Browsing by Subject "Heart Ventricles"
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Item Association of African Ancestry with Electrocardiographic Voltage and Concentric Left Ventricular Hypertrophy: The Dallas Heart Study(2020-05-01T05:00:00.000Z) Alame, Aya J.; Drazner, Mark H.; Garg, Sonia; Kozlitina, JuliaBACKGROUND: 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). METHODS: 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. 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 concentricity^0.67, 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 concentricity^0.67: β, 0.05; P = .045; prevalent LVH: odds ratio, 1.2; 95% CI, 1.03-1.4; P = .02). CONCLUSION: 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.Item [Southwestern News](2002-04-01) Wren, Worth, Jr.Item Validation of Feature Tracking Cardiac MRI for Myocardial Strain: The Dallas Heart Study(2017-01-17) Agusala, Vijay; Berry, Jarett; Martens, Spencer; Pandey, Ambarish; Khera, Rohan; Ayers, ColbyBACKGROUND: Prior studies using speckle tracking echocardiography or cardiac magnetic resonance imaging (CMR) with myocardial tissue tagging show several factors to be associated with higher (worse) left ventricular (LV) strain (e.g. African-American race and male gender). The study aims to assess the validity of a new technique, Feature-tracking (FT) CMR, by evaluating the associations between strain measured by FT CMR and demographics and cardiovascular risk factors previously shown to be associated with strain by more established techniques. METHODS: Left ventricular longitudinal (GLS) and circumferential (GCS) strain values were measured in participants from the Dallas Heart Study (DHS), a multi-ethnic, population-based probability sample of adults in Dallas County. Linear regression models were constructed with GCS and GLS as the outcome variables in separate models adjusted for cardiovascular risk factors and left ventricular MRI characteristics (stroke volume (SV), LV mass, end diastolic volume (EDV), and LV ejection fraction(LVEF)). RESULTS: An interim analysis was conducted on 1,134 MRI studies. Greater LV mass was associated with increased (worse) GCS and GLS (ß=0.21, p<0.0001; ß=0.14, p<0.0001, respectively), while higher SV (ß=-0.15, p<0.0001; ß=-0.24, p<0.0001, respectively) and higher LVEF (ß=-0.-0.50, p<0.0001; ß=-0.22, p<0.0001, respectively) were found to be associated with decreased (better) strain values of both types. Higher EDV was associated with increased (worse) GCS strain values (ß=0.18, p<0.0001) but decreased (better) GLS strain values (ß= -0.07, p=0.0279). Male gender was associated with increased (worse) GCS and GLS strain values (ß=0.23, p<0.0001; ß=0.28, p<0.0001, respectively), and African-American race was also similarly associated with increased strain values (ß=0.12, p=0.0004; ß=0.11, p=0.0011, respectively). CONCLUSION: FT CMR is a reliable method of measuring GCS and GLS. Known factors associated with higher (worse) strain in prior studies were reflected in the FT CMR data, as conversely were factors that associated with decreased (better) strain, such as higher LVEF and SV.