Impact of electrophysiologists at daily multidisciplinary report in a paediatric cardiac care unit.

BACKGROUND: Paediatric cardiac electrophysiologists are essential in CHD inpatient care, but their involvement is typically limited to consultation with individual patients. In our integrated heart centre, an electrophysiologist reviews all cardiac inpatient telemetry over the preceding 24 hours and participates in daily multidisciplinary morning report. This study investigates the impact of the strategy of consistent, formalised electrophysiologist presence at multidisciplinary morning report. METHODS: This is a single-centre, prospective, observational study of electrophysiologist participation in patient encounters during heart centre multidisciplinary morning report from 10/20/2021 to 10/31/2022. Multidisciplinary morning report includes discussion of all intensive care and non-intensive care cardiac patients. An encounter was defined as reporting on one patient for one day. Electrophysiologists were initially blinded to observations. RESULTS: Two electrophysiologists were observed over 215 days encompassing 6413 patient encounters. Electrophysiologists made comments on 581(9.1%) encounters in 234 unique patients with diverse diagnoses, equating to a median of 3[interquartile range:1-4] encounters per day. These included identifications of arrhythmias and describing electrocardiographic findings. Recommendation to change management occurred in 282(48.5%) encounters, most commonly regarding medications (n = 142, 24.4%) or pacemaker management (n = 48, 8.3%). Of the 581 encounters, there were 61(10.5%) in which they corrected another physician's interpretation of rhythm or electrocardiogram. CONCLUSION: Routine electrophysiologist involvement in multidisciplinary morning report provides significant, frequent, and timely input in patient management by identifying precise rhythm-related diagnoses and allowing nuanced, patient-specific medication and pacemaker management of all cardiac patients, not just those consulted. Electrophysiologist presence at multidisciplinary morning report is a vital resource and this practice should be considered at integrated paediatric cardiac centres.

Current State of Cardiac Implantable Electronic Device Remote Monitoring in Pediatrics and Congenital Heart Disease: A PACES-Sponsored Quality Improvement Initiative.

Cardiac implantable electronic device (CIED) remote transmissions are an integral part of longitudinal follow-up in pediatric and adult congenital heart disease (ACHD) patients. To evaluate baseline CIED remote monitoring (RM) data among pediatric and ACHD centers prior to implementation of a Pediatric and Congenital Electrophysiology  Society (PACES)-sponsored quality improvement (QI) project. This is a cross-sectional study of baseline CIED RM. Centers self-reported baseline data: individual center RM compliance was defined as high if there was > 80% achievement and low if < 50%. A total of 22 pediatric centers in the USA and Australia submitted baseline data. Non-physicians were responsible for management of the RM program in most centers: registered nurse (36%), advanced practice provider (27%), combination (23%), and third party (9%). Fifteen centers (68%) reported that > 80% of their CIED patients are enrolled in RM and only two centers reported < 50% participation. 36% reported high compliance of device transmission within 14 days of implant and 77% of centers reported high compliance of CIED patients enrolled in RM. The number of centers achieving high compliance differed by device type: 36% for pacemakers, 50% for ICDs, and 55% for Implantable Cardiac Monitors (ICM). All centers reported at least 50% adherence to recommended follow-up for PM and ICD, with 23% low compliance rate for ICMs. Based on this cross-sectional survey of pediatric and ACHD centers, compliance with CIED RM is sub-optimal. The PACES-sponsored QI initiative will provide resources and support to participating centers and repeat data will be evaluated after PDSA cycles.

Pacemaker Management and In-Hospital Outcomes in Neonatal Congenital Atrioventricular Block.

BACKGROUND: Neonatal congenital atrioventricular block (nCAVB) is rare, causes bradycardia, confers high mortality, and frequently requires pacing. In-hospital outcomes and pacemaker management in nCAVB are limited. OBJECTIVES: The purpose of this study was to analyze pacing and outcomes of nCAVB with and without congenital heart disease (CHD) using a multicenter database. METHODS: A Pediatric Health Information System database review from January 1, 2004, to June 30, 2022. Patients <31 days of age with a nCAVB International Classification of Diseases-9th/10th Revision diagnosis code and no cardiac surgeries except pacemaker were included. Pacing and in-hospital mortality were analyzed using univariate and multivariable logistic statistics and competing risk and event-free survival models. RESULTS: Of 1,146 patients with nCAVB, 659 (57.5%) were girls and 506 (44.2%) were premature. Among the 326 (28.4%) with CHD, 134 (41.1%) underwent pacemaker insertion as initial intervention and 56 (17.2%) had temporary pacing wires. In-hospital mortality occurred in 118 (36.2%), with increased adjusted odds with temporary pacing wires placed at 0 to 1 or 2 to 7 days of age relative to no wires, and with decreased odds among pacemakers placed at 2 to 7 or 8+ days of age relative to no pacemaker. Of 820 (71.6%) without CHD, 334 (40.7%) underwent pacemaker insertion as the initial intervention and 81 (9.9%) had temporary pacing wires. In-hospital mortality occurred in 69 (8.4%) with increased adjusted odds in prematurity and decreased odds among pacemaker placement at 2 to 7 days of age relative to no pacemaker. CONCLUSIONS: Over 18.5 years, in-hospital mortality occurred in 36.2% of nCAVB patients with CHD and 8.4% with non-CHD. Associations with increased in-hospital mortality included CHD and prematurity and decreased with pacemaker placement. Prospective registries are needed to better characterize and standardize management of this rare but high-mortality disease.

Long QT and Hearing Loss in High-Risk Infants Prospective Study Registry.

The objective of this study is to determine the prevalence of an abnormal electrocardiogram showing a prolonged QTc greater than 450 ms in infants with unilateral or bilateral sensorineural hearing loss. We conducted a prospective study of healthy term infants (≥37 weeks gestational age) who failed their newborn auditory brainstem response hearing screen, were seen by an audiologist and diagnosed as having sensorineural hearing loss during follow-up to 1 year of age. In infants with a diagnosis of hearing loss, we collected a detailed family history and performed an ECG between 2 and 6 months of age. We obtained follow-up for 1 year by calling the parent requesting the hearing and cardiac status of their child. Two of the 40 infants with sensorineural hearing loss (5%) had a QTc greater than 450 ms. Both had mild bilateral hearing loss and genetic testing did not identify a known mutation for long QT syndrome. The remaining 38 infants had QTc intervals of ≤ 450 ms. One patient diagnosed with bilateral severe sensorineural hearing loss had a normal ECG (QTc = 417 ms). Several months after the ECG was performed, the infant's mother contacted the study cardiologist after she learned that the infant's maternal grandmother was diagnosed with a cardiomyopathy and arrhythmias. Genetic testing was recommended even though the child was asymptomatic and was positive for a pathogenic mutation in the KCNQ1 gene. We speculate that molecular genetic testing in infants with hearing loss may become the standard of care rather than targeted electrocardiograms.Clinical Trial Registration NCT02082431 https://www.clinicaltrials.gov/ct2/show/NCT02692521?cond=NCT02692521&rank=1 .

Arrhythmias Requiring ECMO in Infants Without Structural Congenital Heart Disease.

Arrhythmias account for 55 per 100,000 patient evaluations in pediatric emergency departments. Most arrhythmias in children are amenable to medical management or cardioversion. Rarely, arrhythmias lead to significant hemodynamic instability requiring extracorporeal membrane oxygenation (ECMO) support. This study seeks to evaluate children under 1 year of age with a structurally normal heart requiring ECMO for an arrhythmia. This is a retrospective review of the Extracorporeal Life Support Organization Registry. All patients less than 1 year of age between 2009 and 2019 with a diagnosis of arrhythmia and without a diagnosis of structural heart malformation were included. Demographics, clinical characteristics, and outcomes were assessed with descriptive statistics and univariate and multivariable analyses. A total of 140 eligible patients were identified from the dataset. The most common arrhythmia was supraventricular tachycardia (SVT) in 70 (50%) patients. ECMO complications occurred in 106 (76.3%) patients and survival to discharge was achieved in 120 (85.7%) patients. In-hospital mortality was associated with neuromuscular blockade prior to ECMO [aOR 10.0 (95% CI 2.95-41.56), p < 0.001], neurologic ECMO complication [aOR 28.1 (95% CI 6.6-155.1), p < 0.001], and race with white race being protective [aOR 0.13, (95% CI 0.02-0.21), p = 0.002]. Similar survival and complication rates were found in subgroup analysis of SVT arrhythmias alone. Arrhythmias necessitating ECMO support in infants without structural congenital heart disease is a rare occurrence. However, survival to hospital discharge is favorable at greater than 85%. Given the favorable survival, earlier and more aggressive utilization of ECMO may result in improved outcomes.

Lessons learned from preparticipation cardiovascular screening in a state funded program.

In 2007, the Texas legislature appropriated money for a pilot study to evaluate cardiovascular screening of student athletes to identify those who might be at risk of sudden death using a questionnaire, physical examination, electrocardiography, and limited echocardiography. We sought to determine (1) the feasibility of a state-wide cardiovascular screening program, (2) the ability to reliably identify at-risk subjects, and (3) problems in implementing screening state wide. The data were analyzed using established pediatric electrocardiographic and echocardiographic criteria. Positive results were confirmed by a blinded reviewer. In 31 venues (2,506 students), the electrocardiographic findings met the criteria for cardiovascular disease in 57 (2.3%), with 33 changes suggestive of hypertrophic cardiomyopathy, 14 with long QT syndrome, 7 with Wolff-Parkinson-White syndrome, and 3 with potential ischemic findings related to a coronary anomaly. Of the 2,051 echocardiograms, 11 had findings concerning for disease (9 with hypertrophic cardiomyopathy and 1 with dilated cardiomyopathy). In patients with electrocardiographic findings consistent with hypertrophic cardiomyopathy, the limited echocardiograms were normal in 24 of 33. Of the 33 who remained at risk of sudden death on the electrocardiogram or echocardiogram, 25 (65.8%) pursued the recommended evaluation, which confirmed long QT syndrome in 4, Wolff-Parkinson-White syndrome in 7, and dilated cardiomyopathy in 1. The interobserver agreement was 100% for electrocardiography and 79% for echocardiography. The questionnaire identified 895 (35% of the total) potentially at-risk students, with disease confirmed in 11 (1.23%). In conclusion, in this large state-funded project, electrocardiographic and echocardiographic screening identified 11 of 2,506 patients potentially at risk of cardiovascular disease. The questionnaire was of limited value and had a large number of false-positive results. Interobserver variation was significant for echocardiography and might create problems with limited echocardiographic screening. Finally, many subjects with abnormal screening results declined a follow-up evaluation.

Radiofrequency ablation of nonautomatic focal atrial tachycardia in children with structurally normal hearts.

INTRODUCTION: The majority of children presenting with paroxysmal supraventricular tachycardia (SVT) have either accessory-pathway-mediated tachycardia or AV node reentry tachycardia. The purpose of this study is to report an unusual mechanism of SVT found in children with structurally normal hearts. METHODS AND RESULTS: Records of all patients undergoing an electrophysiology study (EPS) at our institution between 2000 and 2004 were reviewed to identify those with nonautomatic focal atrial tachycardia (NAFAT). Five patients (three males) with an average age of 13.8 years (median 15 years, range 7-18 years) were identified. All presented with paroxysmal palpitations. They all had structurally normal hearts. At EPS, SVT was reproducibly induced with programmed atrial stimulation (single, double, or triple extrastimuli) in all patients. The average cycle length was 276 +/- 9 ms. Adenosine terminated SVT in 2. A 3-D electro-anatomical system mapping was used in all cases. The right atrium (RA) was mapped in all and the left in two. Foci were mapped to the posterior high RA, lateral RA, lower mid RA septum, inferior to the sinus node, and in the right and left posteroseptal areas. Average number of radiofrequency lesions placed was 8.6 +/- 5. The success rate was 80%; there was one late recurrence. No procedural complications were observed. CONCLUSIONS: NAFAT is a rare form of tachycardia that should be considered in the differential diagnosis of children presenting with SVT. It is amenable to mapping and radiofrequency ablation.

Transcatheter closure of patent ductus arteriosus and aorto-pulmonary vessels using non-ferromagnetic Inconel MReye embolization coils.

OBJECTIVES: We report the use of non-ferromagnetic embolization coils for transcatheter PDA closure. BACKGROUND: Transcatheter patent ductus arteriosus (PDA) closure has been performed for 40 years. A number of devices have been used with varying degrees of success. Gianturco embolization coils have been used frequently since 1992 with excellent results. These coils are a stainless steel alloy, and create an artifact when subsequent MRI imaging is performed. METHODS: Eight patients underwent right and left heart catheterization and transcatheter PDA closure. Angiography displayed a PDA with left to right shunting. The minimum PDA diameter was measured. An Inconel MReye coil was implanted using standard retrograde technique. A postimplant angiogram was performed. Evaluations were performed the following morning and after 2 months. RESULTS: The median age was 5.5 years, median weight was 24 kg. The PDA minimum diameter was 1.7 mm (range 1.4-2.4 mm), with a median Qp:Qs=1.33:1. In all patients, the PDA was completely immediately closed using one Inconel coil. Two patients also had a small aorto-pulmonary collateral vessel that was occluded using a separate Inconel coil. All patients had follow-up evaluation the following day; the PDA remained completely occluded and there was no obstruction of the pulmonary artery branches or descending aorta. Seven patients had subsequent follow-up and echocardiograms; the PDA remained completely occluded. There were no complications. CONCLUSION: The Inconel MReye coil is safe and effective for coil occlusion of small PDA and aorto-pulmonary vessels. Additional studies are needed to define the maximum vessel diameter for Inconel coil occlusion.

Ventricular function and long-term pacing in children with congenital complete atrioventricular block.

OBJECTIVE: To determine the sequela of right ventricular pacing in children with congenital complete atrioventricular block. BACKGROUND: Pacing is a well-accepted therapy for patients with congenital complete atrioventricular block. The long-term sequela of right ventricular pacing in this population has not been well described. METHODS: We performed a cohort study on all patients with congenital complete atrioventricular block who underwent pacemaker implantation at our institution from 1972 to 2004. Patients with associated congenital heart disease or ventricular dysfunction prior to pacemaker implantation were excluded. RESULTS: A total of 63 patients were included in the study. The median age at pacemaker implantation was 6.5 years, with an average follow-up of 9.9 years. The cumulative dysfunction free survival at 20 years was 92%. In total, four patients (6%) were noted to develop LV dysfunction an average of 15.1 years after pacemaker implantation. Of 30 patients who were paced for >10 years, only three (10%) developed echocardiographic evidence of LV dysfunction. Right ventricular apex pacing and prolonged QRS duration were found to be predictive of decreased long-term LV systolic function (P < 0.05). CONCLUSIONS: Left ventricular dysfunction in patients with congenital complete atrioventricular block is a rare finding, even in those who have been paced for more than 10 years. Right ventricular apex pacing and prolonged QRS duration may be associated with decreased ventricular function over time. At this time, with such a low incidence of cardiac dysfunction, right ventricular pacing should be considered an acceptable first-line therapy in this population.

Can pediatric electrophysiologists safely perform electrophysiology studies on adults with congenital heart disease?

INTRODUCTION: Adults with congenital heart disease (ACHD) are known to have arrhythmias. The purpose of this study was to review the safety and efficacy of a pediatric electrophysiologist performing electrophysiology studies (EPS) on ACHD. METHODS: All ACHD >18 years of age who underwent an EPS performed by a pediatric electrophysiologist between 1995 and 2004 were included. Patient records were reviewed for demographics, cardiac diagnosis, surgery, arrhythmia, and catheterization issues such as vascular access, fluoroscopy time, complications, procedure performed, and success rates. RESULTS: The study identified 70 patients who underwent 93 EPS: 42 with ventricular tachycardia (VT) and 28 with supraventricular tachycardia (SVT). With respect to safety, vascular access was obtained in 100% of patients, fluoroscopy time averaged 34.2 minutes, and complications occurred in 3 patients (4%) including permanent (1) or transient (1) atrio-ventricular node injury and coagulum on the catheter (1), but no deaths. With respect to efficacy, 30 patients had an attempted radiofrequency ablation that was successful in 21 of 28 (75%) with SVT and 1 of 2 (50%) with VT. CONCLUSIONS: (1) ACHD can safely undergo an electrophysiology study performed by pediatric electrophysiologists, with low fluoroscopy times and few complications. (2) Success rates for ablation in this patient population approach 75%.

Atrial flutter in infants.

OBJECTIVES: We sought to characterize the clinical nature of atrial flutter (AFL) in a large cohort of infants. BACKGROUND: There are no large studies describing the natural history of AFL in infants. Previous studies vary in the therapy used and expected prognosis. METHODS: We reviewed the records of all children younger than 1 year of age who were diagnosed with AFL at our hospital during the past 25 years, excluding those with previous cardiac surgery. RESULTS: We identified 50 infants with AFL. Most, 36 (72%), presented within the first 48 h of life. Congestive heart failure was evident in 10 infants, with 6 presenting at 1 day of age, and 4 presenting beyond 1 month of age. The remainder were asymptomatic. A large atrial septal defect was the only structural heart disease. Spontaneous conversion to sinus rhythm occurred in 13 (26%) infants. Sinus rhythm was restored in 20 of 23 (87%) attempts at direct current cardioversion and 7 of 22 (32%) attempts at transesophegeal pacing; 7 required antiarrhythmic therapy. An additional arrhythmia, all supraventricular, appeared in 11 (22%) infants. The recurrence of AFL developed in 6 infants; 5 of 6 of these incidents occurred within 24 h of the first episode. All patients with recurrence had an additional arrhythmia. CONCLUSIONS: Infants with AFL usually present within the first 2 days of life. No association was found with structural heart disease. Direct current cardioversion appears to be most effective at establishing sinus rhythm. Chronic AFL has the potential to cause cardiovascular compromise. Atrial flutter in the absence of other arrhythmias has a low risk of recurrence. Once in sinus rhythm, infants with AFL have an excellent prognosis and may not require chronic antiarrhythmic therapy.

Innovative techniques for placement of implantable cardioverter-defibrillator leads in patients with limited venous access to the heart.

BACKGROUND: Because of venous occlusion, intracardiac shunting, previous surgery, or small size placement of implantable cardioverter-defibrillator (ICD) leads may not be possible using traditional methods. The purpose of this study was to evaluate and describe innovative methods of placing ICD leads. METHODS: The records of all patients undergoing ICD implantation at our institution were reviewed to identify patients with nontraditional lead placement. Indications for ICD, method of lead and coil placement, defibrillation thresholds, complications, and follow-up results were reviewed retrospectively. RESULTS: Eight patients (aged 11 months to 29 years) were identified. Six patients with limited venous access to the heart (four extracardiac Fontan, one bidirectional Glenn, one 8 kg 11-month-old) underwent surgical placement of an ICD coil directly into the pericardial sac. A second bipolar lead was placed on the ventricle for sensing and pacing. Two patients with difficult venous access had a standard transvenous ICD lead inserted directly into the right atrium (transatrial approach) and then positioned into the ventricle. All patients had a defibrillation threshold of <20 J, although one patient required placement of a second coil due to an elevated threshold. There have been no complications and two successful appropriate ICD discharges at follow-up (median 22 months, range 5-42 months). CONCLUSIONS: Many factors may prohibit transvenous ICD lead placement. Nontraditional surgical placement of subcutaneous ICD leads on the pericardium or the use of a transatrial approach can be effective techniques in these patients. These procedures can be performed at low risk to the patient with excellent defibrillation thresholds.

Salvaging the failing Fontan: lateral tunnel versus extracardiac conduit.

BACKGROUND: Since Fontan revision has been demonstrated to provide hemodynamic and symptomatic improvement in select patients with failing Fontan circulations, we now believe it is important to determine if one type of revision (lateral tunnel [LT] or extracardiac conduit [ECC]) provides superior outcomes. METHODS: Thirty-five Fontan revisions were performed (Jun 1997 to Dec 2004): 19 ECC (54%) and 16 LT. Preoperative variables were similar: New York Heart Association (NYHA) IV (LT = 4 vs ECC = 2, p = not significant [NS]), preoperative arrhythmias (LT = 13 vs ECC = 16, p = NS) and systemic right ventricle (LT = 4 vs ECC = 2, p = NS). Twenty-eight patients (80%) underwent a modified maze procedure (LT = 12 vs ECC = 16, p = NS) and 29 (83%) had pacemaker placement (LT = 11 vs ECC = 18, p < 0.05). RESULTS: There were no hospital deaths and no arrhythmias at hospital discharge. There were no differences in mean duration of intubation (LT 0.6 vs ECC 0.9 days, p = NS), inotropic support (LT 1.5 vs ECC 2.1 days, p = NS), intensive care unit stay (LT 2.6 vs ECC 3.5 days, p = NS), hospital stay (LT 8.8 vs ECC 9.7 days, p = NS), or episodes of acute postoperative arrhythmias (LT = 2 vs ECC = 4, p = NS). On intermediate follow-up (29 +/- 22 months), the overall cohort had 94% survival, 97% of survivors in NYHA class I/II, 91% freedom from late arrhythmias requiring medication, and no patient required cardiac transplantation. Follow-up revealed no differences in NYHA I/II (LT = 14 vs ECC = 18, p = NS), mortality (LT = 2 vs ECC = 0, p = NS), or late arrhythmia (LT = 4 vs ECC = 4, p = NS). CONCLUSIONS: Both the LT and ECC revisions provide symptomatic benefit for a failing Fontan connection and have equivalent early and intermediate results including arrhythmia recurrence.

Atrial flutter following placement of an umbilical venous catheter.

Atrial flutter is a rare complication of the insertion of an umbilical venous catheter. We report a neonate who had an umbilical venous catheter placed within the first 24 hours of life and developed a hemodynamically stable tachyarrhythmia. The arrhythmia was successfully managed with synchronized cardioversion, with no further complications. The presentation and management are discussed. Physicians should be watchful for such potentially life-threatening complications from the placement of indwelling lines.

Atrioventricular junction ablation and pacemaker therapy in patients with drug-resistant atrial tachyarrhythmias after the Fontan operation.

INTRODUCTION: Drug-resistant intraatrial reentrant tachycardia (IART) occurs frequently after the Fontan operation and is a major cause of morbidity and rarely mortality. We describe our experience with AV junction ablation after pacemaker implantation in postoperative Fontan patients with drug-resistant IART. METHODS AND RESULTS: We performed retrospective analysis of Fontan patients with IART and attempted radiofrequency ablation (RFA) of the AV junction. Seven patients (6 male) were identified, with a mean age at Fontan of 9.3 years (range 5.8-13.3) and a median age at RFA of 18 years (range 14.5-23.3). Mean follow-up prior to RFA was 764 +/- 235 days and after RFA 1,541 +/- 1,235 days. IART was refractory to antiarrhythmic drugs in all patients, and all had undergone pacemaker placement. Mean onset of IART was 44.1 months (range 0-142) after Fontan. Mean duration of atrial arrhythmia prior to RFA was 72 +/- 48 m (range 16-148). Ablation of the AV junction was successful or partially successful in all patients. Complete AV block occurred in 6 patients. Normal AV conduction was not seen during a mean follow-up of 1,541 days. The mean number of antiarrhythmic medications decreased from 2.8 +/- 1.5 to 0.7 +/- 0.8 (P <0.05). CONCLUSION: In Fontan patients with drug-resistant IART, RFA of the AV junction with prior pacemaker implant is an effective therapeutic option. Despite the introduction of pacemaker dependence, this option should be considered in patients who did not respond to RFA of IART or who are at high operative risk for Fontan conversion.

Improved early results with the Fontan operation in adults with functional single ventricle.

BACKGROUND: A growing number of adults with functional single ventricles are presenting as candidates for first-time and redo-Fontan operations. This study describes the clinical presentation and early operative results of adults who have undergone Fontan modifications. METHODS: Between July 1995 and April 2003, 23 patients (>18 years old) had Fontan operations. We retrospectively reviewed their perioperative courses. RESULTS: Twenty-three Fontan operations (first-time [n = 8] and redo [n = 15]) were performed with no early or late deaths. No patient has required reoperation. One patient has been listed for orthotopic heart transplantation. The overall mean age is 23 years (18 to 41 years); mean follow-up, 30 months; median postoperative hospital stay, 8 days (4 to 34 days); and median duration of chest tube drainage, 4 days (2 to 12 days). The postoperative New York Heart Association (NYHA) functional class was improved in 22 of 23 patients. Eight first-time Fontan operations (7 of 8 nonfenestrated) were performed; lateral tunnel (n = 7) and extracardiac conduit (n = 1). Two patients had preoperative arrhythmias. New onset arrhythmias (ventricular tachycardia and sinus node dysfunction), requiring treatment, occurred in two patients. Fifteen redo-Fontan operations (all nonfenestrated) were performed; lateral tunnel (n = 5) and extracardiac conduit (n = 10). Fifteen patients had preoperative arrhythmias, thirteen of which had intraatrial reentry tachycardia (IART) and required antiarrhythmic medications. Concomitant intraoperative radiofrequency ablation (RFA) (n = 11) and cryoablation (n = 1) procedures were performed. In the immediate postoperative period, there was IART recurrence in five patients (post-RFA [n = 4] and postcryoablation [n = 1]). At latest follow-up, no patient is being treated with antiarrhythmic medications. Two patients had new onset atrial arrhythmias that required treatment. CONCLUSIONS: The Fontan operation can be performed in adults with minimal morbidity and improved NYHA functional class. New onset arrhythmias requiring treatment are sources of perioperative morbidity. Complete arrhythmia resolution of the preoperative arrhythmia may not be achieved in the immediate postoperative period in redo-Fontan patients. However, modification (intraoperative radiofrequency ablation-right atrial debulking) of the atrial tachycardia circuits in the redo-Fontan patients can result in complete resolution of preoperative atrial tachyarrhythmias at early follow-up.

Clinical course of atrial ectopic tachycardia is age-dependent: results and treatment in children < 3 or > or =3 years of age.

OBJECTIVES: We assessed the clinical presentation, natural history, and treatment response of atrial ectopic tachycardia (AET) in children <3 years of age (group 1) compared with those > or =3 years of age (group 2). BACKGROUND: Atrial ectopic tachycardia is a common cause of chronic supraventricular tachycardia in children and can be resistant to pharmacologic therapy. Radiofrequency ablation (RFA) can eliminate AET arising from a single focus. METHODS: A retrospective review identified all children at Texas Children's Hospital diagnosed with AET from March 1991 to November 2000. Data obtained included clinical presentation, echocardiographic evaluation, response to antiarrhythmic therapy, spontaneous resolution, and outcomes of radiofrequency and surgical ablation. RESULTS: Sixty-eight children were identified (22 children <3 years and 46 children > or =3 years of age). Control of AET with antiarrhythmic therapy was achieved in 91% of the younger children but only 37% of the older children (p < 0.001). There was a higher rate of spontaneous resolution in the younger group (78%) compared with the older group (16%) (p < 0.001). Radiofrequency ablation was performed in 35 of the older children, with ultimate success in 74%. Surgical intervention was required for six children. CONCLUSIONS: Younger children respond to antiarrhythmic therapy and have a high incidence of AET resolution, thus warranting a trial of antiarrhythmic therapy. In children > or =3 years, AET is unlikely to resolve spontaneously, and antiarrhythmic medications are frequently ineffective. Thus, RFA should be considered early in the course of treatment for these children; however, surgical intervention may be necessary.

Late pacemaker requirement after pediatric orthotopic heart transplantation may predict the presence of transplant coronary artery disease.

BACKGROUND: Few data are available regarding pacemaker implantation after pediatric orthotopic heart transplantation. The purpose of this study was to assess the incidence, indications and associations with regard to pacemaker placement in children who have undergone orthotopic heart transplantation. METHODS: We performed a retrospective study of all patients undergoing orthotopic heart transplantation at our institution from October 1984 to March 2001. Data obtained included demographics, indications for pacemaker, presence of transplant coronary artery disease and long-term follow-up. Patients were divided into: Group 1, patients requiring a pacemaker within 3 months of transplantation; and Group 2, patients requiring a pacemaker beyond 3 months. RESULTS: Pacemakers were required in 7 of 106 (6.6%) transplant recipients. Pacing indications for patients in Group 1 (n = 2) were persistent bradycardia with pause-related ventricular arrhythmia and atrial flutter with resultant sinus pauses of up to 4 seconds. In Group 2 patients (n = 5), indications for pacing were high-grade atrioventricular (AV) block in 1 patient and episodic sinus pauses up to 3.3 seconds associated with syncope/dizziness in the remaining 4 patients. All patients in Group 2 had transplant coronary disease diagnosed within 1 year of pacemaker implantation. All had resolution of symptoms and no complications after implantation. CONCLUSIONS: Pacemakers are infrequently required after cardiac transplantation in children. Despite not meeting classic symptomatic sinus bradycardia criteria, pacemaker placement should be considered post-transplantation in patients with episodic sinus pauses and dizziness or syncope. Patients who present with the aforementioned symptoms or high-grade AV block should be evaluated closely for the presence or development of transplant coronary artery disease, as it may be their first symptom.

Frequency of recurrence among infants with supraventricular tachycardia and comparison of recurrence rates among those with and without preexcitation and among those with and without response to digoxin and/or propranolol therapy.

Approximately 60% of children with supraventricular tachycardia (SVT) develop their initial episode by 1 year of age. Despite resolution in most of these patients by 1 year, approximately 30% of the SVT will recur. We performed a retrospective review of all patients <1 year of age with SVT between January 1984 and December 2000. Recurrence was defined as documented SVT at >1 year of age. Patients were divided into: (1) a first line (FL) group (controlled with digoxin and/or propranolol) and (2) a second line (SL) group (requiring additional antiarrhythmics). The groups were divided based on the presence of preexcitation. The FL group included 116 patients, 20 of whom (17%) had Wolff-Parkinson-White (WPW) syndrome. The SL group included 34 patients, 21 of whom (62%) had WPW (p <0.001). Recurrence of SVT occurred in 32 patients (28%) in the FL group and in 23 patients (68%) in the SL group (p <0.001). SVT recurred in 36 of 41 patients (88%) with WPW compared with 19 of 109 patients (17%) without WPW syndrome (p <0.001). Logistic regression analysis demonstrated that the presence of WPW syndrome was associated with a 29-fold higher odds of SVT recurrence (p <0.001), and that patients with WPW syndrome were more likely to require additional antiarrhythmic therapy (p <0.001). Thus, patients with WPW syndrome who had SVT at <1 year of age have 29-fold higher odds of recurrence at >1 year of age versus those patients with preexcitation. These patients are also more likely to require additional antiarrhythmic therapy to control SVT. Furthermore, children with WPW syndrome who are refractory to treatment with digoxin and/or propranolol are at increased risk of SVT recurrence.

The use of implantable cardioverter-defibrillators in pediatric patients awaiting heart transplantation.

BACKGROUND: This multicenter study evaluated experience with implantable cardioverter defibrillators (ICD) as a bridge to orthotopic heart transplantation (OHT) in children. METHODS: The application of ICD therapy continues to expand in pediatric populations, due in part to improved technology and new indications, including the prevention of sudden death while awaiting OHT. METHODS: We performed a retrospective review of ICD databases at 9 pediatric transplant centers. RESULTS: Twenty-eight patients (16 males) underwent implantation or had a preexisting ICD while awaiting OHT between 1990 and 2002. The median age at implant was 14.3 years (11 months to 21 years) with a median weight of 49 kg (11.7-88 kg). Diagnoses included cardiomyopathy (n=22), and congenital heart disease (n=6). Indications for ICD implantation included ventricular tachycardia/fibrillation (n=23), syncope (n=5), aborted sudden death with no documentation of rhythm disturbance (n=5), ventricular ectopy (n=1), and poor function (n=5). Of the 28 ICDs, 23 were implanted by a transvenous approach and 5 by epicardial route. There were 55 defibrillator discharges in 17 patients, 47 (85%) of which (in 13 patients) were appropriate. The 8 inappropriate discharges (in 6 patients) were triggered by sinus tachycardia, inappropriate sensing, and atrial flutter. The mean time from implantation to first appropriate shock was 6.9 months (1 day to 2.6 years). Twenty-one patients underwent transplantation during the study period, whereas 2 died while awaiting a donor. Morbidity included a lead fracture, 3 episodes of electromechanical dissociation, and 1 episode of electrical storm. CONCLUSIONS: ICD implantation represents an effective bridge to transplantation in pediatric patients. The complication rate is low, with inappropriate device discharge due primarily to sinus tachycardia or atrial flutter. There is a high incidence of appropriate ICD therapy for malignant ventricular arrhythmias in this highly selected group of patients.