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Atrial and ventricular filling pressures are routinely used in pediatric heart transplant (PHTx) recipients to assess graft function. We hypothesized that cardiac magnetic resonance (CMR) diastolic indices correlate with filling pressures, providing a noninvasive method of hemodynamic assessment.Pediatric heart transplant recipients were prospectively enrolled at the time of cardiac catheterization. Pulmonary capillary wedge pressure (PCWP) and right atrial pressure (RAP) were measured. CMR included standard volumetric analysis. Filling curves were calculated by contouring every phase in the short-axis stack. Global longitudinal and circumferential strain (GLS, GCS) were calculated using feature tracking. Atrial volumes and ejection fraction were calculated from 4-chamber and 2-chamber cine images. Correlations were analyzed using Spearman's Rho; modeling was performed with multivariable logistic regression.A total of 35 patients with a mean age of 15.5 years were included, 12 with acute rejection. The median time post-transplant was 6.2 years. Peak filling rate (PFR) and peak LV ejection rate/end-diastolic volume (PER/EDV) correlated with PCWP (rho = 0.48 p = .005, and rho = -0.35 p = .046, respectively) as did GLS and GCS (rho = 0.52 p = .002, and 0.40 p = .01). Indexed maximum and minimum left atrial (LA) volume correlated with PCWP (rho = 0.41, p = .01, rho = 0.41 p = .01), and LA ejection fraction inversely correlated with PCWP (rho = -0.40, p = .02). GLS and GCS correlated with RAP (rho = 0.55, p = .001 and rho = 0.43, p = .01). A model including LV GLS and PFR estimated PCWP ≥12 mmHg with an area under the curve of 0.84.Cardiac magnetic resonance can be a useful noninvasive modality to assess for signs of diastolic dysfunction after PHTx.

Background: Physical activity, assessed by accelerometers, has been proposed as a quantitative outcome measure for patients with DMD, but research is limited Objective: To assess the total amount and patterns of physical activity in patients with DMD using accelerometers. Methods: Physical activity was assessed in patients with DMD (n = 49, 13.6±4.0-year-old) and age- and sex-matched healthy controls (n = 15, 14.0±2.3-year-old) using wrist- and ankle-worn accelerometers. To assess the amount of activity, accelerometer recordings were converted into acceleration estimates (counts/min). Patterns of activity were assessed as the time that participants spent in sedentary, low-intensity, and moderate-to-vigorous physical activity categories. The sedentary category was divided into three (sedentary -1, -2, and -3) and the low-intensity into two (low-intensity-1, and -2) subcategories. Results: Physical activity across intensity categories differed between study groups (p

Introduction: To promote the rational use of cardiovascular imaging in the delivery of high-quality and cost-effective care to patients with congenital heart disease (CHD), the American College of Cardiology developed Appropriate Use Criteria (AUC). We aimed to evaluate the appropriateness of indications for cardiac CT and MRI in patients with conotruncal defects and to identify factors associated with Maybe or Rarely Appropriate (M/R) indications. Methods: Twelve US centers contributed a median of 147 studies performed prior to AUC publication (01/2020) on patients with conotruncal defects. Studies were excluded if the patient did not receive primary cardiac care at the center or were not seen > 5 years prior to study date. To account for the nesting of physicians within center, a hierarchical generalized linear mixed model was used to account for center-level variation with physicians nested within center. Results: Of the 1,753 studies (20% CT, 80% MRI) from 12 centers, 16% (range 4-39%) were rated M/R and 2.4% were unclassifiable (Figure 1). Patients age Conclusions: Most cardiac CTs and MRIs ordered for the follow-up care of patients with conotruncal defects were rated Appropriate and nearly all were able to be classified. However, there was significant center-level variation and higher annual MRI volume was independently associated with lower odds of M/R rating. These findings inform future quality improvement initiatives.

Background Myocarditis is a potential complication after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and a known cause of sudden cardiac death. Given the athletic demands of soldiers, identification of myocarditis and characterization of post-acute sequelae of SARS-CoV-2 infection with cardiovascular symptoms (CV PASC) may be critical to guide return-to-service. This study sought to evaluate the spectrum of cardiac involvement among soldiers with cardiopulmonary symptoms in the late convalescent phase of recovery from SARS-CoV-2 compared to a healthy soldier control group, and to determine the rate of progression to CV PASC. Methods All soldiers referred for cardiovascular magnetic resonance (CMR) imaging for cardiopulmonary symptoms following COVID-19 were enrolled and matched by age, gender, and athletic phenotype 1:1 to soldiers undergoing CMR in the year prior to the first case of COVID-19 at our institution. Demographic, clinical, laboratory, and imaging parameters were compared between groups. The diagnosis of acute myocarditis was made using modified Lake Louise criteria. Wilcoxon rank sum and chi-squared tests were used for comparison of continuous and categorical variables, respectively. Results Fifty soldier cases and 50 healthy soldier controls were included. The median time from SARS-CoV-2 detection to CMR was 71 days. The majority of cases experienced moderate symptoms (N = 43, 86%), while only 10% required hospitalization. The right ventricular (RV) ejection fraction (RVEF) was reduced in soldier cases compared to controls (51.0% vs. 53.2%, p = 0.012). Four cases were diagnosed with myocarditis (8%), 1 (2%) was diagnosed with Takotsubo cardiomyopathy, and 1 (2%) had new biventricular systolic dysfunction of unclear etiology. Isolated inferior RV septal insertion late gadolinium enhancement (LGE) was present in 8 cases and 8 controls (16% vs. 24%, p = 0.09). Seven of the 19 (37%) cases that completed an intermediate-term follow-up survey reported CV PASC at a median of 139 days of follow-up. Two of the 7 soldiers (29%) with CV PASC had a pathological clinical diagnosis (myocarditis) on CMR. Conclusions Cardiovascular pathology was diagnosed in 6 symptomatic soldiers (12%) after recovery from SARS-CoV-2, with myocarditis found in 4 (8%). RVEF was reduced in soldier cases compared to controls. CV PASC occurred in over one-third of soldiers surveyed, but did not occur in any soldiers with asymptomatic acute SARS-CoV-2 infection.

Introduction:Distinguishing between hypertrophic cardiomyopathy and other causes ofleft ventricular hypertrophy can be difficult in children. We hypothesised that cardiac MRI T1 mapping could improve diagnosis of paediatric hypertrophic cardiomyopathy and that measures of myocardial function would correlate with T1 times and extracellular volume fraction.Methods:Thirty patients with hypertrophic cardiomyopathy completed MRI with tissue tagging, T1-mapping, and late gadolinium enhancement. Left ventricular circumferential strain was calculated from tagged images. T1, partition coefficient, and synthetic extracellular volume were measured at base, mid, apex, and thickest area of myocardial hypertrophy. MRI measures compared to cohort of 19 healthy children and young adults. Mann–Whitney U, Spearman’s rho, and multivariable logistic regression were used for statistical analysis.Results:Hypertrophic cardiomyopathy patients had increased left ventricular ejection fraction and indexed mass. Hypertrophic cardiomyopathy patients had decreased global strain and increased native T1 (−14.3% interquartile range [−16.0, −12.1] versus −17.3% [−19.0, −15.7], p < 0.001 and 1015 ms [991, 1026] versus 990 ms [972, 1001], p = 0.019). Partition coefficient and synthetic extracellular volume were not increased in hypertrophic cardiomyopathy. Global native T1 correlated inversely with ejection fraction (ρ = −0.63, p = 0.002) and directly with global strain (ρ = 0.51, p = 0.019). A logistic regression model using ejection fraction and native T1 distinguished between hypertrophic cardiomyopathy and control with an area under the receiver operating characteristic curve of 0.91.Conclusion:In this cohort of paediatric hypertrophic cardiomyopathy, strain was decreased and native T1 was increased compared with controls. Native T1 correlated with both ejection fraction and strain, and a model using native T1 and ejection fraction differentiated patients with and without hypertrophic cardiomyopathy.

Introduction: Cardiomyopathy (CM) is the leading cause of death in boys with Duchenne Muscular Dystrophy (DMD). Diastolic dysfunction precedes systolic dysfunction in DMD, but while CMR is used routinely to assess fibrosis and left ventricular ejection fraction (LVEF), CMR measures of DMD diastolic dysfunction have not been reported. Hypothesis: Boys with DMD have diastolic dysfunction based on CMR indices when compared with healthy controls. Methods: Prospectively enrolled DMD patients (n = 54) and healthy male controls (n = 40) underwent CMR. Standard volumes and function were calculated. LV filling curves were generated by contouring every phase in the short axis. Indices were compared between groups using a Wilcoxon rank sum and within DMD using a Spearman’s rho test. Results: There was no difference in LVEF between DMD and controls, though DMD patients had significantly smaller indexed left ventricular end diastolic volume (LVEDVi) (see data in Table 1). Peak ventricular filling rates (PFR) were significantly slower in DMD vs controls as were peak ventricular emptying rates (PER). Mean time to PFR (tPFR) and mean time to PER (tPER) were significantly shorter in DMD patients vs controls. In a subset analysis excluding patients with LVEF < 55%, observed differences in PFR, PER, tPFR and TPER remain statistically significant. In DMD patients, tPER correlates negatively with LVEF (rho = -0.57, p Conclusions: Despite having normal baseline systolic function, boys with DMD have significantly different CMR diastolic indices compared with controls. CMR diastolic indices may help detect subclinical dysfunction in DMD. Future analyses should evaluate for correlation between diastolic dysfunction and clinical outcomes.

Introduction: Pediatric heart transplant recipients (PHTx) undergo frequent surveillance endomyocardial biopsies (EMB). Non-invasive screening for acute rejection (AR) could decrease morbidity, improve quality of life, and decrease healthcare costs. Hypothesis: We hypothesized that cardiac magnetic resonance (CMR) extracellular volume (ECV), native T1, and T2 mapping can detect AR in PHTx. Methods: PHTx (n=29) were prospectively enrolled at two sites at time of surveillance EMB or EMB for AR. AR was defined as a clinical change or positive EMB requiring intensification of immunosuppression. Subjects with cardiac allograft vasculopathy (n=3) were excluded; ECV was not measured in 2 subjects without rejection (no IV, poor breathholds). CMR without sedation included standard volumetrics, modified Look-Locker inversion recovery before and after contrast, and T2 mapping. A Wilcoxon rank sum was used to assess for a difference between groups. Results: Median age was 17 y/o (range 9-19). There were 9 subjects with and 17 subjects without AR. Base ECV, mid ECV, 4-ch ECV, and average ECV were increased in AR vs non-rejection (Table 1, Fig 1). Native T1 and T2 times were also increased in patients with AR (Table 1). A cut-off of 29% for mid ECV and 1070ms for mid native T1 identifies all patients with rejection with 6 false positive results in non-rejection (Fig 1) and could potentially decrease the need for EMB by 65%. Conclusions: ECV, native T1, and T2 mapping can non-invasively distinguish between PHTx with and without AR and have potential to decrease the required number of surveillance EMBs.

Background: Atrial and ventricular filling pressures are routinely used in pediatric heart transplant (HTx) recipients to assess graft function. Cardiac magnetic resonance (CMR) can provide a non-invasive assessment of diastolic function, but data are lacking in pediatric HTx. We hypothesized that CMR indices of diastolic function correlate with filling pressures, providing a non-invasive approach to assessment of ventricular dysfunction. Method: Pediatric HTx recipients were prospectively enrolled at the time of cardiac catheterization. Pulmonary capillary wedge pressure (PCWP) and right atrial pressure (RAP) were measured. CMR included standard volumetric analysis and T1 and extracellular volume (ECV) mapping in the short axis at the mid-left ventricle (LV) to evaluate extracellular matrix expansion. Filling curves were calculated by contouring every phase in the short axis stack and global longitudinal and circumferential strain (GLS, GCS) were calculated using feature tracking. Correlations were analyzed using Spearman’s correlation. Results: A total of 31 patients with a mean age of 16.2 y/o were included, 9 with biopsy-proven acute rejection. The median time from transplant was 6.9 years and the mean LVEF was 58%. Peak LV ejection rate/end-diastolic volume (PER/EDV) correlated with PCWP (rho=-0.43, p=0.02, Fig 1) and RAP (rho=-0.40, p=0.03). GLS and GCS correlated with RAP (rho=0.51 p=0.007, and rho=0.38 p=0.05, respectively); GLS also correlated with PCWP (rho=0.46, p=0.02). Native T1 time-correlated with PCWP (rho=0.54, p=0.003), while the correlation between ECV and PCWP did not reach statistical significance (rho=0.37, p=0.06). Conclusion: CMR can be a useful non-invasive modality to assess for early signs of diastolic dysfunction in patients after pediatric HTx. Further research is needed to describe the clinical significance of these associations.

BackgroundDuchenne muscular dystrophy (DMD) leads to progressive cardiomyopathy. Detection of myocardial fibrosis with late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR) is critical for clinical management. Due to concerns of brain deposition of gadolinium, non-contrast methods for detecting and monitoring myocardial fibrosis would be beneficial.ObjectivesWe hypothesized that native T1 mapping and/or circumferential (εcc) and longitudinal (εls) strain can detect myocardial fibrosis.Methods156 CMRs with gadolinium were performed in 66 DMD boys and included: (1) left ventricular ejection fraction (LVEF), (2) LGE, (3) native T1 mapping and myocardial tagging (εcc-tagmeasured using harmonic phase analysis). LGE was graded as: (1) presence/absence by segment, slice, and globally; (2) global severity from 0 (no LGE) to 4 (severe); (3) percent LGE using full width half maximum (FWHM). εlsand εccmeasured using feature tracking. Regression models to predict LGE included native T1 and either εcc-tagor εlsand εccmeasured at each segment, slice, and globally.ResultsMean age and LVEF at first CMR were 14 years and 54%, respectively. Global εlsand εccstrongly predicted presence or absence of LGE (OR 2.6 [1.1, 6.0],p = 0.029, and OR 2.3 [1.0, 5.1],p = 0.049, respectively) while global native T1 did not. Global εcc, εls, and native T1 predicted global severity score (OR 2.6 [1.4, 4.8],p = 0.002, OR 2.6 [1.4, 6.0],p = 0.002, and OR 1.8 [1.1, 3.1],p = 0.025, respectively). εlscorrelated with change in LGE by severity score (n = 33, 3.8 [1.0, 14.2],p = 0.048) and εcc-tagcorrelated with change in percent LGE by FWHM (n = 34, OR 0.2 [0.1, 0.9],p = 0.01).ConclusionsPre-contrast sequences predict presence and severity of LGE, with εlsand εccbeing more predictive in most models, but there was not an observable advantage over using LVEF as a predictor. Change in LGE was predicted by εls(global severity score) and εcc-tag(FWHM). While statistically significant, our results suggest these sequences are currently not a replacement for LGE and may only have utility in a very limited subset of DMD patients.

Background Transplant-free survival for single right ventricle (RV) lesions remains less than 70% at 3 years. Arrhythmia burden, influence of shunt type at Norwood procedure (RV-to-pulmonary artery shunt [RVPAS] versus Blalock-Taussig shunt [BTS]), and implications for mortality risk are not well defined. Methods The authors performed a single-center retrospective analysis of patients with single RV lesions enrolled in a prospective study of arrhythmias after congenital heart surgery. Results Fifty-eight patients received a RVPAS and 62 received a BTS, with a median follow-up of 773 days. Overall arrhythmia incidence was 78%, two-thirds of which prompted intervention. Among all types of arrhythmias, only ventricular arrhythmias (VAs) differed by shunt type, which were more common in patients receiving an RVPAS (29% RVPAS versus 14% BTS; p = 0.049). The majority of VAs were transient (69% less than 1 minute), and typically occurred early post-Norwood procedure (median 12 days). No additional variables were associated with development of VAs. Shunt type did not influence transplant-free survival. Within the entire cohort, there was a trend toward increased mortality with prior history of VA (odds ratio, 2.90; 95% confidence interval, 0.99 to 8.90; p = 0.052). For interstage survivors to Glenn palliation, any VA associated with a 14-fold increased risk of death or transplant (hazard ratio, 14.00; 95% confidence interval, 3.66 to 53.40; p .001). No other tachyarrhythmia or bradyarrhythmia was associated with mortality. Conclusions In this cohort with single RV lesions and prospective rhythm surveillance, patients receiving an RVPAS at Norwood surgery had an increased incidence of VAs compared with patients with a BTS. VAs correlated with late mortality in patients who survived the interstage period.

Patients with Duchenne muscular dystrophy (DMD) develop skeletal muscle weakness and cardiomyopathy. Validated skeletal muscle outcome measures are limited to ambulatory patients, but most DMD patients in cardiac trials are non-ambulatory. New objective functional assessments are needed. This study's objective was to assess the correlation and longitudinal change of two measures: quantitative muscle testing (QMT) and accelerometry. Patients with DMD were prospectively enrolled and underwent QMT and wore wrist and ankle accelerometers for seven days at baseline, 1-, and 2-years. QMT measures were indexed to age. Accelerometer recordings were total vector magnitudes and awake vector magnitude. Correlations were assessed using a Spearman correlation, and longitudinal change was evaluated using a paired t-test or a Wilcoxon signed rank test. Forty-eight participants were included. QMT and accelerometry measures had a moderate or strong correlation, particularly indexed arm QMT with total wrist vector magnitude (rho=0.85, p

Background Patients with Duchenne muscular dystrophy (DMD) require frequent imaging to assess left ventricular (LV) function. Poor imaging windows can limit the diagnostic utility of echocardiography. Cardiac magnetic resonance imaging (CMR) is the gold standard for the assessment of LV function but has not been universally adopted in patients with DMD. The study objectives were (1) to evaluate the reproducibility of echocardiographic measures of LV function, (2) to evaluate which echocardiographic methods correlate best with CMR LV ejection fraction (LVEF), and (3) to evaluate whether CMR provides additional value compared with echocardiography. Methods Twenty-eight participants with DMD prospectively underwent echocardiography and CMR. Two blinded readers measured fractional shortening from M-mode and two-dimensional images and LVEF using four-chamber, biplane Simpson, 5/6 area-length, and three-dimensional methods. Speckle-tracking echocardiography was used to analyze circumferential strain. Readers subjectively rated function and segmental wall motion. Agreement was assessed using intraclass correlation coefficients, Bland-Altman plots, Spearman correlation, and weighted κ. Results Two-dimensional fractional shortening and 5/6 area-length LVEF had the best combination of reproducibility and correlation with CMR LVEF, though both misclassified approximately 20% as either normal or abnormal function. Other measures of LV function were less reproducible, with worse correlations with CMR LVEF. Thirty-seven percent of segments not visible on echocardiography were believed to have wall motion abnormalities by CMR. Conclusions Two-dimensional fractional shortening and 5/6 area-length LVEF represent the most accurate and reproducible echocardiographic measures of LV function in patients with DMD. CMR should be considered when neither of these techniques is measurable or when it is necessary to detect more subtle cardiovascular changes.

Cardiomyopathy with associated ventricular dysfunction is the primary cause of death in Duchenne muscular dystrophy (DMD). Standard biomarkers of heart failure are only elevated in late disease. We aimed to identify novel biomarkers that correlate with ventricular dysfunction in boys with DMD.

Cardiomyopathy is the leading cause of death in Duchenne muscular dystrophy (DMD). Standard cardiac biomarkers are poor indicators of DMD cardiovascular disease. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) regulate collagen turnover. Given the cardiac fibrosis seen in DMD, we hypothesized that MMPs and TIMPs correlate with severity of DMD cardiomyopathy.Prospectively enrolled DMD subjects (n = 42) underwent cardiac magnetic resonance imaging for function and late gadolinium enhancement (LGE), including LGE severity from 0 (no LGE) to 4 (severe). Serum from DMD and healthy male control subjects (n = 15) analyzed for MMPs 1, 2, 3, 7, 9, and 10 and TIMPs 1-4. MMP1, MMP7, and MMP10 were higher in DMD than in control (respectively, median 5080 pg/mL vs 2120 pg/mL [P = .007], 2170 pg/mL vs 1420 pg/mL [P.001], and 216 pg/mL vs 140pg/mL [P = .040]); TIMP4 was lower in DMD (124 pg/mL vs 263 pg/mL; P = .046). Within DMD, MMP7 correlated inversely with left ventricular ejection fraction (r = -0.40; P = .012) and directly with strain (r = 0.54; P = .001) and LGE severity (r = 0.47; P = .003). MMP7 was higher in DMD patients with LGE compared with those without LGE and control subjects (P.001).Multiple MMPs are elevated in DMD compared with control subjects. MMP7 is related to DMD cardiac dysfunction and myocardial fibrosis, possibly through remodeling of the extracellular matrix.

Cardiomyopathy (CM) is the leading cause of death in boys with Duchenne muscular dystrophy (DMD). Therapy with angiotensin converting enzyme inhibitors (ACEi), beta-blockers (BB), and aldosterone antagonists (AI) delays onset of CM. Previous studies demonstrated short-term improvement in left

Postoperative arrhythmias complicate approximately half of surgeries to correct congenital heart defects. Postoperative arrhythmias are often poorly tolerated in this patient population and are associated with prolonged mechanical ventilation, hospital stay, and mortality. NT-proBNP is a well

This article describes one MSW program's innovative and informed response to the pervasive problem of inadequate professional writing skills. We articulate the rationale, implementation, and assessment of our systemic response, which includes (a) requiring a professional writing course, (b) implementing curricular infusion of a standard writing rubric, (c) using sequential papers and peer reviews, (d) incorporating writing assessment into admissions decisions and culminating projects, (e) collaborating with the university writing center, (f) offering a writing coach, and (g) mentoring students for professional scholarship. This curricular case example provides specific and comprehensive strategies for other programs to address this ubiquitous educational concern, demonstrates adherence to CSWE's (2008) Educational Policy and Accreditation Standards in multiple dimensions, and contributes to literature on curriculum development.

Postoperative thrombosis complicates 11% of surgeries to correct congenital heart defects and is associated with increased in-hospital mortality, longer ICU stay, longer mechanical ventilation and longer total hospital length of stay. We report a novel prognostic model to identify patients at risk

Background: A familial variant of complete heart block (CHB) is described in association with a substitution mutation in Connexin-40 (GJA5 Q58L) resulting in impaired gap junction formation. We sought to identify genomic predictors that may independently predispose children to the development of early postoperative complete atrioventricular (AV) block following congenital heart surgery. Methods: Subjects undergoing congenital heart surgery at our institution were consecutively recruited and enrolled from September 2007 through December 2014. In addition to DNA, demographic and perioperative clinical data were obtained from all subjects. Results: Over the course of the study period, there were 1466 subjects enrolled who underwent 1986 operative procedures; DNA was available for analysis in 1756 cases (1424 subjects). The incidence of at least one episode of postoperative complete AV block was 3.7% (n=65). Genotyping of the common missense polymorphism rs10465885 in GJA5 among subjects yielded allele frequencies in Hardy Weinberg equilibrium (p=0.73), and analysis demonstrated a gene-dose effect association between T allele presence and incidence of postoperative complete AV block (linear by linear association, p=0.009). Multivariate logistic regression analysis demonstrates that TT homozygosity is associated with a two-fold increased odds of new onset complete AV block (OR 2.1, 95%CI 1.2-3.5, p=0.006), independent of other significant univariate predictors including patient weight (p Conclusions: A common missense single nucleotide polymorphism within a gene encoding Connexin-40 is associated with the development of early postoperative complete heart block, independent of established risk factors. A refined understanding of genotype-phenotype relationships may serve to guide early postoperative care following congenital heart surgery.

Background Duchenne muscular dystrophy (DMD) cardiomyopathy is a progressive disease for which there is no cure. Disease-specific therapies are needed that can be initiated before irreversible myocardial damage ensues. In order to evaluate therapeutic efficacy, surrogate endpoints other than ejection fraction must be found. The hypothesis of this study is that T1 and extracellular volume fraction (ECV) mapping using cardiovascular magnetic resonance (CMR) can detect diffuse extracellular matrix expansion in DMD patients with normal left ventricular ejection fraction (LVEF) and without myocardial late gadolinium enhancement (LGE). Methods Thirty-one DMD and 11 healthy control participants were prospectively enrolled. CMR using a modified Look-Locker (MOLLI) sequence was performed in all participants before and after contrast administration. T1 and ECV maps of the mid left ventricular myocardium were generated and regions of interest were contoured using the standard 6-segment AHA model. Global and segmental values were compared between DMD and controls using a Wilcoxon rank-sum test. Results The DMD participants had significantly higher mean native T1 compared with controls (1045 ms vs 988 ms, p = 0.001). DMD participants with normal LVEF and without evidence of LGE also demonstrated elevated mean native T1 (1039 ms vs 988 ms, p = 0.002, and 1038 ms vs 988 ms, p = 0.011). DMD participants had a significantly greater mean ECV than controls (0.31 vs 0.24, p