Early and delayed atrioventricular conduction block after routine surgery for congenital heart disease

Different leadless pacemakers working in harmony (Aveir in the atrium/Micra AV2 in the ventricle) in a patient with dextrocardia and double outlet right ventricle after high-risk infected device extraction

INTRODUCTION

Patients with congenital heart disease are at increased risk for requiring cardiac pacing during their lifetime.

METHODS

We present the first described case of using two leadless pacing systems manufactured by separate companies implanted within the same patient to provide atrial and ventricular pacing due to complex congenital anatomy.

RESULTS

A 27-year-old male with dextrocardia with double outlet right ventricle, subaortic ventricular septal defect, and pulmonary stenosis status-post pulmonary valve replacement complicated by ventricular pacing dependence and subsequent atrial pacing dependence after atriotomy-based atypical flutter ablation developed recurrent mediastinitis and pocket infection with erosion despite prolonged antibiotic treatment. Due to atrial and ventricular pacing dependence, a comprehensive congenital care team concluded the need for lead extraction and replacement of pacemaker via leadless peacemaking device. Laser-lead extraction and temporary atrial pacemaker placement was performed. Afterward, a transesophageal echocardiogram guided implantation of both a Micra AV 2 (Medtronic) leadless pacemaker in the interventricular septum within the right ventricle and an Aveir (Abbott) leadless pacemaker in the superior base of the right atrial appendage was performed with successful pacing. Although there is no communication between these devices, atrial-mechanical ventricular pacing was reliable with good implant thresholds, impedances and sensing from both devices.

CONCLUSION

Our case demonstrates the feasibility of using dual leadless pacing modalities to simultaneously pace someone at complex, prohibitive risk for temporary permanent or permanent pacemaker devices.

Retrievable leadless pacemakers (Aveir VR) may be beneficial in adult patients with congenital heart disease

INTRODUCTION

Congenital heart disease may present in up to 1.6 % of newborns. Given high burden of pacing need in adult patients with repaired congenital heart disease and availability of different pacing options, more information on outcomes of newer pacemaker types are needed. Retrievable leadless pacemaker implants in adult congenital patients have not been described.

METHODS

Retrospective review of three Aveir (Abbott) retrievable leadless pacemaker implants were reviewed at the UC Davis Medical Center. All patients underwent implant via femoral access.

RESULTS

All patients had one deployment only, after mapping prior. No complications occurred. Implant thresholds were 0.5 V (V) @0.2msilliseconds (ms) for patients 1 and 2 and 1 V @0.4 ms for patient 3. With impedances between 500 and 1290 Ω. Sensing was 5.5-8 mV (mV). Follow-up occurred up to one year (for two patients) with similar values overall. The predicted longevities of each device were between 22.6 and >25 years.

CONCLUSION

Safety and short-mid-term parameters of retrievable leadless pacemaker implantation is reported in three patients with adult congenital heart disease.

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.

Pacing in Pediatric Patients with Postoperative Atrioventricular Block

Surgery for congenital heart disease may compromise atrioventricular (AV) nodal conduction, potentially resulting in postoperative AV block. In the majority of cases, AV nodal function recovers during the early postoperative period and may only require short-term pacing support, typically provided via temporary epicardial wires. Permanent pacing is indicated when the postoperative AV block persists for more than 7 to 10 days due to the risk of mortality if a pacemaker is not implanted. Although there is a subset of patients who may have late recovery of AV nodal function, those with continued postoperative AV block will need lifelong pacing therapy.

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.

Pulmonary artery banding: still a role for staged bi-ventricular repair of intracardiac shunts?

OBJECTIVES

Although pulmonary artery banding remains a useful palliation in bi-ventricular shunting lesions, single-stage repair holds several advantages. We investigate outcomes of the former approach in high-risk patients.

METHODS

Retrospective cohort study including all pulmonary artery banding procedures over 9 years, excluding single ventricle physiology and left ventricular training.

RESULTS

Banding was performed in 125 patients at a median age of 41 days (2-294) and weight of 3.4 kg (1.8-7.32). Staged repair was undertaken for significant co-morbidity in 81 (64.8%) and anatomical complexity in 44 (35.2%). The median hospital stay was 14 days (interquartile range 8-33.5) and 14 patients (11.2%) required anatomical repair before discharge. Nine patients died during the initial admission (hospital mortality 7.2 %) and five following discharge (inter-stage mortality 4.8%). Of 105 banded patients who survived, 19 (18.1%) needed inter-stage re-admission and 18 (14.4%) required unplanned re-intervention. Full repair was performed in 93 (74.4%) at a median age of 13 months (3.1-49.9) and weight of 8.5 kg (3.08-16.8). Prior banding, 54% were below the 0.4th weight centile, but only 28% remained so at repair. Post-repair, 5/93 (5.4%) developed heart block requiring permanent pacemaker, and 11/93 (11.8%) required unplanned re-intervention. The post-repair mortality (including repairs during the initial admission) was 6/93 (6.5%), with overall mortality of the staged approach 13.6% (17/125).

CONCLUSIONS

In a cohort with a high incidence of co-morbidity, pulmonary artery banding is associated with a significant risk of re-intervention and mortality. Weight gain improves after banding, but heart block, re-intervention, and mortality remain frequent following repair.

Percutaneous epicardial pacing in infants using direct visualization: A feasibility animal study

BACKGROUND

Pacemaker implantation in infants and small children is limited to epicardial lead placement via open chest surgery. We propose a minimally invasive solution using a novel percutaneous access kit.

OBJECTIVE

To evaluate the acute safety and feasibility of a novel percutaneous pericardial access tool kit to implant pacemaker leads on the epicardium under direct visualization.

METHODS

A custom sheath with optical fiber lining the inside wall was built to provide intrathoracic illumination. A Veress needle inside the illumination sheath was inserted through a skin nick just to the left of the xiphoid process and angled toward the thorax. A needle containing a fiberscope within the lumen was inserted through the sheath and used to access the pericardium under direct visualization. A custom dilator and peel-away sheath with pre-tunneled fiberscope was passed over a guidewire into the pericardial space via modified Seldinger technique. A side-biting multipolar pacemaker lead was inserted through the sheath and affixed against the epicardium.

RESULTS

Six piglets (weight 3.7-4.0 kg) had successful lead implantation. The pericardial space could be visualized and entered in all animals. Median time from skin nick to sheath access of the pericardium was 9.5 (interquartile range [IQR] 8-11) min. Median total procedure time was 16 (IQR 14-19) min. Median R wave sensing was 5.4 (IQR 4.0-7.3) mV. Median capture threshold was 2.1 (IQR 1.7-2.4) V at 0.4 ms and 1.3 (IQR 1.2-2.0) V at 1.0 ms. There were no complications.

CONCLUSION

Percutaneous epicardial lead implantation under direct visualization was successful in six piglets of neonatal size and weight with clinically acceptable acute pacing parameters.

Update on percutaneous and perventricular device closure of congenital ventricular septal defect

INTRODUCTION

Ventricular septal defect is the most common congenital heart defect. Surgical repair has been standard therapy for symptomatic ventricular septal defects since the 1950's. Catheter-based device closure of ventricular septal defects emerged in the 1980's and has become a safe and effective alternative in select patients.

AREAS COVERED

This review focuses on patient selection and procedural techniques for device closure of ventricular septal defects, including percutaneous and hybrid perventricular approaches. The available devices used for these procedures, and outcomes of their use, are reviewed.

EXPERT OPINION

Percutaneous and perventricular device closure of ventricular septal defects is safe and effective in select patients. However, the majority of ventricular septal defects requiring closure continue to be managed with conventional surgery. Further development and investigation of transcatheter and hybrid surgical approaches for closing ventricular septal defects is required.

General anesthesia with a transcutaneous pacemaker for a Noonan syndrome patient with advanced atrioventricular block discovered in the remote period after open-heart surgery: a case report

We provided general anesthesia management to a patient with advanced atrioventricular block, which was discovered in the remote period after open-heart surgery. A 21-year-old man with Noonan syndrome was scheduled to undergo excision of a median intramandibular tumor. At 2 months of age, the patient underwent endocardial repair for congenital heart disease. During our preoperative examination, an atrioventricular block was detected, which had not been previously noted. Emergency drugs were administered, and a transcutaneous pacemaker was placed. During anesthesia induction, mask ventilation was easy, and intubation was performed smoothly using a video laryngoscope. The transcutaneous pacemaker was activated in demand mode at a pacing rate of 50 cycles/min approximately throughout the anesthesia time, and the hemodynamic status remained stable. The effect of intraoperatively administered atropine was brief, lasting only a few seconds. Although body movements due to thoracoabdominal muscle spasm were observed during pacemaker activation, they did not interfere with surgery. In postoperative patients with congenital heart disease, an atrioventricular block may be identified in the remote period, and preoperative evaluation should be based on this possibility. In addition, during anesthesia management, it is important to prepare multiple measures to maintain hemodynamic status.

Long-Term Follow-up of Transcatheter Ventricular Septal Defect Closure in Children, and Comparison of Single-Hole Versus Multi-holes Ventricular Septal Defects

Background: Evaluation of complications after transcatheter ventricular septal defect (VSD) closure in long-term follow-up and large samples of children is limited. Objectives: We compared the residual shunt after transcatheter closure in VSDs with a single hole and multiple holes, a new task that has not been done so far. Methods: This retrospective study included all patients who underwent transcatheter device closure for VSD in a tertiary cardiovascular center from 2009 to 2020. Follow-up evaluation using transthoracic echocardiography (TTE) and electrocardiogram (ECG) was performed at 1, 6, 12 months, and annually after the procedure. Results: A total of 409 patients underwent transcatheter VSD closure. The mean age was 7 years (2 - 15 years), and the median follow-up duration was 48 months (1 - 10 years). The number of patients with a singular VSD was 259 (63.4%), and those with multiple exit holes were 150 (36.6%). The incidence of a residual shunt immediately after implantation was significantly higher in VSDs with multiple holes than those with a single hole (P = 0.008). During the follow-up, the residual shunts decreased in the group of VSDs with a single hole. Forty-five patients (11%) and 16 patients (4%) had a new-onset of mild and moderate tricuspid regurgitation (TR), respectively, and it decreased dramatically over time. Only 1 patient showed a new-onset mild aortic regurgitation (AR). The most crucial complication shown in 2 patients was a persistent complete heart block. Conclusions: Ventricular septal defects with multiple exit holes are a risk factor for a residual shunt. After transcatheter VSD closure, the residual shunt in patients with a multiple-hole VSD was significantly higher (P = 0.008). Although TR may increase during the procedure, it decreases dramatically over time. Interestingly, patients who had pre-procedure tricuspid or aortic regurgitation disappeared after 2 years of the procedure. The most important complication was a complete heart block in 2 patients.

Prolonged QT and Torsades de Pointes in a child with late-onset post-operative complete heart block

A young child presented with syncope attacks. Late-onset post-operative complete atrioventricular block and Torsades de Pointes were diagnosed. She was treated with surgical epicardial pacemaker implantation. This report is the description of Torsades de Pointes due to late-onset post-operative complete atrioventricular block followed by R on T phenomenon in a child.

Micra pacemaker in adult congenital heart disease patients: a case series

INTRODUCTION

implantation of transvenous endocardial or epicardial pacemakers presents specific challenges in adult congenital heart disease (ACHD) patients. Micra leadless pacemaker (Micra PPM) may overcome some of these difficulties.

METHODS

15 ACHD patients who underwent Micra PPM insertion were retrospectively evaluated.

RESULTS

males 53.3%. Mean age at study: 37.5±10.7 years. Mean age at Micra PPM insertion: 35.5±11.0 years. Mean follow-up so far: 2.0±0.3 years. Concerning the ACHD patients, 6.7% had a simple defect, 66.6% had a moderately complex defect, 26.7% were complex. Four patients (26.7%) had a previous PPM implantation. Three patients (20%) had a systemic right ventricle. Two patients (13.3%) had a single ventricle physiology. Five (33.3%) had Trisomy 21. The most commonly used Micra PPM modality was VVI (73.3%). Mean threshold post implantation was 0.48 V [range: 0.25-1.13 V], while mean threshold at 6 months control was 0.60 V [range: 0.38-1.13 V] (p=ns). Mean R wave post implantation was 10.3 V [range: 3.25-19.4 V], whilst mean R wave at 6 months follow-up was 10.1 V [range:3.5-19.0 V] (p=ns). No major peri and post-procedural complications were encountered.

CONCLUSIONS

since ACHD patients are living longer and surviving into adulthood, the incidence of conduction disorders continues to increase, as part of the natural history of some lesions or as early or late complication of surgery. The Micra leadless PPM can be successfully implanted in ACHD patients and have significant theoretical advantages. They should be considered when transvenous and epicardial pacing are either contraindicated or represent an otherwise suboptimal approach. This article is protected by copyright. All rights reserved.

Transcatheter closure of ventricular septal defects: preliminary results in children weighing 10 kg or less

INTRODUCTION

Ventricular septal defect is one of the commonest heart defect in children and closure of this defect with devices has seen a rapid progression over a period of time. The availability of new and safer devices has made the transcatheter closure of ventricular septal defect a suitable option even in young children.

AIM

The study was done to evaluate the feasibility and complications of device closure of ventricular septal defect in children weighing 10 kg or less with different types of devices.

METHODS

The present study was undertaken in a newly established dedicated Paediatric Cardiac Unit at a Tertiary Care Hospital. Relevant data were obtained retrospectively from the case files and the catheterisation records and data were analysed for first 50 patients with ventricular septal defect weighing 10 kg or less between March 2018 and March 2021.

RESULTS

Among these 50 patients selected, device closure was successfully done in 45 (90%) cases while 5 (10%) attempts were unsuccessful for various reasons. The mean weight in this study was 7.46 ± 1.89 kg (2.3-10 kg), 21 (42%) cases were females while 29 (58%) were males; mean age was 19.4 ± 11.88 months (4-48 months). Right heart catheterisation study showed 21 (42%) patients with normal pulmonary artery pressures (no pulmonary artery hypertension). Among 29 patients with pulmonary arterial hypertension, 13 patients (22%) were having mild pulmonary arterial hypertension, 4 (8%) were with moderate pulmonary arterial hypertension, and 12 (24%) were with severe pulmonary arterial hypertension. Mean Qp/Qs was 2.73 ± 0.72 (2.5-4.5) and mean pulmonary vascular resistance was 1.5 ± 1.04 (0.6-4.6 WU). Amplatzer Duct Occluder (ADOI) was used in 15 (30%) cases, 27 (52%) cases were closed with Amplatzer Duct Occluder (ADOII), and the 3 (6%) cases closure was done with Amplatzer muscular ventricular septal defect occluder.

CONCLUSIONS

Transcatheter closure of ventricular septal defect in children 10 kg or less is feasible and safe alternative to surgical ventricular septal defect closure. The immediate and short-term outcomes have proven this method to be safe and valid.

A review of the therapeutic management of multiple ventricular septal defects

BACKGROUND AND AIM

We showed in our anatomical review, ventricular septal defects existing as multiple entities can be considered in terms of three major subsets. We address here the diagnostic challenges, associated anomalies, the role and techniques of surgical instead of interventional closure, and the outcomes, including reinterventions, for each subset.

METHODS

We reviewed 80 published investigations, noting radiographic findings, and the results of clinical imaging elucidating the location, number, size of septal defects, associated anomalies, and the effect of severe pulmonary hypertension.

RESULTS

Overall, perioperative mortality for treatment of residual multiple defects has been cited to be between 0% and 14.2%, with morbidity estimated between 6% and 13%. Perioperative mortality is twice as high for perimembranous compared to muscular defects, with the need for reoperation being over four times higher. Perventricular hybrid approaches are useful for the closure of high anterior or apical defects. Overall, the results have been unsatisfactory. Pooled data reveals incidences between 2.8% and 45% for device-related adverse events. Currently, however, outcomes cannot be assessed on the basis of the different anatomical subsets.

CONCLUSIONS

We have addressed the approaches, and the results, of therapeutic treatment in terms of coexisting discrete defects, the Swiss-cheese septum, and the arrangement in which a solitary apical muscular defect gives the impression of multiple defects when viewed from the right ventricular aspect. Treatment should vary according to the specific combination of defects.

Comparison of Long-Term Complications of Using Amplatzer Ductal Occluder and Ventricular Septal Defect Occluder for Transcatheter Ventricular Septal Defect Closure

Background:

Ventricular Septal Defect (VSD) is the most common type of congenital heart disease and perimembranous type is the commonest form of these defects. Trans-catheter management of these defects is a challenging procedure.

Objectives:

The purpose of this study was to compare of Trans-catheter closure of perimembranous ventricular septal defect (PMVSD) using Amplatzer Ductal Occluder (ADO) and VSD occluder and their complications and follow-up.

Patients and Methods:

Between 2013 and April 2019, 69 patients underwent percutaneous closure of PMVSD using ADO (29 patients) and VSD occluder (40 patients). After obtaining the size of VSD from the ventriculogram at least 2 mm larger than the orifice diameter of VSD at the right ventricular side was chosen. The devices were positioned after verification of the proper device position by echocardiography, aortogram and left ventriculography.

Results:

The mean age of patients were 9.07 ± 7.73 years, mean weight 26.12 ±16.25 kg. The mean defect size of the right ventricular orifice and device sizes were 5.54 ± 1.83 mm 7.72 ± 1.94 mm respectively.

Small residual shunts were seen at the completion of the procedure, but they disappeared during follow-up in all but one patient. Two patients had mild AI before the procedure in ADO group that disappeared during the follow-up. The mean follow-up period was 3.3 ± 1.7 years (range 1 to 6 years). Complete atrioventricular block (CAVB) was seen in one patient (VSD occluder) during the procedure that disappeared after the retrieval of the device. Major complication or death was not observed in our study.

Conclusions:

Trans-catheter closures of PMVSD with ADO or VSD occluder had similar effects in these patients and are safe and effective treatment associated with excellent success and closure rates. Long-term follow-up in a large number of patients is warranted.

Revising ventricular septal defect residual shunts without aortic re-cross-clamping: a safe and effective surgical procedure

Background

The conventional approach to revising a residual shunt following ventricular septal defect (VSD) closure is to re-occlude the aorta and repair the residual shunt under cardioplegic arrest. The present study evaluated the safety and effectiveness of a new approach for revising residual shunts following VSD repair without re-occluding the aorta. This approach is known as on beating heart surgery.

Methods

This retrospective study included 80 pediatric patients who underwent surgical closure of a simple VSD. Residual shunts larger than 2 mm were intraoperatively detected by transesophageal echocardiography (TEE) and these patients received immediate reintervention. Of the patients, 37 received on beating heart surgery without aortic cross-clamping (Group A) and 43 patients were operated on with aortic cross-clamping and cardioplegia (Group B).

Results

Residual VSD closures were successfully performed in all patients. Group A had significantly shorter aortic cross-clamp times (P<0.0001), significantly shorter CPB times (P<0.01), a lower incidence of prolonged ventilation (>6 hours) (P=0.04), a lower incidence of prolonged intensive care unit (ICU) stay (ICU stay >1 day) (P=0.02), and reduced in-hospital expenses (P<0.0001) compared with Group B. There was no significant difference in the incidence of recurrent residual shunts (P=0.96), prolonged postoperative hospital stay (>5 days) (P=0.24), or the incidence of perioperative complications (P=0.81) between the groups.

Conclusions

On beating heart surgery is a safe and effective approach for the closure of residual VSDs and is significantly associated with a lower incidence of prolonged ventilation, a lower incidence of prolonged ICU stay, and reduced in-hospital expenses.

Surgical pericardial adhesions do not preclude minimally invasive epicardial pacemaker lead placement in an infant porcine model

BACKGROUND

Pericardial adhesions in infants and small children following cardiac surgery can impede access to the epicardium. We previously described minimally invasive epicardial lead placement under direct visualization in an infant porcine model using a single subxiphoid incision. The objective of this study was to assess the acute feasibility of this approach in the presence of postoperative pericardial adhesions.

METHODS

Adhesion group piglets underwent left thoracotomy with pericardiotomy followed by a recovery period to develop pericardial adhesions. Control group piglets did not undergo surgery. Both groups underwent minimally invasive epicardial lead placement using a 2-channel access port (PeriPath) inserted through a 1 cm subxiphoid incision. Under direct thoracoscopic visualization, pericardial access was obtained with a 7-French sheath, and a pacing lead was affixed against the ventricular epicardium. Sensed R-wave amplitudes, lead impedances and capture thresholds were measured.

RESULTS

Eight piglets underwent successful pericardiectomy and developed adhesions after a median recovery time of 45 days. Epicardial lead placement was successful in adhesion (9.5 ± 2.7 kg, n = 8) and control (5.6 ± 1.5 kg, n = 7) piglets. There were no acute complications. There were no significant differences in capture thresholds or sensing between groups. Procedure times in the adhesion group were longer than in controls, and while lead impedances were significantly higher in the adhesion group, all were within normal range.

CONCLUSIONS

Pericardial adhesions do not preclude minimally invasive placement of epicardial leads in an infant porcine model. This minimally invasive approach could potentially be applied to pediatric patients with prior cardiac surgery.

Adult Ventricular Septal Defect Repair Using a Robotic Totally Endoscopic Approach: A Case Report

The growth and advancement of minimally invasive cardiac surgery in recent years has allowed robotic and totally endoscopic procedures to become safe and effective options for the treatment of patients with various diseases of the heart. However, despite these advances, outcome data for robotic correction of congenital cardiac anomalies are scarce. This is particularly true for robotic ventricular septal defect (VSD) repair with initial experiences only recently having been published by a single group. Here, we present the case of a 29-year-old female who underwent robotic totally endoscopic VSD repair due to persistent symptoms with resolution of preoperative shunting and severe tricuspid regurgitation following surgery. This unique case adds to the limited data currently available in the literature on robotic VSD repair to show that it is a safe procedure when performed by a dedicated surgical team experienced in minimally invasive robotic cardiac surgery. We feel that, in this setting, the benefits of a robotic surgical approach can be afforded to more patients with excellent results.

Diagnostic and Therapeutic Approach to Arrhythmias in Adult Congenital Heart Disease

PURPOSE OF REVIEW

Adult survivors of congenital heart disease (CHD) are at increased risk of arrhythmia. The goal of this review is to outline diagnostic and therapeutic approaches to arrhythmia in adult CHD patients.

RECENT FINDINGS

Macro-reentrant atrial tachyarrhythmia is the most common arrhythmia encountered in adults with CHD. Approximately 25% of hospitalizations associated with arrhythmia. The risk of ventricular arrhythmia is estimated as high as 25-100 times that for the general population and increased after two decades. Routine ambulatory monitoring is important for arrhythmia risk assessment in adults with CHD. There are limitations, potential adverse effects, and risk of recurrence with antiarrhythmic drugs, catheter ablation, and surgical approaches. Adults with CHD suffer various forms of arrhythmia, are at increased risk of sudden death, and require special consideration for medical and interventional therapy.

An Imaging Protocol to Discriminate Specialized Conduction Tissue During Congenital Heart Surgery

We performed preclinical validation of intraoperative fiber-optic confocal microscopy (FCM) and assessed its safety and efficacy in an ovine model of the pediatric heart. Intraoperative imaging was performed using an FCM system (Cellvizio, Mauna Kea Technology, Paris, France) with specialized imaging miniprobe (GastroFlex UHD, Mauna Kea Technologies). Before imaging, we applied an extracellular fluorophore, sodium fluorescein, to fluorescently label extracellular space. We imaged arrested hearts of ovine (1-6 months) under cardiopulmonary bypass. Image sequences (1-10 seconds duration) were acquired from regions of the sinoatrial and atrioventricular node, as well as subepicardial and subendocardial working myocardium from atria and ventricle. The surgical process was evaluated for integration of the imaging protocol during the operative procedure. In addition, fluorescein cardiotoxicity studies (n = 3 animals) were conducted by comparing electrocardiogram (PR and QRS intervals) and ejection fraction at baseline and after topical application of fluorescein at 1:10, 1:100, and 1:1000 dilutions on a beating ovine heart. Our studies suggest that intraoperative FCM can be used to identify regions associated with specialized conducting tissue in ovine hearts in situ. The imaging protocol was integrated with conventional open heart surgical procedures with minimal changes to the operative process. Application of fluorescein in varying concentrations did not affect the normalized PR interval, QRS interval, and ejection fraction. These preclinical validation studies demonstrated both safety and efficacy of the proposed intraoperative imaging approach. The studies constitute an important step toward first-in-human clinical trials.

Device Closure of Perimembranous Ventricular Septal Defect: Choosing Between Amplatzer Occluders

Background: Off-label device closure of perimembranous ventricular septal defect (pmVSD) is well reported in the literature with encouraging results. However, technical challenges may be encountered. Objectives: To evaluate and compare feasibility, technical aspects, procedural outcomes, and mid-term follow-up of pmVSD closure using Amplatzer™ occluders. Patients and Methods: From July 2015 to July 2018, patients in whom pmVSD closure was attempted using an Amplatzer occluder were retrospectively identified from our institution's database. Device selection was made according to the defect anatomy that was obtained via ventriculography and trans-esophageal echocardiography. Follow-up evaluations were done at discharge, then at 1, 3, 6, and 12 months and yearly thereafter with transthoracic echocardiography and electrocardiogram. Results: In total, 8 Amplatzer Duct Occluder (ADO), 27 ADO II, and 17 Amplatzer Muscular VSD Occluder (AMO) were used in 51 patients with a mean age of 7.4 ± 6.9 years and a mean weight of 25.4 ± 19.8 kg. Implantation was successful in 50/51 patients (98.0%). There was no procedure related mortality. One ADO accidentally embolized to the aorta after release and was surgically recaptured from the iliac artery. All ADO II were delivered retrogradely with the least amount of time (p = 0.002) and the lowest radiation exposure (p < 0.001). Minor valvular disturbances occurred in 8/49 patients (16.3%), including five tricuspid regurgitation (three with ADOII and two with AMO) and three trivial aortic regurgitations (two with ADO and one with ADOII). On a median follow-up of 194 days (range, 60-895 days), no surgical device removal was necessary. At 6 months of follow-up, trivial residual shunt was present in 5/49 patients (10.2%), among which none occurred with ADO. One complete atrioventricular block was detected 18 months after ADO implantation and required permanent pacing. Conclusions: Transcatheter closure of PmVSD using Amplatzer occluders is feasible, safe and efficacious in properly selected patients. The major key factor behind high procedural success rate is proper device selection. ADOII is remarkably superior in terms of device softness, flexibility and faster implantation process. Yet, its use is limited to small defects with particular anatomy.

Atrioventricular block after congenital heart surgery: Analysis from the Pediatric Cardiac Critical Care Consortium

OBJECTIVES

Our primary aims were to describe the contemporary epidemiology of postoperative high-grade atrioventricular block (AVB), the timing of recovery and permanent pacemaker (PPM) placement, and to determine predictors for development of and recovery from AVB.

METHODS

Patients who underwent congenital heart surgery from August 2014 to June 2017 were analyzed for AVB using the Pediatric Cardiac Critical Care Consortium registry. Predictors of AVB with or without PPM were identified using multinomial logistic regression. We used these predictors to model the probability of PPM for the subgroup of patients with intraoperative complete AVB.

RESULTS

We analyzed 15,901 surgical hospitalizations; 422 (2.7%) were complicated by AVB and 162 (1.0%) patients underwent PPM placement. In patients with transient AVB, 50% resolved by 2 days, and 94% resolved by 10 days. In patients who received a PPM, 50% were placed by 8 days and 62% were placed by 10 days. Independent risk factors associated with PPM compared with resolution of AVB were longer duration of cardiopulmonary bypass (relative risk ratio, 1.04; P = .023) and a high-risk operation (relative risk ratio, 2.59; P < .001). Among patients with complete AVB originating in the operating room, those with the highest predicted probability of PPM had a PPM placed only 77% of the time.

CONCLUSIONS

In this cohort, postoperative AVB complicated almost 3% of congenital heart surgery cases and 1% of patients underwent PPM placement. Because almost all patients (94%) with transient AVB had resolution by 10 days, our results suggest there is limited benefit to delaying PPM placement beyond that time frame.

Late presenting complete heart block after surgical repair of ventricular septal defect

Late onset of complete heart block is a life-threatening uncommon complication after surgical repair of congenital heart diseases. In this report, we discuss two cases of Perimembranous ventricular septal defect (VSD) that had late presentation of complete heart block after surgical repair. We are aiming to highlight this unusual complication for more awareness, better understanding and management of this unusual complication after pediatric cardiac surgery.

Percutaneous closure of perimembranous ventricular septal defect using patent ductus arteriosus occluders

OBJECTIVES

To assess the safety and efficacy of percutaneous closure of perimembranous ventricular septal defect (PmVSD) using patent ductus arteriosus (PDA) occluders.

BACKGROUND

Widespread use of conventional PmVSD closure devices has been limited by unacceptable high rate of complete heart block (CHB). The elegant design of PDA occluders is supposed to ease implantation, increase closure rate and minimize damage to adjacent structures. Thus, PDA occluders may reduce complications, especially the CHB, and offer a good alternative for PmVSD closure.

METHOD

From September 2008 to October 2015, patients who underwent attempted percutaneous VSD closure using PDA occluders were included in the study. Patient demographics, echocardiography measurements, procedure details and follow-up data until October 2017 were collected.

RESULTS

In total, 321 patients with a mean age of 15.5±12.6 years and mean a weight of 33.3±20.5 kg were included in this study. The mean defect size was 4.8±2.1 mm. Implantation was successful in 307 (95.6%) patients. The median follow-up time was 63 months (24 to 108 months). The closure rates were 89.5%, 91.5%, and 99.3% after the procedure 24 hours, 6 months and 2 years, respectively. Major complications occurred in 5 (1.7%) patients during the procedure and follow-up, including persistent CHB in 2 (0.7%) patients and device embolization in 3 (1.0%) patients. No death, disability, or other major complication was detected.

CONCLUSION

Percutaneous closure of PmVSD using PDA occluders is feasible, safe and efficacious in selected patients.

Undiagnosed Congenital Heart Defects as a Cause of Sudden, Unexpected Death in Children

Despite advances in the diagnosis and treatment of congenital heart defects (CHDs), these defects are still an important cause of sudden, unexpected death in young children. This retrospective study identified 64 cases of CHDs presenting as a cause of sudden, unexpected death in a busy, urban Medical Examiner's Office pediatric population between 2006 and 2016. The majority of cases (52 of 64, 81%) were infants. Interestingly, 52% of cases were undiagnosed prior to autopsy. Ventricular septal defects and atrioventricular septal defects were the most common simple (14%) and complex (17%) malformations observed, respectively. In many cases, there were coexistent simple and/or complex defects. Most of the cases diagnosed with CHD prior to autopsy (48%) had undergone some type of surgical repair. This study highlights the importance of considering undiagnosed CHDs as a cause of sudden, unexpected death, particularly in young children.

The Current State and Future Potential of Pediatric and Congenital Electrophysiology

Pediatric electrophysiologists specialize in the diagnosis and treatment of rhythm abnormalities in pediatric, congenital heart disease, and inherited arrhythmia syndrome patients. The field originated out of the unique knowledge base that rhythm management in young patients required. In the 1970s, pediatric electrophysiology was recognized as a distinct cardiac subspecialty and it has evolved rapidly since that time. Despite the considerable growth in personnel, technology, and complexity that the field has undergone, further opportunities to progress pediatric electrophysiology exist. In this review, we highlight some of the clinical focus of pediatric and adult congenital electrophysiologists to date and identify areas within this specialty where the pediatric and congenital electrophysiology community could come together in order to drive improvements in rhythm management for patients.

Genotypic and phenotypic predictors of complete heart block and recovery of conduction after surgical repair of congenital heart disease

BACKGROUND

Complete heart block (CHB) is a major complication that occurs after congenital heart surgery. We hypothesized that genetic and clinical factors are associated with the development of postoperative CHB and recovery of atrioventricular (AV) conduction.

OBJECTIVE

The purpose of this study was to identify predictors of CHB and recovery after congenital heart surgery.

METHODS

Patients undergoing congenital heart surgery at our institution from September 2007 through June 2015 were prospectively enrolled in a parent study of postoperative arrhythmias. Patients with onset of CHB within 48 hours postoperatively were included in the study. Daily rhythm assessment was performed until demonstration of 1:1 conduction or pacemaker implantation.

RESULTS

Of 1199 subjects enrolled, 56 (4.7%) developed postoperative CHB. In multivariate analysis, preoperative digoxin exposure (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.3-4.4), aortic cross-clamp time (OR 1.08, 95% CI 1.04-1.11), ventricular septal defect closure (OR 2.2, 95% CI 1.2-4.1), and a common polymorphism in the gene encoding connexin-40 (GJA5 rs10465885 TT genotype; OR 2.1, 95% CI 1.2-3.8) were independently associated with postoperative CHB. Junctional acceleration (JA) (OR 4.0, 95% CI 1.1-15.1) and intermittent conduction noted during complete AV block (OR 9.1, 95% CI 1.0-80) were independently associated with 1:1 AV conduction recovery. Use of a multivariate model including both JA and intermittent conduction demonstrated good discrimination with a positive predictive value of 86% (95% CI 67%-96%) in predicting 1:1 conduction recovery.

CONCLUSION

Preoperative factors, including a missense polymorphism in GJA5, are independently associated with increased risk for CHB. JA and intermittent conduction may prove useful in predicting recovery of AV conduction among patients with CHB after congenital heart surgery.

Evaluation and Management of Maternal Cardiac Arrhythmias

Pregnant women often complain of palpitations. The differential diagnosis for new-onset palpitations in pregnancy ranges from benign conditions to life-threatening arrhythmias. Maternal arrhythmias can occur in isolation or in the setting of underlying structural heart disease. Optimal management of maternal cardiac arrhythmias includes identification of the specific arrhythmia, diagnosis of comorbid conditions, and appropriate intervention. In general, management of maternal cardiac arrhythmias is similar to that of the general population. Special consideration must be given as to the effects of medications and procedures on both the mother and fetus to optimize outcomes. The importance of multidisciplinary care with cardiology, obstetrics, and anesthesia is emphasized.

Incidental Ventricular Septal Defect (VSD) in the Donor of a Live Donor Liver Transplant: Tackle and Proceed

Live Donor Liver Transplantation (LDLT) is an act of selflessness on the part of the donor who is subjected to a major hepatectomy. Ensuring safety and long-term well being of the donor is of utmost priority. We describe a 21-year-old otherwise healthy donor with perimembranous Ventricular Septal Defect (VSD) who successfully underwent donor hepatectomy after closure of the VSD. There is no literature available to guide regarding course of action in such a condition neither any study to substantiate the risk involved. Optimum anticoagulation, endocarditis prophylaxis and optimum interval between the two procedures are areas to be defined as our experience with similar cases increases. Our case emphasizes the importance of multidisciplinary approach and management of such patient at high volume centers.

A Review of Surgical Atrioventricular Block with Emphasis in Patients with Single Ventricle Physiology

We perceived an increased incidence of surgical atrioventricular (AV) block in patients with single ventricle physiology undergoing two ventricle rehabilitation for hypoplastic left heart syndrome compared to the overall incidence of surgical AV block for our institution. Retrospective investigation of our center's data revealed a statistically significant increase in the incidence of surgical AV block in the single ventricle population and two ventricle rehabilitation population compared to the two ventricle population. Here we review the literature with respect to historic definitions, incidence, risk factors, pre- and post-op management, current indications for pacemaker placement and added cost and comorbidity associated with surgical AV block. We then offer possible strategies for decreasing the incidence of surgical AV block within both the single and two ventricle populations.

Surgical strategies and novel alternatives for the closure of ventricular septal defects

A variety of therapies are available to close ventricular septal defects (VSDs). These include surgical closure on bypass, percutaneous device closure, as well as perventricular hybrid closure. Due to the incidence of heart block (1-5%) associated with percutaneous device closure of perimembranous VSDs, surgical closure presently remains the gold standard and preferred therapy for these defects. Therapeutic options are more varied for muscular VSDs. Beyond infancy, transcatheter closure offers excellent results with low morbidity and mortality, without the need for cardiopulmonary bypass. Infants however have a higher incidence of adverse events using a percutaneous approach. Large mid-muscular VSDs in infants can be treated successfully using a hybrid approach, surgical closure on bypass or a percutaneous approach. However, VSDs located apically or anteriorly are difficult to identify surgically and for these infants, perventricular hybrid closure should be considered as the preferred therapeutic modality. However, some VSD's also can be closed percutaneously.

Late-presenting complete heart block after pediatric cardiac surgery

Late presenting complete heart block after pediatric cardiac surgery is a rare complication and its management is well defined once the initial diagnosis in made timely and appropriately. In this report we described a child who underwent atrioventricular septal defect repair with a normal sinus rhythm during the postoperative period, as well as during the first 2 years of follow up. She subsequently developed complete heart block with bradycardia that required insertion of a pacemaker. Here we discuss this unusual late-presenting complication, possible risk factors, and management.

Efficacy and Safety of Using Amplatzer Ductal Occluder for Transcatheter Closure of Perimembranous Ventricular Septal Defect in Pediatrics

Background:

Perimembranous Ventricular Septal Defect (PMVSD) is the most common subtype of ventricular septal defects. Transcatheter closure of PMVSD is a challenging procedure in management of moderate or large defects.

Objectives:

The purpose of this study was to show that transcatheter closure of perimembranous ventricular septal defect with Amplatzer Ductal Occluder (ADO) is an effective and safe method.

Patients and Methods:

Between April 2012 and April 2013, 28 patients underwent percutaneous closure of PMVSD using ADO. After obtaining the size of VSD from the ventriculogram a device at least 2 mm larger than the narrowest diameter of VSD at right ventricular side was chosen. The device deployed after confirmation of its good position by echocardiography and left ventriculography. Follow up evaluations were done 1 month, 6 months, 12 months and yearly after discharge with transthoracic echocardiography and 12 lead electrocardiography.

Results:

The mean age of patients at procedure was 4.7 ± 6.3 (range 2 to 14) years, mean weight 14.7 ± 10.5 (range 10 to 40) kg. The mean defect size of the right ventricular side was 4.5 ± 1.6 mm. The average device size used was 7.3 ± 3.2mm (range 4 to 12 mm). The ADOs were successfully implanted in all patients. The VSD occlusion rate was 65.7% at completion of the procedure, rising up to 79.5% at discharge and 96.4% during follow-up. Small residual shunts were seen at completion of the procedure, but they disappeared during follow-up in all but one patient. The mean follow-up period was 8.3 ± 3.6 months (range 1 to 18 months). Complete atrioventricular block (CAVB), major complication or death was not observed in our study.

Conclusions:

Transcatheter closure of PMVSD with ADO in children is a safe and effective treatment associated with excellent success and closure rates, but long-term follow-up in a large number of patients would be warranted.

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.

[Atrioventricular block after cardiac surgery: report of 23 cases]

Le bloc auriculo-ventriculaire (BAV) représente une complication non négligeable de la chirurgie cardiaque. Il est responsable de séquelles lourdes et graves compromettant le pronostic de la maladie et conduisant à la mise en place d'un stimulateur cardiaque définitif. Il est primordial d’étudier et de déterminer les différents facteurs prédictifs de BAV post opératoire, son histoire naturelle, son incidence ainsi que le délai exact de la mise en place d'un pacemaker. Notre étude est une étude rétrospective descriptive à propos de 23 patients opérés pour chirurgie cardiaque sous circulation extracorporelle entre octobre 1989 et août 2010 ayant présentés des troubles conductifs auriculo-ventriculaires en post opératoire. Plusieurs facteurs de risque ont été étudiés dans notre série, liés surtout à l'atteinte directe du noeud auriculo-ventriculaire ou à l'ischémie myocardique. Le délai d'apparition du trouble conductif ainsi que le délai d'implantation on été également étudié. Plusieurs facteurs favorisants de survenue de BAV ont été identifiés liés essentiellement au type de la cardiopathie opérée avec une prédominance de la cardiopathie congénitale, d'autres facteurs ont été rapportés notamment la présence d'hypertrophie ventriculaire gauche (HVG) de troubles conductifs en préopératoire, une durée du clampage aortique et de CEC prolongée. La moitié des patients ont présenté un BAV immédiat. Le délai d'implantation par rapport à la date de la découverte du BAV varie dans notre série d'une implantation immédiate après le diagnostic positif (J0) à un délai d'implantation allant jusqu’à 57 jours. Plusieurs facteurs de risques déterminent la survenue de BAV post chirurgie cardiaque, leur connaissance est primordial ainsi que le délai exact de l'implantation du stimulateur cardiaque définitif.

GATA4 loss-of-function mutations underlie familial tetralogy of fallot

Tetralogy of Fallot (TOF) represents the most common form of cyanotic congenital heart disease and accounts for significant morbidity and mortality in humans. Emerging evidence has implicated genetic defects in the pathogenesis of TOF. However, TOF is genetically heterogeneous and the genetic basis for TOF in most patients remains unclear. In this study, the GATA4 gene were sequenced in 52 probands with familial TOF, and three novel heterozygous mutations, including A9P and L51V both located in the putative first transactivational domain and N285S in the C-terminal zinc finger, were identified in three probands, respectively. Genetic analysis of the pedigrees demonstrated that in each family the mutation cosegregated with TOF with complete penetrance. The missense mutations were absent in 800 control chromosomes and the altered amino acids were highly conserved evolutionarily. Functional analysis showed that the GATA4 mutants were consistently associated with diminished DNA-binding affinity and decreased transcriptional activity. Furthermore, the N285S mutation completely disrupted the physical interaction between GATA4 and TBX5. To our knowledge, this report associates GATA4 loss-of-function mutations with familial TOF for the first time, providing novel insight into the molecular mechanism involved in TOF and suggesting potential implications for the early prophylaxis and allele-specific therapy of TOF.

Incidence and risk factors of complete atrioventricular block after operative ventricular septal defect repair

BACKGROUND

Complete atrioventricular block (AVB) is a recognized complication of ventricular septal defect (VSD) repair. The objective of this study was to examine incidence and risk factors.

METHODS

This is a single-center, retrospective study. All pediatric patients (age <18 years) who underwent VSD repair between November 2001 and August 2009 with concordant atrioventricular and ventriculoarterial connections were included. Patients were classified as having no AVB or transient AVB, and outcomes of early pacemaker placement (before hospital discharge) or late pacemaker placement (after hospital discharge) were recorded.

RESULTS

Eight hundred twenty-eight patients (48.6% female) underwent VSD repair during the study period. Mean age at repair was 14 ± 29.4 months. A total of 64 patients (7.7%) developed surgical AVB. Among those patients who developed AVB, 48 (75%) had transient AVB. Sixteen patients (1.9%) required a pacemaker, 14 early (88%) and 2 late (12%). Patients <4 kg (4.2% vs. 1%, P ≤ .01) and those with inlet VSDs (11.6% vs. 1.4%, P ≤ .01) were more likely to develop surgical AVB. Surgical AVB was not influenced by the presence of chromosomal abnormalities or other congenital heart disease.

CONCLUSION

The overall incidence of surgical AVB is consistent with previous reports. Weight <4 kg and presence of an inlet VSD were significant risk factors.

Pattern of recovery for transient complete heart block after open heart surgery for congenital heart disease: duration alone predicts risk of late complete heart block

Transient complete heart block (TCHB) is defined as complete interruption of atrioventricular conduction (AVC) after cardiac surgery followed by return of conduction. This study aimed to assess the risk for the development of late complete heart block (LCHB) after recovery of TCHB and to examine the electrocardiographic and electrophysiologic properties of the AVC system after TCHB. Of the 44 patients in this study who experienced TCHB, 37 recovered completely. Seven patients progressed from TCHB to intermittent CHB or LCHB requiring pacemaker implantation. Preoperative, early postoperative, and late postoperative electrocardiograms as well as postoperative atrial stimulation were obtained. The results showed that the median duration of TCHB was 5 days in the TCHB group compared with 9 days in the LCHB group (p = 0.01). All 37 subjects with TCHB recovered AVC within 12 days, but only two with LCHB did so (p = 0.02). The risk of LCHB for the patients with 7 days of postoperative TCHB or longer was 13 times greater than for the patients with fewer than 7 days of TCHB (p = 0.01). The median late postoperative PR interval was slightly but significantly longer in the LCHB group than in the TCHB group (p = 0.02). In contrast, the electrophysiologic properties between the two groups did not differ significantly. From those findings, we concluded that delayed recovery of AVC after surgical TCHB (≥7 days), but not electrophysiologic properties of recovered AVC assessed early in the postoperative period strongly, predicts risk of LCHB. Follow-up evaluation of AVC is particularly indicated for the delayed recovery group.

Long-term electrocardiographic follow-up after repair of tetralogy of Fallot

BACKGROUND

Fallot patients with conduction disturbances are prone to sudden cardiac death. However, knowledge about long-term electrocardiographic changes after Fallot repair is limited.

METHODS

Measurements were performed on electrocardiograms recorded preoperatively, postoperatively, and during annual follow-up in 35 Fallot patients included in three groups: G1 if they received no patch (n = 7), G2 if they received a transannular patch (n = 13), and G3 if they received a pulmonary homograft (n = 15).

RESULTS

PR interval increased over the study period in all groups (Z-score: from 0.9 ± 1.1 to 1.3 ± 0.9 in G1, 0.9 ± 1.2 to 1.7 ± 1.6 in G2, and 0.7 ± 0.7 to 1.4 ± 1.3 in G3). The QRS duration increased during the follow-up at a rate of 1.78 msec/year in G1, 2.34 msec/year in G2 despite pulmonary valve replacement in 10 patients, and 1.81 msec/year in G3 despite conduit replacement in 9. At the later follow-up, the QRS duration was significantly increased (Z= 4.5 ± 3.6 in G1, 5.7 ± 1.4 in G2, and 4.6 ± 1.9 in G3). One patient in each group had QRS duration of 170 msec or longer and the one in G3 had a history of serious ventricular arrhythmia. Three patients had a QTc duration above 460 msec.

CONCLUSIONS

Progressive conduction disorders are noted during long-term follow-up in Fallot patients who received transannular patch but also in those who received no patch or a pulmonary homograft. It suggests that volume overloading related to the transannular patch but also pressure overloading and myocardial injury related to surgery contribute to their development.