OBJECTIVES

Our objective was to describe contemporary outcomes of post-operative AJR/JET and develop a risk-prediction score to identify patients at highest risk.

METHODS

Retrospective cohort study of children 0-18 years undergoing cardiac surgery (2011-2018). AJR was defined as usual complex tachycardia with ≥1:1 ventricular-atrial association and junctional rate >25^th percentile of sinus rate for age but < 170 bpm while JET was defined as a rate >170 bpm. A risk prediction score was developed using random forest analysis and logistic regression.

RESULTS

From 6364 surgeries, AJR occurred in 215 (3.4%) and JET in 59 (0.9%). Age, heterotaxy syndrome, aortic cross-clamp time, ventricular septal defect closure and atrio-ventricular canal repair were independent predictors of AJR/JET on multivariate analysis and included in the risk prediction score. The model accurately predicted the risk of AJR/JET with a C-index of 0.72 [95% CI 0.70, 0.75]. Post-operative AJR and JET was associated with prolonged ICU and hospital length of stay, but not with early mortality.

CONCLUSION

We describe a novel risk prediction score to estimate the risk of post-operative AJR/JET permitting early identification of at-risk patients who may benefit from prophylactic treatment.

A Comparative Effectiveness Systematic Review and Meta-analysis of Drugs for the Prophylaxis of Junctional Ectopic Tachycardia

BACKGROUND

Junctional Ectopic Tachycardia (JET) is an arrhythmia originating from the AV junction, which may occur following congenital heart surgery, especially when the intervention is near the atrioventricular junction.

OBJECTIVE

The aim of this systematic review and meta-analysis is to compare the effectiveness of amiodarone, dexmedetomidine, and magnesium in preventing JET following congenital heart surgery.

METHODS

This meta-analysis was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement, where 11 electronic databases were searched from the date of inception to August 2020. The incidence of JET was calculated with the relative risk of 95% Confidence Interval (CI). Quality assessment of the included studies was assessed using the Consolidated Standards of Reporting Trials (CONSORT) 2010 statement.

RESULTS

Eleven studies met the predetermined inclusion criteria and were included in this meta-analysis. Amiodarone, dexmedetomidine, and magnesium significantly reduced the incidence of postoperative JET [Amiodarone: risk ratio 0.34; I2= 0%; Z=3.66 (P=0.0002); 95% CI 0.19-0.60. Dexmedetomidine: risk ratio 0.34; I2= 0%; Z=4.77 (P<0.00001); 95% CI 0.21-0.52. Magnesium: risk ratio 0.50; I2= 24%; Z=5.08 (P<0.00001); 95% CI 0.39-0.66].

CONCLUSION

All three drugs have shown promising results in reducing the incidence of JET. Our systematic review found that dexmedetomidine is better in reducing the length of ICU stays as well as mortality. In addition, dexmedetomidine also has the least pronounced side effects among the three. However, it should be noted that this conclusion was derived from studies with small sample sizes. Therefore, dexmedetomidine may be considered as the drug of choice for preventing JET.

Critical arrhythmia in postoperative cardiac children: Recognition and management

Arrhythmias after pediatric cardiac surgery are common and can be life-threatening. They occur intraoperatively or may appear shortly after surgery during postoperative care. They require early management and specific intervention. In this review, we describe important critical arrhythmias that are encountered during postoperative management of children undergoing cardiac surgery. We review the diagnosis, management, and explain the role of epicardial electrocardiogram in diagnosing certain types of postoperative rhythm abnormalities seen during early period after pediatric cardiac surgery.

Junctional Ectopic Tachycardia: Recognition and Modern Management Strategies

Junctional ectopic tachycardia is a common dysrhythmia after congenital heart surgery that is associated with increased perioperative morbidity and mortality. Risk factors for development of junctional ectopic tachycardia include young age (neonatal and infant age groups); hypomagnesemia; higher-complexity surgical procedure, especially near the atrioventricular node or His bundle; and use of exogenous catecholamines such as dopamine and epinephrine. Critical care nurses play a vital role in early recognition of dysrhythmias after congenital heart surgery, assessment of hemodynamics affecting cardiac output, and monitoring the effects of antiarrhythmic therapy. This article reviews the underlying mechanisms of junctional ectopic tachycardia, incidence and risk factors, and treatment options. Currently, amiodarone is the pharmacological treatment of choice, with dexmedetomidine increasingly used because of its anti-arrhythmic properties and sedative effect.

Junctional ectopic tachycardia (JET)

Junctional ectopic tachycardia (JET) is a tachyarrhythmia arising from the atrioventricular node and His bundle area. Enhanced normal automaticity has been postulated as the mechanism of JET in the majority of patients. It is more common in children and can be seen as congenital or in postoperative settings. It is often a narrow complex tachycardia but can present as a wide complex tachycardia as a result of aberrant conduction. Its differentiation from other arrhythmias especially atrioventricular nodal reentrant tachycardia (AVNRT) can be challenging. Medical treatment of JET is difficult, and catheter ablation remains the mainstay of treatment in refractory cases with a high risk of atrioventricular block and recurrence.

Efficacy of prophylactic dexmedetomidine in preventing postoperative junctional ectopic tachycardia in pediatric cardiac surgery patients: A systematic review and meta-analysis

BACKGROUND

Junctional ectopic tachycardia is a serious tachyarrhythmic complication following pediatric cardiac surgery. It is difficult to manage and is associated with significant morbidity and mortality. Conventional nonpharmacological and pharmacological measures have shown limited effects. Dexmedetomidine is an α2 agonist which has recently been shown in multiple studies to be effective.

AIMS

The aim of this systematic review with meta-analysis was to evaluate the efficacy of prophylactic dexmedetomidine administration in the prevention of junctional ectopic tachycardia in pediatric patients following cardiac surgeries.

METHODS

We searched MEDLINE, EMBASE, Cochrane, Web of Science, and relevant references published in English before December 20, 2017 and performed meta-analysis on the selected studies, with one group receiving prophylactic perioperative dexmedetomidine administration and another group receiving placebo. The primary outcome was the incidence of junctional ectopic tachycardia, secondary outcomes included bradycardia, hypotension, intensive care unit stay, total hospital stay, inotropic scores, and total mechanical ventilation time. Odds ratio or mean difference with 95% confidence intervals were calculated using a random effect model.

RESULTS

Seven studies (5 prospective randomized studies and 2 retrospective case-controlled studies) with a total of 1616 patients were analyzed. The incidence of junctional ectopic tachycardia in the dexmedetomidine group was significantly reduced compared to placebo. Similarly, intensive care unit stay, inotropic scores, and total mechanical ventilation time were also significantly decreased in the dexmedetomidine group. No significant increases in adverse events were found. Mortality was low in both groups.

CONCLUSION

Prophylactic dexmedetomidine is effective in reducing the incidence of postoperative junctional ectopic tachycardia without significant increases in adverse events in pediatric patients undergoing surgery for congenital heart diseases.

Junctional ectopic tachycardia following tetralogy of fallot repair in children under 2 years

Background

Junctional ectopic tachycardia is a serious arrhythmia that frequently occurs after tetralogy of Fallot repair. Arrhythmia prophylaxis is not feasible for all pediatric cardiac surgery patients and identification of high risk patients is required. The objectives of this study were to characterize patients with JET, identify its predictors and subsequent complications and the effect of various treatment strategies on the outcomes in selected TOF patients undergoing total repair before 2 years of age.

Methods

From 2003 to 2017, 609 patients had Tetralogy of Fallot repair, 322 were included in our study. We excluded patients above 2 years and patients with preoperative arrhythmia. 29.8% of the patients (n = 96) had postoperative JET.

Results

JET patients were younger and had higher preoperative heart rate. Independent predictors of JET were younger age, higher preoperative heart rate, cyanotic spells, non-use of B-blockers and low Mg and Ca (p = 0.011, 0.018, 0.024, 0.001, 0.004 and 0.001; respectively). JET didn’t affect the duration of mechanical ventilation nor hospital stay (p = 0.12 and 0.2 respectively) but prolonged the ICU stay (p = 0.011). JET resolved in 39.5% (n = 38) of patients responding to conventional measures. Amiodarone was used in 31.25% (n = 30) of patients and its use was associated with longer ICU stay (p = 0.017). Ventricular pacing was required in 4 patients (5.2%). Median duration of JET was 30.5 h and 5 patients had recurrent JET episode. Timing of JET onset didn’t affect ICU (p = 0.43) or hospital stay (p = 0.14) however, long duration of JET increased ICU and hospital stay (p = 0.02 and 0.009; respectively).

Conclusion

JET increases ICU stay after TOF repair. Preoperative B-blockers significantly reduced JET. Patients with preoperative risk factors could benefit from preoperative arrhythmia prophylaxis and aggressive management of postoperative electrolyte disturbance is essential.

Selective autonomic stimulation of the AV node fat pad to control rapid post-operative atrial arrhythmias

Junctional ectopic tachycardia (JET) and atrial fibrillation (AF) occur in patients recovering from open-heart surgery (OHS). Pharmacologic treatment is used for the control of post-operative atrial arrhythmias (POAA), but is associated with side effects. There is a need for a reversible, modulated solution to rate control. We propose a non-pharmacologic technique that can modulate AV nodal conduction in a selective fashion. Ten mongrel dogs underwent OHS. Stimulation of the anterior right (AR) and inferior right (IR) fat pad (FP) was done using a 7-pole electrode. The IR was more effective in slowing the ventricular rate (VR) to AF (52 +/- 20 vs. 15 +/- 10%, p = 0.003) and JET (12 +/- 7 vs. 0 +/- 0%, p = 0.02). Selective site stimulation within a FP region could augment the effect of stimulation during AF (57 +/- 20% (maximum effect) vs. 0 +/- 0% (minimum effect), p<0.001). FP stimulation at increasing stimulation voltage (SV) demonstrated a voltage-dependent effect (8 +/- 14% (low V) vs. 63 +/- 17 (high V) %, p<0.001). In summary, AV node fat pad stimulation had a selective effect on the AV node by decreasing AV nodal conduction, with little effect on atrial activity.

Management of postoperative junctional ectopic tachycardia in pediatric patients: a survey of 30 centers in Germany, Austria, and Switzerland

Postoperative junctional ectopic tachycardia (JET) is a frequent complication after pediatric cardiac surgery. Current recommendations on how and when to treat JET are inconsistent. We evaluated the management strategies of postoperative JET in German-speaking countries. We sent an online survey to 30 centers of pediatric cardiology that perform surgery for congenital heart defects in Germany (24), Austria (4), and Switzerland (2). The survey asked 18 questions about how and in what treatment sequence postoperative JET was managed. All 30 centers completed the survey (100% return rate). There was general agreement that the management of JET is based on administration of antiarrhythmic drugs, body surface cooling, and temporary pacing. Many centers presented treatment algorithms based on published literature, all centers named amiodarone as the first drug of choice. Significant disagreement was found concerning the timing and sequential order of additional therapeutic measures and particularly about the dosing of amiodarone and the role of R-wave synchronized atrial pacing.

CONCLUSION

This survey reveals that from center to center, the treatment of postoperative JET may vary substantially. Future work should focus on those treatment modalities where a high rate of variation is found. Such studies may be of value to achieve commonly adopted treatment recommendations. What is known: • Treatment of postoperative junctional ectopic tachycardia is predominantly based on administration of antiarrhythmic drugs, therapeutic cooling, and temporary pacing. • Amiodarone is the antiarrhythmic drug of choice in this context. What is new: • Dosing and duration of administration of amiodarone differ relevantly from center to center. • The sequential order of drug administration, therapeutic cooling, and pacing is not consistent.

Magnesium sulfate in pediatric anesthesia: the Super Adjuvant

Magnesium is an essential chemical element in all organisms, intervening in most cellular enzymatic reactions; thus, its importance in homeostasis and as a therapeutic tool in highly challenging patients such as pediatrics. The primary purpose of this paper was to review the role of magnesium sulfate as an adjuvant drug in pediatric anesthesia. This compound already has the scientific backing in certain aspects such as analgesia or muscle relaxation, but only theoretical or empirical backing in others such as organ protection or inflammation, where it seems to be promising. The multitude of potential applications in pediatric anesthesia, its high safety, and low cost make magnesium sulfate could be considered a Super Adjuvant.