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.

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.

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.

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 Rx^TM (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 Rx^TM 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 SharpSense^TM 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). SharpSense^TM 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 Rx^TM 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 Rx^TM ICM missed.

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.

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.

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.

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.

Cor Triatriatum: A Tale of Two Membranes

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Cor triatriatum is a rare congenital abnormality with two forms, sinister and dexter.

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Five cases in which both types are present in the same patient have been published.

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A neonate with bilateral cor triatriatum and hypoxemia presented a diagnostic dilemma.

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.

Bilateral Ductus Arteriosus and Discontinuity of the Pulmonary Branches and Pulmonary Atresia: An Unusual Anatomy Diagnosed by Echocardiography

• Echocardiography can delineate complex congenital anatomy without additional imaging. • A wide range of branch pulmonary artery anatomy is seen in pulmonary atresia. • Bilateral patent ductus arteriosus is an uncommon finding in pediatric cardiology.

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.

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.

Atrial fibrillation induction by transesophageal electrophysiology studies in patients with asymptomatic ventricular preexcitation

OBJECTIVE

Ventricular preexcitation is a conduction abnormality caused by an accessory pathway bridging the atria and ventricles. If the accessory pathway conducts rapidly during atrial fibrillation (AFib), sudden death may result. The purpose of this study was to determine the ability of transesophageal electrophysiology studies (TEEPS) to induce AFib in pediatric patients with asymptomatic ventricular preexcitation (aVPE).

DESIGN

A retrospective review of patients with aVPE who had a TEEPS was conducted. Inclusion criteria were evidence of ventricular preexcitation on electrocardiogram; age <18 years; and no history of tachycardia, palpitations, or syncope. Data gathered included age, weight, height, form of sedation, and TEEPS results. If AFib was induced, patients were classified as at risk of sudden death if the shortest preexcited RR interval during AFib was <250 ms or no risk if ≥ 250 ms.

RESULTS

A total of 26 patients met the inclusion criteria, with average age of 11.9 years, weight of 48.9 kg, and height of 149.2 cm. During the procedure, nine patients underwent conscious sedation (34.6%), and 17 underwent general anesthesia (65.4%). AFib was induced in 23 patients (88.5%), of whom 17 (73.9%) had no risk and six (26.1%) had risk. No statistical differences were noted in age, weight, height, or form of sedation when comparisons were made between AFib induction and no AFib induction.

CONCLUSIONS

TEEPS induced AFib in 88.5% of patients. Age, weight, height, and form of sedation had no effect upon AFib inducibility. TEEPS is an effective modality to induce AFib in pediatric patients with aVPE.

Induction of atrial fibrillation with adenosine during a transesophageal electrophysiology study to risk stratify a patient with asymptomatic ventricular preexcitation

An asymptomatic adolescent male athlete was incidentally found to have ventricular preexcitation on electrocardiogram during a sports preparticipation physical. A transesophageal electrophysiology study (TEEPS) was performed after an exercise stress test failed to delineate the patient's risk of sudden cardiac death. The TEEPS was favored in this case over a transvenous electrophysiology study due to reduced invasiveness. The goal of the TEEPS was to place the patient into atrial fibrillation (AFib) and evaluate the shortest preexcited RR interval during AFib, thereby assessing the risk of his accessory pathway. Conventional pacing modalities were unable to induce AFib. During atrial burst pacing, adenosine was then administered, which successfully induced AFib. This case highlights adenosine's potential to induce atrial fibrillation during transesophageal electrophysiology studies when atrial pacing alone was unable to do so.

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.

Intermittent cyanosis years after a Mustard repair for dextro-transposition of the great arteries

A 28-year-old woman, who as an infant had undergone the Mustard atrial switch procedure for dextro-transposition of the great arteries, presented with a baffle leak and consequent intermittent cyanosis. In addition, an occlusive thrombus had formed in the systemic venous baffle after a failed attempt to remove infected pacemaker leads. Corrective surgery was successful. In addition to the case of our patient, we discuss long-term sequelae of the atrial switch procedure that present challenges in patient care.

Management of atrial tachycardia in the newborn with enterovirus myocarditis

Neonatal enterovirus myocarditis is a rare but serious infection that is often an underrecognized cause of cardiovascular collapse. Enterovirus myocarditis in patients with such collapse should be suspected when signs of congestive heart failure and tachyarrhythmia are present. The majority of reported electrical disturbances associated with enterovirus myocarditis are ventricular in origin, but the infection can present as atrial tachyarrhythmia. Atrial tachyarrhythmias associated with enterovirus myocarditis are difficult to manage because of their resistance to conventional antiarrhythmic therapy. We present 2 cases of neonates with atrial tachycardia associated with enterovirus myocarditis who responded to a combination of amiodarone and flecainide.

Atrial ectopic tachycardia in a patient with marfan syndrome

The fibrillin defect central to Marfan syndrome is believed to affect myocardial conduction and predispose affected patients to various arrhythmias, including ventricular tachycardia, atrial fibrillation, and atrioventricular nodal reentry tachycardia. Here we describe an adult Marfan patient with atrial ectopic tachycardia. To our knowledge, this is the first reported case of atrial ectopic tachycardia in the setting of Marfan syndrome.

A newborn with congenital complete atrioventricular block, lissencephaly, and skeletal abnormalities: a case of suspected cytomegalovirus infection

We present a case of congenital complete atrioventricular block in a preterm microcephalic male with multiple additional congenital anomalies, including spinal and rib abnormalities. The heart was structurally normal, and maternal tests for autoimmune disorders were negative. The brain had an immature lissencephalic appearance, suggestive of an insult early in gestation. Genetic testing was normal, virtually excluding chromosomal disorders that are known to cause lissencephaly. Viral studies were suggestive of cytomegalovirus infection during early gestation, and we believe that the patient's clinical presentation was most likely the result of an early cytomegalovirus infection. The finding of complete atrioventricular block in a patient with presumed cytomegalovirus infection would represent a very rare complication. "Isolated" complete atrioventricular block in a fetus should be considered an incentive for an extensive work-up in search for a possible etiology, rather than accepted as a final diagnosis.

Induction of left ventricular fascicular tachycardia with transesophageal pacing in a toddler

J.V. is a 3(1/2)-year-old patient with left ventricular fascicular ventricular tachycardia that had been well controlled on verapamil for 3 years. He was taken for a transesophageal electrophysiology study prior to discontinuing medication in an attempt to induce his tachycardia. We report the use of transesophageal electrophysiology study as a noninvasive method to induce left ventricular fascicular ventricular tachycardia in a toddler.

Rate-dependent left bundle-branch block in a child with propionic aciduria

In most cases, a left bundle-branch block pattern on an electrocardiogram is a postoperative phenomenon. Under rare circumstances, it can be found in patients after myocardial infarction or in patients with hypertrophic cardiomyopathy, or it can be exercised induced. We describe a pediatric patient with propionic aciduria, dilated cardiomyopathy, and rate-dependent left bundle-branch block on her electrocardiogram.

Postoperative ventricular tachycardia in patients with congenital heart disease: diagnosis and management

Ventricular tachycardia (VT) after palliative repair of congenital heart disease is relatively rare. Despite this rarity, VT is a known cause of early, intermediate and late morbidity and mortality in these patients. A number of factors have been linked to the development of VT in this unique patient population. The purpose of this article is to provide a concise overview regarding the etiology, diagnosis and treatment of VT in patients with congenital heart disease. In-depth information will be provided to aid diagnosis and the treatment of early postoperative VT. The use of additional diagnostic methods such as echocardiography, cardiac catheterization and electrophysiology studies to risk assess patients with postoperative VT will also be discussed. In addition, I examine the long-term management strategies for VT in these patients, from medical management and cardiovascular surgery to implantation of cardioverter-defibrillators.

Survival of a Newborn with 2:1 Atrioventricular Block, Long QT Syndrome, and Torsades de Pointes

Long QT syndrome is a rare disorder that can manifest as syncope, Torsades de Pointes, or sudden cardiac death. We report a newborn with asymptomatic bradycardia, 2:1 atrioventricular block, long QT syndrome, and episodes of Torsades de Pointes. The patient was managed with mexiletine and propranolol and continued to have episodes of Torsades de Pointes, so she underwent epicardial pacemaker implantation. No further episodes of Torsades de Pointes were noted prior to discharge.

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%.

Early postoperative arrhythmias after pediatric cardiac surgery

OBJECTIVE

Early postoperative arrhythmias are a known complication of cardiac surgery; however, little data exists specific to pediatrics. The purpose of this study was to determine the incidence and risk factors associated with the development of arrhythmias immediately after surgery in a pediatric population.

METHODS

Data were collected in a prospective observational format from pediatric patients undergoing cardiac surgery between September 2000 and May 2003. This format included age, anatomy, surgical repair, and serum magnesium and calcium levels, as well as cardiopulmonary bypass and aortic crossclamp times. Patients were continuously monitored, and hemodynamically significant arrhythmias were recorded.

RESULTS

Arrhythmias occurred in 28 of the 189 patients enrolled (15%) including 16 with junctional ectopic tachycardia, 7 with complete atrioventricular block, 4 with ventricular tachycardia, and 1 with re-entrant supraventricular tachycardia. Significant differences were found between the arrhythmia and nonarrhythmia groups with regard to age (22 vs 45 months), cardiopulmonary bypass time (189 vs 109 minutes), and aortic crossclamp time (105 vs 44 minutes); P < .05. Magnesium and calcium levels were not significantly different between the groups. Two repairs carried an increased risk: complete atrioventricular septal defect repair, 8 of 11 patients (72%), and the arterial switch 5 of 8 patients (62.5%); P < .05. Atrioventricular septal defects had an even higher incidence when controlled for age, bypass time, and crossclamp time (odds ratio = 7.65).

CONCLUSIONS

Hemodynamically significant postoperative arrhythmias are a frequent complication of pediatric cardiac surgery. Younger age and longer bypass and crossclamp times are risk factors for arrhythmia. In addition, the repair of atrioventricular septal defects carries an independent risk of arrhythmias.

Is exercise stress testing a cost-saving strategy for risk assessment of pediatric wolff-Parkinson-white syndrome patients?

BACKGROUND

In Wolff-Parkinson-White syndrome (WPW) patients the loss of pre-excitation in a single heartbeat during exercise stress testing (EST) is a predictor of low risk of sudden death. The purpose of this study was to: 1) assess the frequency of loss of pre-excitation in a single heartbeat during exercise testing, and 2) compare the cost of EST versus trans-catheter electrophysiology study (EPS) in the risk assessment of WPW patients.

METHODS

A retrospective review of 50 cases of patients with WPW who underwent EST was conducted including demographics, history of supraventricular tachycardia, associated congenital heart disease, maximum heart rate achieved, and loss of pre-excitation in a single heartbeat. Hospital costs of EST and EPS were compared.

RESULTS

Of the 50 patients who underwent EST, 4 (8%), lost pre-excitation in a single heartbeat during EST. No differences were found regarding gender, age at diagnosis or EST, history of supraventricular tachycardia, presence of congenital heart disease or maximal heart rate. A cost comparison, utilizing the cost data: EST ($62.75) and EPS ($5,597) found EST to be a cost-saving approach in WPW patients. With 4 patients losing pre-excitation during EST, the cost saving of EST was $22,388 for this population of WPW patients.

CONCLUSIONS

A frequency of 8% loss of pre-excitation was found in a pediatric sample that underwent EST. Additionally, EST was shown to be a cost-saving strategy in risk assessment of pediatric WPW patients.

Stent implantation as a stabilization technique in supracardiac total anomalous pulmonary venous connection

A 6-week-old male presented in-extremis with obstructed supra-cardiac total anomalous pulmonary venous connection. Balloon dilation and stent implantation in the stenotic segment of the vertical vein relieved the obstruction until the patient was stable enough to undergo surgical repair. An unusual form of extrinsic vertical vein compression was found at surgery.

Can pediatric residents interpret electrocardiograms?

The purpose of this study was to assess the electrocardiogram (ECG) interpretation skills of pediatric residents in a controlled environment and determine if the level of residency training (intern vs senior) improves accuracy. A list of ECG diagnoses was provided to four pediatric residency educators with instructions to categorize each diagnosis as follows: I, all residents; II, the majority of residents, including all senior residents; III, less than the majority of residents; and IV, few residents should be able to interpret correctly. Only those categories that the entire panel believed all residents (category I) or all senior residents (category II) should be able to interpret correctly were included. The test included 17 ECGs: 14 category I and 3 category II. A total of 132 residents participated: 78 interns and 54 seniors. Both groups scored below expected levels. Mean correct score among seniors was 10.9 out of the expected 17 (p < 0.001). Mean correct score for interns was 7.7 out of the expected 14 (p < 0.00l). No difference in ECG interpretation accuracy was found between residency programs. In general, pediatric residents' ECG interpretation skills are less accurate than expected. Although there is a trend toward improvement during training, senior residents fell short of the expectations of the panel. We speculate that focused education in this area will improve resident ECG interpretation and benefit patient care by (1) facilitating referral and treatment of patients with cardiovascular disease and (2) decreasing referrals for erroneous interpretations.

Graded blood pressure reduction in hypertensive outpatients associated with use of a device to assist with slow breathing

To study the effects of device-guided breathing on office systolic blood pressure (SBP), five centers randomized 149 untrained hypertensives (50% male, age 59+/-10 years, baseline blood pressure 150+/-9/86+/-9 mm Hg, 77% taking drug therapy). One half received a device to guide slow breathing; all received a home blood pressure monitor and only simple, written instructions. The changes in office SBP (adjusted for office-to-home difference in baseline SBP and accumulated time spent in slow breathing, guided and measured by the device) were significantly (p<0.001 for trend) correlated with accumulated time spent in slow breathing. Greater decreases in SBP (-15.0+/-1.8 vs. -7.3+/-1.9 mm Hg) were observed for those who spent more (vs. less) than 180 minutes over 8 weeks in slow breathing, as well as those who just monitored their blood pressure at home (-9.2+/-1.6 mm Hg). Thus, even without training, hypertensive patients who receive a device to guide slow breathing significantly lowered their office SBP if the total time spent in slow breathing over 8 weeks exceeded a "threshold" value of 180 minutes.

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.