Faculty Bibliography

BACKGROUND:Thromboembolic events related to invasive electrophysiology studies, while rare, can have devastating consequences. Use of systemic anticoagulation for a pediatric or adult-congenital invasive electrophysiology study is recommended, however there is no established standard of practice in this population. OBJECTIVE:To report on procedural practices for thromboembolism prophylaxis during invasive electrophysiology studies for pediatric patients and adults with congenital heart disease. METHODS:An anonymous web-based survey was sent to the members of the Pediatric and Congenital Electrophysiology Society. The survey focused on pre-procedural, intra-procedural, and post-procedural thromboembolism prophylaxis practices during invasive electrophysiology studies. Significant practice variation was defined as <90% concordance among respondents. RESULTS:Survey was completed by 73 members; 52 (71%) practicing in the United States, 65 (89%) practicing in an academic institution, and 14 (19%) in an institution that performs more than 200 invasive electrophysiology procedures annually. Responses showed significant variation in practice. Prior to an invasive electrophysiology procedure, 25% discontinue aspirin while 47% discontinue anticoagulants. Heparin is given for all procedures by 32%. When heparin is administered, the first dose is given by 32% after sheaths are placed, 42% after crossing into the systemic atrium, and 26% just prior to systemic-side ablation. Most target an activated clotting time between 200-300 seconds. Post systemic-side ablation, 58% do not initiate a heparin infusion. Post-procedural oral agents were initiated on day of procedure by 34% of respondents and on post-procedure day 1 by 53%. If treating with aspirin, 74% use low-dose (3-5 mg/kg or 81 mg daily), and 68% treat for 4-6 weeks. CONCLUSION:There is significant variation in thromboembolism prophylaxis for invasive EP studies among pediatric and congenital electrophysiologists. Further studies are needed to optimize the management of thromboembolism prophylaxis in this population.

Epicardial cardiac implantable electronic device implant remains a common option in pediatric patients and certain patients with congenital heart disease due to patient size, complex anatomy, residual intracardiac shunts, and prior surgery precluding transvenous implant. Advantages include the lack of thromboembolic and vascular risks and ability to implant during concomitant surgery. Significant disadvantages include the occurrence of lead dysfunction that can result in bradycardia events in pacemaker patients, inappropriate shocks in implantable cardiac defibrillator patients, and overall a more invasive procedure.

Patients with repaired tetralogy of Fallot are at elevated risk for ventricular arrhythmia and sudden cardiac death. Over the past decade, the pathogenesis and natural history of ventricular tachycardia has become increasingly understood, and catheter ablation has emerged as an effective treatment modality. Concurrently, there has been great progress in the development of a versatile array of transcatheter valves that can be placed in the native right ventricular outflow tract for the treatment of long-standing pulmonary regurgitation. Although such valve platforms may eliminate the need for repeat cardiac operations, they may also impede catheter access to the myocardial substrates responsible for sustained macro-reentrant ventricular tachycardia. This manuscript provides the rationale and design of a recently devised multicenter study that will examine the clinical outcomes of a uniform, preemptive strategy to eliminate ventricular tachycardia substrates before transcatheter pulmonary valve implantation in patients with tetralogy of Fallot.

BACKGROUND:Guidelines addressing magnetic resonance imaging (MRI) in patients with cardiac implantable electronic devices (CIEDs) provide algorithms for imaging pediatric and congenital heart disease (CHD) patients. Guideline acceptance varies by institution. Guidelines also do not support routine MRI scans in patients with epicardial or abandoned leads, common in pediatric and CHD patients. OBJECTIVE:The purpose of this study was to determine the incidence of MRI-related complications in pediatric and CHD patients with CIEDs, including epicardial and/or abandoned leads. METHODS:A multicenter retrospective review included patients with CIEDs who underwent any MRI between 2007 and 2022 at congenital cardiac centers. The primary outcome was any patient adverse event or clinically significant CIED change after MRI, defined as pacing lead capture threshold increase >0.5 V with output change, P- or R- wave amplitude decrease >50% with sensitivity change, or impedance change >50%. RESULTS:Across 14 institutions, 314 patients (median age 18.8 [1.3; 31.4] years) underwent 389 MRIs. There were 288 pacemakers (74%) and 87 implantable cardioverter-defibrillators (22%); 52% contained epicardial leads, and 14 (4%) were abandoned leads only. Symptoms or CIED changes occurred in 4.9% of MRI scans (6.1% of patients). On 9 occasions (2%), warmth or pain occurred. Pacing capture threshold or lead impedance changes occurred in 1.4% and 2.0% of CIEDs post-MRI and at follow-up. CONCLUSION/CONCLUSIONS:Our data provide evidence that MRIs can be performed in pediatric and CHD patients with CIEDs, including non-MRI-conditional CIEDs and epicardial and/or abandoned leads, with rare minor symptoms or CIED changes but no other complications.

Wide complex tachycardia (WCT) is an infrequently encountered condition in paediatric patients and may be due to a variety of causes including supraventricular tachycardia with aberrant conduction, ventricular activation via an accessory pathway, ventricular pacing, or ventricular tachycardia. Immediate tachycardia termination is required in haemodynamically unstable patients. After stabilization or in those with haemodynamically tolerated WCT, a careful review of electrocardiographic tracings and diagnostic manoeuvres are essential to help elucidate the cause. Subacute and chronic management for WCT will depend on the underlying cause as well as features of the patient and the tachycardia presentation. This article will review the epidemiology, potential causes, and management of WCT in children. A detailed review of the pathophysiology, differential diagnosis, and diagnostic and treatment options is provided to enable the reader to develop a practical approach to managing this condition in young patients.

Background The objective of this international multicenter study was to investigate both early and late outcomes of cardiac resynchronization therapy (CRT) in patients with a systemic right ventricle (SRV) and to identify predictors for congestive heart failure readmissions and mortality. Methods and Results This retrospective international multicenter study included 13 centers. The study population comprised 80 adult patients with SRV (48.9% women) with a mean age of 45±14 (range, 18-77) years at initiation of CRT. Median follow-up time was 4.1 (25th-75th percentile, 1.3-8.3) years. Underlying congenital heart disease consisted of congenitally corrected transposition of the great arteries and dextro-transposition of the great arteries in 63 (78.8%) and 17 (21.3%) patients, respectively. CRT resulted in significant improvement in functional class (before CRT: III, 25th-75th percentile, II-III; after CRT: II, 25th-75th percentile, II-III; P=0.005) and QRS duration (before CRT: 176±27; after CRT: 150±24 milliseconds; P=0.003) in patients with pre-CRT ventricular pacing who underwent an upgrade to a CRT device (n=49). These improvements persisted during long-term follow-up with a marginal but significant increase in SRV function (before CRT; 30%, 25th-75th percentile, 25-35; after CRT: 31%, 25th-75th percentile, 21-38; P=0.049). In contrast, no beneficial change in the above-mentioned variables was observed in patients who underwent de novo CRT (n=31). A quarter of all patients were readmitted for heart failure during follow-up, and mortality at latest follow-up was 21.3%. Conclusions This international experience with CRT in patients with an SRV demonstrated that CRT in selected patients with SRV dysfunction and pacing-induced dyssynchrony yielded consistent improvement in QRS duration and New York Heart Association functional status, with a marginal increase in SRV function.

Phenytoin is a versatile drug with utility in neurological, dermatological, and even cardiac disease processes. Though phenytoin is widely available due to its excellent anti-epileptic properties, it is now rarely used as an antiarrhythmic. Phenytoin has well-studied sodium-channel blocking abilities which can be taken advantage of to treat ventricular arrhythmias. Thus, it should remain in the arsenal of antiarrhythmics for any electrophysiologist. We present two cases of intractable ventricular arrhythmia in children that were controlled with phenytoin at supra-therapeutic serum levels, preventing the need for heart transplantation. This article is protected by copyright. All rights reserved.