Initial Counseling Prior to Palliation for Hypoplastic Left Heart Syndrome: 2021 vs 2011.

We sought to examine current practices and changes in practice regarding initial counseling for families of patients with hypoplastic left heart syndrome (HLHS) given the evolution of options and outcomes over time. Counseling (Norwood with Blalock-Taussig-Thomas shunt (NW-BTT), NW with right ventricle to pulmonary artery conduit (NW-RVPA), hybrid palliation, heart transplantation, or non-intervention/hospice (NI)) for patients with HLHS were queried via questionnaire of pediatric care professionals in 2021 and compared to identical questionnaire from 2011. Of 322 respondents in 2021 (39% female), 299 respondents were cardiologists (92.9%), 17cardiothoracic surgeons (5.3%), and 6 were nurse practitioners (1.9%). Respondents were largely from North America (96.9%). In 2021, NW-RVPA procedure was the preferred palliation for standard risk HLHS patient (61%) and was preferred across all US regions (p < 0.001). NI was offered as an option by 71.4% of respondents for standard risk patients and was the predominant strategy for patients with end-organ dysfunction, chromosomal abnormality, and prematurity (52%, 44%, and 45%, respectively). The hybrid procedure was preferred for low birth-weight infants (51%). In comparison to the identical 2011 questionnaire (n = 200), the NW-RVPA was endorsed more in 2021 (61% vs 52%, p = 0.04). For low birth-weight infants, hybrid procedure was more recommended than in 2011 (51% vs 21%, p < 0.001). The NW-RVPA operation is the most recommended strategy throughout the US for infants with HLHS. The hybrid procedure for low birth-weight infants is increasingly recommended. NI continues to be offered even in standard risk patients with HLHS.

Diagnostic Accuracy and Safety of Confirm Rx™ Insertable Cardiac Monitor in Pediatric Patients.

Insertable cardiac monitors (ICM) are subcutaneously implanted devices that monitor a patient's heart rate and rhythm (Rossano in Pediatrics 112(3):e228, 2003). The diagnostic accuracy and safety of the Confirm RxTM (Abbott, Minneapolis, MN) ICM in pediatric patients is unknown. This is a single center, retrospective, IRB-approved review of patients ≤ 21 years implanted with Confirm RxTM ICMs from 2017 to 2020. Data collected included demographics, indications, presence of P-wave and R-wave amplitude at implantation and follow-up, number/appropriateness of transmissions pre and post implementation of SharpSenseTM technology, reprogramming to improve accuracy, time from implantation to arrhythmia detection, and complications. There were 29 patients (median age: 8 years, 59% females). P-waves were identified in all patients and average R-wave amplitude was 0.85 mV (0.26-1.03 mV). There was no significant difference in R-wave amplitude based on size (BSA ≥ 1.5 m2: 0.76 mV, < 1.5 m2: 0.91 mV) or congenital heart disease (+CHD: 0.86 mV, -CHD: 0.85 mV). Arrhythmias identified were the following: wide complex tachycardia (1), supraventricular tachycardia (4), bradycardia/sinus pause (3), and premature ventricular contraction (1). SharpSenseTM implementation decreased the false-positive rate in device-initiated transmissions (55.4% to 0%, p < 0.00001). Average time from implantation to arrhythmia detection was 2.63 months (range: 0-8.8). A single complication of cellulitis occurred. Confirm RxTM is appropriate for implant in pediatric patients regardless of age, BSA, or CHD. Implementation of SharpSense™ technology dramatically decreased the false-positive rate. Follow-up studies could utilize additional monitoring devices to provide analysis on potential events that the Confirm RxTM ICM missed.

Symptomatic atrial bigeminy masquerading as congenital complete heart block.

Newborn male with symptomatic bradycardia initially diagnosed with complete atrioventricular block. Isoproterenol drip was initiated, and the patient was scheduled for pacemaker implantation. During the hospital course, repeat electrocardiogram and Holter monitor revealed evidence of near continuous blocked atrial bigeminy with occasional aberrantly conducted premature atrial contractions. Flecainide was started, resulting in normal sinus rhythm, and the pacemaker implantation was cancelled.

Telehealth for Pediatric Cardiology Practitioners in the Time of COVID-19.

Due to the COVID-19 pandemic, there has been an increased interest in telehealth as a means of providing care for children by a pediatric cardiologist. In this article, we provide an overview of telehealth utilization as an extension of current pediatric cardiology practices and provide some insight into the rapid shift made to quickly implement these telehealth services into our everyday practices due to COVID-19 personal distancing requirements. Our panel will review helpful tips into the selection of appropriate patient populations and specific cardiac diagnoses for telehealth that put patient and family safety concerns first. Numerous practical considerations in conducting a telehealth visit must be taken into account to ensure optimal use of this technology. The use of adapted staffing and billing models and expanded means of remote monitoring will aid in the incorporation of telehealth into more widespread pediatric cardiology practice. Future directions to sustain this platform include the refinement of telehealth care strategies, defining best practices, including telehealth in the fellowship curriculum and continuing advocacy for technology.

Ventricular tachycardia recorded in a competitive swimmer using Confirm Rx™ loop recorder.

Conventional ambulatory heart rhythm monitoring is limited in its ability to provide rapid diagnosis of arrhythmias in athletes participating in water or high-intensity sports. This case report is of a 17-year-old female competitive swimmer who underwent loop recorder implantation with Confirm Rx™ ICM 3500 (Abbott, Minneapolis, MN) to monitor for arrhythmias during swimming. The purpose of this case report is to describe the utility of implantable loop recorders in arrhythmia diagnosis and symptom evaluation in water sport athletes.

The HAV pattern in pediatric patients with atrioventricular node reentrant tachycardia.

OBJECTIVES: The purpose of this study is to assess the prevalence of a His-Atrial-Ventricular (HAV) pattern, i.e. the atrial electrogram following the His bundle -HB- electrogram and preceding the ventricular one, on the catheter placed in the His position in pediatric patients during typical atrioventricular node reentry (AVNRT). MATERIALS AND METHODS: The pediatric electrophysiology databases of two separate institutions were queried for patients with a diagnosis of AVNRT. Demographic, clinical data and the electrophysiology study (EPS) information were assessed. RESULTS: Thirty-nine consecutive patients were included. Twenty-five were female. The average age at the time of the EPS was 12 ± 3.7 years. Induction was achieved with atrial pacing in 23, with a single atrial extra stimulus in 8 and with dual atrial extra stimuli in 8. Isoproterenol was needed to induce tachycardia in 21. Tachycardia cycle length averaged 320 ± 50 ms. An HAV pattern was present in 35 (74%) of the patients, and in 100% of the patients younger than 8. CONCLUSIONS: An HAV pattern on the catheter placed in the His position, is common in pediatric patients with AVNRT, occurring in up to 74% of the patients in this population, being more common in younger patients.

Ambulatory Arrhythmia Detection with ZIO® XT Patch in Pediatric Patients: A Comparison of Devices.

Ambulatory electrocardiogram monitoring devices can be used for 24-72 h to detect arrhythmias. A new device, the ZIO® XT Patch has cardiac monitoring capabilities that can be utilized for up to 14 days. The purpose of this study is to describe duration of ZIO use by age, and to compare its time to arrhythmia detection with the Holter monitor in a pediatric population. A single-center, retrospective review of patients < 18 years of age who underwent clinical investigation with ZIO from October 2014 to February 2016 was performed. An age-matched cohort was utilized to compare ZIO to Holter monitor results. Demographic and diagnostic data, time to first arrhythmia, and arrhythmia burden were analyzed. A total of 406 ZIO were prescribed; median age 12.7 years and 50% male subjects. Median duration of ZIO monitoring significantly increased with age (p < 0.001). 499 Holter monitors were prescribed on a statistically different age group. Arrhythmia detection rates were similar between groups, 10% (n = 42) by ZIO and 9% (n = 45) by Holter (p = NS). The majority of arrhythmias (57%) detected by ZIO were after 24 h (p < 0.0001). All arrhythmias detected by Holter monitor occurred within 24 h (p < 0.0001), mean duration of wear was 24.1 h, range 0.5-48 h. The ZIO® XT Patch may be considered as an ambulatory ECG monitor to diagnose arrhythmia in pediatric patients of all ages. Increasing patient age resulted in increasing duration of ZIO monitoring. Majority of arrhythmias detected with ZIO were identified after 24 h, which would have been missed by other short-term monitors.

Cost-effectiveness of treating infantile haemangioma with propranolol in an outpatient setting.

BACKGROUND: Infantile haemangioma is one of the most commonly known benign vascular tumours of infancy and childhood, having an incidence of 3-10%. Most lesions regress spontaneously; however, some may require treatment owing to their clinical and cosmetic effects. Propranolol has become the treatment of choice for infantile haemangioma, but treatment protocols are largely institutional based without any specific consensus guidelines. Our aim was to evaluate the cost-effectiveness of propranolol use as inpatient versus outpatient therapy. METHODS: A decision tree model was created depicting alternate strategies for initiating propranolol treatment on an inpatient versus outpatient basis combined with the option of a pretreatment echocardiogram applied to both strategies. Cost analysis was assumed to be based on treatment of haemangioma in patients who were born at term, had no chronic illnesses, a non-life-threatening location of the haemangioma, and those who were not taking any other medications that could potentiate the side effects of propranolol. A sensitivity analysis was performed to evaluate the probability of side effects. RESULTS: The average cost incurred for inpatient treatment of infantile haemangioma was approximately $2603 for a single hospital day and increased to $2843 with the addition of an echocardiogram. The expected cost of treatment in the outpatient setting was $138, which increased to $828 after the addition of an echocardiogram. CONCLUSION: Treating infantile haemangioma with propranolol is more cost-effective when initiated on an outpatient basis.

Identifying arrhythmias in adults with congenital heart disease by 24-h ambulatory electrocardiography.

Adults with congenital heart disease (CHD) are at risk for the development of arrhythmias. This study aimed to assess the incidence of unsuspected arrhythmias among adults with CHD identified on electrocardiograms (ECGs) and 24-h ambulatory electrocardiographic monitoring (Holter monitoring). A review of the cardiology database at the authors' institution from July 2004 through December 2007 identified all clinic patients 18 years old or older who had a recent ECG and Holter monitoring. Data collection included diagnosis, ECG and Holter monitoring results, arrhythmias, and the presence or absence of symptoms. The review identified 140 patients. Analysis of the ECGs showed that 15% of the patients had an arrhythmia. These arrhythmias consisted of ectopy (6%), supraventricular tachycardia (SVT) (3%), pacemaker issues (2%), and previously unrecognized atrioventricular block (AVB) (1%). The majority of the patients with arrhythmias were asymptomatic (76%). Analysis of the Holter monitoring results showed that 31% of the patients had arrhythmias consisting of ectopy (17%), SVT (12%), ventricular tachycardia (7%), high-grade AVB (5%), and pacemaker issues (3%). Of the patients with arrhythmias, 80% were asymptomatic. Among the patients without arrhythmias on ECG, 26% had arrhythmias noted on Holter monitoring. Of the patients with multiple Holter monitorings performed, 34% had a new arrhythmia noted on repeat monitoring. In conclusion, arrhythmias were present in a significant number of adults with CHD, but the majority were asymptomatic. Among adults with CHD, even those with normal ECGs, arrhythmias were frequently detected on Holter monitoring. In addition, repeat Holter monitoring may identify significant arrhythmias over time.

Improving Compliance with Dyslipidemia Screening Guidelines in a Single-center U.S. Outpatient Pediatric Cardiology Clinic.

The development of atherosclerotic cardiovascular disease begins in childhood. The American Academy of Pediatrics (AAP) endorsed guidelines recommending universal hyperlipidemia screening of children ages 9-11 and again at 17-21 years. An AAP Periodic Survey of Fellows demonstrated less than half of pediatricians report adherence to these guidelines. This quality improvement initiative's objective was to improve compliance with AAP hyperlipidemia guidelines in an outpatient pediatric cardiology clinic at a single academic center to 80% over a 2-month time frame. METHODS: We report the results of an IRB-approved chart review at a single-center outpatient pediatric cardiology practice. We defined pediatric cardiologists' compliance as documented prior lipid screening, ordering a lipid panel, or documented recommendation for follow-up screening. Two plan-do-study-act (PDSA) cycles were undertaken. The first intervention included an informational session to provide pediatric cardiologists with AAP recommendations. The second intervention involved weekly email reminders and a statement for physicians in the electronic medical record. RESULTS: We collected data from 600 individual charts of patients seen over 35 clinic days. We received charts before the first PDSA intervention. Baseline compliance with outpatient hyperlipidemia screening was 0%. After the first PDSA cycle, the average screening rate improved to 49%. After the second PDSA cycle, the average screening rate improved to 89%, and there was a centerline shift in the data, indicating improvement. CONCLUSION: We improved the pediatric cardiologists' compliance with the AAP-recommended hyperlipidemia screening guidelines from 0% to 89% through 2 intervention cycles. Further efforts may be required to sustain this change.

Sudden Death in the Young: Information for the Primary Care Provider.

There are multiple conditions that can make children prone to having a sudden cardiac arrest (SCA) or sudden cardiac death (SCD). Efforts have been made by multiple organizations to screen children for cardiac conditions, but the emphasis has been on screening before athletic competition. This article is an update of the previous American Academy of Pediatrics policy statement of 2012 that addresses prevention of SCA and SCD. This update includes a comprehensive review of conditions that should prompt more attention and cardiology evaluation. The role of the primary care provider is of paramount importance in the evaluation of children, particularly as they enter middle school or junior high. There is discussion about whether screening should find any cardiac condition or just those that are associated with SCA and SCD. This update reviews the 4 main screening questions that are recommended, not just for athletes, but for all children. There is also discussion about how to handle post-SCA and SCD situations as well as discussion about genetic testing. It is the goal of this policy statement update to provide the primary care provider more assistance in how to screen for life-threatening conditions, regardless of athletic status.

Intracardiac radiofrequency ablation in living swine guided by polarization-sensitive optical coherence tomography.

SIGNIFICANCE: Pulmonary vein isolation with catheter-based radiofrequency ablation (RFA) is carried out frequently to treat atrial fibrillation. However, RFA lesion creation is only guided by indirect information (e.g., temperature, impedance, and contact force), which may result in poor lesion quality (e.g., nontransmural) and can lead to reoccurrence or complications. AIM: The feasibility of guiding intracardiac RFA with an integrated polarization-sensitive optical coherence tomography (PSOCT)-RFA catheter in the right atria (RA) of living swine is demonstrated. APPROACH: In total, 12 sparse lesions were created in the RA of three living swine using an integrated PSOCT-RFA catheter with standard ablation protocol. PSOCT images were displayed in real time to guide catheter-tissue apposition. After experiments, post-processed PSOCT images were analyzed to assess lesion quality and were compared with triphenyltetrazolium chloride (TTC) lesion quality analysis. RESULTS: Five successful lesions identified with PSOCT images were all confirmed by TTC analysis. In two ablations, PSOCT imaging detected gas bubble formation, indicating overtreatment. Unsuccessful lesions observed with PSOCT imaging were confirmed by TTC analysis. CONCLUSIONS: The results demonstrate that the PSOCT-RFA catheter provides real-time feedback to guide catheter-tissue apposition, monitor lesion quality, and possibly help avoid complications due to overtreatment, which may enable more effective and safer RFA treatment.

Imaging of Atrioventricular Nodal Conduction Tissue in Porcine Hearts Using Optical Coherence Tomography.

Optical coherence tomography (OCT) employs near-infrared light to image the microstructure of different tissues. Clinically, it has been used to image the walls of coronary arteries. In research settings, one of the applications for OCT is visualizing endocardial and subendocardial structures. The present experiment sought to determine whether OCT can identify native conduction tissues in adult porcine hearts. During the study, the right atrial endocardial surfaces of excised adult porcine hearts were exposed. The triangle of Koch was imaged with the OCT system and the conduction tissue was identified. The area was then prepared for histologic examination with Masson's trichrome stain. The results of histologic preparations and OCT images were then compared. Ultimately, nine porcine hearts were examined using this methodology. OCT imaging successfully identified subendocardial structures presumed to be the compact atrioventricular node. Histologic images of the preparations delineated the different tissue types and conduction tissue was easily identified. The location of distinctive hyporeflective areas in the OCT images correlated with the location of conduction tissue in the histology images. In light of the findings of this study, it is suggested that atrioventricular nodal tissue can be identified by OCT in freshly dissected unfixed porcine hearts. OCT images distinguished the differentiated conduction tissue in close proximity with the endocardium, myofibers, and fibrous tissue, and the success of this was verified with histology. This technology may be useful for the direct visualization of the native conduction system during procedures in the operating room and electrophysiology laboratory. Further studies with perfused tissue samples and live animal experiments are needed to better assess the efficacy of this novel application.

Confirm RX™ Cardiac Monitor Placement in a Pediatric Patient.

We present the first known report of a pediatric implantation of the Bluetooth™-enabled Confirm RX™ insertable cardiac monitor (Abbott Laboratories, Chicago, IL, USA) in a 17-year-old patient with unexplained syncopal episodes. This case illustrates the ability to obtain immediate rhythm information from a patient using a Bluetooth™-enabled device following a minimally invasive procedure.

Tilt table testing to diagnose pseudosyncope in the pediatric population.

OBJECTIVE: Pseudosyncope can be difficult to distinguish from true syncope. Often, pediatric patients with pseudosyncope undergo multiple tests and referrals before the appropriate diagnosis is reached. The purpose is to describe the utility of the head-up tilt table test to elicit the diagnosis of pseudosyncope in the pediatric population. DESIGN: Retrospective chart review from November 2012 to December 2015 of patients age ≤23 years referred for 30-minute, 80-degree tilt table test. Pretest probability for pseudosyncope was high if there was no response to traditional management, atypical episodes, occurrence during undesirable exercise, or prolonged episode duration. Inductive techniques were utilized to persuade patients of the likelihood of experiencing an episode during the procedure. Pseudosyncope was confirmed when a patient had normal vital signs during their event and had reflex responses to disruptive maneuvers. RESULTS: Tilt table testing was performed on 89 patients [median age 16 years (5-23); 26% male] with the majority (60%) being negative for pseudosyncope, including 51 true negatives and 2 false-negatives. Of the 36 patients with syncope during tilt table testing, 28 were diagnosed with vasovagal syncope and 8 with pseudosyncope [median age 16 years (15-21); 38% male]. Pseudosyncope episodes were observed immediately in 2 patients. All patients with late-onset pseudosyncope required inductive techniques prior to the recorded episode. CONCLUSIONS: Pseudosyncope can be identified during tilt table testing if inductive techniques are utilized in patients with a high index of suspicion. Disruptive maneuvers are excellent adjunctive methods to confirm the diagnosis. Tilt table testing is an effective means to identify pseudosyncope and allow appropriate diagnosis and treatment.

Isolated Left Subclavian Artery, Complete Atrioventricular Block, and Tricuspid Atresia in a Neonate.

Isolated left subclavian artery is one of the rarer aortic arch anomalies. It has been associated with other congenital heart diseases, typically tetralogy of Fallot, double-outlet right ventricle, and atrial and ventricular septal defects. Its significant clinical implications include a left-to-right shunt from the vertebrobasilar system, which causes pulmonary overcirculation and subclavian steal. We present an unusual case of a premature infant who was diagnosed prenatally with congenital complete atrioventricular block and tricuspid atresia and was found to have an isolated left subclavian artery postnatally. The patient underwent implantation of a permanent single-chamber epicardial pacing system. To our knowledge, this combination of lesions has not been reported-and in our case, it influenced our surgical planning.

Flecainide and sotalol: a new combination therapy for refractory supraventricular tachycardia in children <1 year of age.

OBJECTIVES: The goal of this study was to assess the efficacy and safety of the combination therapy of flecainide and sotalol for the treatment of refractory supraventricular tachycardia (SVT) in children <1 year of age. BACKGROUND: Supraventricular tachycardia in infants can be refractory to single-drug as well as standard combination medical therapy. Radiofrequency ablation (RFA) is the definitive treatment of refractory SVT; however, interventional therapy poses a high risk of morbidity and mortality in this age group. METHODS: A retrospective review was performed identifying infants who required flecainide and sotalol to control refractory SVT. Patient age, previous drug therapy, duration of treatment, flecainide levels and corrected QT intervals were recorded; 24 h Holter monitoring was utilized to gauge efficacy of treatment. Efficacy was defined as suppression of SVT to no more than rare nonsustained episodes or slowing of SVT to a clinically tolerable rate. RESULTS: Ten patients (median age: 29 days, range: 1 to 241 days) failed at least two antiarrhythmic agents including either flecainide or sotalol as single agents before initiating combination therapy. Efficacy was achieved in all patients. The failure rate for therapy was reduced from 100% to 0% (95% confidence interval: 0% to 26%). The median doses used were: flecainide 100 mg/m(2)/day (range: 40 to 150 mg/m(2)/day) and sotalol 175 mg/m(2)/day (range: 100 to 250 mg/m(2)/day). Median duration of therapy was 16 months (range: 5 to 35 months). No proarrhythmia occurred. CONCLUSIONS: The combination of flecainide and sotalol can safely and effectively control refractory SVT and may obviate the need for RFA in children <1 year.

T-wave reversion in pediatric patients during exercise stress testing.

OBJECTIVE: T-wave inversion in lateral electrocardiogram (ECG) leads (II, III, aVF, V4 -V6 ) is suspicious of cardiac pathology in pediatric patients, though many are found to have structurally normal hearts. The purpose of this study is to evaluate T-wave response during exercise stress testing (EST) in pediatric patients with structurally normal hearts and lateral-lead T-wave inversion on resting ECG. DESIGN: An IRB-approved, retrospective review of EST databases at two centers identified patients with lateral-lead T-wave inversion on resting ECG. Inclusion criteria were normal exam and echocardiogram, absence of anginal chest pain, and age <18 years. All patients underwent treadmill or cycle ergometer EST. Data recorded included demographics, echocardiogram results, baseline ECG, EST method, peak heart rate and metabolic equivalents (METs), and heart rate and METs at T-wave reversion. T-wave reversion was considered complete if T-waves reverted in all leads, partial if reversion occurred in only some leads, and none if no reversion occurred. RESULTS: The search identified 14 patients: nine females and five males (10 Caucasians and four African Americans) and an average age of 16 (range 12-18) years. Complete T-wave reversion occurred in 11 (79%) patients, partial in two (14%), and none in one (7%). Reversion occurred in both genders, ethnicities, and EST methods. No complications occurred during EST; no adverse outcomes occurred during 2-year follow-up. CONCLUSIONS: EST in pediatric patients with lateral-lead T-wave inversion on resting ECG and structurally and functionally normal hearts resulted in either complete or partial T-wave reversion in the vast majority of patients.

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.

Intraoperative radiofrequency ablation of the atrium: effectiveness for treatment of supraventricular tachycardia in congenital heart surgery.

BACKGROUND: Supraventricular tachycardia (SVT) is common in surgical patients with congenital heart disease. Ablation and maze operations have been shown to be effective in treating SVT, but these procedures can be complex and time-consuming because of variable anatomy and a thickened right atrium. To simplify and shorten these procedures, we used a long, flexible radiofrequency probe capable of producing long ablation lines quickly and effectively. We report the initial results with this procedure. METHODS: Six patients aged 6 weeks to 40 years with refractory SVT were referred for reoperation for repair of complex congenital heart disease (transposition of the great vessels, Ebstein's anomaly, single ventricle, tetralogy of fallot). Intraoperative radiofrequency ablation was performed in the right atrium for refractory SVT as an adjunct to surgical reconstruction (redo Fontan, right atrial reduction plasty, right ventricular outflow tract reconstruction, tricuspid repair). Lesions were made with a radiofrequency probe using temperatures of 70 degrees C for 60 seconds. Lesions were placed between the coronary sinus and the tricuspid valve, between the tricuspid valve and the inferior vena cava, between the atrial septal defect and the superior and inferior vena cava in patients with intraatrial reentry tachycardia/atrial flutter, and at the location of the accessory pathway in a patient with Wolff-Parkinson-White syndrome. The long, flexible probe has multiple independently controlled segments allowing ablation lesions that conform to the atrial morphology. RESULTS: An average of five intraoperative radiofrequency ablation lesions per patient were made. Average time for ablation was 14 minutes. With up to 25 months' follow-up, 5 patients are in sinus rhythm, and 1 is in a paced atrial rhythm. The patient with Wolff-Parkinson-White syndrome showed no preexcitation after operation. No complications resulting from intraoperative radiofrequency ablation were encountered. CONCLUSIONS: Intraoperative radiofrequency ablation in the atrium is a safe, effective, and expeditious procedure for control of SVT in patients undergoing reoperation for congenital heart disease with refractory SVT.