Cardiomyopathy develops in >90% of Duchenne muscular dystrophy (DMD) patients by the second decade of life. We assessed the associations between DMD gene mutations, as well as Latent transforming growth factor-beta-binding protein 4 (LTBP4) haplotypes, and age at onset of myocardial dysfunction in DMD. DMD patients with baseline normal left ventricular systolic function and genotyping between 2004 and 2013 were included. Patients were grouped in multiple ways: specific DMD mutation domains, true loss-of-function mutations (group A) versus possible residual gene expression (group B), and LTBP4 haplotype. Age at onset of myocardial dysfunction was the first echocardiogram with an ejection fraction <55% and/or shortening fraction <28%. Of 101 DMD patients, 40 developed cardiomyopathy. There was no difference in age at onset of myocardial dysfunction among DMD genotype mutation domains (13.7±4.8 versus 14.3±1.0 versus 14.3±2.9 versus 13.8±2.5, p=0.97), groups A and B (14.4±2.8 versus 12.1±4.4, p=0.09), or LTBP4 haplotypes (14.5±3.2 versus 13.1±3.2 versus 11.0±2.8, p=0.18). DMD gene mutations involving the hinge 3 region, actin-binding domain, and exons 45-49, as well as the LTBP4 IAAM haplotype, were not associated with age of left ventricular dysfunction onset in DMD.

In the ED setting, approximately one-third of pediatric patients exhibited QTc values of ≥440 milliseconds and had significant normalization of QTc values in follow-up evaluations. First-time ECGs obtained after a syncopal episode must be interpreted with caution, particularly in the context of so-called borderline QT intervals.

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 utero Intrapartum 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.

Objectives To evaluate whether a quality improvement intervention reduces sternal wound infection (SWI) rates in children after cardiac surgery. Design This is a pre- and post-intervention quality improvement study. Setting A 16-bed cardiac intensive care unit in a university-affiliated pediatric tertiary care children’s hospital. Patients All patients undergoing cardiac surgery via median sternotomy from January 2010 to December 2014 are included. The SWI rates for primary closure (PC) and delayed sternal closure (DSC) are reported per 100 sternotomies. The hospital acquired infection (HAI) records were used to identify pre- intervention cases, while post-intervention cases were collected prospectively. Intervention Implementation of a sternal wound prevention bundle (SWPB) during the preoperative, intraoperative and postoperative periods for cardiac surgical cases. Measurements and Main Results During the pre-intervention period, 32 (3.8%) patients developed SWI while only 19 (2.1%) developed SWI during the post-intervention period (p=0.04). The rates of SWI following PC were not significantly different pre- and post-intervention (2.4% vs. 1.6%; p=0.35). However, patients with DSC had significantly lower post-intervention infection rates (10.6% vs. 3.9%; p=0.02). Conclusions Implementation of a SWPB during the perioperative period was associated with lower SWI rates in surgeries with DSC.

The objective of this study is to assess changes in cardiac deformation during acute cellular- and antibody-mediated rejection in pediatric HT recipients. Pediatric HT recipients aged ≤18 years with at least one episode of biopsy-diagnosed rejection from 2006 to 2013 were included. Left ventricular systolic S (SS) and SR (SSr) data were acquired using 2D speckle tracking on echocardiograms obtained within 12 h of right ventricular endomyocardial biopsy. A mixed effect model was used to compare cardiac deformation during CR (Grade ≥ 1R), AMR (pAMR ≥ 2), and mixed rejection (CR and AMR positive) versus no rejection (Grade 0R and pAMR 0 or 1). A total of 20 subjects (10 males, 50%) with 71 rejection events (CR 35, 49%; AMR 21, 30% and mixed 15, 21%) met inclusion criteria. The median time from HT to first biopsy used for analysis was 5 months (IQR 0.25-192 months). Average LV longitudinal SS and SSr were reduced significantly during rejection (SS: -17.2 ± 3.4% vs. -10.7 ± 4.5%, p < 0.001 and SSr: -1.2 ± 0.2 s vs. -0.9 ± 0.3 s; p < 0.001) and in all rejection types. Average LV short-axis radial SS was reduced only in CR compared to no rejection (p = 0.04), while average LV circumferential SS and SSr were reduced significantly in AMR compared to CR (SS: 18.9 ± 4.2% vs. 20.8 ± 8.8%, p = 0.03 and SSr: 1.35 ± 0.8 s vs. 1.54 ± 0.9 s; p = 0.03). In pediatric HT recipients, LV longitudinal SS and SSr were reduced in all rejection types, while LV radial SS was reduced only in CR. LV circumferential SS and SSr further differentiated between CR and AMR with a significant reduction seen in AMR as compared to CR. This novel finding suggests mechanistic differences between AMR- and CR-induced myocardial injury which may be useful in non-invasively predicting the type of rejection in pediatric HT recipients.

Long-term outcome after the Fontan procedure is adversely impacted by higher residential altitude.

Objective: To identify risk factors for pediatric mechanical mitral valve replacement (mMVR) to improve management in this challenging population. Methods: From 1993 to 2019, 93 children underwent 119 mMVR operations (median age, 8.8 years [interquartile range [IQR]: 2.1-13.3], 54.6% females) at our institution. Twenty-six (21.8%) patients underwent mMVR at ≤2 years and 93 (78.2%) patients underwent mMVR at >2 years. Median follow-up duration was 7.6 years [IQR: 3.2-12.4]. Results: Early mortality was 9.7%, but decreased with time and was 0% in the most recent era (13.9% from 1993 to 2000, 7.3% from 2001 to 2010, 0% from 2011 to 2019, P = .04). It was higher in patients ≤2 years compared to patients >2 years (26.9% vs 2.2%, P < .01). On multivariable analysis for mitral valve reoperation, valve size <23 mm was significant with a hazard ratio of 5.38 (4.87-19.47, P = .01);. Perioperative stroke occurred in 1% and permanent pacemaker was necessary in 12%. Freedom from mitral valve reoperation was higher in patients >2 years and those with a prosthesis ≥23 mm. Median time to reoperation was 7 years (IQR: 4.5-9.1) in patients >2 years and 3.5 years (IQR: 0.6-7.1) in patients ≤2 years ( P = .0511), but was similar between prosthesis sizes ( P = .6). During follow-up period (median 7.6 years [IQR: 3.2-12.4], stroke occurred in 10%, prosthetic valve thrombosis requiring reoperation in 4%, endocarditis in 3%, and bleeding in 1%. Conclusion: Early and late outcomes of mMVR in children are improved when performed at age >2 years and with prosthesis size ≥23 mm. These factors should be considered in the timing of mMVR.

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