Echocardiographic Reference Ranges of Non-invasive Myocardial Work Indices in Children.

Global myocardial work (GMW) is an emerging method to characterize left ventricle (LV) function with potential advantages over both ejection fraction and global longitudinal strain (GLS). We aimed to determine the feasibility and reproducibility for echocardiographic-derived GMW in a healthy pediatric population; establish normal reference values; and investigate the influence of age, gender, and other clinical factor on normal reference ranges. We prospectively enrolled 212 individuals (median age of 9 years; interquartile range, 6 to 12 years, 112 female). Global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were measured from LV pressure-strain loops. Quantification of GMW was performed using a GE Vivid E95 system and available software package (Echopac V.203, GE). The mean LV EF was 64 ± 3% with GLS of -21.3 ± 1.5%. GWI was 1688 ± 219 mmHg% with mean GWE of 96.5 ± 1.4%. The GCW was 1959 ± 207 mmHg%, and the mean GWW of 61.1 ± 30.9 mmHg%. No significant difference was found in MW indices across age group and gender (p > 0.05 for all). There were significant correlations between both GWI and GCW with GLS and systolic blood pressure (p < 0.001), but not with GWE and GWW. Linear regression model revealed that GWI and GCW were more closely correlated with systolic blood pressure than GLS. LV MW indices had good intra-observer and inter-observer reproducibility. This study establishes both the feasibility and reference ranges for non-invasive echocardiographic indices of GMW in healthy children. Myocardial work appears to be a complementary modality to assess LV performance in children.

Cardiac remodeling after anthracycline and radiotherapy exposure in adult survivors of childhood cancer: A report from the St Jude Lifetime Cohort Study.

BACKGROUND: Limited data exist regarding left ventricular remodeling patterns observed in adult survivors of childhood cancer after therapy. METHODS: Among 1190 adult survivors diagnosed with childhood cancer (median age at diagnosis, 9 years [interquartile range (IQR), 3.8-14.4 years]; age at evaluation, 35.6 years [IQR, 29.5-42.8 years]), treatment exposures included anthracyclines (n = 346), chest radiotherapy (n = 174), both (n = 245), or neither (n = 425). Prospective echocardiographic assessment compared survivors with 449 noncancer controls classified according to left ventricle geometric patterns. Associations between left ventricle geometric patterns and decreased exercise tolerance were assessed. RESULTS: Overall, 28.2% of survivors (95% confidence interval [CI], 25.6%-30.8%) exhibited concentric remodeling, 2.4% (95% CI, 1.6%-3.5%) exhibited eccentric hypertrophy, and 1.1% (95% CI, 0.6%-1.9%) exhibited concentric hypertrophy. A greater proportion of survivors who received only chest radiotherapy (41%) had concentric remodeling compared with those who received only anthracyclines (24%), both (27%), or neither (27%; all P < .001), and all were greater than the proportions in noncancer controls (18%; all P < .05). Concentric remodeling was associated with radiation exposure, but not with anthracycline exposure, in multivariable models. Survivors who had concentric remodeling were more likely to have a maximal oxygen uptake peak <85% compared with those who had normal geometry (81.0% vs 66.3%; odds ratio, 1.75; 95% CI, 1.15-2.68). CONCLUSIONS: Chest radiation therapy, but not anthracycline therapy, increased the risk for concentric remodeling in survivors of childhood cancer. The presence of concentric remodeling was associated with increased exercise intolerance.

Machine learning method for predicting pacemaker implantation following transcatheter aortic valve replacement.

BACKGROUND: An accurate assessment of permanent pacemaker implantation (PPI) risk following transcatheter aortic valve replacement (TAVR) is important for clinical decision making. The aims of this study were to investigate the significance and utility of pre- and post-TAVR ECG data and compare machine learning approaches with traditional logistic regression in predicting pacemaker risk following TAVR. METHODS: Five hundred fifity seven patients in sinus rhythm undergoing TAVR for severe aortic stenosis (AS) were included in the analysis. Baseline demographics, clinical, pre-TAVR ECG, post-TAVR data, post-TAVR ECGs (24 h following TAVR and before PPI), and echocardiographic data were recorded. A Random Forest (RF) algorithm and logistic regression were used to train models for assessing the likelihood of PPI following TAVR. RESULTS: Average age was 80 ± 9 years, with 52% male. PPI after TAVR occurred in 95 patients (17.1%). The optimal cutoff of delta PR (difference between post and pre TAVR PR intervals) to predict PPI was 20 ms with a sensitivity of 0.82, a specificity of 0.66. With regard to delta QRS, the optimal cutoff was 13 ms with a sensitivity of 0.68 and a specificity of 0.59. The RF model that incorporated post-TAVR ECG data (AUC 0.81) more accurately predicted PPI risk compared to the RF model without post-TAVR ECG data (AUC 0.72). Moreover, the RF model performed better than logistic regression model in predicting PPI risk (AUC: 0.81 vs. 0.69). CONCLUSIONS: Machine learning using RF methodology is significantly more powerful than traditional logistic regression in predicting PPI risk following TAVR.

T-wave and its association with myocardial fibrosis on cardiovascular magnetic resonance examination.

BACKGROUND: Risk stratification in non-ischemic myocardial disease poses a challenge. While cardiovascular magnetic resonance (CMR) is a comprehensive tool, the electrocardiogram (ECG) provides quick impactful clinical information. Studying the relationships between CMR and ECG can provide much-needed risk stratification. We evaluated the electrocardiographic signature of myocardial fibrosis defined as presence of late gadolinium enhancement (LGE) or extracellular volume fraction (ECV) ≥29%. METHODS: We evaluated 240 consecutive patients (51% female, 47.1 ± 16.6 years) referred for a clinical CMR who underwent 12-lead ECGs within 90 days. ECG parameters studied to determine association with myocardial fibrosis included heart rate, QRS amplitude/duration, T-wave amplitude, corrected QT and QT peak, and Tpeak-Tend. Abnormal T-wave was defined as low T-wave amplitude ≤200 µV or a negative T wave, both in leads II and V5. RESULTS: Of the 147 (61.3%) patients with myocardial fibrosis, 67 (28.2%) had ECV ≥ 29%, and 132 (54.6%) had non-ischemic LGE. An abnormal T-wave was more prevalent in patients with versus without myocardial fibrosis (66% versus 42%, p < .001). Multivariable analysis demonstrated that abnormal T-wave (OR 1.95, 95% CI 1.09-3.49, p = .03) was associated with myocardial fibrosis (ECV ≥ 29% or LGE) after adjustment for clinical covariates (age, gender, history of hypertension, and heart failure). Dynamic nomogram for predicting myocardial fibrosis using clinical parameters and the T-wave was developed: https://normogram.shinyapps.io/CMR_Fibrosis/. CONCLUSION: Low T-wave amplitude ≤ 200 µV or negative T-waves are independently associated with myocardial fibrosis. Prospective evaluation of T-wave amplitude may identify patients with a high probability of myocardial fibrosis and guide further indication for CMR.

Contractile Differences Detected by Speckle Tracking Echocardiography in Pediatric Patients with Mitral Valve Prolapse.

Mitral valve prolapse (MVP) is the most common valvar dysfunction in children. There is emerging evidence that MVP is not always a benign entity, hence identification of underlying mechanisms is pertinent to clinical management. Our group previously identified a ventricular contraction abnormality named end-systolic basal eversion (ESBE) in adults that contributed to MVP. The aim of this study was to evaluate regional circumferential strain in pediatric patients with MVP and ESBE compared to normal controls. Left ventricular circumferential strain was assessed in 16 pediatric patients referred for clinical echocardiographic examination with MVP and ESBE (MVP group) and compared to age-gender-matched healthy subjects. ESBE has been previously described as late systolic bileaflet mitral valve prolapse, papillary traction, and concomitant late systolic outward movement of the basal inferior myocardium. The mean age of the MVP group was 13.8 ± 4.6 year and 75% were female. All patients with MVP and controls had qualitatively normal systolic cardiac function. The MVP group had significantly lower regional strain values for 11/16 of the segments including all 6 basal segments. Importantly, the basal inferior (- 17.02 ± 8.32% vs. - 26.10 ± 3.18, p = 0.001) and basal inferolateral (- 19.53 ± 9.76 vs. - 26.10 ± 3.18, p = 0.03) had the lowest strain values compared to the average of all other segments suggesting weaker contraction in the basal inferior segments. Pediatric patients with MVP and ESBE are subject to a similar left ventricular mechanical dysfunction previously described in adults. ESBE was evident by decreased basal circumferential strain values. These findings denoted weaker contraction which is believed to propagate the late systolic outward movement of the basal ventricular myocardium.

Left Atrial Strain in the Repaired Tetralogy of Fallot Population: Comparisons to Biventricular Function, Native T1 Values, Exercise Parameters and Healthy Controls.

BACKGROUND: Non-invasive imaging markers in patients with repaired tetralogy of Fallot (rTOF) are still being investigated to inform clinical decision making. Atrial function is a prognostic indicator in many acquired and congenital heart diseases. We sought to examine the relationship between cardiac MRI (CMR)-derived indices of left atrial (LA) function, native left ventricular (LV) T1 values, biventricular systolic function, and exercise capacity in rTOF. METHODS: Sixty-six patients with rTOF without prior pulmonary valve replacement who underwent CMR (median age 18.5 years) were identified. Twenty-one adult rTOF patients (age range 19-32 years) were compared with 20 age-matched healthy volunteers (age range 19-34 years). LA reservoir, conduit, and pump global longitudinal strain (GLS) and strain rate (SR) were determined by tissue tracking. Native LV T1 values were measured on rTOF patients. Pearson correlations were performed to determine bivariate associations. RESULTS: Adult rTOF patients had higher pump GLS, pump:conduit, and pump:reservoir GLS ratios, and lower conduit:reservoir GLS ratio, LV ejection fraction (EF), and right ventricular EF compared to controls (p < 0.001 for each comparison). LA conduit:reservoir GLS and pump:reservoir GLS had correlations to native LV T1 (ρ = 0.26, p = 0.03 and ρ = - 0.26, p = 0.03, respectively). LA reservoir SR had positive correlation to RV EF (ρ = 0.27, p = 0.03). There were no statistically significant correlations between LA function and exercise capacity. CONCLUSIONS: LA function is altered in adolescent and young adult patients with rTOF indicating worse diastolic function and relates to increasing native LV T1 values. Future studies are indicated to investigate the progression of adverse atrial-ventricular interactions and poor outcomes in this population.

Left atrial strain and diastolic function abnormalities in obese and type 2 diabetic adolescents and young adults.

BACKGROUND: Adults with obesity and type 2 diabetes mellitus (T2DM) related to obesity are at increased risk of heart failure with preserved ejection fraction (HFpEF). Whether left ventricular (LV) diastolic function abnormalities related to obesity and T2DM start in adolescence and early adulthood is unknown. We non-invasively evaluated the differences seen in LV diastolic and left atrial (LA) function in adolescents and young adults with obesity and T2DM. METHODS: We analyzed echocardiographic measures of LV diastolic function in patients with structurally normal hearts which were divided into 3 groups (normal weight, obese, and T2DM). Spectral and tissue Doppler and 2-D speckle tracking measurements of diastolic function were obtained. Logistic regression was performed to compare the prevalence of abnormalities in diastolic function based on the worst 25th percentile for each measure to determine the prevalence of diastolic and LA function abnormalities in obese and T2DM patients. RESULTS: 331 teenagers and young adults (median age 22.1 years) were analyzed (101 normal weight, 114 obese, 116 T2DM). Obese and T2DM group had lower E/A and higher E/e'. Obese and T2DM patients had significantly lower atrial reservoir, conduit, and booster strain and worse reservoir and conduit strain rate compared to normal patients (p < 0.001 for all measures). All patients had normal LA volumes. On multivariable analysis, conduit strain and reservoir and conduit strain rate were independently associated with having below the 25th percentile e'. Conduit strain rate was independently associated with having below the 25th percentile for mitral E/A ratio on multivariable analysis. CONCLUSIONS: Abnormal indices of LV diastolic function are detected in adolescents and young adults with obesity and T2DM. LA function and strain analysis were able to detect evidence of decreased reservoir, conduit, and booster strain in these patients although LA volume was normal. The use of LA function strain may increase our ability to detect early diastolic function abnormalities in this population.

Left and right atrial speckle tracking: Comparison of three methods of time reference gating.

BACKGROUND: Atrial function has a close interdependence with ventricular function and plays a central role in maintaining optimal cardiac function. There are two well-defined timing methods used to determine the start point. The aim of this prospective study was to objectively assess the influence of gating method selection on reported left and right strain values within the same group of healthy subjects. METHODS: 101 volunteers (44 male, 57 female) had adequate tracking for analysis on TomTec Imaging Systems (Unterschleissheim, Germany). The median age was 41 years (range 19-79 years, interquartile range 30-52 years). Atrial strain by 2D-speckle tracking echocardiography was evaluated using two commonly applied zero baseline time reference methods: R-R gating and P-P gating, in addition to volume gating (defining end-systole at the atrial maximum and end-diastole at the atrial minimum). RESULTS: True atrial minimum occurred prior to the onset of the QRS in most healthy volunteers. There was a significant difference for LA and RA reservoir strain between volume gating and R-R gating (mean difference, 4.63%; P < .001 for LA; mean difference, 4.23%; P < .001 for RA), as well as volume gating and P-P gating (mean difference, 5.26%; P < .001 for LA; mean difference, 6.24%; P < .001 for RA). Noticeably, reservoir strain was comparable between R-R gating and P-P gating (mean difference, 0.58%, P = .06) in LA, but not on RA (mean difference, 2.02%, P < .001). CONCLUSIONS: There was variability in atrial strain values depending on the zero baseline time reference method used.

Atrial Function and Its Role in the Non-invasive Evaluation of Diastolic Function in Congenital Heart Disease.

Diastolic dysfunction has correlated with adverse outcomes in various forms of unrepaired and repaired or palliated congenital heart disease (CHD). The non-invasive assessment of diastolic function in pediatric and adult patients with CHD remains challenging. Atrial size has a pivotal role in the evaluation of diastolic function; however, a growing body of evidence supports the additional role of atrial function as a more sensitive parameter of ventricular diastolic dysfunction. While the importance of atrial function is becoming clearer in adult acquired heart disease, it remains ambiguous in those with CHD. In this review we set the stage with the current understanding of diastolic function assessment in CHD, followed by insight into atrial form and function including its non-invasive assessment, and conclude with the current knowledge of atrial function in CHD. A general pattern of decrease in reservoir and conduit function with compensatory increase followed by decompensatory decrease in contractile function seems to be the common pathway of atrial dysfunction in most forms of CHD.

Changes in mechanical dyssynchrony in severe aortic stenosis patients undergoing transcatheter aortic valve replacement.

INTRODUCTION: Aortic stenosis (AS) imposes a significant afterload on the left ventricle, but regional manifestations of the overall load may not be uniform, leading to mechanical dyssynchrony. Accordingly, we evaluated the prevalence of dyssynchrony in patients with severe AS at baseline as well as changes after transfemoral aortic valve replacement (TAVR). METHODS: This study is a retrospective analysis of 225 patients in sinus rhythm who underwent TAVR for severe AS, in whom inter-ventricular and intra-ventricular dyssynchrony were measured at baseline, discharge, 1 month, and 1 year. Inter-ventricular dyssynchrony was defined as the difference between left and right ventricular pre-ejection intervals; intra-ventricular dyssynchrony was defined as the difference between time to peak systolic velocity of the basal septal and lateral segments. Patients were further stratified into those with QRS <120 ms or >120 ms. RESULTS: At baseline, a quarter of patients met the criterion for significant inter-ventricular dyssynchrony, and a third had evidence of intra-ventricular dyssynchrony. Both decreased after TAVR although only the intra-ventricular dyssynchrony reached statistical significance. The interplay between QRS duration and changes in inter- and intra-ventricular dyssynchrony are also explored. CONCLUSIONS: In patients with severe AS, there was evidence of mechanical dyssynchrony that is improved post-TAVR. Whether dyssynchrony is clinically and prognostically significant, and if it represents a potential target for additional therapy remains to be studied.

Effect of transcatheter aortic valve replacement on left atrial function.

OBJECTIVES: To investigate the effect of transcatheter aortic valve replacement on left atrial volumetric function and left atrial volume for the prediction of adverse outcomes. METHODS: This is a retrospective analysis of 121 patients in sinus rhythm who underwent TAVR for severe AS. Maximum LA volume index (LAVI max), minimum LA volume index (LAVI min), and "pre-A" volume index (LAVIpre-A, the volume before atrial contraction) were measured by biplane Simpson's method at baseline, 1 month, and 1 year. The reservoir function, conduit function, booster pump function were calculated. All patients were followed for new-onset of atrial fibrillation, hospitalization and all-cause mortality. RESULTS: The reservoir function, conduit function and booster function before TAVR were 46%, 21%, 32%, respectively. LA volumetric function assessment demonstrated that reservoir function, conduit function increased over the time (all P < 0.01). There was no difference in booster function after TAVR (P = 0.18). Baseline markedly enlarged LA was significantly increased for AF (HR: 4.72; 95% CI, 1.11-20.13, P = 0.04). In addition, There was a progressive decrease in LAVI max (P = 0.02) and RVSP (P = 0.03) over the time in non-AF group but not in AF group (P = 0.62 and P = 0.65, respectively). Although, the proportion of high left ventricular filling pressure decreased in both groups but a marked decrease was noted in non AF group in compared with AF group. CONCLUSION: Reservoir function, conduit function increased over time. Lack of negative LA remodeling post TAVR was associated with higher incidence of AF.

Isolated Aneurysms of the Membranous Ventricular Septum Without Residual Shunts: Systematic Review and Description of 3 Cases in Adults.

A ventricular septal defect is the most common congenital cardiac abnormality encountered in infants and children. Many of them survive through adulthood before diagnosis. Two-thirds of the cases involve the membranous part of the septum. In the absence of an interventricular shunt or concomitant cardiac surgery, guidelines for surgical intervention or resection of isolated aneurysms of the membranous septum are not well established. In this report, we discuss a multi-imaging modality approach for the diagnosis and assessment of membranous ventricular septal aneurysms and review the experts' consensuses for follow-up and treatment strategies.

Elevated Myocardial Extracellular Volume Fraction in Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is a genetic, X-linked recessive disease with an associated cardiomyopathy characterized by myocardial fibrosis leading to heart failure, arrhythmias, and death. Earlier detection and treatment of cardiac involvement in DMD hold potential to improve outcomes. Cardiovascular magnetic resonance (CMR) extracellular volume (ECV) quantification using T1 mapping is a histologically validated, non-invasive marker of diffuse fibrosis. This study aims to determine the ECV in a pediatric DMD population, and correlate it with metrics of left ventricular function. A retrospective review of pediatric DMD subjects who underwent CMR at a single institution. A total of 47 DMD patients (mean age 14 ± 2 years) were included for analysis. Global myocardial ECV was significantly higher in the DMD group (29 ± 6%) compared with published normal values (24 ± 2%, p = 0.0001). Higher ECV values correlate with indices of left ventricular function, including decreased left ventricular ejection fraction (r = -0.46, p = 0.001) and indexed left ventricular end diastolic volume (r = 0.41, p = 0.004). ECV was not significantly higher in DMD patients with late gadolinium enhancement (LGE) (30 ± 7%) compared to DMD patients without LGE (27 ± 5%, p = 0.0717). CMR T1 mapping is a feasible method for quantification of ECV in patients with DMD. Global myocardial ECV is significantly higher in the DMD population compared to healthy controls and correlates with other metrics of myocardial function. Global myocardial ECV may serve as an important tool to determine cardiac involvement in DMD population and help guide medical management.

Mechanical effects of left ventricular midwall fibrosis in non-ischemic cardiomyopathy.

BACKGROUND: Left ventricular (LV) mid-wall fibrosis (MWF), which occurs in about a quarter of patients with non-ischemic cardiomyopathy (NICM), is associated with high risk of pump failure. The mid LV wall is the site of circumferential myocardial fibers. We sought to determine the effect of MWF on LV myocardial mechanics. METHODS: Patients with NICM (n = 116; age: 62.8 ± 13.2 years; 67% male) underwent late gadolinium enhancement cardiovascular magnetic resonance (CMR) and were categorized according to the presence (+) or absence (-) of MWF. Feature tracking (FT) CMR was used to assess myocardial deformation. RESULTS: Despite a similar LVEF (24.3 vs. 27.5%, p = 0.20), patients with MWF (32 [24%]) had lower global circumferential strain (Ɛcc: -6.6% vs. -9.4 %, P = 0.004), but similar longitudinal (Ɛll: -7.6 % vs. -9.4 %, p = 0.053) and radial (Ɛrr: 14.6% vs. 17.8% p = 0.18) strain. Compared with - MWF, + MWF was associated with reduced LV systolic, circumferential strain rate (-0.38 ± 0.1 vs. -0.56 ± 0.3 s(-1), p = 0.005) and peak LV twist (4.65 vs. 6.31°, p = 0.004), as well as rigid LV body rotation (64 % vs. 28 %, P <0.001). In addition, +MWF was associated with reduced LV diastolic strain rates (DSRcc: 0.34 vs. 0.46 s(-1); DSRll: 0.38 vs. 0.50s(-1); DSRrr: -0.55 vs. -0.75 s(-1); all p <0.05). CONCLUSIONS: MWF is associated with reduced LV global circumferential strain, strain rate and torsion. In addition, MWF is associated with rigid LV body rotation and reduced diastolic strain rates. These systolic and diastolic disturbances may be related to the increased risk of pump failure observed in patients with NICM and MWF.

Relationship of Right Ventricular Size and Function with Respiratory Status in Duchenne Muscular Dystrophy.

The relationship between pulmonary function and right ventricle (RV) in Duchenne muscular dystrophy (DMD) has not been evaluated. Using cardiac magnetic resonance (CMR), we describe the relationship of RV size and function with spirometry in a DMD cohort. Fifty-seven boys undergoing CMR and pulmonary function testing within 1 month at a single center (2013-2015) were enrolled. Comparisons of RV ejection fraction (RVEF) and end-diastolic volume index (RVEDVI) were made across categories of percent forced vital capacity (FVC%), and relationships were assessed. Mean age was 15.5 ± 3.5 years. Spirometry and CMR were performed within 3.9 ± 4.1 days. Median FVC% was 92.0 % (67.5-116.5 %). Twenty-three (40 %) patients had abnormal FVC% (<80 %) of which 13 (57 %) had mild (FVC% 60-79 %), 6 (26 %) had moderate (FVC% 40-59 %), and 4 (17 %) had severe (FVC <40 %) reductions. Mean RVEF was 58.3 ± 3.7 %. Patients with abnormal FVC% were older and had lower RVEF and RVEDVI. Both RVEF and RVEDVI were significantly associated with FVC% (r = 0.31, p = 0.02 and r = 0.39, p = 0.003, respectively). In a large DMD cohort, RVEF and RVEDVI were related to FVC%. Worsening respiratory status may guide monitoring of cardiac function in these patients.

Myocardial Fibrosis and Left Ventricular Dysfunction in Duchenne Muscular Dystrophy Carriers Using Cardiac Magnetic Resonance Imaging.

The goal of our study was to characterize the degree of myocardial fibrosis and left ventricular dysfunction in our cohort of Duchenne muscular dystrophy (DMD) carriers using cardiac magnetic resonance imaging (CMR). Seventy percent of males with DMD have mothers who are carriers of the Xp21 mutation. Carrier phenotypic characteristics range from asymptomatic to left ventricular (LV) dysfunction and cardiomyopathy. The true prevalence of cardiac involvement in DMD carriers is unknown. We performed a retrospective observational study. All female DMD carriers who underwent clinical CMR studies at Cincinnati Children's Hospital Medical Center from December 6, 2006, to August 28, 2013, were evaluated. Patients underwent standard CMR assessment with LV function assessment and late gadolinium enhancement (LGE). In addition, offline feature tracking strain analysis was performed on the basal, mid, and apical short axis. Twenty-two patients were studied, of which 20 underwent adequate testing for myocardial LGE. Four of 22 patients (18 %) were found to have LV dysfunction (ejection fraction <55 %). Seven of 20 DMD carriers (35 %) were found to have LGE. The patients with evidence of LGE had an overall trend to lower absolute deformation parameters; however, this did not meet statistical significance when correcting for multiple comparisons. Our study demonstrates a high rate of LGE as well as LV dysfunction in DMD carriers. Cardiovascular and musculoskeletal symptoms were not statistically different between those with and without cardiac involvement. This study demonstrates the importance of surveillance CMR evaluation of DMD carriers.

Regional circumferential strain is a biomarker for disease severity in duchenne muscular dystrophy heart disease: a cross-sectional study.

The aim of this study is to determine the contribution of strain ε cc in mid left ventricular (LV) segments to the reduction of composite LV circumferential ε cc in assess severity of duchenne muscular dystrophy (DMD) heart disease as assessed by cardiac magnetic resonance imaging (CMR). DMD patients and control subjects were stratified by age, LV ejection fraction, and late gadolinium enhancement (LGE) status. Tagged CMR images were analyzed for global ventricular function, LGE imaging, and composite and segmental ε cc. The relationship between changes in segmental ε cc changes and LGE across patient groups was assessed by a statistical step-down model. LV ε cc exhibited segmental heterogeneity; in control subjects and young DMD patients, ε cc was greatest in LV lateral free wall segments. However, with increasing age and cardiac disease severity as demonstrated by decreased EF and development of myocardial strain the segmental differences diminished. In subjects with advanced heart disease as evidenced by reduced LV ejection fraction and presence of LGE, very little segmental heterogeneity was present. In control subjects and young DMD patients, ε cc was greatest in LV lateral free wall segments. Increased DMD heart disease severity was associated with reduced composite; ε cc diminished regional ε cc heterogeneity and positive LGE imaging. Taken together, these findings suggest that perturbation of segmental, heterogeneous ε cc is an early biomarker of disease severity in this cross-section of DMD patients.

Comparison of area-length method by echocardiography versus full-volume quantification by cardiac magnetic resonance imaging for the assessment of left atrial volumes in children, adolescents, and young adults.

Left atrial (LA) size is a known predictor of adverse cardiovascular events. Echocardiography is the modality of choice for the evaluation of atrial size; however, cardiac magnetic resonance imaging (cMRI) remains the "gold standard." We sought to calculate atrial volumes using the area-length method by both echocardiography and cMRI and compare them with area-volume quantification by cMRI. Thiry-eight patients (mean age 20 ± 12 years, 71% male) who underwent cMRI and echocardiography between September 2010 and June 2012 were retrospectively identified. The time interval between the two studies was ≤ 6 months. LA volumes by echocardiogram were estimated using the area-length method: LA volume = (0.85 × area(4ch) × area(2ch))/(shortest atrial length). The atrial length and area were measured in standard apical two-chamber and four-chamber planes. Measured values were indexed to body surface area (BSA). CMRI measurements were obtained from prospectively gated steady-state free precession cine stack images obtained in a standard four-chamber plane. LA volumes were calculated using Simpson's method: LA volume = LA area × (slice thickness + gap) per slice. Slice thickness ranged from 5 to 7 mm with contiguous slices of 5 to 7 mm. The values were indexed to BSA. Statistics were summarized using measures of central tendency. LA volumes by echocardiography were significantly less than those by full-volume cMRI quantification. The mean LA volume by echocardiography and full-volume cMRI were 35 ± 14.5 and 42.4 ± 17.2, respectively (p = 0.05). The mean difference between LA volumes obtained by the two methods was 7.4 ± 10.6. LA volume measured by cMRI using the area-length method closely approximated full-volume assessment by cMRI with mean values of 42.9 ± 17.4 versus 42.4 ± 17.2, respectively (p = 0.91). There were no significant differences in the patient characteristics between the two study modalities. LA volumes as measured by echocardiography using the area-length method consistently underestimated the true volume when compared with cMRI. LA volumes measured using the area-length method by cMRI is an alternative technique for accurately quantifying chamber size and can be useful in decreasing scan time or when full-volume data sets are incomplete.

Left ventricular noncompaction in Duchenne muscular dystrophy.

BACKGROUND: Left ventricular noncompaction (LVNC) describes deep trabeculations in the left ventricular (LV) endocardium and a thinned epicardium. LVNC is seen both as a primary cardiomyopathy and as a secondary finding in other syndromes affecting the myocardium such as neuromuscular disorders. The objective of this study is to define the prevalence of LVNC in the Duchenne Muscular Dystrophy (DMD) population and characterize its relationship to global LV function. METHODS: Cardiac magnetic resonance (CMR) was used to assess ventricular morphology and function in 151 subjects: DMD with ejection fraction (EF) > 55% (n = 66), DMD with EF < 55% (n = 30), primary LVNC (n = 15) and normal controls (n = 40). The non-compacted to compacted (NC/C) ratio was measured in each of the 16 standard myocardial segments. LVNC was defined as a diastolic NC/C ratio > 2.3 for any segment. RESULTS: LVNC criteria were met by 27/96 DMD patients (prevalence of 28%): 11 had an EF > 55% (prevalence of 16.7%), and 16 had an EF < 55% (prevalence of 53.3%). The median maximum NC/C ratio was 1.8 for DMD with EF > 55%, 2.46 for DMD with EF < 55%, 1.54 for the normal subjects, and 3.69 for primary LVNC patients. Longitudinal data for 78 of the DMD boys demonstrated a mean rate of change in NC/C ratio per year of +0.36. CONCLUSION: The high prevalence of LVNC in DMD is associated with decreased LV systolic function that develops over time and may represent muscular degeneration versus compensatory remodeling.