Cardioneuroablation for pediatric patients with functional sinus node dysfunction and paroxysmal atrioventricular block.

INTRODUCTION: Severe transitory episodes of bradycardia with subsequent syncope in children are common, and generally portend a benign prognosis. Rarely, patients may experience prolonged asystolic episodes secondary to significant sinus pauses (SP) or paroxysmal atrioventricular block (AVB). Cardioneuroablation (CNA) is a catheter-based intervention, used to identify and ablate the epicardial ganglionated plexi (GP), which results in disruption of the vagal-mediated parasympathetic input to the sinus and atrioventricular node. OBJECTIVE: Describe the methodology and role of CNA for treatment of pediatric patients with functional AVB or SP. METHODS: This is a single-center, case series study. Patients with SP or AVB, 21 years of age or younger, who underwent CNA between 2015 and 2021 were included. CNA was performed via anatomically guided and high-frequency stimulation methods. RESULTS: Six patients were included. The median age was 18.9 years (range 12.3-20.9 years), 33% female. Two patients had prolonged SP, two had paroxysmal AVB, and two had both SP and AVB. Four patients had prior syncope. The median longest pause was 8.9 s (range 3.9-16.8) with 11 total documented pauses (range 2-231) during the 6 months pre-CNA. Post-CNA, the median longest pause was 1.3 s (range 0.8-2.2) with one documented SP after termination of atrial tachycardia at the 3-month follow-up. At 6 months, the median longest pause was 1.1 s (0.8-1.3) with 0 documented pauses. No patients had syncope post-CNA. CONCLUSION: CNA may be an effective alternative to pacemaker implantation in pediatric patients with syncope or significant symptoms secondary to functional SP or AVB.

Predictors of Atrial Arrhythmia in Adults with Repaired Tetralogy of Fallot.

Tetralogy of Fallot (TOF), the most common cyanotic congenital heart disease in adults, has excellent long-term survival. However, many patients (30-45%) develop late arrhythmias. Previous studies have identified predictors of arrhythmia (atrial or ventricular) using clinical markers that predate arrhythmia onset by many years. Our objective was to develop a predictive model for incident atrial arrhythmias within two years of clinical evaluation and diagnostic testing. A single-center nested unmatched case-control study of 174 adults with repaired TOF. We included only patients with results from ECG and echocardiogram data in the required time interval (3-24 months before first arrhythmia for cases; 24 months of follow-up for controls). A predictive multivariable model for risk of incident atrial arrhythmia was developed using logistic regression with a least absolute shrinkage and selection operator (LASSO). Of 41 demographic, surgical, and diagnostic variables, six were selected as having predictive value for atrial arrhythmia based on cross validation. The factors with the greatest predictive value in decreasing order were moderate / severe tricuspid regurgitation (adjusted odds ratio (OR) 149.42), QRS fragmentation (OR 28.08), severe pulmonary regurgitation (OR 8.22), RV systolic dysfunction (OR 2.95), 1st degree AV block (OR 2.59), and age at time of surgical repair (OR 1.02). Predictors for atrial arrhythmia in our study suggested abnormal right ventricle anatomical function and electrophysiologic properties (conduction and repolarization) as the primary underlying substrate.

Cardiac arrhythmias in postural tachycardia syndrome and orthostatic intolerance.

BACKGROUND AND OBJECTIVES: There is sparse literature on cardiac arrhythmias and the utility of ambulatory rhythm monitoring in patients with postural tachycardia syndrome and orthostatic intolerance. This study's primary aim was to investigate the prevalence of arrhythmias in this population. Knowing the prevalence and types of arrhythmias in dysautonomia patients could influence the decision to pursue ambulatory rhythm monitoring and ultimately guide therapy. METHODS: This retrospective descriptive study examined the frequency of cardiac arrhythmias, as detected by ambulatory rhythm monitoring, in children with postural tachycardia syndrome/orthostatic intolerance or syncope who were seen at the Children's National Hospital Electrophysiology Clinic between January 2001 and December 2020. RESULTS: In postural tachycardia syndrome/orthostatic intolerance patients, arrhythmia was detected on 15% of 332 ambulatory rhythm monitors. In syncope patients, arrhythmia was detected on 16% of 157 ambulatory rhythm monitors, not significantly different from the postural tachycardia syndrome/orthostatic intolerance group. The difference in rate of arrhythmia detection between 24-hour Holter and 2-week Zio® monitoring was not statistically significant. CONCLUSION: This study suggests that a substantial proportion of postural tachycardia syndrome/orthostatic intolerance patients may have concomitant underlying cardiac arrhythmias, at a frequency similar to what is seen in patients undergoing primary evaluation for cardiac symptoms such as chest pain, palpitations, and syncope. In the appropriate clinical context, physicians caring for postural tachycardia syndrome/orthostatic intolerance patients should consider additional evaluation for arrhythmias beyond sinus tachycardia.

Median Arcuate Ligament Syndrome with Orthostatic Intolerance: Intermediate-Term Outcomes following Surgical Intervention.

OBJECTIVES: To report the intermediate-term outcome following surgical intervention for median arcuate ligament syndrome (MALS) in adolescents and young adults with orthostatic intolerance (OI) to assess clinical improvement in the gastrointestinal and 5 other functional domains and if relief of arterial obstruction is associated with resolution of clinical symptoms. STUDY DESIGN: Thirty-one patients were given 2 dysautonomia-designed questionnaires to assess changes in symptoms following operative intervention in 6 functional domains and underwent postoperative repeat abdominal ultrasound examinations. RESULTS: Average follow-up after surgery was 22.4 ± 14.8 months. Self-assessed quality of health on a Likert scale (1-10 with 10 being normal) improved from 4.5 ± 2.1 preoperatively to 5.3 ± 2.4 postoperatively (P = not significant). Gastrointestinal symptoms of abdominal pain, nausea, and vomiting improved in 63% (P = .007), 53% (P = .040), and 62% (P = .014) of patients, respectively. Cardiovascular symptoms of dizziness, syncope, chest pain, and palpitations improved in 45% (P = not significant), 50% (P = not significant), 54% (P = .043), and 54% (P = .037) of patients, respectively. Transabdominal ultrasound peak supine expiratory velocity decreased from 348 ± 105 cm/s preoperatively to 251 ± 109 cm/s at 6 months or more after a ligament release procedure. Decrease of the postoperative celiac artery Doppler velocity was not associated with an improvement in gastrointestinal symptoms (P = .075). CONCLUSIONS: Adolescent and young adult patients with median arcuate ligament syndrome and OI have a good response to surgical intervention. About two-thirds of patients report significant improvement in symptoms of abdominal pain, nausea, and vomiting. Despite these encouraging data, many patients with MALS and OI continue to have an impaired quality of health.

Can the 12-lead ECG distinguish RVOT from aortic cusp PVCs in pediatric patients?

BACKGROUND: The ability to differentiate right ventricular outflow tract (RVOT) from coronary cusp (CC) site of origin (SOO) by 12-lead ECG in pediatric patients may impact efficacy and procedural time. The objective of this study was to predict RVOT versus CC SOO by ECG in pediatric patients. METHODS: Pediatric patients (<21 years) without structural heart disease with RVOT or CC premature ventricular contraction (PVC) ablations performed (2014-2018) were evaluated through multi-institution retrospective review. Demographics, ECG PVC parameters, ablation site, recurrence, and repeat procedures were collected. RESULTS: Thirty-seven patients were evaluated (mean age 14.6 years, weight 60.6 kg): 11 CC and 26 RVOT PVC SOO. CC PVCs were less likely to exhibit left bundle branch block (64% vs 100%, P = .005), had larger R-wave amplitude in V1 (0.27 vs 0.11 mV, P = .03), larger R/S ratio in V1 (0.37 vs 0.09, P = .003), and had precordial transition in V3 or earlier (73% vs 15%, P = .002). A composite score was created with the following variables: isodiphasic or positive QRS in V1, R/S ratio in V1 > 0.05, S wave in V1 < 0.9 mV, and precordial transition at or before V3. Composite score ≥ 2 was associated with a CC SOO (OR 42.0, P = .001, and AUC 0.86). CONCLUSIONS: 12-lead ECG of PVCs from the CC was associated with larger V1 R-wave amplitude, larger R/S ratio in V1, and precordial transition at or before V3. A composite score may help predict PVC/VT arising from the CC.

Treadmill exercise testing improves diagnostic accuracy in children with concealed congenital long QT syndrome.

BACKGROUND: Resting electrocardiogram (ECG) identification of long QT syndrome (LQTS) has limitations. Uncertainty exists on how to classify patients with borderline prolonged QT intervals. We tested if exercise testing could help serve to guide which children with borderline prolonged QT intervals may be gene positive for LQTS. METHODS: Pediatric patients (n = 139) were divided into three groups: Controls (n = 76), gene positive LQTS with borderline QTc (n = 21), and gene negative patients with borderline QTc (n = 42). Borderline QTc was defined between 440-470 (male) and 440-480 (female) ms. ECGs were recorded supine, sitting, and standing. Patients then underwent treadmill stress testing with Bruce protocol followed by a 9-minute recovery phase. RESULTS: Supine resting QTc, age, and Schwartz score for the three groups were: (a) gene positive: 446 ± 23 ms, 12.4 ± 3.4 years old, 3.2 ± 1.8; (b) gene negative: 445 ± 20 ms, 12.1 ± 2 years old, 2.0 ± 1.2; and (c) control: 400 ± 24 ms, 15.0 ± 3 years old. The three groups could be differentiated by their QTc response at two time points: standing and recovery phase at 6 minutes. Standing QTc ≥460 ms differentiated borderline prolonged QTc patients (gene positive and gene negative) from controls. Late recovery QTc ≥480 ms distinguished gene positive from gene negative patients. CONCLUSION: Exercise stress testing can be useful to identify children who are gene positive borderline LQTS from a normal population and gene negative borderline QTc children, allowing for selective gene testing in a higher risk group of patients with borderline QTc intervals and intermediate Schwartz scores.

Percutaneous epicardial placement of a prototype miniature pacemaker under direct visualization: An infant porcine chronic survival study.

INTRODUCTION: Pacemaker implantation in infants typically consists of surgical epicardial lead placement with an abdominal generator. Here, we describe the chronic performance of our minimally invasive prototype miniature pacemaker implanted under direct visualization in an immature porcine model. METHODS: Twelve piglets underwent miniature pacemaker implantation. A self-anchoring two-channel access port was inserted into a 1 cm incision in the subxiphoid space, and a thoracoscope was inserted into the main channel to visualize the thoracic cavity under insufflation. The pacemaker leadlet was inserted through a sheath via secondary channel and affixed against the epicardium using a helical side-biting electrode. The miniature pacemaker was tucked into the incision, which was sutured closed. Ventricular sensing, leadlet impedance, and capture thresholds were measured biweekly. A limited necropsy was performed after euthanasia. RESULTS: Nine piglets were followed for a median of 78 (IQR 52-82) days and gained 6.6 ± 3.2 kg. Three animals were censored from the analysis due to complications unrelated to the procedure. Capture thresholds rose above maximal output after a median of 67 (IQR 40-69) days. At termination, there was a significant decrease in R-wave amplitude (P = .03) and rise in capture thresholds at 0.4 ms (P = .01) and 1.0 ms pulse widths (P = .02). There was no significant change in leadlet impedance (P = .74). There were no wound infections. CONCLUSIONS: There were no infections following minimally invasive implantation of our prototype miniature pacemaker. Improvements to epicardial fixation are necessary to address diminished leadlet efficacy over time.

Utility of Diagnostic Studies for Upper Gastrointestinal Symptoms in Children with Orthostatic Intolerance.

OBJECTIVE: To assess the utility of gastrointestinal (GI) diagnostic studies in the evaluation of patients with orthostatic intolerance. STUDY DESIGN: Medical records of 103 consecutive children/young adults with orthostatic intolerance and gastrointestinal symptoms were reviewed. All patients had undergone antroduodenal manometry in conjunction with the tilt table test, autonomic testing, and upper gastrointestinal endoscopy (EGD). A gastric emptying study (GES) was performed in 81 patients. RESULTS: The median age of the cohort was 17 years (IQR, 15-19) with a female predominance (females:males, 3:1). As expected, the tilt table test was abnormal in all patients. Antroduodenal manometry was abnormal in 83 of 103 patients (81%), showing neurogenic intestinal dysmotility in 50%, rumination in 20%, and visceral hyperalgesia in 10%. The GES results were abnormal in 23 of 81 patients (28.4%), mostly (21 of 23) with delayed GES. None of the tilt table test or autonomic results were predictive of abnormal antroduodenal manometry or GES. Analysis of EGD biopsy samples revealed nonspecific esophagitis and/or gastritis in 16 of 103 patients (15%). CONCLUSIONS: Antroduodenal manometry with the tilt table test were the most insightful investigations in adolescents and young adults with orthostatic intolerance and gastrointestinal symptoms. GES and EGD provided limited information. Gastrointestinal symptoms were related more to functional rather than mucosal or organic etiologies, suggesting a limited role of endoscopy alone in evaluating patients with orthostatic intolerance presenting with gastrointestinal symptoms.

Comparison of the Medtronic SelectSecure and conventional pacing leads: Long-term follow-up in a multicenter pediatric and congenital cohort.

INTRODUCTION: The Medtronic SelectSecure™ (Minneapolis, MN, USA) pacing lead (SS) has theoretical advantages compared to conventional (C) transvenous pacing leads (PLs). The study purpose was to determine whether differences in electrical function and lead survival exist between these PLs in a large data set of pediatric and congenital patients. METHODS: A multicenter historical longitudinal cohort study was performed comparing SS and CPL performance over a 72-month follow-up (FU). Ten centers provided data for both SS and CPL, matched for age, implanted pacing chamber, time period of implantation, and presence of heart disease. RESULTS: The cohort consisted of 141 subjects in each group. No statistical differences were observed in age, gender, presence of heart disease, or pacing indication. Atrial and ventricular capture thresholds were stable throughout FU and higher in the SS group (atrial: 0.75 ± 0.02 vs 0.5 ± 0.04 V, ventricular: 1.0 ± 0.04 vs 0.75 ± 0.04 V), P < 0.001. Group PL sensing thresholds did not differ. The SS group required greater energy to pace (atrial: 0.57 ± 0.05 vs 0.32 ± 0.02 mJ, ventricular: 0.83 ± 0.05 vs 0.56 ± 0.06 mJ), P = 0.001. Early lead dislodgement and phrenic nerve stimulation were greater in the SS group (P = 0.03). Long-term lead survival was high and similar between the two groups, P = 0.35. CONCLUSIONS: Long-term survival of both PL was high with a low fracture rate. The SS had excellent electrical function but did show higher capture thresholds and increased energy to pace; these differences are offset by other advantages of the SS PL.

Feasibility of Non-invasive Fetal Electrocardiographic Interval Measurement in the Outpatient Clinical Setting.

Non-invasive fetal electrocardiography (ECG) is a promising method for evaluating fetal cardiac electrical activity. Despite advances in fetal ECG technology, its ability to provide reliable, interpretable results in a typical outpatient fetal cardiology setting remains unclear. We sought to determine the feasibility of measuring standard ECG intervals in an outpatient fetal cardiology practice using an abdominal fetal ECG device that employs blind source separation with reference, an innovative signal-processing technique for fetal ECG extraction. Women scheduled for clinically indicated outpatient fetal echocardiogram underwent 10 min of fetal ECG acquisition from the maternal abdomen using specialized gel electrodes. A bedside laptop computer performed fetal ECG extraction, allowing real-time visualization of fetal and maternal ECG signals. Offline post-processing of 1 min of recorded data yielded fetal P-wave duration, PR interval, QRS duration, RR interval, QT interval, and QTc. Fifty-five fetuses were studied with gestational age 18-37 weeks, including 13 with abnormal fetal echocardiogram findings and three sets of twins. Interpretable results were obtained in 91% of fetuses, including 85% during the vernix period and 100% of twin fetuses. PR interval and RR interval of 18-24 week gestation fetuses were significantly shorter than those with gestational age 25-31 and 32-37 weeks. Of the six fetuses with abnormal rhythms on fetal echocardiogram, fetal ECG tracing was interpretable in five and matched the rhythm noted on fetal echocardiogram. Abdominal fetal ECG acquisition is feasible for arrhythmia detection and ECG interval calculation in a routine clinical setting.

Risk Factors for Development of Ectopic Atrial Tachycardia in Post-operative Congenital Heart Disease.

Ectopic atrial tachycardia (EAT) is common in surgically repaired congenital heart disease (CHD) and carries the potential for significant hemodynamic compromise. Our objective was to determine the incidence, and risk factors of EAT after CHD surgery. Prospective study of patients that underwent surgery for CHD from February to October 2016 was performed. Demographic, perioperative and electrophysiologic data were collected. Sustained EAT (> 30 s) was documented by telemetry or electrocardiogram and confirmed by a pediatric electrophysiologist. All patients were followed through index hospitalization. During the study period, 17/204 (8%) of patients developed EAT with median time-to-event of 14 days. 15/17 (88%) received anti-arrhythmic therapy for sustained EAT. By univariate analysis, younger age (5 vs. 284 days, P < .001), lower weight (3.2 vs. 7.5 kg, P < .001), single ventricle physiology (P = .05), longer cardiopulmonary bypass time (176 vs. 94 min, P < .001), need for delayed sternal closure (P < .001), and higher STAT category (P < .001) were associated with EAT. Incidence among single ventricle patients was 7/44 (16%), and of those 7/13 (54%) were < 30 days of age. Multivariable Cox regression analysis confirmed age at surgery < 30 days (hazard ratio = 11.7, P = .002) and use of milrinone (hazard ratio = 4.4, P = .007) as independent predictors of EAT. Post-operative EAT is frequent following surgery for CHD especially in neonates. Further study is warranted, specifically in the single ventricle population, given the high potential risk for arrhythmia-induced hemodynamic compromise in this vulnerable population.

Acute Cardiac MRI Assessment of Radiofrequency Ablation Lesions for Pediatric Ventricular Arrhythmia: Feasibility and Clinical Correlation.

BACKGROUND: Arrhythmia ablation with current techniques is not universally successful. Inadequate ablation lesion formation may be responsible for some arrhythmia recurrences. Periprocedural visualization of ablation lesions may identify inadequate lesions and gaps to guide further ablation and reduce risk of arrhythmia recurrence. METHODS: This feasibility study assessed acute postprocedure ablation lesions by MRI, and correlated these findings with clinical outcomes. Ten pediatric patients who underwent ventricular tachycardia ablation were transferred immediately postablation to a 1.5T MRI scanner and late gadolinium enhancement (LGE) imaging was performed to characterize ablation lesions. Immediate and mid-term arrhythmia recurrences were assessed. RESULTS: Patient characteristics include median age 14 years (1-18 years), median weight 52 kg (11-81 kg), normal cardiac anatomy (n = 6), d-transposition of great arteries post arterial switch repair (n = 2), anomalous coronary artery origin post repair (n = 1), and cardiac rhabdomyoma (n = 1). All patients underwent radiofrequency catheter ablation of ventricular arrhythmia with acute procedural success. LGE was identified at the reported ablation site in 9/10 patients, all arrhythmia-free at median 7 months follow-up. LGE was not visible in 1 patient who had recurrence of frequent premature ventricular contractions within 2 hours, confirmed on Holter at 1 and 21 months post procedure. CONCLUSIONS: Ventricular ablation lesion visibility by MRI in the acute post procedure setting is feasible. Lesions identifiable with MRI may correlate with clinical outcomes. Acute MRI identification of gaps or inadequate lesions may provide the unique temporal opportunity for additional ablation therapy to decrease arrhythmia recurrence.

Off the pedal: Fluoroless transseptal puncture in pediatric supraventricular tachycardia ablation.

BACKGROUND: Fluoroless transseptal (TS) puncture may represent the final step toward elimination of fluoroscopy in pediatric supraventricular tachycardia ablation in normal hearts. We aimed to demonstrate the safety and feasibility of fluoroless TS puncture in pediatric patients and compare procedural timing with the fluoroscopic approach. METHODS: We performed a retrospective cohort analysis of all TS procedures performed without fluoroscopy at our institution; fluoroless TS procedures were performed under intracardiac echocardiography (ICE) guidance after the creation of a 3D electroanatomic map and identification of fossa ovalis (FO) on 3D map. TS procedure times reported are the time from sheath insertion (8.5F short sheath for ICE catheter and SL-1 for TS needle) to the time of confirmed left atrial access. Prior TS procedures performed by the same operator utilizing a combination of ICE and fluoroscopy and by a second operator utilizing fluoroscopic guidance alone were used for comparison. RESULTS: Fluoroless TS puncture was performed in nine patients (mean age 13.8 years); the site of TS puncture was within 2 mm of the FO identified on the EA map. The mean TS procedure time was 22.2 minutes (range 10-45). There was no significant difference in TS procedure times between the three groups. There were no complications related to any TS procedure. CONCLUSION: Fluoroless TS procedures utilizing ICE can safely be performed in pediatric patients without adding substantial procedural times compared with those utilizing fluoroscopic guidance.

Ablation of the vanishing PVC, facilitated by quantitative morphology-matching software.

BACKGROUND: Ablation of cardiac arrhythmias in children and teenagers often necessitates the use of anesthesia, which can suppress ventricular arrhythmias (VAs), making it difficult to map the site of origin using activation time (AT). Pace mapping, a technique employed to assist with VA origin localization, depends on subjective comparison of paced and targeted QRS morphology. We assessed the utility of a quantitative approach to paced QRS to VA morphology matching using the PaSo software (Carto 3, Biosense Webster), to localize the VA site of origin. METHODS: Twenty-four patients underwent 26 procedures for frequent VAs, 29 for targeted VA. If AT mapping was precluded due to infrequent VA, pace mapping was executed using the PaSo software, after regionalization based on targeted VA QRS morphology. RESULTS: Subjects were aged 1-32 (mean 14 ± 6) years; 10 were male. Heart disease was present in six patients. PVC frequency prior to onset of anesthesia was 15 ± 16/min, decreasing to 0-1 PVC/min in 17 cases prior to ablation. Arrhythmia localization was performed by AT mapping + PaSo (12) or PaSo only (17). Pace mapping exhibited an intraventricular gradient of percent QRS morphology match. Highest achieved QRS match averaged 96 ± 2%. Successful ablation (> 1-month follow-up) was achieved in 24/29 targeted VAs, 11/12 ablated using AT and pace mapping, and 13/17 VA ablated using pace mapping only, P  =  0.29. CONCLUSIONS: (1) Spontaneous VA frequency was markedly reduced following anesthesia, despite catecholamine administration. (2) Notwithstanding the ability to perform AT mapping, successful ablation can still be performed using pace mapping only, facilitated by the PaSo software.

Antroduodenal Manometry Is Abnormal in Children Presenting With Orthostatic Intolerance and Gastrointestinal Symptoms.

OBJECTIVES: Gastrointestinal (GI) symptoms of nausea, vomiting, and abdominal pain are common in patients with orthostatic intolerance (OI), including neurally mediated hypotension (NMH) and postural orthostatic tachycardia syndrome (POTS). Autonomic dysregulation is considered the underlying pathophysiology behind the cardiovascular symptoms of POTS. Because the autonomic nervous system also regulates GI motility, we hypothesized that patients with POTS and GI symptoms will have evidence of autonomic dysmotility of the upper GI tract. METHODS: Thirty-five subjects with OI and GI symptoms were studied. All the subjects had a 24-hour antroduodenal manometry (ADM) study, in conjunction with pharmacologic challenge and autonomic and tilt table testing (TTT). RESULTS: The mean subject age was 16.2 ±â€Š2.8 years (range 10-23.8 years), and male to female ratio was 10:25. TTT was abnormal in all the 35 subjects, whereas Valsalva testing was abnormal (+40 mmHG) in 21 of 34 (62%) subjects, and corrected QT interval was ≥0.44 seconds in 19 of 35 (54%) subjects. During TTT, GI symptoms were reproduced in 31 of 35 (89%) studies. ADM was found to be abnormal at baseline, before the TTT in 5 of 35 (14%) subjects, whereas it became abnormal in 23 of 34 (68%) subjects during TTT. In addition, the expected response to the pharmacologic challenge was limited. Overall, ADM was abnormal in 26 of 35 (74%) patients either at baseline or during TTT in these subjects with OI. CONCLUSIONS: ADM is frequently abnormal in children with OI and GI symptoms. Upper GI motility studies should be a part of the comprehensive evaluation in this population.

Intravenous Hydration for Management of Medication-Resistant Orthostatic Intolerance in the Adolescent and Young Adult.

Orthostatic intolerance (OI) is common in teenagers (T) and young adults (A). Despite treatment with oral fluids, medication, and exercise, a significant number have symptoms from multiple organ systems and suffer low quality of life (QOL). Previous studies showed that acute intravenous (IV) hydration (IH) could help restore orthostatic tolerance; however, no data are available about the intermediate-term effects of IH. We therefore studied the efficacy of IH to improve QOL and manage medication-refractory OI patients. Our study population consisted of 39 patients (mean age = 16.1 ± 3.3) years; thirty-two were female. Average number of medications failed = 3.1. Average QOL score on self-reported OI questionnaire was 4.2 (normal QOL = 10). IV hydration consisted of normal saline (1-2 l/day, 3-7 days/week). 1) Orthostatic testing revealed Postural Orthostatic Tachycardia (24), Neurally Mediated Hypotension (14) or OI (1). 2) Average orthostatic change in heart rate was 48 ± 18 bpm. 3) IH was performed via intermittent IV access (10), PICC line (22), and Port (7). 4) Duration of IH varied from 1 week to 3.8 years (mean = 29 ± 47 weeks). 5) Overall, 79 % (n = 31) demonstrated clinically improved self-reported QOL. 6) Six patients who discontinued IH requested to restart treatment. (7) Complications consisted of upper extremity deep vein thrombosis (n = 3) and infection (n = 4). IH is an effective therapy to improve QOL in T&A with medication-resistant OI. Most patients continued to report improved QOL once IH was discontinued. IH should be considered a therapeutic option in medication-resistant OI patients with low QOL.

Catecholaminergic Ventricular Tachycardia, Pregnancy and Teenager: Are They Compatible?

Arrhythmias in pregnancy are becoming more common given more available and effective medical, ablation and device treatment options. Several changes associated with pregnancy, increased blood volume, cardiac output, and heart rate secondary to an increased sympathetic state, facilitate more frequent occurrences of arrhythmias throughout the pregnancy and during labor and delivery. We present a case of successful pregnancy in a teenage female with a previous diagnosis of CPVT, followed by a review of the literature.

Magnesium Lowers the Incidence of Postoperative Junctional Ectopic Tachycardia in Congenital Heart Surgical Patients: Is There a Relationship to Surgical Procedure Complexity?

Magnesium sulfate was given to pediatric cardiac surgical patients during cardiopulmonary bypass period in an attempt to reduce the occurrence of postoperative junctional ectopic tachycardia (PO JET). We reviewed our data to evaluate the effect of magnesium on the occurrence of JET and assess a possible relationship between PO JET and procedure complexity. A total of 1088 congenital heart surgeries (CHS), performed from 2005 to 2010, were reviewed. A total of 750 cases did not receive magnesium, and 338 cases received magnesium (25 mg/kg). All procedures were classified according to Aristotle score from 1 to 4. Overall, there was a statistically significant decrease in PO JET occurrence between the two groups regardless of the Aristotle score, 15.3 % (115/750) in non-magnesium group versus 7.1 % (24/338) in magnesium group, P < 0.001. In the absence of magnesium, the risk of JET increased with increasing Aristotle score, P = 0.01. Following magnesium administration and controlling for body weight, surgical and aortic cross-clamp times in the analyses, reduction in adjusted risk of JET was significantly greater with increasing Aristotle level of complexity (JET in non-magnesium vs. magnesium group, Aristotle level 1: 9.8 vs. 14.3 %, level 4: 11.5 vs. 3.2 %; odds ratio 0.54, 95 % CI 0.31-0.94, P = 0.028). Our data confirmed that intra-operative usage of magnesium reduced the occurrence of PO JET in a larger number and more diverse group of CHS patients than has previously been reported. Further, our data suggest that magnesium's effect on PO JET occurrence seemed more effective in CHS with higher levels of Aristotle complexity.

Universal ECG changes in pediatric patients undergoing procainamide challenge.

BACKGROUND: Procainamide is known to prolong PR, QRS, and QTc intervals in adults and is utilized to unmask the distinct electrocardiographic signatures, including right bundle branch block pattern and right precordial ST segment elevation seen with Brugada syndrome. This study analyzes a pediatric case series of procainamide challenges done to evaluate for possible Brugada syndrome. Our goal was to quantify the impact of procainamide on electrocardiographic intervals in all pediatric patients, regardless of the eventual determination of Brugada syndrome status. METHODS: We retrospectively reviewed all children undergoing procainamide challenge, consecutively from March 2009 to September 2012. Patients received intravenous procainamide over 15 minutes. All electrocardiograms (ECGs) performed during the drug challenge were reviewed. Analysis and ECG measurements were performed by investigators blinded to clinical diagnoses. RESULTS: All patients undergoing procainamide infusion had prolongation of their PR (mean +14%; 0-45%), QRS (+13%; 2-49%), and QTc (+15%; 4-30%) intervals regardless of testing outcome. QTc prolongation to >460 ms following procainamide infusion occurred in 76% of patients. No sustained arrhythmias or adverse events occurred. CONCLUSIONS: ECG changes including prolongation of the PR, QRS, and QTc intervals were seen in all children who underwent procainamide challenge for evaluation of possible Brugada syndrome. An increase in the PR, QRS, and QTc intervals of at least 20% occurred in all children without any adverse events. The QTc prolongation was not completely explained by the QRS prolongation.

Outcomes of fetal echocardiographic surveillance in anti-SSA exposed fetuses at a large fetal cardiology center.

BACKGROUND: Echocardiography screening in anti-SSA antibody exposed fetuses is controversial. OBJECTIVE: The aim of this study is to evaluate utility of fetal echocardiography in anti-SSA exposure. METHODS: Echocardiograms performed over 9 years for maternal anti-SSA exposure were reviewed for atrioventricular (AV) block, cardiomyopathy, arrhythmias, effusion, valve abnormalities, or other abnormalities identified by the echocardiographer. Fetuses with AV block referred to our institution and subsequently found to be anti-SSA exposed were also identified. RESULTS: Six hundred thirty six echocardiograms were performed on 140 fetuses (Cohort 1) of 134 women screened for maternal anti-SSA +/- anti-SSB antibodies. No fetuses developed second or third-degree AV block or cardiomyopathy (odds ratio 0.1, CI 0.0051 to 1.9410, p = 0.13). Dexamethasone was administered to three fetuses for sinus bradycardia, echogenicity near AV node, and ventricular systolic dysfunction with valve regurgitation; all normalized. Screening echocardiograms identified: sinus bradycardia (n = 1), PR prolongation (n = 5), premature atrial contractions (n = 3), valve regurgitation (n = 24), echogenic myocardium (n = 4), and pericardial effusion (n = 1). Isolated tricuspid regurgitation and first-degree AV block did not progress. Nine cases of SSA-mediated AV block (Cohort 2) were referred after heart block developed. CONCLUSIONS: Serial fetal echocardiography in anti-SSA exposed fetuses did not detect AV block. In rare cases, dexamethasone treatment may have affected disease course.