Association of global longitudinal strain by feature tracking cardiac magnetic resonance imaging with adverse outcomes among community-dwelling adults without cardiovascular disease: The Dallas Heart Study

AIM

Left ventricular (LV) global longitudinal strain (GLS) may detect subtle abnormalities in myocardial contractility among individuals with normal LV ejection fraction (LVEF). However, the prognostic implications of GLS among healthy, community-dwelling adults is not well-established.

METHODS AND RESULTS

Overall, 2234 community-dwelling adults (56% women, 47% Black) with LVEF ≥50% without a history of cardiovascular disease (CVD) from the Dallas Heart Study who underwent cardiac magnetic resonance (CMR) with GLS assessed by feature tracking CMR (FT-CMR) were included. The association of GLS with the risk of incident major adverse cardiovascular events (MACE; composite of incident myocardial infarction, incident heart failure [HF], hospitalization for atrial fibrillation, coronary revascularization, and all-cause death), and incident HF or death were assessed with adjusted Cox proportional hazards models. A total of 309 participants (13.8%) had MACE during a median follow-up duration of 17 years. Participants with the worst GLS (Q4) were more likely male and of the Black race with a history of tobacco use and diabetes with lower LVEF, higher LV end-diastolic volume, and higher LV mass index. Cumulative incidence of MACE was higher among participants with worse (Q4 vs. Q1) GLS (20.4% vs. 9.0%). In multivariable-adjusted Cox models that included clinical characteristics, cardiac biomarkers and baseline LVEF, worse GLS (Q4 vs. Q1) was associated with a significantly higher risk of MACE (hazard ratio [HR] 1.55, 95% confidence interval [CI] 1.07-2.24, p = 0.02) and incident HF or death (HR 1.57, 95% CI 1.03-2.38, p = 0.04).

CONCLUSIONS

Impaired LV GLS assessed by FT-CMR among adults free of cardiovascular disease is associated with a higher risk of incident MACE and incident HF or death independent of cardiovascular risk factors, cardiac biomarkers and LVEF.

Academic Medicine Faculty Perceptions of Work-Life Balance Before and Since the COVID-19 Pandemic

IMPORTANCE

How the COVID-19 pandemic has affected academic medicine faculty's work-life balance is unknown.

OBJECTIVE

To assess the association of perceived work-life conflict with academic medicine faculty intention to leave, reducing employment to part time, or declining leadership opportunities before and since the COVID-19 pandemic.

DESIGN, SETTINGS, AND PARTICIPANTS

An anonymous online survey of medical, graduate, and health professions school faculty was conducted at a single large, urban academic medical center between September 1 and September 25, 2020.

MAIN OUTCOMES AND MEASURES

Self-assessed intention to leave, reducing employment to part time, or turning down leadership opportunities because of work-life conflict before and since the COVID-19 pandemic.

RESULTS

Of the 1186 of 3088 (38%) of faculty members who answered the survey, 649 (55%) were women and 682 (58%) were White individuals. Respondents were representative of the overall faculty demographic characteristics except for an overrepresentation of female faculty respondents and underrepresentation of Asian faculty respondents compared with all faculty (female faculty: 649 [55%] vs 1368 [44%]; Asian faculty: 259 [22%] vs 963 [31%]). After the start of the COVID-19 pandemic, faculty were more likely to consider leaving or reducing employment to part time compared with before the pandemic (leaving: 225 [23%] vs 133 [14%]; P < .001; reduce hours: 281 [29%] vs 206 [22%]; P < .001). Women were more likely than men to reduce employment to part time before the COVID-19 pandemic (153 [28%] vs 44 [12%]; P < .001) and to consider both leaving or reducing employment to part time since the COVID-19 pandemic (leaving: 154 [28%] vs 56 [15%]; P < .001; reduce employment: 215 [40%] vs 49 [13%]; P < .001). Faculty with children were more likely to consider leaving and reducing employment since the COVID-19 pandemic compared with before the pandemic (leaving: 159 [29%] vs 93 [17%]; P < .001; reduce employment: 213 [40%] vs 130 [24%]; P < .001). Women with children compared with women without children were also more likely to consider leaving since the COVID-19 pandemic than before (113 [35%] vs 39 [17%]; P < .001). Working parent faculty and women were more likely to decline leadership opportunities both before (faculty with children vs without children: 297 [32%] vs 84 [9%]; P < .001; women vs men: 206 [29%] vs 47 [13%]; P < .001) and since the COVID-19 pandemic (faculty with children vs faculty without children: 316 [34%] vs 93 [10 %]; P < .001; women vs men: 148 [28%] vs 51 [14%]; P < .001).

CONCLUSIONS AND RELEVANCE

In this survey study, the perceived stressors associated with work-life integration were higher in women than men, were highest in women with children, and have been exacerbated by the COVID-19 pandemic. The association of both gender and parenting with increased perceived work-life stress may disproportionately decrease the long-term retention and promotion of junior and midcareer women faculty.

Association of African Ancestry With Electrocardiographic Voltage and Concentric Left Ventricular Hypertrophy: The Dallas Heart Study

Importance

Compared with white individuals, black individuals have increased electrocardiographic voltage and an increased prevalence of concentric left ventricular (LV) hypertrophy. Whether environmental or genetic factors lead to these racial differences is unknown.

Objective

To determine whether proportion of genetically determined African ancestry among self-reported black individuals is associated with increased electrocardiographic voltage and concentric LV hypertrophy (LVH).

Design, Setting, and Participants

The Dallas Heart Study is a probability-based cohort study of English- or Spanish-speaking Dallas County, Texas, residents, with deliberate oversampling of black individuals. Participants underwent extensive phenotyping, which included electrocardiography (ECG), cardiac magnetic resonance imaging (CMR), and dual-energy radiography absorptiometry (DEXA) at a single center. Participants aged 18 to 65 years who enrolled in the Dallas Heart Study between July 2000 and December 2002, self-identified as black (n = 1251) or white (n = 826), and had ECG, CMR, and DEXA data were included in this analysis. Data were analyzed from June 2017 to September 2018.

Exposures

Proportion of African ancestry.

Main Outcomes and Measures

Electrocardiographic voltage (12-lead and 9-lead) and markers of concentric LVH as assessed by CMR (LV concentricity0.67 [LV mass/end-diastolic volume0.67], LV wall thickness [LVWT], and prevalent LVH [defined by LV mass/height2.7]).

Results

Of the 2077 participants included in the study, 1138 (54.8%) were women, and the mean (SD) age was 45.2 (9.9) years. Black race and African ancestry were individually associated with increased ECG voltage, LV concentricity0.67, LVWT, and prevalent LVH in multivariable analyses adjusting for age, sex, systolic blood pressure, antihypertensive medication use, and body composition. When African ancestry and black race were entered together into multivariable models, African ancestry but not black race remained associated with ECG voltage, LVWT, LV concentricity0.67, and prevalent LVH. Among black participants, African ancestry remained associated with these 4 phenotypes (12-lead voltage: β, 0.05; P = .04; LVWT: β, 0.05; P = .02; LV concentricty0.67: β, 0.05; P = .045; prevalent LVH: odds ratio, 1.2; 95% CI, 1.03-1.4; P = .02).

Conclusions and Relevance

Genetically determined African ancestry was associated with electrocardiographic voltage, measures of concentric LV remodeling, and prevalent LVH. These data support a genetic basis related to African ancestry for the increased prevalence of these cardiovascular traits in black individuals.

Association of Concentric Left Ventricular Hypertrophy With Subsequent Change in Left Ventricular End-Diastolic Volume: The Dallas Heart Study

BACKGROUND

In the conventional paradigm of the progression of left ventricular hypertrophy, a thick-walled left ventricle (LV) ultimately transitions to a dilated cardiomyopathy. There are scant data in humans demonstrating whether this transition occurs commonly without an interval myocardial infarction.

METHODS AND RESULTS

Participants (n=1282) from the Dallas Heart Study underwent serial cardiac magnetic resonance ≈7 years apart. Those with interval cardiovascular events and a dilated LV (increased LV end-diastolic volume [EDV] indexed to body surface area) at baseline were excluded. Multivariable linear regression models tested the association of concentric hypertrophy (increased LV mass and LV mass/volume^0.67) with change in LVEDV. The study cohort had a median age of 44 years, 57% women, 43% black, and 11% (n=142) baseline concentric hypertrophy. The change in LVEDV in those with versus without concentric hypertrophy was 1 mL (-9 to 12) versus -2 mL (-11 to 7), respectively, P<0.01. In multivariable linear regression models, concentric hypertrophy was associated with larger follow-up LVEDV (P≤0.01). The progression to a dilated LV was uncommon (2%, n=25).

CONCLUSIONS

In the absence of interval myocardial infarction, concentric hypertrophy was associated with a small, but significantly greater, increase in LVEDV after 7-year follow-up. However, the degree of LV enlargement was minimal, and few participants developed a dilated LV. These data suggest that if concentric hypertrophy does progress to a dilated cardiomyopathy, such a transition would occur over a much longer timeframe (eg, decades) and perhaps less common than previously thought.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00344903.

Dynamic Relation of Changes in Weight and Indices of Fat Distribution With Cardiac Structure and Function: The Dallas Heart Study

BACKGROUND

Obesity may increase heart failure risk through cardiac remodeling. Cross-sectional associations between adiposity and cardiac structure and function have been elucidated, but the impact of longitudinal changes in adiposity on cardiac remodeling is less well understood.

METHODS AND RESULTS

Participants in the Dallas Heart Study without cardiovascular disease or left ventricular dysfunction underwent assessment of body weight, anthropometrics, and cardiac magnetic resonance imaging at baseline and 7 years later. Associations between changes in indices of generalized and central adiposity with changes in left ventricular mass, volume, mass/volume ratio (concentricity), wall thickness, and ejection fraction were assessed using multivariable linear regression. The study cohort (n=1262) mean age was 44 years with 57% women, 44% black, and 36% obese participants. At follow-up, 41% had ≥5% weight gain, and 15% had ≥5% weight loss. Greater weight gain was associated with younger age, lower risk factor burden, and lower body mass index at baseline. In multivariable models adjusting for age, sex, race, comorbid conditions at baseline and follow-up, baseline adiposity, and cardiac measurement, increasing weight was associated with increases in left ventricular mass (β=0.10, P<0.0001), wall thickness (β=0.10, P<0.0001), and concentricity (β=0.06, P=0.002), with modest effects on end-diastolic volume (β=0.04, P=0.044) and ejection fraction (β=0.05, P=0.046). Similar results were seen with other adiposity indices.

CONCLUSIONS

Concentric left ventricular remodeling is the predominant phenotype linked to increasing adiposity in middle age. Our findings support the importance of weight management to prevent secular changes in adiposity, concentric remodeling, and eventual heart failure over time.

Cardiac magnetic resonance imaging to assess the impact of maternal habitus on cardiac remodeling during pregnancy

BACKGROUND

It is well known that the maternal cardiovascular system undergoes profound alterations throughout pregnancy. Interest in understanding these changes has led investigators to use evolving and increasingly sophisticated techniques to study these changes, most recently with 2-dimensional echocardiography. Despite its clinical utility, echocardiography has limitations, and cardiac magnetic resonance imaging (CMRI) has become increasingly used for evaluation of cardiac structure and function.

OBJECTIVE

We used CMRI to evaluate cardiac remodeling according to maternal habitus throughout pregnancy and postpartum.

STUDY DESIGN

This was a prospective, observational study of nulliparous women aged 18-30 years, without preexisting medical conditions, conducted from October 2012 through December 2014. Women were classified according to prepregnancy body mass index (BMI) as either normal (BMI 18.5-24.9 kg/m(2)) or overweight (BMI 25-35 kg/m(2)). All women underwent CMRI during 5 epochs throughout gestation: 12-16 weeks, 26-30 weeks, 32-36 weeks, at delivery, and 3 months' postpartum. Using left ventricular mass (LVM) as a marker of cardiac remodeling, the 2 cohorts were compared.

RESULTS

There were 14 normal-weight (BMI 22.2 ± 1.3) and 9 overweight (BMI 29.1 ± 2.0) women who participated in the study. Beginning at 26-30 weeks and continuing to delivery, LVM of both normal-weight and overweight women was significantly increased compared with the respective first-trimester studies for each cohort (P < .001). LVM of both cohorts returned to their index values by 3 months' postpartum. The geometric ratio of LVM to left ventricular end-diastolic volume was calculated, and both normal-weight and overweight women demonstrated concentric remodeling throughout gestation, however this resolved by 12 weeks' postpartum.

CONCLUSION

There is substantial cardiac remodeling during pregnancy with significant increases in LVM that are proportional to maternal size. Left ventricular geometric remodeling was concentric in both normal-weight and overweight women. All changes in cardiac remodeling resolved by 3 months' postpartum.

Cardiovascular response to exercise training in the systemic right ventricle of adults with transposition of the great arteries

KEY POINTS

Patients with transposition of the great arteries (TGA) and systemic right ventricles have premature congestive heart failure; there is also a growing concern that athletes who perform extraordinary endurance exercise may injure the right ventricle. Therefore we felt it essential to determine whether exercise training might injure a systemic right ventricle which is loaded with every heartbeat. Previous studies have shown that short term exercise training is feasible in TGA patients, but its effect on ventricular function is unclear. We demonstrate that systemic right ventricular function is preserved (and may be improved) in TGA patients with exercise training programmes that are typical of recreational and sports participation, with no evidence of injury on biomarker assessment. Stroke volume reserve during exercise correlates with exercise training response in our TGA patients, identifying this as a marker of a systemic right ventricle (SRV) that may most tolerate (and possibly even be improved by) exercise training.

ABSTRACT

We aimed to assess the haemodynamic effects of exercise training in transposition of the great arteries (TGA) patients with systemic right ventricles (SRVs). TGA patients have limited exercise tolerance and early mortality due to systemic (right) ventricular failure. Whether exercise training enhances or injures the SRV is unclear. Fourteen asymptomatic patients (34 ± 10 years) with TGA and SRV were enrolled in a 12 week exercise training programme (moderate and high-intensity workouts). Controls were matched on age, gender, BMI and physical activity. Exercise testing pre- and post- training included: (a) submaximal and peak; (b) prolonged (60 min) submaximal endurance and (c) high-intensity intervals. Oxygen uptake (V̇O2; Douglas bag technique), cardiac output (Q̇c, foreign-gas rebreathing), ventricular function (echocardiography and cardiac MRI) and serum biomarkers were assessed. TGA patients had lower peak V̇O2, Q̇c, and stroke volume (SV), a blunted Q̇c/V̇O2 slope, and diminished SV response to exercise (SV increase from rest: TGA = 15.2%, controls = 68.9%, P < 0.001) compared with controls. After training, TGA patients increased peak V̇O2 by 6 ± 8.5%, similar to controls (interaction P = 0.24). The magnitude of SV reserve on initial testing correlated with Q̇c training response (r = 0.58, P = 0.047), though overall, no change in peak Q̇c was observed. High-sensitivity troponin T (hs-TnT) and N-terminal prohormone of brain naturetic peptide (NT pro-BNP) were low and did not change with acute exercise or after training. Our data show that TGA patients with SRVs in this study safely participated in exercise training and improved peak V̇O2. Neither prolonged submaximal exercise, nor high-intensity intervals, nor short-term exercise training seem to injure the systemic right ventricle.

The Effects of Maternal Position and Habitus on Maternal Cardiovascular Parameters as Measured by Cardiac Magnetic Resonance

OBJECTIVE

To evaluate left ventricular stroke volume (LVSV) and cardiac output (CO) according to maternal position and habitus throughout pregnancy and postpartum using serial cardiac magnetic resonance imaging (c-MRI).

STUDY DESIGN

This was a prospective study of normotensive nulliparous women using 1.5-T c-MRI performed in both left lateral decubitus and supine positions during three epochs in pregnancy and at 12 weeks' postpartum. Women were stratified according to prepregnancy body mass indices (BMIs) as normal or overweight/obese and compared for LVSV and CO using repeated measures, mixed-random, and fixed-effects model.

RESULTS

Between October 2012 and December 2014, 14 normal-weight (BMI 22.2 ± 1.3) and 9 overweight/obese (BMI 29.1 ± 2.0) women underwent c-MRI. During early pregnancy, position did not alter LVSV or CO for either cohort. Beginning at 26 to 30 weeks and continuing to 32 to 36 weeks, normal-weight women demonstrated significant positional differences for LVSV and CO (both p < 0.01). In contrast, positional differences did not influence these parameters in overweight/obese women. At 12 weeks' postpartum, all influence of position had dissipated for both cohorts.

CONCLUSION

Maternal position has no effect on LVSV or CO during the first half of pregnancy. In the second half, however, only normal-weight women exhibit significant changes in cardiac parameters when comparing the left lateral decubitus with supine position.

Effect of Mineralocorticoid Receptor Antagonists on Cardiac Structure and Function in Patients With Diastolic Dysfunction and Heart Failure With Preserved Ejection Fraction: A Meta-Analysis and Systematic Review

Background

There has been an increasing interest in use of mineralocorticoid receptor antagonists (MRAs) in patients with heart failure with preserved ejection fraction (HFPEF). However, a comprehensive evaluation of MRA effects on left ventricular (LV) structure and function in these patients is lacking. In this meta‐analysis, we evaluated the effects of MRAs on LV structure and function among patients with diastolic dysfunction or HFPEF.

Methods & Results

Randomized, controlled clinical trials evaluating the efficacy of MRAs in patients with diastolic dysfunction or HFPEF were included. The primary outcome was change in E/e’, a specific measure of diastolic function. Secondary outcomes included changes in other measures of diastolic function, LV structure, surrogate markers for myocardial fibrosis (carboxy‐terminal peptide of procollagen type I [PICP] and amino‐terminal peptide of pro‐collagen type‐II [PIIINP]), blood pressure, and exercise tolerance. In the pooled analysis, MRA use was associated with significant reduction in E/e’ (weighted mean difference [WMD] [95% confidence interval {CI}]: −1.68 [−2.03 to −1.33]; P<0.0001) and deceleration time (WMD [95% CI]: −12.0 ms [−23.3 to −0.7]; P=0.04) as compared with control, suggesting and improvement in diastolic function. Furthermore, blood pressure and levels of PIIINP and PICP were also significantly reduced with MRA therapy with no significant change in LV mass or dimensions.

Conclusion

MRA therapy in patients with asymptomatic diastolic dysfunction or HFPEF is associated with significant improvement in diastolic function and markers of cardiac fibrosis without a significant change in LV mass or dimensions.

Appropriate use and clinical impact of transthoracic echocardiography

IMPORTANCE

Transthoracic echocardiography (TTE) accounts for almost half of all cardiac imaging services and is a widely available and versatile tool. Appropriate use criteria (AUC) for echocardiography were developed to improve patient care and health outcomes. Prior studies have shown that most TTEs are appropriate by AUC. However, the associations among TTE, AUC, and their clinical impact have not been well explored.

OBJECTIVES

To describe the proportion of TTEs that affect clinical care in an academic medical center overall and in subgroups defined as appropriate and inappropriate by AUC.

DESIGN AND SETTING

Retrospective review of medical records from 535 consecutive TTEs at an academic medical center was performed. The TTEs were classified according to 2011 AUC by 2 cardiologists blinded to clinical impact and were assessed for clinical impact by 2 cardiologists blinded to AUC. Clinical impact was assigned to 1 of the following 3 categories: (1) active change in care, (2) continuation of current care, or (3) no change in care.

PARTICIPANTS

Five hundred thirty-five patients undergoing TTE.

EXPOSURE

Transthoracic echocardiography. MAIN OUTCOMES AND MEASURES Prevalence of appropriate, inappropriate, and uncertain TTEs and prevalence of clinical impact subcategories.

RESULTS

Overall, 31.8% of TTEs resulted in an active change in care; 46.9%, continuation of current care; and 21.3%, no change in care. By 2011 AUC, 91.8% of TTEs were appropriate; 4.3%, inappropriate; and 3.9%, uncertain. We detected no statistically significant difference between appropriate and inappropriate TTEs in the proportion of TTEs that led to active change in care (32.2% vs 21.7%; P= .29).

CONCLUSIONS AND RELEVANCE

Although 9 in 10 TTEs were appropriate by 2011 AUC, fewer than 1 in 3 TTEs resulted in an active change in care, nearly half resulted in continuation of current care, and slightly more than 1 in 5 resulted in no change in care. The low rate of active change in care (31.8%) among TTEs mostly classified as appropriate (91.8%) highlights the need for a better method to optimize TTE utilization to use limited health care resources efficiently while providing high-quality care.

Left atrial structure and function and clinical outcomes in the general population

AIMS

Left atrial (LA) structural and functional abnormalities may be subclinical phenotypes, which identify individuals at increased risk of adverse outcomes.

METHODS AND RESULTS

Maximum LA volume (LAmax) and LA emptying fraction (LAEF) were measured via cardiac magnetic resonance imaging in 1802 participants in the Dallas Heart Study. The associations of LAEF and LAmax indexed to body surface area (LAmax/BSA) with traditional risk factors, natriuretic peptide levels, and left ventricular (LV) structure [end-diastolic volume (EDV) and concentricity(0.67) (mass/EDV(0.67))] and function (ejection fraction) were assessed using linear regression analysis. The incremental prognostic value of LAmax/BSA and LAEF beyond traditional risk factors, LV ejection fraction, and LV mass was assessed using the Cox proportional-hazards model. Both increasing LAmax/BSA and decreasing LAEF were associated with hypertension and natriuretic peptide levels (P < 0.05 for all). In multivariable analysis, LAmax/BSA was most strongly associated with LV end-diastolic volume/BSA, while LAEF was strongly associated with LV ejection fraction and concentricity(0.67). During a median follow-up period of 8.1 years, there were 81 total deaths. Decreasing LAEF [hazard ratio (HR) per 1 standard deviation (SD) (8.0%): 1.56 (1.32-1.87)] but not increasing LAmax/BSA [HR per 1 SD (8.6 mL/m(2)): 1.14 (0.97-1.34)] was independently associated with mortality. Furthermore, the addition of LAEF to a model adjusting Framingham risk score, diabetes, race, LV mass, and ejection fraction improved the c-statistic (c-statistics: 0.78 vs. 0.77; P < 0.05, respectively), whereas the addition of LAmax/BSA did not (c-statistics: 0.76, P = 0.20).

CONCLUSION

In the general population, both LAmax/BSA and LAEF are important subclinical phenotypes but LAEF is superior and incremental to LAmax/BSA.

Abstract 87: Comparison of Pretest Probability Clinical Assessment and 2011 ACCF/ASE/AHA/ASNC/HFSA/HRS/ SCAI/SCCM/SCCT/SCMR Appropriate Use Criteria for Transthoracic Echocardiography and Association with Clinical Impact

Background: Although most transthoracic echocardiograms (TTEs) performed today meet Appropriate Use Criteria (AUC), the ability of AUC to predict whether these TTEs will impact clinical management remains unclear.

Methods: The charts of 143 consecutive inpatient or outpatient TTEs at an academic medical center were retrospectively reviewed. Patients with a history of cardiac transplant or left ventricular assist device, or with inadequate pre-/ post- TTE clinical documentation were excluded; 123 studies were analyzed. Each TTE was assigned an AUC, pre-test, and clinical impact category. TTE indications were assigned by a cardiologist blinded to pre-study and post-study clinical data and categorized as: 1) inappropriate; 2) appropriate; or 3) uncertain based on 2011 AUC. Pre-test clinical course was analyzed by two independent cardiologists blinded to AUC and post-TTE clinical course and categorized as 1) TTE should not be performed, 2) TTE would likely alter clinical management, 3) TTE should be performed for reassurance/ continuity of care. Post-test clinical course was analyzed by two independent cardiologists blinded to AUC and pre-test assignment and categorized as 1) TTE did not alter clinical management, 2) TTE led to active change in management, 3) TTE led solely to reassurance/ continuity of current care.

Results: By 2011 AUC, 85% of studies were appropriate, 11% were inappropriate, and 4% were uncertain. Active change resulted from 30% of studies, while 49% of studies provided reassurance/ continuity of care, and 21% had no clinical impact. These proportions were not statistically significant across AUC categories (p=0.54). Pretest clinical assessment suggested that 31% should not have been performed, 63% should have been performed for reassurance / continuity of care alone, and 7% were likely to alter clinical management. These pretest assessments were significantly associated with impact on clinical management (p=0.0067), with 75% (n=6/8) of those studies expected to alter clinical management actually doing so, 56% (n=43/77) of those predicted to primarily result in reassurance actually doing so, and 37% (n=14/38) of those predicted not to alter clinical management actually having no clinical impact.

Conclusions: Classification by AUC is not associated with clinical impact. Although classification by pre-test probability is associated with clinical impact, a significant number of studies not predicted to have clinical impact actually had clinical impact. Further studies on methods to improve prediction of clinical utility for transthoracic echocardiography are warranted.

Association of Health Aging and Body Composition (ABC) Heart Failure score with cardiac structural and functional abnormalities in young individuals

BACKGROUND

The Health ABC Heart Failure score has recently been shown to predict 5-year risk of incident heart failure in the elderly. We tested whether this risk score is associated with subclinical phenotypes of heart failure in a younger population.

METHODS

We stratified participants in the Dallas Heart Study aged 30 to 65 years who had a cardiac magnetic resonance imaging and no self-reported history of heart failure or cardiomyopathy into 4 previously defined Health ABC Heart Failure risk groups: low (<5%), average (5%-10%), high (10%-20%), and very high (>20% risk for heart failure within 5 years). We compared left ventricular (LV) structural and functional parameters and levels of B-type natriuretic peptide (BNP) and N-terminal proBNP among the 4 groups.

RESULTS

In the study cohort (N = 2,540), the percentage of subjects in the low-, average-, high-, and very high risk groups was 78%, 15%, 6%, and 1%, respectively. Indexed LV mass (80 +/- 15 vs 90 +/- 20 vs 95 +/- 25 vs 116 +/- 41 g/m(2)), concentricity (1.6 +/- 0.3 vs 1.8 +/- 0.4 vs 2.0 +/- 0.5 vs 2.2 +/- 0.7 g/mL), median BNP (2.8 vs 3.7 vs 4.9 vs 7.5 pg/mL) and N-terminal proBNP (26 vs 30 vs 40 vs 58 pg/mL), and prevalent LV systolic dysfunction and LV hypertrophy progressively increased across risk groups (P < .001 for all) independent of gender or method of indexing LV mass.

CONCLUSIONS

The Health ABC Heart Failure score was associated with subclinical cardiac structural changes in the general population 30 to 65 years of age, suggesting that it may be a valid tool for identification of young individuals at increased risk for heart failure.

Magnetic resonance myocardial fiber-orientation mapping with direct histological correlation

Functional properties of the myocardium are mediated by the tissue structure. Consequently, proper physiological studies and modeling necessitate a precise knowledge of the fiber orientation. Magnetic resonance (MR) diffusion tensor imaging techniques have been used as a nondestructive means to characterize tissue fiber structure; however, the descriptions so far have been mostly qualitative. This study presents a direct, quantitative comparison of high-resolution MR fiber mapping and histology measurements in a block of excised canine myocardium. Results show an excellent correspondence of the measured fiber angles not only on a point-by-point basis (average difference of -2.30 +/- 0.98 degrees, n = 239) but also in the transmural rotation of the helix angles (average correlation coefficient of 0.942 +/- 0.008 with average false-positive probability of 0.004 +/- 0.001, n = 24). These data strongly support the hypothesis that the eigenvector of the largest MR diffusion tensor eigenvalue coincides with the orientation of the local myocardial fibers and underscore the potential of MR imaging as a noninvasive, three-dimensional modality to characterize tissue fiber architecture.