Association of Wolff-Parkinson-White With Left Ventricular Noncompaction Cardiomyopathy in Children.

BACKGROUND: Wolff-Parkinson-White (WPW) has been associated with left ventricular noncompaction (LVNC) in children. Little is known about the prevalence of this association, clinical outcomes, and treatment options. METHODS: Retrospective review of subjects with LVNC. LVNC was defined by established criteria; those with congenital heart disease were excluded. Electrocardiograms (ECGs) were reviewed for presence of pre-excitation. Outcomes were compared between those with isolated LVNC and those with WPW and LVNC. RESULTS: A total of 348 patients with LVNC were identified. Thirty-eight (11%) were found to have WPW pattern on ECG, and 84% of those with WPW and LVNC had cardiac dysfunction. In Kaplan-Meier analysis, there was significantly lower freedom from significant dysfunction (ejection fraction ≤ 40%) among those with WPW and LVNC (P < .001). Further analysis showed a higher risk of developing significant dysfunction in patients with WPW and LVNC versus LVNC alone (hazard ratio 4.64 [2.79, 9.90]). Twelve patients underwent an ablation procedure with an acute success rate of 83%. Four patients with cardiac dysfunction were successfully ablated, 3 having improvement in function. CONCLUSION: WPW is common among children with LVNC and is associated with cardiac dysfunction. Ablation therapy can be safely and effectively performed and may result in improvement in function.

Non-infectious thrombosis of the melody® valve: A tale of two cities.

Bioprosthetic valve thrombosis is an uncommon complication. We report two young women with prior uncomplicated percutaneous pulmonary valve replacement (Melody® , Medtronic, Inc. Minneapolis, MN) who later developed symptomatic pulmonary emboli and pulmonary valve dysfunction without evidence of infection. Thrombophilia risk factors included oral contraceptive use and mild thrombophilia. Both experienced recovery of valve function following anticoagulation. Acute changes in Melody® valve function should prompt a thorough investigation for and treatment of potential thrombotic causes. © 2016 Wiley Periodicals, Inc.

Unconventional 2:1 Ventricular Pacing in a Neonate with Congenital Heart Block and Biventricular Noncompaction.

Congenital complete heart block with concomitant biventricular noncompaction cardiomyopathy has been reported once previously. Although not universal, when restrictive physiology is present, impaired diastolic filling may pose a distinct challenge to pacing during the neonatal period. We present the case of a neonate with congenital complete heart block and biventricular noncompaction that resulted in severe diastolic dysfunction and atrioventricular dyssynchrony. We intentionally used 2:1 ventricular pacing to provide atrioventricular synchrony with every paced beat, and this resulted in hemodynamic and clinical improvement. This unconventional pacing technique may be beneficial in other neonates who have complete heart block and diastolic dysfunction.

Fontan Failure Secondary to Charcot-Marie-Tooth-Induced Phrenic Neuropathy.

Charcot-Marie-Tooth disease comprises a vast array of defects in myelin integrity that causes progressive peripheral sensorimotor neuropathy. It is the most prevalent inherited peripheral neuropathy, and it can affect the management of coexisting medical conditions. We report the case of a 25-year-old woman who had undergone successful Fontan surgery during childhood, but her Fontan circulation failed as a result of diaphragmatic paresis caused by Charcot-Marie-Tooth disease type 1A. This diagnosis precluded cardiac transplantation.

Left Axis Deviation in Children Without Previously Known Heart Disease.

BACKGROUND: Left axis deviation (LAD) discovered in children via electrocardiogram (ECG) is uncommon but can be associated with heart disease (HD). The optimal diagnostic approach in a seemingly healthy child with LAD is unclear. We sought to better stratify which patients with LAD but without previously known HD may warrant additional workup. METHODS: A retrospective chart review was performed to identify patients ≥1 to <18 years of age with LAD (QRS frontal plane axis 0 to -90) on an ECG between January 2002 and December 2014. Patients with known HD before their initial ECG were excluded. RESULTS: Overall, 296 patients were identified (n = 181 [61%] male; mean age: 10.8 ± 4.6 years; mean QRS axis: -24 ± 22°). An echocardiogram was performed in 158 (53%) patients, with 24 (15%) having HD. Compared with those with an echocardiogram but without HD (n = 134), patients with HD had a more negative mean QRS axis (-42 vs -27°; P = .002) and were more likely to have a QRS axis ≤-42° (58% vs 26%; P = .003), ECG chamber enlargement or hypertrophy (38% vs 5%; P < .0001), and abnormal cardiac physical examination findings (75% vs 8%; P < .0001). CONCLUSIONS: LAD discovered in isolation in the asymptomatic pediatric patient may not necessitate further cardiovascular investigation. Clinicians should consider obtaining an echocardiogram in patients with LAD and ECG cardiac chamber enlargement or hypertrophy, a QRS axis ≤-42°, and/or the presence of abnormal cardiac physical examination findings.

Early experience with intravenous sotalol in children with and without congenital heart disease.

BACKGROUND: Arrhythmias are common in the pediatric population. In patients unable to take oral medications or in need of acute therapy, options of intravenous (IV) antiarrhythmic medications are limited. Recently IV sotalol has become readily available, but experience in children is limited. OBJECTIVE: The purpose of this study was to describe our initial experience with the use of IV sotalol in the pediatric population. METHODS: A retrospective study of all pediatric patients receiving IV sotalol was performed. Patient demographic characteristics, presence of congenital heart disease, arrhythmia type, efficacy of IV sotalol use, and adverse effects were evaluated. RESULTS: A total of 47 patients (26 (55%) male and 24 (51%) with congenital heart disease) received IV sotalol at a median age of 2.05 years (interquartile range 0.07-10.03 years) and a median weight of 12.8 kg (interquartile range 3.8-34.2 kg), and 13 (28%) received IV sotalol in the acute postoperative setting. Supraventricular arrhythmias occurred in 40 patients (85%) and ventricular tachycardia in 7 (15%). Among 24 patients receiving IV sotalol for an active arrhythmia, acute termination was achieved in 21 (88%). Twenty-three patients received IV sotalol as maintenance therapy for recurrent arrhythmias owing to inability to take oral antiarrhythmic medications; 19 (83%) were controlled with sotalol monotherapy. No patient required discontinuation of IV sotalol secondary to adverse effects, proarrhythmia, or QT prolongation. CONCLUSION: IV sotalol is an effective antiarrhythmic option for pediatric patients and may be an excellent agent for acute termination of active arrhythmias. It was well tolerated, with no patient requiring discontinuation secondary to adverse effects.

Effect of Left Cardiac Sympathetic Denervation on the Electromechanical Window in Patients with either Type 1 or Type 2 Long QT Syndrome: A Pilot Study.

BACKGROUND: Left cardiac sympathetic denervation (LCSD) exerts significant antifibrillatory effects in patients with long QT syndrome (LQTS). Recently, electromechanical window (EMW) has emerged as a novel torsadogenic marker in LQTS, superior to QT interval (QTc) in distinguishing symptomatic from asymptomatic patients. OBJECTIVE: To explore the hypothesis that LCSD improves EMW most favorably in patients with LQT1. DESIGN: From September 2006 to July 2015, 44 LQT1 and 25 LQT2 patients underwent LCSD. Subset analysis was performed on the six LQT1 and seven LQT2 patients who had echocardiograms both pre-LCSD and ≥3 months post-LCSD. EMW is defined as the time difference (ms) between aortic valve closure and the end of the QT interval, measured from an ECG on the concurrent echocardiogram. RESULTS: Compared to published normal EMW values of 22 ± 19 ms, pre-LCSD EMW mean values were -78 ± 36 ms in LQT1 and -71 ± 35 ms in LQT2 (P < .001). Following LCSD, there was a 57 ± 35 ms decrease in QTc in LQT1 (P = .16) and 23 ± 21 ms decrease in QTc in LQT2 (P = .3). Overall, there was a 35 ± 57 ms mean improvement in EMW post-LCSD (P = .04). Five of the 6 (83%) LQT1 subjects had a favorable EMW change post-LCSD (mean improvement 56 ± 25 ms, P = .04). Five of the 7 (71%) LQT2 subjects had a favorable EMW change post-LCSD (mean improvement 18 ± 19 ms, P = .2). CONCLUSIONS: The precise mechanism of the LCSD therapeutic effect in LQTS patients is not fully understood. This pilot study raises the possibility that LCSD's antitorsadogenic effect in patients with LQT1 could be conferred in part by restoration of electromechanical order, evidenced by normalization of the EMW.

Minimally invasive epicardial implantable cardioverter-defibrillator placement for infants and children: An effective alternative to the transvenous approach.

BACKGROUND: Young patients have high rates of implantable cardioverter-defibrillator (ICD) lead fractures and are at risk for venous occlusion or tricuspid regurgitation with transvenous lead placement. Epicardial ICDs have the potential to circumvent complications associated with transvenous ICDs, but the literature on young patients remains limited. OBJECTIVE: The purpose of this study was to evaluate the results of a minimally invasive epicardial ICD lead placement approach in young patients. METHODS: A retrospective, institutional review board-approved electronic medical record review of all patients undergoing epicardial ICD placement at our institution from January 2011 to December 2015 was performed. RESULTS: A total of 46 patients (20 female [43%]; mean age 10.3 years, range 0.7-18.2 years; mean weight 41 ± 21 kg) were identified; 24 (52%) were ≤10 years old. A minithoracotomy was used in 28 patients (61%). All had acceptable defibrillation, right ventricular sensing, and stimulation thresholds. Median follow-up was 2.0 ± 1.3 years (range 0.02-4.5 years). Eight surgical complications occurred in 7 patients (15%), and 8 device-related complications occurred in 6 patients (13%). Fifty-eight appropriate shocks were delivered in 7 patients (15%). Four patients received inappropriate shocks in relation to lead fractures/microfractures. One patient in this cohort who had long QT syndrome type 8 died of a hypoglycemic seizure. CONCLUSION: Minimally invasive epicardial ICD placement provides an effective, alternative method for implanting an ICD system, particularly in very young patients (<6 years of age) or patients who are concerned about cosmetic appearance. This technique is an acceptable alternative to traditional transvenous ICD placement.

Percutaneous coronary intervention in pediatric and adolescent patients.

OBJECTIVE: Percutaneous coronary intervention (PCI) is commonly used in adult patients with coronary artery disease, but data on PCI in children and adolescents remain limited. Herein, we describe our experience with the use of PCI in pediatric and adolescent patients. DESIGN: This is a retrospective review. SETTING: The study was conducted at Mayo Clinic, Rochester, MN. PATIENTS: All patients ≤18 years old who underwent PCI from 2004 to 2012 were included. INTERVENTIONS: Intravascular ultrasound and balloon angioplasty were performed in all patients, with subsequent stent placement in 6/7 (86%) procedures. OUTCOME MEASURES: Residual postintervention stenosis, early procedural morbidity and mortality were the outcome measures. RESULTS: Overall, seven unique PCI procedures were performed in five patients (four males, mean age 13.2 ± 3.8 years, range 8-18 years). Mean follow-up interval was 2 (0.6-5.5) years. Indications for the procedures included transplant coronary vasculopathy (n = 1), coronary dissection (n = 1), and acute coronary thrombosis/myocardial infarction (n = 1). Additionally, there were two patients (n = 2) who experienced coronary compression as a sequelae of prior heart surgery. Intravascular ultrasound and balloon angioplasty were performed in all patients, with subsequent stent placement in 6/7 (86%) procedures. A total of eight stents were placed (average stent diameter 3 ± 0.5 mm), including six (75%) drug-eluting stents. The targeted coronary artery lesions were successfully treated in all seven procedures. There was no early procedural morbidity or mortality. Two patients were noted to have angiographic evidence of in-stent restenosis at 3 and 15 months postdeployment, respectively, despite treatment with aspirin and clopidogrel. CONCLUSION: PCI in children and adolescents can be utilized to improve coronary blood flow in a variety of clinical situations. It may be particularly effective in cases of postsurgical coronary compression. Close angiographic follow-up is critical as these patients are at risk for in-stent restenosis.