Use of a modified, commercially available temporary pacemaker for R wave synchronized atrial pacing in postoperative junctional ectopic tachycardia

Navigating Arrhythmias in Tetralogy of Fallot Throughout the Lifespan: A Case-based Review

Arrhythmias are a common complication associated with tetralogy of Fallot (ToF), one of the most prevalent forms of congenital heart disease. As illustrated by this case-based review, various forms of arrhythmias can be encountered across the lifespan of patients with ToF, from infancy to older adulthood. These include atrioventricular block, junctional ectopic tachycardia, and atrial and ventricular arrhythmias. Arrhythmias have important implications on the health and quality of life of patients with ToF and require treatment by caregivers with dedicated expertise. The choice of pharmacologic and/or interventional therapies to alleviate symptoms, avoid complications, and mitigate risks depends in part on the type, severity, and frequency of the arrhythmia, as well as on the particularities of individual clinical scenarios. Preventing, monitoring for, and managing arrhythmias are an integral component of the care of patients with ToF throughout their lifespan that is critical to optimizing health outcomes.

Early and Late Postoperative Tachyarrhythmias in Children and Young Adults Undergoing Congenital Heart Disease Surgery

The population of patients with congenital heart disease is constantly growing with an increasing number of individuals reaching adulthood. A significant proportion of these children and young adults will suffer from tachyarrhythmias due to the abnormal anatomy, the hemodynamic burden, or as a sequela of surgical treatment. Depending on the underlying mechanism, arrhythmias may arise in the early postoperative period (hours to days after surgery) or in the late postoperative period (usually years after surgery). A good understanding of the electrophysiological characteristics and pathophysiological mechanisms is therefore crucial to guide the therapeutic approach. Here, we synthesize the current state of knowledge on epidemiological features, risk factors, pathophysiological insights, electrophysiological features, and therapy regarding tachyarrhythmias in children and young adults undergoing reparative surgery for congenital heart disease. The evolution and latest data on treatment options, including pharmacological therapy, ablation procedures, device therapy decision, and thromboprophylaxis, are summarized. Finally, throughout this comprehensive review, knowledge gaps and areas for future research are also identified.

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.

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.

Standardized training for AVT pacing in paediatric patients with postoperative junctional ectopic tachycardia

BACKGROUND

Junctional ectopic tachycardia is a serious complication of surgery for paediatric congenital heart disease. R-wave synchronized atrial (AVT) pacing, an innovative temporary pacing technique, restores atrioventricular synchrony in these patients. The method is highly effective but technically complex. A standardized training model exists for doctors but not for paediatric intensive care nurses.

AIMS

This study seeks to evaluate whether a standardized programme involving simulation and vignettes increases knowledge of AVT pacing and accuracy of its documentation, as well as recognition and management of specific complications.

STUDY DESIGN

This study was an experimental simulation test with before and after descriptive evaluation.

METHODS

A custom-made simulation model was used in combination with standardized training. Before and after training, 10 paediatric nurse specialists were asked to document pacing, to identify complications and to intervene as necessary. Four clinical scenarios were presented: effective AVT pacing, ineffective AVT pacing, pacing with narrow interval between atrial pacing and ventricular sensing and pacemaker-induced tachycardia. Identification and management of complications were evaluated using a 3-point scale.

RESULTS

Training improved the quality of documentation and complication management. At outset, documentation by 1 of 10 participants was completely correct, and after training, documentation by 8 of 10 participants was completely correct. Before training, 30% of interpretations of the four presented clinical scenarios were correct (12/40) versus 83% (33/40) after training. The decision to notify a doctor of a complication was correct in 83% (33/40) before versus 95% (38/40) after the training.

CONCLUSION

Standardized simulation training improves quality and safety in AVT pacing, with more accurate documentation of the pacing mode and better recognition and management of specific complications during pacing.

RELEVANCE TO CLINICAL PRACTICE

AVT pacing should be performed in conjunction with standardized simulation training in paediatric cardiac intensive care units.

Retrospective study of complete atrioventricular canal defects: Anesthetic and perioperative challenges

Objective:

The objective of this study was to highlight anesthetic and perioperative management and the outcomes of infants with complete atrioventricular (AV) canal defects.

Design:

This retrospective descriptive study included children who underwent staged and primary biventricular repair for complete AV canal defects from 1999 to 2013.

Setting:

A single-center study at a university affiliated heart center.

Participants:

One hundred and fifty-seven patients with a mean age at surgery of 125 ± 56.9 days were included in the study. About 63.6% of them were diagnosed as Down syndrome. Mean body weight at surgery was 5.6 ± 6.3 kg.

Methods:

Primary and staged biventricular repair of complete AV canal defects. Measurements and main results: A predefined protocol including timing of surgery, management of induction and maintenance of anesthesia, cardiopulmonary bypass, and perioperative intensive care treatment was used throughout the study. Demographic data as well as intraoperative and perioperative Intensive Care Unit (ICU) data, such as length of stay in ICU, total duration of ventilation including reintubations, and total length of stay in hospital and in hospital mortality, were collected from the clinical information system. Pulmonary hypertension was noted in 60% of patients from which 30% needed nitric oxide therapy. Nearly 2.5% of patients needed permanent pacemaker implantation. Thorax was closed secondarily in 7% of patients. In 3.8% of patients, reoperations due to residual defects were undertaken. Duration of hospital stay was 14.5 ± 4.7 days. The in-hospital mortality was 0%.

Conclusion:

Protocolized perioperative management leads to excellent outcome in AV canal defect repair surgery.

R-wave synchronised atrial pacing in pediatric patients with postoperative junctional ectopic tachycardia: the atrioventricular interval investigated by computational analysis and clinical evaluation

Background

R-wave synchronised atrial pacing is an effective temporary pacing therapy in infants with postoperative junctional ectopic tachycardia. In the technique currently used, adverse short or long intervals between atrial pacing and ventricular sensing (AP–VS) may be observed during routine clinical practice.

Objectives

The aim of the study was to analyse outcomes of R-wave synchronised atrial pacing and the relationship between maximum tracking rates and AP–VS intervals.

Methods

Calculated AP–VS intervals were compared with those predicted by experienced pediatric cardiologist.

Results

A maximum tracking rate (MTR) set 10 bpm higher than the heart rate (HR) may result in undesirable short AP–VS intervals (minimum 83 ms). A MTR set 20 bpm above the HR is the hemodynamically better choice (minimum 96 ms). Effects of either setting on the AP–VS interval could not be predicted by experienced observers. In our newly proposed technique the AP–VS interval approaches 95 ms for HR > 210 bpm and 130 ms for HR < 130 bpm. The progression is linear and decreases strictly (− 0.4 ms/bpm) between the two extreme levels.

Conclusions

Adjusting the AP–VS interval in the currently used technique is complex and may imply unfavorable pacemaker settings. A new pacemaker design is advisable to allow direct control of the AP–VS interval.

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.

A Low-Cost Simulation Model for R-Wave Synchronized Atrial Pacing in Pediatric Patients with Postoperative Junctional Ectopic Tachycardia

Background

Postoperative junctional ectopic tachycardia (JET) occurs frequently after pediatric cardiac surgery. R-wave synchronized atrial (AVT) pacing is used to re-establish atrioventricular synchrony. AVT pacing is complex, with technical pitfalls. We sought to establish and to test a low-cost simulation model suitable for training and analysis in AVT pacing.

Methods

A simulation model was developed based on a JET simulator, a simulation doll, a cardiac monitor, and a pacemaker. A computer program simulated electrocardiograms. Ten experienced pediatric cardiologists tested the model. Their performance was analyzed using a testing protocol with 10 working steps.

Results

Four testers found the simulation model realistic; 6 found it very realistic. Nine claimed that the trial had improved their skills. All testers considered the model useful in teaching AVT pacing. The simulation test identified 5 working steps in which major mistakes in performance test may impede safe and effective AVT pacing and thus permitted specific training. The components of the model (exclusive monitor and pacemaker) cost less than $50. Assembly and training-session expenses were trivial.

Conclusions

A realistic, low-cost simulation model of AVT pacing is described. The model is suitable for teaching and analyzing AVT pacing technique.

Association of temporary complete AV block and junctional ectopic tachycardia after surgery for congenital heart disease

AIM

Junctional ectopic tachycardia (JET) is a postoperative complication with a mortality rate of up to 14% after surgery for congenital heart disease. This study evaluated the risk factors of JET and explored the association of postoperative temporary third degree atrioventricular (AV) block and the occurrence of JET.

MATERIALS AND METHODS

Data were collected retrospectively from 1158 patients who underwent surgery for congenital heart disease.

RESULTS

The overall incidence of JET was 2.8%. Temporary third degree AV block occurred in 1.6% of cases. Permanent third degree AV block requiring pacemaker implantation occurred in 1% of cases. In all, 56% of patients with JET had temporary AV block (P < 0.001), whereas no case of postoperative JET was reported in patients with permanent AV block (P = 0.56). temporary third degree AV block did not suffer from JET.

CONCLUSIONS

A correlation between temporary third degree AV block and postoperative JET could be observed. The risk factors identified for JET include younger age groups at the time of surgery, longer aortic cross clamping time and surgical procedures in proximity to the AV node.

R-wave synchronised atrial pacing in post-operative junctional ectopic tachycardia using a transoesophageal pacemaker

We report the first case of R-wave synchronised atrial pacing using a transoesophageal pacemaker. A 3-month-old baby developed a junctional ectopic tachycardia after surgical closure of a ventricular septal defect. R-wave synchronised atrial pacing with an external pacemaker was not possible owing to dislocation of the atrial epimyocardial pacing wires. Therefore, a temporary oesophageal pacemaker was connected in series to the external pacemaker to allow transoesophageal atrial pacing triggered by the preceding ventricular actions.

Pacemaker therapy of postoperative arrhythmias after pediatric cardiac surgery

OBJECTIVE

To summarize the practical operation of temporary pacemakers in common use pertinent to the intensivist caring for the postcardiac patient. Pacemaker therapy is commonly required in the postoperative period after congenital cardiac surgery.

DATA SYNTHESIS

Monitoring the hemodynamic status and availability of equipment for resuscitation is always important in any patient requiring a temporary pacemaker. Two important scenarios to consider in the pediatric intensive care unit are: 1) the patient in whom pacing has been initiated to optimize cardiac function; and 2) the patient without demonstrable spontaneous electrical activity or with extreme bradycardia. A number of different models of temporary pacemaker are available. Management of the child requiring cardiac pacing requires an understanding of the indications for pacing, a thorough knowledge of the available pacemaker, and an ability to troubleshoot problems.

CONCLUSIONS

As the most common arrhythmias post congenital cardiac surgery involve either rate or conduction abnormalities, temporary pacemaker systems are a common form of electrical therapy in the postoperative period.