Prevalence of and risk factors for perioperative arrhythmias in neonates and children after cardiopulmonary bypass: continuous holter monitoring before and for three days after surgery

Dexmedetomidine and magnesium sulfate in preventing junctional ectopic tachycardia after pediatric cardiac surgery

BACKGROUND

Junctional ectopic tachycardia (JET) is a serious tachyarrhythmia following pediatric cardiac surgery. It isn't easy to treat and better to be prevented. This study aimed to examine the prophylactic effects of dexmedetomidine, MgSO4, or their combination in reducing JET following pediatric open cardiac surgery.

METHODS

Hundred and twenty children under 5 years, weighing more than 5 kg, who were scheduled for corrective acyanotic cardiac surgeries were randomized into three groups. Group MD (Dexmedetomidine-MgSO4 group): received dexmedetomidine 0.5 μg/kg IV over 20 min after induction, then infusion 0.5 μg/kg/h for 72 h, and 50 mg/kg bolus of MgSO4 with aortic cross-clamp release, then continued administration for 72 h postoperatively at a dose of 30 mg/kg/day. Group D (the dexmedetomidine group) received the same dexmedetomidine as the MD group in addition to normal saline instead of MgSO4. Group C (control group): received normal saline instead of dexmedetomidine and MgSO4. The primary outcome was the detection of JET incidence; the secondary outcomes were hemodynamic parameters, ionized Mg, vasoactive-inotropic score, extubation time, PCCU and hospital stay, and perioperative complications.

RESULTS

The incidence of JET was significantly reduced in Group MD and Group D (p = .007) compared to Group C. Ionized Mg was significantly higher in Group MD than in Groups D and C during rewarming and in the ICU (p < .001). Better hemodynamic profile in Group MD compared to Group D and Group C throughout surgery and in the ICU, the predictive indexes were significantly better in Group MD than in Groups D and C (p < .001). Including the extubation time, PCCU, and hospital stay.

CONCLUSION

Dexmedetomidine alone or combined with MgSO4 had a therapeutic role in the prevention of JET in children after congenital heart surgery.

Postoperative Cardiac Arrhythmias in Pediatric and Neonatal Patients with Congenital Heart Disease-A Narrative Review

Cardiac arrhythmias are a frequent complication in the evolution of patients with congenital heart disease. Corrective surgery for these malformations is an additional predisposition to the appearance of arrhythmias. Several factors related to the patient, as well as to the therapeutic management, are involved in the etiopathogenesis of cardiac arrhythmias occurring post-operatively. The risk of arrhythmias in the immediate postoperative period is correlated with the patient's young age and low weight at surgery. The change in heart geometry, hemodynamic stress, and post-surgical scars represent the main etiopathogenic factors that can contribute to the occurrence of cardiac arrhythmias in the population of patients with operated-on congenital heart malformations. Clinical manifestations differ depending on the duration of the arrhythmia, underlying structural defects, hemodynamic conditions, and comorbidities. The accurate diagnosis and the establishment of specific management options strongly influence the morbidity and mortality associated with arrhythmias. As such, identifying the risk factors for the occurrence of cardiac arrhythmias in the case of each patient is essential to establish a specific follow-up and management plan to improve the life expectancy and quality of life of children.

Unravelling early sinus node dysfunction after pediatric cardiac surgery: a pre-existing arrhythmogenic substrate

Early post-operative sinus node dysfunction (SND) is common in paediatric patients undergoing surgical correction of congenital heart defects (CHD). At present, the pathophysiology of these arrhythmias is incompletely understood. In this case series, we present three paediatric patients in whom we performed intraoperative epicardial mapping and who developed early post-operative SND. All patients had either an inferior or multiple sinoatrial node (SAN) exit sites, in addition to extensive conduction disorders at superior and inferior right atrium. Our findings contribute to the hypothesis that pre-existing alterations in SAN exit sites in combination with atrial conduction disorders may predispose paediatric patients with CHD for early post-operative SND. Such insights in the development of arrhythmias are crucial as it may be the first step in identifying high-risk patients.

Impact of obesity on post-operative arrhythmias after congenital heart surgery in children and young adults

BACKGROUND

Obesity increases the risk of post-operative arrhythmias in adults undergoing cardiac surgery, but little is known regarding the impact of obesity on post-operative arrhythmias after CHD surgery.

METHODS

Patients undergoing CHD surgery from 2007 to 2019 were prospectively enrolled in the parent study. Telemetry was assessed daily, with documentation of all arrhythmias. Patients aged 2-20 years were categorised by body mass index percentile for age and sex (underweight <5, normal 5-85, overweight 85-95, and obese >95). Patients aged >20 years were categorised using absolute body mass index. We investigated the impact of body mass index category on arrhythmias using univariate and multivariate analysis.

RESULTS

There were 1250 operative cases: 12% underweight, 65% normal weight, 12% overweight, and 11% obese. Post-operative arrhythmias were observed in 38%. Body mass index was significantly higher in those with arrhythmias (18.8 versus 17.8, p = 0.003). There was a linear relationship between body mass index category and incidence of arrhythmias: underweight 33%, normal 38%, overweight 42%, and obese 45% (p = 0.017 for trend). In multivariate analysis, body mass index category was independently associated with post-operative arrhythmias (p = 0.021), with odds ratio 1.64 in obese patients as compared to normal-weight patients (p = 0.036). In addition, aortic cross-clamp time (OR 1.007, p = 0.002) and maximal vasoactive-inotropic score in the first 48 hours (OR 1.03, p = 0.04) were associated with post-operative arrhythmias.

CONCLUSION

Body mass index is independently associated with incidence of post-operative arrhythmias in children after CHD surgery.

Risk factors of early postoperative cardiac arrhythmia after pediatric cardiac surgery: A single-center experience

OBJECTIVES

To evaluate the incidence of arrhythmia in the early postoperative period and to identify its risk factors among pediatric patients following cardiac surgery at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia, between 2015-2020.

METHODS

Out of 1242 patients, a total of 821 aged <18 years who underwent cardiac surgery were included in this retrospective cohort carried out in June 2021 at KAUH, Jeddah, Saudi Arabia. Information retrieved from the hospital medical records had patients' demographics, types of arrhythmias, hemodynamic stability, electrolyte disturbances, cardiopulmonary bypass (CPB), and aortic cross-clamp (AXC) durations. Univariate and multivariate logistic regression analyses were used to evaluate the possible risk factors associated with postoperative arrhythmia.

RESULTS

Of the 821 patients, 140 (17.1%) developed arrhythmia postoperatively. The most common arrhythmias were junctional ectopic tachycardia (JET, 51.4%), atrioventricular block (27.1%), and supraventricular tachycardia (10%). The majority of cases occurred on the first day postoperatively (79.3%). Patients with postoperative arrhythmias had a more prolonged CPB (p=0.0001) and AXC (p=0.005) time, electrolytes disturbances (p=0.021), and hemodynamic instability (p=0.0001) than other patients.

CONCLUSION

Postoperative arrhythmia, especially JET, is common after pediatric cardiac surgery. Prolonged cardiopulmonary bypass, prolonged aortic cross-clamping, electrolytes disturbances, and hemodynamic instability are possible risk factors for postoperative cardiac arrhythmias.

Extrasystoles or short bradycardias of the newborn seldom require subsequent 24-hour electrocardiographic monitoring

AIM

To retrospectively assess the indications for and findings on 24-hour electrocardiographic (Holter) monitoring in newborns, focussing on bradycardias and extrasystoles.

METHODS

Data included 337 term-born infants. Holter indications were categorised into bradycardias below 80 beats per minute, extrasystoles, any tachycardia and other. Heart rate below 60 beats per minute, pathological atrioventricular conduction, supraventricular or ventricular tachycardia, or either atrial premature contractions over 10% or ventricular premature contractions over 5% of total beats were defined as significant arrhythmia on Holter.

RESULTS

The median age was 6 days (range: 2-62 days). Bradycardia (42%) or extrasystoles (32%) were the most common Holter indications. Fifty-three infants (16%) had significant arrhythmia on Holter. Heart disease or 12-lead electrocardiogram expressing extrasystoles or conduction abnormalities were associated with significant arrhythmias (p = 0.046 and p < 0.001, respectively). Twenty-seven of 109 infants (25%) with extrasystoles as a Holter indication had abnormal Holter results, but only seven (6.4%) had significant arrhythmia on Holter if the 12-lead electrocardiogram was normal. No pathology was found behind bradycardias below 80 beats per minute in the absence of heart disease.

CONCLUSION

Among term newborns with extrasystoles or bradycardias, Holter monitoring could be targeted to infants with heart disease or abnormal electrocardiograms.

Perioperative junctional ectopic tachycardia associated with congenital heart disease: risk factors and appropriate interventions

The risk factors and the appropriate interventions for perioperative junctional ectopic tachycardia (JET) in congenital heart disease (CHD) surgery have not been sufficiently investigated despite the severity of this complication. This study aimed to examine the risk factors and interventions for perioperative JET. From 2013 to 2020, 1062 surgeries for CHD (median patient age: 4.3 years, range 0.0-53.0) with or without a cardiopulmonary bypass (CPB) were performed at Hokkaido University, Japan. We investigated the correlation between perioperative JET morbidity factors, such as age, genetic background, CPB/aortic cross-clamp (ACC) time, use of inotropes and dexmedetomidine, STAT score, and laboratory indices. The efficacy of JET therapies was also evaluated. Of the 1062 patients, 86 (8.1%) developed JET. The 30-day mortality was significantly high in JET groups (7% vs. 0.8%). The independent risk factors for JET included heterotaxy syndrome [odds ratio (OR) 4.83; 95% confidence interval (CI) 2.18-10.07], ACC time exceeding 90 min (OR 1.90; CI 1.27-2.39), and the use of 3 or more inotropes (OR 4.11; CI 3.02-5.60). The combination of anti-arrhythmic drugs and a temporary pacemaker was the most effective therapy for intractable JET. Perioperative JET after CHD surgery remains a common cause of mortality. Inotrope use was a risk factor for developing JET overall surgery risk. In short ACC surgeries, heterotaxy syndrome could increase the risk of JET, which could develop even without inotrope use in long ACC surgeries. It is crucial not to delay the treatment in cases with unstable hemodynamics caused by this arrhythmia. It is recommended to reduce numbers not dose of inotropes.

Diagnosis and management of junctional ectopic tachycardia in children

Junctional ectopic tachycardia (JET) is more common in its postoperative form. A thorough understanding of its etiology, pathophysiology, and management strategies is essential. Classically, postoperative JET is considered to arise from surgical trauma. Genetic susceptibility and an intrinsic morphologic/functional defect in the conduction system inherent in congenital heart diseases likely play a significant role. The devastating effects on postoperative hemodynamics warrant prompt attention. A multipronged management approach with general measures, pharmacotherapy, and pacing has decreased morbidity and mortality. Amiodarone and procainamide remain the preferred drugs, while ivabradine appears promising. Carefully planned randomized trials can go a long way in developing a systematic management protocol for postoperative 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 in infants and children

Tachyarrhythmias originating in the atrioventricular (AV) node and AV junction including the bundle of His complex (BH) are called junctional tachycardia (JT) or junctional ectopic tachycardia (JET). Congenital JET (CJET) is a rare arrhythmia that occurs in patients without a preceding cardiac surgery and can be refractory to medical therapy and associated with high morbidity and mortality. CJET has a high rate of morbidity and mortality with death occurring in 35% of cases. JET occurring within 72 hours after cardiac surgery is referred to as postoperative JET (POJET) and caused by direct trauma, ischemic, or stretch injury to the AV conduction tissues during surgical repair of congenital heart defects. Focal junctional tachycardia (FJT) is also known as automatic junctional tachycardia and includes paroxysmal or non-paroxysmal forms. We discuss a staged approach to therapy with improved pharmacological therapies and the use of catheter-based therapies.

Predictors of Early Postoperative Supraventricular Tachyarrhythmias in Children After the Fontan Procedure

Postoperative arrhythmias are a frequent and fatal complication after the Fontan operation. However, clinical evidence demonstrating early postoperative arrhythmias in children undergoing the Fontan operation is limited. This study aimed to evaluate the prevalence of arrhythmias and identify the predictors of early postoperative supraventricular tachyarrhythmias (SVTs) after the Fontan procedure.Data were analyzed from 80 pediatric patients who underwent Fontan procedures between April 2000 and December 2017 in a single-center retrospective study. Early postoperative SVTs were defined as arrhythmias within 30 days after the Fontan procedure. We divided the patients into two groups, with or without early postoperative arrhythmias, and the predictors of early postoperative arrhythmias were analyzed. A multivariate logistic regression analysis was performed to determine independent predictors of early postoperative SVTs after the Fontan procedure.Early postoperative SVTs were observed in 21 patients (26.3%). The most common arrhythmia was junctional ectopic tachycardia. After an adjustment, an atrioventricular valve regurgitation (AVVR) grade of ≥2 (odds ratio 10.54, 95% confidence interval 2.52 to 44.17, P = 0.001) and preoperative arrhythmias (odds ratio 26.49, 95% confidence interval 1.64 to 428.62, P = 0.021) were significant predictors of early postoperative SVTs after the Fontan operation.An AVVR grade ≥2 and preoperative arrhythmia were significant predictors associated with early postoperative SVTs. Intervention for AVVR may provide clinical benefit for preventing early postoperative arrhythmias after the Fontan operation.

Ivabradine as an Adjunct for Refractory Junctional Ectopic Tachycardia Following Pediatric Cardiac Surgery: A Preliminary Study

Objectives:

Junctional ectopic tachycardia (JET) is a relatively common narrow complex rhythm typically characterized by atrioventricular dissociation or retrograde atrial conduction in a 1:1 pattern. Junctional ectopic tachycardia can be a life-threatening disorder, causing severe hemodynamic compromise and increased morbidity and mortality. The treatment of refractory JET can be very difficult, even with multimodal therapeutic interventions. The purpose of this study was to assess the role of ivabradine in cases of JET refractory to amiodarone and esmolol.

Methods:

A total of 480 congenital heart surgeries were carried out at our center in 2017. Twenty (4.16%) patients had postoperative JET. Among these, five infants, aged 7 to 12 months (median: 8 months), had refractory JET. These patients (three tetralogy of Fallot, one ventricular septal defect, one complete atrioventricular septal defect) were treated with oral ivabradine in the dose range of 0.1 to 0.2 mg/kg/12 h as an adjunct to amiodarone.

Results:

All five patients achieved rate reduction and eventual conversion to sinus rhythm. Mean duration to achieve heart rate of <140 bpm after initiation of ivabradine therapy was 16.8 hours (±7.2 hours), while mean duration to achieve sinus rhythm was 31.6 hours (±13.6 hours). No patient had any recurrence of JET. No patient exhibited any hemodynamic derangement nor side effects attributable to oral ivabradine.

Conclusion:

Oral ivabradine has the potential to be used as an adjunct to amiodarone in the treatment of JET in infants after surgery for congenital heart disease.

Association Between Postoperative Dexmedetomidine Use and Arrhythmias in Infants After Cardiac Surgery

BACKGROUND

Dexmedetomidine has been suggested as an arrhythmia prophylactic agent after surgery for congenital heart disease due to its heart rate lowering effect, though studies are conflicting. We sought to study the effect of dexmedetomidine in infants that are at highest risk for arrhythmias.

METHODS

Retrospective cohort study of infants less than six months of age undergoing cardiopulmonary bypass for congenital heart disease. The arrhythmia incidence in the first 48 hours after surgery in infants receiving dexmedetomidine for sedation was compared to those that did not receive dexmedetomidine.

RESULTS

A total of 309 patients were included, 206 patients who did not receive dexmedetomidine and 103 patients who did. The incidence of tachyarrhythmias was similar between the non-DEX group and the DEX group (19% vs 15%, P = .34). When adjusted for baseline differences, the non-DEX group did not have an increased risk of postoperative tachyarrhythmias (odds ratio [OR]: 1.4, 95% confidence interval [CI]: 0.5-3.8). The non-DEX group had an increased need for treatment for arrhythmias (18% vs 8%, P = .012). The three lesions with baseline higher risk for arrhythmias (tetralogy of Fallot, transposition of the great arteries, and complete atrioventricular canal) had an increased incidence of tachyarrhythmias in the non-DEX group (34% vs 6%, P = .027). This risk was not significant in multivariate analysis (OR: 2.5, 95% CI: 0.4-15.5).

CONCLUSIONS

High-risk infants had decreased incidence of tachyarrhythmias when receiving dexmedetomidine, though this was not significant after accounting for baseline differences between groups.

Incidence, Risk Factors, and Outcome of Cardiac Arrhythmia Postcardiac Surgery in Children

Objective

To study the incidence of postoperative cardiac arrhythmias in children undergoing cardiac surgery and to evaluate the risk factors and outcome of these patients.

Materials and Methods

This retrospective observational study was conducted in the cardiac pediatric intensive care unit and included children <18 years of age. Children were monitored in the early postoperative period (72 h) for any sustained rhythm abnormality and were classified using standard definition. Details of treatment and their response were assessed. Risk factors for arrhythmias were evaluated using multivariate logistic regression analysis.

Results

Five hundred and thirty-six children were included and the prevalence of arrhythmia was 14.4% (n = 77). The most common arrhythmia was complete heart block (CHB) (n = 28; 5.2%), followed by junctional ectopic tachycardia (JET) (n = 25; 4.7%), junctional escape rhythm (n = 13; 2.4%), supraventricular tachycardia (SVT) (n = 8; 1.5%), and ventricular tachycardia (VT) (n = 3; 0.6%). Cardiac pacing was required in all CHB; 8 (28.6%) required a permanent pacemaker. Six (24%) patients with JET responded to conventional measures; 19 (76.0%) patients required amiodarone and 5 (20%) required cooling to 34°C or cardiac pacing. Temporary cardiac pacing was required in 9 (69.2%) cases of junctional escape rhythm. Seven (87.5%) events of SVT responded to adenosine and 1 (12.5%) required cardioversion. Two (66.7%) of VT responded to cardioversion while 1 (33.3%) was refractory. Five (6.5%) patients with arrhythmia died. In the multivariate logistic regression analysis, age <1 year, risk adjustment for congenital heart surgery category ≥3, and cross-clamp time >67 min were independent risk factors.

Conclusion

Early postoperative period following cardiac surgery is extremely vulnerable to cardiac arrhythmias. Although majority are self-limiting, some can be life-threatening.

Incidence and effect of early postoperative ventricular arrhythmias after congenital heart surgery

BACKGROUND

Postoperative arrhythmias after pediatric congenital heart disease (CHD) surgery are a known cause of morbidity and are associated with mortality. A comprehensive evaluation of early postoperative ventricular arrhythmias (VAs) after CHD surgery has not been reported.

OBJECTIVES

We sought to determine the incidence of in-hospital VAs after CHD surgery and assess the clinical relevance of this arrhythmia during the postoperative hospital course.

METHODS

Patients undergoing CHD surgery at our center from September 2007 through December 2016 were prospectively enrolled. Univariate and multivariate analysis was used to assess the association between postoperative VAs and in-hospital mortality, adjusting for postoperative extracorporeal membrane oxygenation and stage 1 single ventricle palliation operations.

RESULTS

A total of 2503 postoperative courses in 1835 patients were included. In all, 464 (18.5%) had VAs, of whom 135 (29.1%) received treatment. Monomorphic ventricular tachycardia was the most frequently treated ventricular arrhythmia (TVA; n=91 [62.3%]). TVAs were associated with increased postoperative extracorporeal membrane oxygenation (13.3% vs 5.5%; P < .001) and in-hospital mortality (14.9% vs 4.0%; P < .001). In multivariate analysis, TVA was an independent risk factor for in-hospital mortality (adjusted odds ratio 2.44; 95% confidence interval 1.21-4.92).

CONCLUSION

Early postoperative VAs after CHD surgery are more common than previously reported. Postoperative VAs are associated with increased in-hospital mortality, and the subgroup of TVAs is an independent risk factor for in-hospital mortality.

The Prevalence and Risk Factors of Early Arrhythmias Following Pediatric Open Heart Surgery in Egyptian Children

AIM:

This study aimed to assess the prevalence of early postoperative arrhythmias after cardiac operation in the pediatric population, and to analyse possible risk factors.

MATERIAL AND METHODS:

Cross-sectional study included 30 postoperative patients, with age range four up to 144 months. They were selected from those admitted to the Cardiology Unit in the Pediatric department of Ain Shams University hospitals, after undergoing cardiopulmonary bypass (CPB) surgery for correction of congenital cardiac defects. All patients had preoperative sinus rhythm and normal preoperative electrolytes levels. All patients’ records about age, weight, type of surgery, intraoperative arrhythmias, cardiopulmonary bypass time, ischemic time and use of inotropic drugs were taken before they were admitted to the specialised pediatric post-surgery intensive care unit (ICU).

RESULTS:

Arrhythmia was documented in 15 out of 30 patients (50%). Statistically significant difference between the arrhythmic and non-arrhythmic group were recorded in relation to the age of operation (23 vs 33 months), weight (12 vs. 17 kg), ischemic time (74.5 vs. 54 min), cardiopulmonary bypass time (125.5 vs. 93.5min), inotrope use (1.6 vs. 1.16) and postoperative ICU stay (5.8 vs. 2.7 days), P<0.05.

CONCLUSION:

Early postoperative arrhythmias following surgery for congenital heart disease are relatively frequent in children (50%). Younger age, lower body weight, longer ischemic time and bypass time, and more inotrope use are all risk factors for postoperative arrhythmias and lead to increase the hospital stay.

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.

Impact of Different Diagnostic Criteria on the Reported Prevalence of Junctional Ectopic Tachycardia After Pediatric Cardiac Surgery

OBJECTIVES

Junctional ectopic tachycardia is a frequent complication after pediatric cardiac surgery. A uniform definition of postoperative junctional ectopic tachycardia has yet to be established in the literature. The objective of this study is to analyze differences in the general and age-related prevalence of postoperative junctional ectopic tachycardia according to different diagnostic definitions.

DESIGN

Data files and electrocardiograms of 743 patients (age, 1 d to 17.6 yr) who underwent surgery for congenital heart disease during a 3-year period were reviewed. The prevalence of postoperative junctional ectopic tachycardia in this cohort was determined according to six different definitions identified in the literature and one definition introduced for analytical purposes. Agreement between the definitions was analyzed according to Cohen κ coefficients. A receiver operating characteristic analysis was performed to determine the ability of different definitions to discriminate between patients with increased postoperative morbidity and without.

SETTING

A university-affiliated tertiary pediatric cardiac PICU.

PATIENTS

Infants and children who underwent heart surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The prevalence of postoperative junctional ectopic tachycardia ranged from 2.0% to 8.3% according to the seven different definitions. Even among definitions for which the general prevalence was almost equal, the distribution according to age varied. Most definitions used a frequency criterion to define postoperative junctional ectopic tachycardia. Definitions based on a fixed frequency criterion did not identify cases of postoperative junctional ectopic tachycardia in patients older than 12 months. The grade of agreement was moderate or poor between definitions using a fixed or dynamic frequency criterion and those not based on a critical heart rate (κ = 0.37-0.66). In the receiver operating characteristic analysis, the definition with a fixed frequency criterion of 180 beats/min or an age-related frequency criterion according to the 95th percentile showed the optimal cut-off value to determine increased postoperative morbidity.

CONCLUSIONS

Different definitions of junctional ectopic tachycardia after pediatric cardiac surgery lead to relevant differences in the reported prevalence and age distribution pattern. A uniform definition of postoperative junctional ectopic tachycardia is needed to provide comparable study results and to improve the diagnosis of junctional ectopic tachycardia in pediatric patients.

Ischemia-reperfusion destabilizes rhythmicity in immature atrioventricular pacemakers: A predisposing factor for postoperative arrhythmias in neonate rabbits

BACKGROUND

Postoperative arrhythmias such as junctional ectopic tachycardia and atrioventricular block are serious postoperative complications for children with congenital heart disease. We hypothesize that ischemia-reperfusion (I/R) related changes exacerbate these postoperative arrhythmias in the neonate heart and administration of postoperative inotropes is contributory.

OBJECTIVE

The purpose of this study was to study the effects of I/R and postischemic dopamine application on automaticity and rhythmicity in immature and mature pacemaker cells and whole heart preparations.

METHODS

Single pacemaker cells and whole heart models of postoperative arrhythmias were generated in a rabbit model encompassing 3 primary risk factors: age, I/R exposure, and dopamine application. Single cells were studied using current clamp and line scan confocal microscopy, whereas whole hearts were studied using optical mapping.

RESULTS

Four responses were observed in neonatal atrioventricular nodal cells (AVNCs): slowing of AVNC automaticity (from 62±10 to 36 ± 12 action potentials per minute, P<.05); induction of arrhythmicity or increased beat-to-beat variability (0.08 ± 0.04 to 3.83 ± 1.79, P<.05); altered automaticity (subthreshold electrical fluctuations); and disruption of calcium transients. In contrast, these responses were not observed in mature AVNCs or neonatal sinoatrial cells. In whole heart experiments, neonatal hearts experienced persistent postischemia arrhythmias of varying severity, whereas mature hearts exhibited no arrhythmias or relatively transient ones.

CONCLUSION

Neonatal pacemaker cells and whole hearts demonstrate a susceptibility to I/R insults resulting in alterations in automaticity, which may predispose neonates to postoperative arrhythmias such as junctional ectopic tachycardia and atrioventricular block.

Prevalence of arrhythmias among children below 15 years of age with congenital heart diseases attending Mulago National Referral Hospital, Uganda

BACKGROUND

In Uganda, few children with congenital heart diseases (CHD) benefit from early corrective cardiac surgery. These children are at high risk of developing heart failure and electrolyte imbalances; factors which increase their risk of developing arrhythmias. This study aimed to determine the prevalence and factors associated with arrhythmias among children with congenital heart diseases receiving care at Mulago Hospital.

METHODS

This was a cross-sectional study carried out from August 2013 to March 2014 at Mulago Hospital. Children were consecutively enrolled into the study. Standard 12-lead electrocardiograms (ECGs) were performed on 194 children with CHD (age range 10 days-15 years). Data was analysed using SPSS 16.0.

RESULTS

Out of 194 children studied, 53/194 (27.3 %, 95 % CI 21.0 - 33.6) children had arrhythmias. Of the CHD children, 44/194 (22.7 %, 95 % CI 16.8 - 28.6) had first degree AV block while 9/194 (4.6 %, 95 % CI 1.7 - 7.6) children had either ectopic atrial rhythm, premature atrial contractions, junctional rhythm, complete atrioventricular (AV) dissociation or premature ventricular contractions. Children using digoxin were more likely to have first degree AV block (OR 3.75, 95 % CI 1.60-8.86) while those aged 5 years and below were less likely to have first degree AV block (OR 0.16, 95 % CI 0.07-0.37).

CONCLUSION

Arrhythmias are common among children with CHD receiving care from Mulago Hospital. These are associated with digoxin use, child's age and electrolyte imbalances; factors which can easily be assessed, managed and where possible modified in these children during their care.

Effects of surgical en bloc rotation of the arterial trunk on the conduction system in children with transposition of the great arteries, ventricular septal defect and pulmonary stenosis

OBJECTIVES

The standard surgical management of patients with transposition of the great arteries, ventricular septal defect, and pulmonary stenosis is the Rastelli operation. Recently, en bloc rotation of the arterial trunk, by cutting out the aortic and the pulmonary root in one block and by rotating it 180°, has been introduced as a new option for anatomical repair.

METHODS

To evaluate the effects of this surgical method on the conduction system, pre-operative, post-operative, and follow-up electrocardiograms as well as patient charts were reviewed retrospectively. A total of 16 consecutive patients with transposition of the great arteries and left outflow tract obstruction were treated with en bloc rotation.

RESULTS

During the post-operative period, there were two patients with complete atrio-ventricular block, one with junctional ectopic tachycardia, one with ventricular tachycardia, and one with supraventricular tachycardia. None of the patients had a typical right bundle branch block pattern before surgery; however, this pattern was detectable after surgery in eight out of 16 patients (50%), which persisted during the follow-up. All patients without typical right bundle branch block pattern showed a median QRS duration of 65 ms (54-112 ms) before surgery, 62 ms (54-122 ms) after surgery, and 84 ms (66-128 ms) at the last follow-up visit. This compares well with a similar Rastelli cohort, where a right bundle branch block prevalence of 77% was reported. Out of 16 patients, 12 showed non-specific ST changes and negative T-waves, which persisted during follow-up with an unknown significance for the future.

CONCLUSION

Our data suggest that en bloc rotation of the arterial trunk seems not to have more negative effects on the conduction system than the Rastelli operation.

Evaluating the Safety of Intraoperative Antiarrhythmics in Pediatric Cardiac Surgery Patients

Cardiac arrhythmias occurring during the intraoperative period for cardiac surgery have been associated with excess morbidity and mortality. Several antiarrhythmics have been utilized for the management of intraoperative arrhythmias. These antiarrhythmic medications can cause undesirable adverse outcomes in the intensive care setting. The incidence and treatment of adult intraoperative arrhythmias have been studied. In addition, the prevalence, risk factors, and optimal treatment of pediatric postoperative arrhythmias have also been studied. However, the literature has not been published on intraoperative antiarrhythmia treatment during pediatric cardiac surgery. The purpose of this study was to determine the safety of intraoperative antiarrhythmic medications utilized in pediatric cardiac surgery patients. This was a retrospective review of all patients who received an intraoperative antiarrhythmic in the cardiovascular operating room at Texas Children's Hospital. Patients were included if they underwent cardiovascular surgery from November 2008 to July 2013 and were excluded if antiarrhythmics were given intraoperatively for other indications (i.e., esmolol for hypertension) or if patients were older than 18 years of age. Safety of antiarrhythmic treatment was determined by the absence or presence of adverse events. Control or recurrence of the arrhythmia was analyzed as a secondary measure to help determine antiarrhythmic efficacy. A total of 45 patients were identified (53.3 % male). Patients were a median of 0.52 years at the time of surgery. Primary surgery types were tetralogy of Fallot repair (n = 6; 13.3 %) and ventricular septal defect closure (n = 5, 11.1 %). Thirty-one patients (68.9 %) had documented adverse events after the administration of antiarrhythmics. Most of these adverse events occurred after the administration of amiodarone (n = 16; 51.6 %) followed by esmolol (n = 15; 48.4 %). Fifty-one percent of the arrhythmias resolved in the operating room (n = 23), and nearly half (n = 19) of all patients were discharged home on an antiarrhythmic medication. A high incidence of adverse events was associated with intraoperative administration of antiarrhythmic medications.

Association between perioperative dexmedetomidine and arrhythmias after surgery for congenital heart disease

BACKGROUND

Dexmedetomidine is commonly used after congenital heart surgery and may be associated with a decreased incidence of postoperative tachyarrhythmias. Using a large cohort of patients undergoing congenital heart surgery, we examined for an association between dexmedetomidine use in the immediate postoperative period and subsequent arrhythmia development.

METHODS AND RESULTS

A total of 1593 surgical procedures for congenital heart disease were performed. Dexmedetomidine was administered in the immediate postoperative period after 468 (29%) surgical procedures. When compared with 1125 controls, the group receiving dexmedetomidine demonstrated significantly fewer tachyarrhythmias (29% versus 38%; P<0.001), tachyarrhythmias receiving intervention (14% versus 23%; P<0.001), bradyarrhythmias (18% versus 22%; P=0.03), and bradyarrhythmias receiving intervention (12% versus 16%; P=0.04). After propensity score matching with 468 controls, the arrhythmia incidence between groups became similar: tachyarrhythmias (29% versus 31%; P=0.66), tachyarrhythmias receiving intervention (14% versus 17%; P=0.16), bradyarrhythmias (18% versus 15%; P=0.44), and bradyarrhythmias receiving intervention (12% versus 9%; P=0.17). After excluding controls exposed to dexmedetomidine at a later time in the hospitalization, dexmedetomidine was associated with increased odds of bradyarrhythmias receiving intervention (odds ratio, 2.18; 95% confidence interval, 1.02-4.65). Furthermore, there was a dose-dependent increase in the odds of bradyarrhythmias (odds ratio, 1.04; 95% confidence interval, 1.01-1.07) and bradyarrhythmias receiving intervention (odds ratio, 1.05; 95% confidence interval, 1.01-1.08).

CONCLUSIONS

Although dexmedetomidine exposure in the immediate postoperative period is not associated with a clinically meaningful difference in the incidence of tachyarrhythmias after congenital heart surgery, it may be associated with increased odds of bradyarrhythmias.

Safety and efficacy of the off-label use of milrinone in pediatric patients with heart diseases

Background and Objectives

Milrinone is often used in children to treat acute heart failure and prevent low cardiac output syndrome after cardiac surgery. Due to the lack of studies on the long-term milrinone use in children, the objective of this study was to assess the safety and efficacy of the current patterns of milrinone use for ≥3 days in infants and children with heart diseases.

Subjects and Methods

We retrospectively reviewed the medical records of patients aged <13 years who received milrinone for ≥3 days from January 2005 to December 2012. Patients' characteristics including age, sex, height, weight, and body surface area were recorded. The following parameters were analyzed to identify the clinical application of milrinone: initial infusion rate, maintenance continuous infusion rate, total duration of milrinone therapy, and concomitantly infused inotropes. The safety of milrinone was determined based on the occurrence of adverse events such as hypotension, arrhythmia, chest pain, headache, hypokalemia, and thrombocytopenia.

Results

We assessed 730 admissions (684 patients) during this period. Ventricular septal defects were the most common diagnosis (42.4%) in these patients. Milrinone was primarily used after cardiac surgery in 715 admissions (97.9%). The duration of milrinone treatment varied from 3 to 64.4 days (≥7 days in 149 admissions). Ejection fraction and fractional shortening of the left ventricle improved in patients receiving milrinone after cardiac surgery. Dose reduction of milrinone due to hypotension occurred in only 4 admissions (0.5%). Although diverse arrhythmias occurred in 75 admissions (10.3%), modification of milrinone infusion to manage arrhythmia occurred in only 3 admissions (0.4%). Multivariate analysis indicated that the development of arrhythmia was not influenced by the pattern of milrinone use.

Conclusion

Milrinone was generally administered for ≥3 days in children with heart diseases. The use of milrinone for ≥3 days was effective in preventing low cardiac output after cardiac surgery when combined with other inotropes, suggesting that milrinone could be safely employed in pediatric patients with heart diseases.

Prevalence of and risk factors for early postoperative arrhythmia in children after cardiac surgery

BACKGROUND

The aims of this study were to (i) evaluate postoperative arrhythmias following congenital heart surgery, on 12-lead electrocardiography and Holter monitoring; and (ii) analyze the association between the type of repair and postoperative arrhythmia.

METHODS

A total of 229 children and 10 neonates with a mean age of 4.71 ± 0.41 years (range, 15 days-17 years) who underwent congenital cardiac surgery were included the study. Twelve-lead electrocardiography and Holter monitoring were used to evaluate arrhythmias after the operation.

RESULTS

Within the evaluation period, 104 patients (43.5%) developed arrhythmias after surgery. No arrhythmias were observed in neonates. Female sex (51.9%) was slightly associated with the occurrence of arrhythmias after operation. The most common arrhythmia was supraventricular extra-systoles (65.4%). Risk factors for supraventricular extra-systoles were repair of secundum atrial septal defect (32.3%), ventricular septal defect (25%) and tetralogy of Fallot (14.7%). Also, ventricular extra-systoles were associated with repair of ventricular septal defect.

CONCLUSIONS

Postoperative arrhythmia is usually a frequent and transient phenomenon after congenital cardiac surgery, and is provoked by both mechanical irritation of the conduction system and humoral factors. Postoperative arrhythmia should be anticipated in patients with congenital cardiac surgery. Finally, the association between this type of surgical repair and arrhythmia may be helpful for estimating the type of arrhythmia that develops after congenital cardiac surgery in children.

Perioperative atrial tachycardia is associated with increased mortality in infants undergoing cardiac surgery

OBJECTIVE

Few data are available on the frequency or importance of perioperative atrial tachycardia in infants. We hypothesized that atrial tachycardia in infants undergoing cardiac surgery is not rare and is associated with increased morbidity and mortality.

METHODS

From 2007 through 2010, 777 infants (median age, 1.8 months; interquartile range, 0.33-5.73) underwent cardiac surgery. Their medical records were reviewed for atrial tachycardia during the perioperative period.

RESULTS

Of the 777 patients, 64 (8.2%) developed atrial tachycardia. The independent risk factors for developing atrial tachycardia included surgical age 6 months or younger (odds ratio, 4.4; 95% confidence interval, 1.1-19.15), use of 3 or more inotropes (odds ratio, 2.9; 95% confidence interval, 1.4-6.2), and heterotaxy syndrome (odds ratio, 2.9; 95% confidence interval, 1.1-7.4). All-cause mortality in the atrial tachycardia group was increased (21.9% vs 7.2%, P<.001) during a median follow-up period of 14.6 months (interquartile range, 6.8-24.6), and atrial tachycardia was independently associated with decreased survival (hazard ratio, 1.9; 95% confidence interval, 1.1-3.8). Infants with perioperative atrial tachycardia had a longer hospital length of stay (32 vs 17 days, P<.001) and duration of inotrope use (10.5 vs 3.0 days, P<.001). A total of 57 patients received antiarrhythmic therapy, with propranolol the most common (n=31). Among the survivors, 48 patients received outpatient antiarrhythmic therapy, which was successfully discontinued in 23 patients at a median duration of 14 months (interquartile range, 5.7-18.6) without recurrence.

CONCLUSIONS

Atrial tachycardia is common in infants undergoing cardiac surgery and is independently associated with decreased survival. Among survivors, antiarrhythmic agents successfully controlled atrial tachycardia in most patients with a low recurrence risk after discontinuation.

Managing arrhythmias before and after aortic valve surgery in children

The proximity of the coronary arteries and the bundle of His to the aortic valve may contribute to the pathogenesis of arrhythmias in patients with aortic valve disease. Severe aortic valve disease may also adversely alter left ventricular hemodynamics (end-diastolic dimensions and wall stress) and thus create a substrate for ventricular arrhythmias before any intervention is performed. The severity of these arrhythmias depends on the severity of the underlying substrate (or the specific problem, such as aortic stenosis or aortic regurgitation), the age at which the aortic valve intervention was performed, the type of intervention (i.e. transcatheter aortic valve interventions or open aortic valve replacement or repair), and the reversibility of the altered hemodynamics after surgery. Both bradyarrhythmias and tachyarrhythmias are known complications of aortic valve interventions. Although data are scant, this review summarizes the incidence of arrhythmias before and after aortic valve interventions from a pediatric perspective.