Transcatheter Leadless Pacing in Children: A PACES Collaborative Study in the Real-World Setting.

BACKGROUND: Transcatheter Leadless Pacemakers (TLP) are a safe and effective option for adults with pacing indications. These devices may be an alternative in pediatric patients and patients with congenital heart disease for whom repeated sternotomies, thoracotomies, or transvenous systems are unfavorable. However, exemption of children from clinical trials has created uncertainty over the indications, efficacy, and safety of TLP in the pediatric population. The objectives of this study are to evaluate clinical indications, procedural characteristics, electrical performance, and outcomes of TLP implantation in children. METHODS: Retrospective data were collected from patients enrolled in the Pediatric and Congenital Electrophysiology Society TLP registry involving 15 centers. Patients ≤21 years of age who underwent Micra (Medtronic Inc, Minneapolis, MN) TLP implantation and had follow-up of ≥1 week were included in the study. RESULTS: The device was successfully implanted in 62 of 63 registry patients (98%) at a mean age of 15±4.1 years and included 20 (32%) patients with congenital heart disease. The mean body weight at TLP implantation was 55±19 kg and included 8 patients ≤8 years of age and ≤30 kg in weight. TLP was implanted by femoral (n=55, 87%) and internal jugular (n=8, 12.6%) venous approaches. During a mean follow-up period of 9.5±5.3 months, there were 10 (16%) complications including one cardiac perforation/pericardial effusion, one nonocclusive femoral venous thrombus, and one retrieval and replacement of TLP due to high thresholds. There were no deaths, TLP infections, or device embolizations. Electrical parameters, including capture thresholds, R wave sensing, and pacing impedances, remained stable. CONCLUSIONS: Initial results from the Pediatric and Congenital Electrophysiology Society TLP registry demonstrated a high level of successful Micra device implants via femoral and internal venous jugular approaches with stable electrical parameters and infrequent major complications. Long-term prospective data are needed to confirm the reproducibility of these initial findings.

Left innominate vein creation using left internal jugular vein tunneled to right internal jugular vein.

BACKGROUND: Left innominate vein occlusion is a known complication of pacemaker and central venous catheter placement. For dialysis-dependent patients with an arteriovenous fistula (AVF), this can prevent successful hemodialysis and may require surgical intervention. CASE REPORT: An 8-month-old male was diagnosed with hemolytic uremic syndrome and became dialysis-dependent at 11 months of age. After multiple vascular access and peritoneal dialysis complications, the patient had construction of a brachiobasalic AVF in his left arm at 13 years old. While waiting for the AVF to mature, an attempt to remove a previously placed left subclavian vein port-a-cath was unsuccessful and a follow-up imaging revealed that the vessel had become occluded. The fistula remained patent, but due to arm swelling and venous obstruction, his fistula was not accessible. Multiple attempts to percutaneously cross the left innominate vein were unsuccessful and the patient was referred for surgical intervention. At 15 years old, the patient was taken to the operating room for transposition of the left internal jugular vein (LIJ) to the right internal jugular vein (RIJ). The LIJ was transected under the mandible and anastomosed to the RIJ. Subsequently the patient underwent VWING insertion rather than venous transposition for constant site dialysis. Although he has required frequent transcatheter dilation of the LIJ-RIJ anastomosis, the patient was successfully dialyzed using this fistula for 5 years. The patient received a cadaveric renal transplant at 5 years 20 days. CONCLUSIONS: In cases of left innominate vein stenosis, transposing the LIJ can create a new left innominate vein that can alleviate venous hypertension and preserve fistula function. This procedure avoids sternotomy and only requires one anastomosis.

Adult congenital pulmonary valve insertion using a new bioprosthetic aortic valve: Inspiris.

We describe successful placement of the Inspiris Resilia aortic valve in the pulmonary position. This valve has advantages for immediate benefit and future percutaneous interventions, making it a promising prosthesis for adult congenital patients.

Neurological Complications of Cardiac Disease.

This article focuses on the complex interactions between the cardiovascular and neurologic systems. Initially, we focus on neurological complications in children with congenital heart disease both secondary to the underlying cardiac disease and complications of interventions. We later discuss diagnosis and management of common syncope syndromes with emphasis on vasovagal syncope. We also review the diagnosis, classification, and management of children and adolescents with postural orthostatic tachycardia syndrome. Lastly, we discuss long QT syndrome and sudden unexpected death in epilepsy (SUDEP), reviewing advances in genetics and current knowledge of pathophysiology of these conditions. This article attempts to provide an overview of these disorders with focus on pathophysiology, advances in molecular genetics, and current medical interventions.

Comparison of corrected QT interval as measured on electroencephalography versus 12-lead electrocardiography in children with a history of syncope.

Long QT syndrome can present with neurological manifestations, including syncope and seizure-like activity. These patients often receive an initial neurologic evaluation, including electroencephalography (EEG). Our previous retrospective study suggested an increased prevalence of prolonged corrected QT interval (QTc) measured during the EEG of patients with syncope. The aim of the current study is to assess the accuracy of the EEG QTc reading compared with the nonsimultaneous 12-lead electrocardiography (ECG) in children with syncope. Abnormal QTc was defined as ≥450 ms in boys, ≥460 ms in girls. Forty-two children were included. There was no significant correlation between QTc readings in the EEG and ECG. EEG failed to identify 2 children with prolonged QTc in the ECG and overestimated the QTc in 3 children with normal QTc in the ECG. This study suggests that interpretation of the QTc segment during an EEG is limited. Further studies with simultaneous EEG and 12-lead ECG are warranted.

Protocols associated with no mortality in 100 consecutive Fontan procedures.

OBJECTIVES: Results of Fontan's procedure have improved considerably, but perioperative mortality still occurs, attributed to ventricular dysfunction, stroke, arrhythmia, thromboembolism, and multi-organ dysfunction. Our protocols of operative and intensive care unit management address these potential issues, and have been associated with zero mortality, even with many high-risk candidates. METHODS: From 1996 to 2006, all Fontan patients were managed as follows: operative strategy based on aortic and single atrial cannulation, cooling on full-flow bypass, and hypothermic circulatory arrest to create the Fontan pathway. No direct caval cannulation. Use of central venous lines was completely avoided. Fresh whole blood was used for pump prime and for volume restoration. Inotropic and vasodilator therapy was continued for at least 48 h. Aspirin was used exclusively as anti-thrombotic therapy. Postoperative pleural drainage was accomplished with small pigtail catheters. The usual Fontan pathway was by lateral atrial tunnel (84), with extra-cardiac conduit when dictated by anatomy (16). RESULTS: One hundred Fontan operations were performed with no mortality. All patients were extubated by postoperative day 1. Hospital stay was 10+/-5 days. Complications were: bleeding (1), reintubation (1), emergent fenestration closure (1), pericardial effusion (4), and seizures (1). Risk factors included Fontan connection to one lung (3), diminutive pulmonary arteries (PAs) and unifocalized major aortopulmonary collateral arteries (MAPCAs) (1), discontinuous PAs (3), right ventricle dependent coronaries (3), neonatal pulmonary venous obstruction (3), Trisomy 21 (1), preoperative pacemaker dependence (2), and heterotaxy (10). No candidate was excluded. CONCLUSIONS: While many surgeons try to avoid bypass or aortic clamping when performing Fontan operations, the strategies we have employed facilitate safe accomplishment of Fontan's operation in diverse anatomic groups with multiple risk factors, with avoidance of operative mortality in 100 consecutive cases.

Subcutaneous array with active can implantable cardioverter defibrillator configuration: a follow-up study.

BACKGROUND: Novel nontransvenous implantable cardioverter defibrillator (ICD) configurations are sometimes required for small children and children with complex congenital heart disease at risk for sudden death. Mid- to long-term follow-up of these nontraditional implant techniques is not well known. We assessed the mid-term performance of a subcutaneous lead technique used in our practice. METHODS: Between July 2002 and November 2003, 4 patients (age 2.1-8.5 years, weight 13-33.3 kg, height 90-126.7 cm) received an ICD with a single-finger (n = 3) or 2-finger (n = 1) subcutaneous array with an active abdominal can and epicardial pace/sense lead. The subcutaneous tunnel was created via a subxiphoid incision using a tunneling tool within a sheath along the seventh intercostal space and extended posterior to the spine. Diagnoses included long QT syndrome (n = 2), idiopathic ventricular fibrillation (n = 1), and idiopathic dilated cardiomyopathy (n = 1). Implantable cardioverter defibrillator indications included syncope (n = 2) and cardiac arrest (n = 2). RESULTS: Mean follow-up was 22.3 +/- 13.9 months. During follow-up, 1 patient underwent heart transplantation and the other 3 patients underwent generator replacement secondary to a manufacturer's advisory. There was 1 appropriate and successful shock for ventricular fibrillation. This patient experienced a second episode of ventricular fibrillation that the ICD discharge failed to terminate. The arrhythmia spontaneously resolved. There were no inappropriate shocks. There was 1 instance of false detection of ventricular fibrillation because of intermittent T wave oversensing but therapy was not administered. There were no infections, lead fractures, or other complications during follow-up. CONCLUSION: This novel nontransvenous ICD configuration can be used safely in a select group of pediatric patients and allows for the applicability of this life-saving technology to small children at high risk for sudden cardiac death.

Long-term rhythm control of drug-refractory atrial fibrillation with "hybrid therapy" incorporating dual-site right atrial pacing, antiarrhythmic drugs, and right atrial ablation.

We evaluated the long-term efficacy, safety, and applicability of a "hybrid" therapy strategy for rhythm control in atrial fibrillation (AF), incorporating dual-site right atrial pacing, antiarrhythmic drugs, and right atrial ablation. One hundred thirteen patients (paroxysmal AF [n = 70], persistent/permanent AF [n = 43]) with refractory symptomatic AF were treated with this strategy and followed for 1 to 81 months (mean 30 +/- 23). All-cause mortality, AF recurrences, and progression to permanent AF were monitored and recorded by implanted device data logs. There was no procedural mortality. Rhythm control was achieved in 90% of all patients at 3 and 5 years, with comparable efficacy in subpopulations with paroxysmal (98%), persistent, or permanent AF (87%, p >2). Overall survival was 84% at 3 years and 80% at 5 years, and was higher in patients with paroxysmal AF than in patients with persistent or permanent AF (86% vs 67% at 4 years, p <0.001). Patients with persistent or permanent AF had a greater need for cardioversion (p <0.004) and right atrial ablation (p <0.04) than patients with paroxysmal AF to achieve comparable rhythm control. A hybrid therapy strategy can provide safe and effective long-term rhythm control in patients with drug-refractory AF, and can be implemented in subpopulations presenting with paroxysmal, persistent, or permanent AF.

Hybrid therapy of atrial fibrillation: algorithms and outcome.

Rhythm control methods have not shown superior outcomes to rate control strategies in atrial fibrillation. Newer approaches to rhythm control employ "hybrid" therapies combining pharmacologic and non pharmacologic interventions. Pathophysiologic insights into mechanisms of atrial fibrillation (AF) suggest that arrhythmogenesis is due to interactions of multiple triggering rhythms and a complex electrophysiologic substrate resulting in the emergence of multiple tachyarrhythmias, often in disparate locations that may coexist in time. Thus, an "hybrid" therapy prescription is more likely to address several of the etiologic factors culminating in clinical AF. Results of pilot clinical studies of hybrid therapy are encouraging and involve drugs, devices and ablation techniques in varying permutations. Hybrid therapy algorithms using right heart procedures can improve efficacy with potentially lower risk. Considerations in implementation of these algorithms include staged or simultaneous interventions and a right versus left heart strategy. The parallel with the current coronary disease management paradigm is obvious and relevant.

Fontan's operation: is aspirin enough? Is coumadin too much?

BACKGROUND: Thromboembolism after Fontan's operation is attributed to low flow states, stasis in venous pathways, right to left shunts, blind cul-de-sacs, prosthetic materials, atrial arrhythmias, and hypercoagulable states. We assessed the efficacy of a strategy to reduce thromboembolic events including aspirin anticoagulation. METHODS: From January 1996 through December 2000, 72 patients underwent Fontan procedures. Management included (1) avoidance of direct caval cannulation and central venous lines, (2) inotropic support for 48 to 72 hours to optimize cardiac output, (3) aortopulmonary anastomosis or suture closure of patent pulmonary valves, and (4) administration of aspirin (81 mg per day) beginning on postoperative day one. No other anticoagulation strategies were used. Surveillance included intraoperative and postoperative transesophageal echo, transthoracic echo at discharge, at first reevaluation, and at 6 month intervals, and catheterization 1 year after surgery. RESULTS: There were no early or late deaths. Follow-up was completed with 2,882 patient-months and a mean of 40 months. There were no documented thromboembolic events; however, all suspicious occurrences were investigated by echo and brain imaging. There were no hemorrhagic events or aspirin-related complications. CONCLUSIONS: Low dose aspirin can be used safely in young patients with Fontan connections. At intermediate follow-up, the strategies described appear effective in preventing thromboembolic complications. Routine use of more aggressive anticoagulation regimens seems unwarranted.