Repair of Sinus Venosus Defect and Anomalous Pulmonary Veins Associated With Vein of Galen Malformation.

Sinus venosus defect (SVD) is a deficiency in the sinus venosus portion of the atrium, often associated with partial anomalous pulmonary venous connections. In patients with vein of Galen malformation (VGAM), SVD provides a unique challenge with respect to embolization treatment. In our case, the child had percutaneous device closure of the SVD prior to VGAM embolization. Nine years later, he required surgical removal of the SVD device and Warden procedure due to progressive right-sided cardiac enlargement.

The Effect of Left Cardiac Sympathetic Denervation on Exercise in Patients With Long QT Syndrome.

OBJECTIVES: This study evaluated the effect of left cardiac sympathetic denervation (LCSD) on heart rate, cardiac contractility, and cardiopulmonary fitness in human subjects. BACKGROUND: The primary treatment for long QT syndrome (LQTS) is beta-blocker (BB) therapy, but some patients experience breakthrough cardiac events or intolerable side effects. LCSD provides a significant antifibrillatory, protective effect in LQTS. However, the effect of LCSD on cardiopulmonary fitness in humans has not been previously described. METHODS: A retrospective analysis of patients with LQTS and LCSD (2006 to 2017) who had both pre- and post-LCSD exercise stress tests (N = 55; 39 females; mean age at LCSD 22 ± 12 years; mean follow-up 5.1 ± 2.5 years; 36 patients with LQT1; 15 patients with LQT2). Forty patients (73%) were receiving BBs pre-LCSD. RESULTS: Mean peak heart rate before LCSD was 143 ± 23 beats/min, mean peak oxygen consumption (VO2) was 32 ± 10 ml/kg/min, and mean peak respiratory exchange ratio was 1.14 ± 0.12. There was no difference in peak heart rate, peak VO2, peak QTc, or respiratory exchange ratio pre- and post-LCSD. To evaluate the isolated effect of LCSD, the study performed a subset analysis of patients with LCSD monotherapy (n = 10) or no change in BB dose (n = 12). Patient-matched pre- and post-LCSD exercise testing showed no difference in heart rate, VO2, or left ventricular function following LCSD. CONCLUSIONS: LCSD provides increased protection from an LQTS-triggered event without negatively affecting peak heart rate, cardiopulmonary fitness, or cardiac contractility, as assessed by both treadmill exercise stress testing and echocardiography.

Innovative 2-Step Management Strategy Utilizing EXIT Procedure for a Fetus With Hypoplastic Left Heart Syndrome and Intact Atrial Septum.

Hypoplastic left heart syndrome (HLHS) with intact atrial septum (HLHS-IAS) carries a high risk of mortality and affects about 6% of all patients with HLHS. Fetal interventions, postnatal transcatheter interventions, and postnatal surgical resection have all been used, but the mortality risk continues to be high in this subgroup of patients. We describe a novel, sequential approach to manage HLHS-IAS and progressive fetal hydrops. A 28-year-old, gravida 4 para 2 mother was referred to Mayo Clinic for fetal HLHS. Fetal echocardiography at 28 weeks of gestation demonstrated HLHS-IAS with progressive fetal hydrops. The atrial septum was thick and muscular with no interatrial communication. Ultrasound-guided fetal atrial septostomy was performed with successful creation of a small atrial communication. However, fetal echocardiogram at 33 weeks of gestation showed recurrence of a pleural effusion and restriction of the atrial septum. We proceeded with an Ex uteroIntrapartum Treatment (EXIT) delivery and open atrial septectomy. This was performed successfully, and the infant was stabilized in the intensive care unit. The infant required venoarterial extracorporeal membrane oxygenator support on day of life 1. The patient later developed hemorrhagic complications, leading to his demise on day of life 9. This is the first reported case of an EXIT procedure and open atrial septectomy performed without cardiopulmonary bypass for an open-heart operation and provides a promising alternative strategy for the management of HLHS-IAS in select cases.

Productive Pumping: A Pilot Study to Help Postpartum Residents Increase Clinical Time.

BACKGROUND: Many female residents choose to start families during training, and they want to breastfeed their infants. Continuing lactation while balancing service and education demands can be challenging. OBJECTIVE: We hypothesized that the presence of a dedicated and fully equipped lactation room with a hospital-grade pump (HGP) would increase ease and efficiency of lactation during residency. METHODS: A quiet HGP was purchased for resident use, and it was stored in a designated room with a computer, telephone, and dictation system. Lactating residents provided information about pumping time and production using their own portable double electric pump (PP) versus the HGP based on the first pump of the morning (for consistency), averaged over the first month back from maternity leave. RESULTS: Among 6 residents, lactation time with PP averaged 24 minutes (range, 15-40 minutes) versus 15.5 minutes with HGP (range, 10-32 minutes). Use of the HGP reduced total pumping time by 8.5 minutes (95% confidence interval 3.8-12.2, P = .045). Production volume increased from 6 ounces (range, 3.5-8.5 ounces) with PP to 8.8 ounces (range, 8-11 ounces) with HGP, for a mean increase of 2.8 ounces (95% confidence interval 1.2-4.3, P = .06) despite decreased lactation time. CONCLUSIONS: In our pilot, an HGP significantly decreased lactation time, while increasing expressed milk volume. Residents completed clinical and educational tasks while pumping. Providing an HGP and equipped lactation space helped residents continue breastfeeding and decreased the burden of lactation on patient care and educational tasks.

Idiopathic Restrictive Cardiomyopathy in Children and Young Adults.

Idiopathic restrictive cardiomyopathy (IRC) is a rare condition characterized by reduced ventricular compliance. Children with IRC have poor outcomes with most patients proceeding to cardiac transplantation. We sought to analyze our institutional experience and assess contemporary outcomes for children with IRC. We reviewed the medical record for patients (<21 years old) evaluated for a primary diagnosis of IRC between 1975 and 2013 at our institution. Demographic, clinical, echocardiographic, and catheterization data were abstracted. The patients were divided into 2 groups comprising a historical cohort (HC) (diagnosis: 1975 to 1993, n = 8) and a contemporary cohort (CC) (diagnosis: 1994 to 2013, n = 12). Twenty children were identified with IRC (mean age at presentation 9.7 ± 6.5 years, 55% female). Mean length of follow-up was 6.5 ± 8.4 years (range 0.1 to 35.6 years). In the CC, 7 of 12 patients (58%) progressed to cardiac transplantation (mean age of 9 ± 4 years at transplant, mean interval from diagnosis of IRC: 1.5 ± 0.9 years). Overall survival was improved significantly in the CC compared with the HC (80% vs. 38%, p = 0.02), but transplantation free survival was no different between the CC and HC over 5 years (38% vs 38%, p = 0.65). In the CC, elevation of mitral valve Doppler E/e' ratio on echocardiography was associated with increased mortality (p = 0.01). In conclusion, IRC continues has a poor prognosis. Early referral for transplantation was associated with improved overall survival in the modern era. Patients with markedly elevated E/e' ratio may have increased risk of death.

Prevalence and Outcome of High-Risk QT Prolongation Recorded in the Emergency Department from an Institution-Wide QT Alert System.

BACKGROUND: QT prolongation is an independent risk factor for sudden death, stroke, and all-cause mortality. However, additional studies have shown that in certain settings, QT prolongation may be transient and a result of external factors. OBJECTIVE: In this study, we evaluated the clinical characteristics and outcomes of patients seen in the emergency department (ED) with QT prolongation. METHODS: Between November 2010 and June 2011, 7522 patients had an electrocardiogram (ECG) obtained during their evaluation in the ED. Clinical, laboratory, and therapeutic information was collected for all patients with QT prolongation (i.e., ≥ 500 ms and QRS < 120 ms). Potential QT-inciting factors (drugs, electrolyte disturbances, and comorbidities) were synthesized into a pro-QT score. RESULTS: Among the 7522 patients with an ECG obtained in the ED, a QT alert was activated in 93 (1.2%; mean QTc 521 ± 34 ms). The majority of ED patients (64%) had more than one underlying condition associated with QT prolongation, with electrolyte disturbances in 51%, a QT prolonging condition in 56%, and QT-prolonging drugs in 77%. Thirty-day mortality was 13% for patients with QT prolongation noted in the ED. CONCLUSIONS: One percent of patients evaluated with an ECG in the ED activated our prolonged QTc warning system, with most demonstrating > 1 QT-prolonging condition. Thirty-day mortality was significant, but it requires further investigation to determine whether the QTc simply provided a non-invasive indicator of increased risk or heralded the presence of a vulnerable host at risk of a QT-mediated sudden dysrhythmic death.

Lidocaine attenuation testing: An in vivo investigation of putative LQT3-associated variants in the SCN5A-encoded sodium channel.

BACKGROUND: Long QT syndrome type 3 (LQT3) accounts for 5%-10% of long QT syndrome and results from gain-of-function mutations in the SCN5A-encoded sodium channel. Approximately 2% of healthy individuals host rare SCN5A variants of uncertain significance (VUS). Distinction of true LQT3-causative mutations from background genetic noise is essential. OBJECTIVE: The purpose of this study was to assess the use of the lidocaine attenuation test (LAT) in evaluating patients with possible LQT3. METHODS: We reviewed the LAT results and medical records for 25 patients with a possible LQT3-associated SCN5A variant. The LAT involved a loading dose of 1 mg/kg of intravenous lidocaine followed by continuous infusion at 50 µg/(kg⋅min) for 20 minutes. If the corrected QT interval shortened by ≥30 ms, the LAT was defined as positive. RESULTS: Sixteen patients (64%) had a positive LAT, 6 of which demonstrated the E1784K variant. A positive LAT correlated in 86% of cases with abnormal in vitro channel function (mean corrected QT interval attenuation 43 ± 3 ms vs 25 ± 5 ms for wild-type variants; P = .03). Four of 5 patients (80%) with a VUS had a positive LAT (T1304M [2 patients], L1786P, and R800L). The T1304M variant demonstrated abnormal in vitro function and a positive LAT, opening the door for a potential variant promotion from VUS to likely pathogenic. CONCLUSION: The LAT may help distinguish true LQT3-causative mutations from an otherwise noncontributory VUS. Given that lidocaine acts as a late sodium current blocker, a positive LAT may enable the early identification of a pathological accentuation of the late sodium current that could be targeted therapeutically.

Septal myectomy for hypertrophic obstructive cardiomyopathy in Friedreich's ataxia.

Hypertrophic cardiomyopathy associated with Friedreich's ataxia is progressive, and there are few, if any, effective treatments available at present. This case report describes a Friedreich's ataxia patient who had a septal myectomy for the management of hypertrophic cardiomyopathy with improved symptoms over a 7-year period. This suggests that septal myectomy may be a viable option to relieve symptoms and interrupt progression of heart disease in appropriately selected Friedreich's ataxia patients.

Phenotype of Children with QT Prolongation Identified Using an Institution-Wide QT Alert System.

QT prolongation is an independent risk factor for cardiovascular mortality in adults. However, there is little information available on pediatric patients with QT prolongation and their outcomes. Herein, we evaluated the prevalence of QT prolongation in pediatric patients identified by an institution-wide QT alert system, and the spectrum of their phenotype. Patients with documented QT prolongation on an ECG obtained between November 2010 and June 2011 were included. There were 1303 pediatric ECGs, and 68 children had electrographically isolated QT prolongation. Comprehensive review of medical records was performed with particular attention to QT-prolonging clinical, laboratory, and medication data, which were summarized into a pro-QTc score. Overall, 68 (5 %) pediatric patients had isolated QT prolongation. The mean age of this pediatric cohort was 9 ± 6 years, and the average QTc was 494 ± 42 ms. All children had 1 or more QT-prolonging risk factor(s), most commonly QT-prolonging medications. One patient was identified with congenital long QT syndrome (LQTS), which was not previously diagnosed. In one-year follow-up, only one pediatric death (non-cardiac) occurred (1.5 %). Potentially QT-offending/pro-arrhythmic medications were changed in 80 % of pediatric patients after the physician received the QT alert. Children with QT prolongation had very low mortality and minimal polypharmacy. Still, medications and other modifiable conditions were the most common causes of QT prolongation. Children with a prolonged QTc should be evaluated for modifiable QT-prolonging factors. However, if no risk factors are present or the QTc does not attenuate after risk factor modification/removal, the child should be evaluated for congenital LQTS.

Marked, transient, emotion-triggered QT accentuation in an adolescent female with type 1 long QT syndrome.

Type 1 long QT syndrome is the most common long QT syndrome genetic subtype. Exercise and emotional stress can precipitate sudden cardiac events in patients with type 1 long QT syndrome; however, the precise mechanism remains elusive. We report the case of a teenage girl with type 1 long QT syndrome secondary to a rare frameshift mutation (p. L191fs+90X) in the KCNQ1-encoded Kv7.1 potassium channel. During emotional distress, her continuous QTc recordings precipitously increased, peaking within minutes to 669 ms and then returning to baseline (520 ms) as she calmed without concomitant increase in heart rate. This is the first described case documenting transient, marked accentuation of the QTc interval in a long QT syndrome patient during emotional distress. Such events may be triggered by transient accentuation of the intrinsic perturbation in cardiac repolarisation and increase the risk of degeneration to a ventricular arrhythmia. This case illustrates the need improved understanding of the complex interaction between emotion and cardiac stability in patients with long QT syndrome.

Cone reconstruction in children with Ebstein anomaly: the Mayo Clinic experience.

OBJECTIVE: Valve repair for pediatric patients with Ebstein anomaly has historically yielded varied results. The cone reconstruction (CR) first described by Da Silva has revolutionized the surgical approach to these patients. This study reports our recent experience with CR in children and young adults with Ebstein anomaly. DESIGN: Electronic medical records were reviewed for all patients < 21 years old who had surgery to repair Ebstein anomaly at Mayo Clinic Rochester between June 2007 and December 2012. Clinical data including preoperative demographics, intraoperative procedures, and postoperative outcomes were recorded. RESULTS: Eighty-four patients initially had a cone reconstruction (54% male, mean age 10.1 ± 5.9 years). Indications for operation included cardiomegaly (42%), cyanosis (19%), and heart failure (19%). The preoperative echocardiogram demonstrated severe tricuspid regurgitation in 91% of patients. There was one early death and 3 early CR breakdowns requiring reoperation (2 re-repair, 1 tricuspid replacement). Eighty-two patients (98%) had successful CR at the time of hospital discharge. Patient age, gender, cardiopulmonary bypass time, and aortic cross-clamp time were not associated with early CR failure. Use of a partial or eccentric annuloplasty ring correlated with successful initial CR (P = .01). There have been no early CR breakdowns since 2010. Follow-up information was available for 77 patients (longest follow-up 6.5 years; mean 0.8 ± 0.2 years). The most recent postoperative echocardiogram demonstrated mild or no tricuspid regurgitation in 83%. Tricuspid stenosis (mean gradient > 5 mm Hg) was present in 6 patients. There was one late death (motor vehicle accident) and one late re-repair of the tricuspid valve 4 years after initial operation. CONCLUSIONS: CR in children and young adults with Ebstein anomaly can be performed with low early mortality and excellent durability at short-term follow-up. CR represents an important surgical option for young patients. It is applicable to patients with a broad range of anatomic variability and precludes valve replacement in the vast majority. CR should be considered prior to the deleterious effects of chronic right ventricular volume overload and the development of systolic dysfunction, which hamper long-term prognosis. Therefore, early referral for surgical evaluation is recommended.