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BACKGROUND: Health agencies recommend that homes of heat-vulnerable occupants (e.g., older adults) be maintained below 24–28°C to prevent heat-related mortality and morbidity. However, there is limited experimental evidence to support these recommendations. OBJECTIVE: To aid in the development of evidence-based guidance on safe indoor temperatures for temperate continental climates, we evaluated surrogate physiological outcomes linked with heat-related mortality and morbidity in older adults during simulated indoor overheating METHODS: Sixteen older adults [six women; median age: 72 y, interquartile range (IQR): 70-73 y; body mass index: 24.6 (IQR: 22.1-27.0 kg/m²] from the Ottawa, Ontario, Canada, region (warm summer continental climate) completed four randomized, 8-h exposures to conditions experienced indoors during hot weather in continental climates (e.g., Ontario, Canada; 64 participant exposures). Ambient conditions simulated an air-conditioned environment (22°C; control), proposed indoor temperature upper limits (26°C), and temperatures experienced in homes without air-conditioning (31°C and 36°C). Core temperature (rectal) was monitored as the primary outcome; based on previous recommendations, between-condition differences >0.3C were considered clinically meaningful. RESULTS: Compared with 22°C, core temperature was elevated to a meaningful extent in 31°C [+0.7C; 95% confidence interval (CI): 0.5, 0.8] and 36°C (+0.9C; 95% CI: 0.8, 1.1), but not 26°C (+0.2C, 95% CI: 0.0, 0.3). Increasing ambient temperatures were also associated with elevated heart rate and reduced arterial blood pressure and heart rate variability at rest, as well as progressive impairments in cardiac and blood pressure responses to standing from supine. DISCUSSION: Core temperature and cardiovascular strain were not appreciably altered following 8-h exposure to 26°C but increased progressively in conditions above this threshold. These data support proposals for the establishment of a 26°C indoor temperature upper limit for protecting vulnerable occupants residing in temperate continental climates from indoor overheating. [ABSTRACT FROM AUTHOR]

Introduction. Despite heightened risk of cardiovascular disease (CVD) among individuals with type 1 diabetes, few studies in this population have investigated the development of CVD using early markers in adolescence. We compared risk factors (blood pressure (BP) and dyslipidemia) and early markers of CVD between adolescents with and without type 1 diabetes and explored effect modification by sex. Methods. Cross-sectional study using data from the CARdiovascular Disease risk in pEdiatric type 1 diAbetes (CARDEA) study. We recruited 100 adolescents with type 1 diabetes at the Sainte-Justine University Hospital Center and 97 adolescents without diabetes (14–18 years). We measured arterial stiffness by carotid-femoral pulse wave velocity, endothelial function by brachial artery flow-mediated dilation test, as well as left ventricular (LV) mass, papillary mass, and wall thickness by cardiac MRI. We used multivariable linear regression models to assess the impact of type 1 diabetes on each outcome adjusting for age, sex, ethnicity, adiposity, and familial income. Results. Adolescents with type 1 diabetes had 0.21 standard deviations (SD) (95% CI: 0.04; 0.38) higher diastolic blood pressure z-score (zDBP), 0.21 mmol/L (95% CI: 0.02; 0.40) higher low-density lipoprotein cholesterol (LDL-c) levels, and 17% (95% CI: 4; 29) higher triglyceride levels and lower endothelial function based on acceleration (−77.4 cm/s2, 95% CI: −133.1; −21.6) compared with adolescents without diabetes. Girls with type 1 diabetes had higher systolic blood pressure z-score (zSBP), and boys with type 1 diabetes had lower LV mass and wall thickness compared to healthy peers. Conclusions. In addition to higher BP and abnormal lipid profiles, adolescents with type 1 diabetes present endothelial dysfunction and alterations in cardiac structure (in boys) compared to adolescents without diabetes, suggesting that CVD prevention should be incorporated into type 1 diabetes management early in the disease. [ABSTRACT FROM AUTHOR]

Background: Cardiovascular disease disproportionately affects North American Indigenous populations. Ethnic differences in cardiac responses to exercise are known, though Indigenous populations response is unknown. To evaluate cardiac responses to aerobic exercise among Canadian Indigenous and European adults. Methods: Indigenous (N = 12, 4 females, 1 male incomplete) and European (N = 12, all completed) Canadian age and sex-matched adults 19-40 years and free of cardiovascular disease or diabetes completed a cycle ergometer maximal aerobic power test and 30 min at 60% maximal aerobic capacity on two separate days. Echocardiographic assessments preceded and immediately followed exercise. Results: Responses to maximal exercise were similar among ethnicities including decreases in stroke volume index, cardiac output index and ejection fraction, and increases in arterial-ventricular coupling. However, following submaximal exercise, only Indigenous adults demonstrated reductions in end systolic volume, end diastolic volume (154.8 ± 40.6 mL to 136.5 ± 33.0 mL, p = 0.01, vs. 149.4 ± 22.4 mL to 147.1 ± 27.0 mL; p = 0.81), stroke volume index (44.9 ± 8.7 mL m−2 to 38.0 ± 6.5 mL m−2, p = 0.002, vs. 46.4 ± 7.1 mL m−2 to 44.0 ± 6.5 mL m−2; p = 0.28) and arterial compliance. Conclusion: Indigenous and European adults demonstrated similar cardiac responses to maximal exercise, though only Indigenous adults demonstrated cardiac responses to submaximal exercise. [ABSTRACT FROM AUTHOR]

Background: Hypertrophic cardiomyopathy (HCM) is usually associated with marked diastolic dysfunction, characterized by impaired myocardial relaxation and increased myocardial stiffness. The noninvasive evaluation of diastolic function in these patients remains a challenge since usual methods have shown a modest correlation with invasive measurements of left ventricular (LV) relaxation and filling pressures. Methods and Results: We retrospectively analyzed 44 patients with obstructive HCM who underwent cardiac catheterization and echocardiography performed within 48 hours. Standard echocardiographic diastolic parameters and systolic and diastolic myocardial mechanics (including longitudinal and circumferential strain [S] and strain rate [Sr]), LV rotation, and early reverse rotation rate (fraction of early apical reverse rotation [FEARR]) were correlated with diastolic hemodynamic indices. Estimated LA pressure by echo and the LV end-diastolic pressure (LVEDP) or the LV pre-A pressure did not correlate. Longitudinal strain was low and circumferential strain was abnormally higher than normal. FEARR and negative dp/dt inversely correlated (R =−0.57, P = 0.0001), and early diastolic Sr to systolic Sr ratio (SrE/SrS) correlated with the LVEDP (r = 0.61, P < 0.0001). Furthermore, a SrE to SrS ratio ≥0.79 had a sensitivity of 87% and a specificity of 75% for predicting elevated LVEDP (≥15 mmHg). Average circumferential strain rate during atrial contraction and LV pre-A pressure (r =−0.62, P < 0.001) inversely correlated. Conclusions: FEARR is decreased in HCM and appears to be a good measure of diastolic dysfunction. Myocardial mechanics can be used to assess LV relaxation and filling pressures in patients with obstructive HCM. [ABSTRACT FROM AUTHOR]

Objectives: Anderson-Fabry disease (AFD) is a lysosomal storage disease, which can involve the heart, mimicking hypertrophic cardiomyopathy (HCM). The underlying mechanism of disease in AFD is an infiltrative, diffuse process, whereas HCM is a primary heart muscle condition with patchy distribution, which may prompt differences in myocardial mechanics. The aim of this study was to assess myocardial mechanics in AFD according to the presence of left ventricular hypertrophy (LVH) compared to nonobstructive HCM (NHCM) and healthy controls. Methods and Results: We carried out a single-center, retrospective study in a small, genetically confirmed AFD cohort, which was divided into a subgroup with LVH (LVH+, n = 19), and without LVH (LVH-, n = 21). Comparison groups were healthy controls (n = 40) and NHCM patients (n = 19). Vector Velocity Imaging was applied to two-dimensional echocardiography studies for assessment of longitudinal strain (LS), circumferential strain (CS), and base-to-apex CS gradients. AFD LVH+ patients had lower global LS than AFD LVH- patients (-14 ± 4% vs -17 ± 3%, P < 0.05), but similarly lowered global CS (-24 ± 5% vs -22 ± 5%, P = ns). AFD LVH+ and NHCM had similarly lowered global LS compared to normals, but significantly lower global CS was observed in AFD LVH+ (-24 ± 5% vs -28 ± 4%, P < 0.05), whereas it was significantly increased in NHCM (-31 ± 2% vs -28 ± 4%, P < 0.05). Unlike NHCM, in both AFD subgroups, patients lost their normal base-to-apex CS gradient. Conclusions: AFD patients without LVH already show abnormal systolic myocardial mechanics. Relevant differences in myocardial mechanics between AFD patients with LVH compared to NHCM reflect the different underlying mechanisms of disease. [ABSTRACT FROM AUTHOR]

Objective Determine how parental nutrition label use, label literacy, and nutrition knowledge may be associated with cardiovascular health in parents and their children. Design and Setting Cross-sectional analyses of 2006 data from the Healthy Heart Project in Montreal, Canada. Participants Among community recruited families, parents were predominantly mothers (n = 127 [80%]; mean age, 45.0 years) and half of their children were female (44%; mean age, 12.5 years). Main Outcome Measures Blood pressure, lipids, and weight. Nutrition label use, label literacy, and nutrition knowledge among parents were collected using existing scales. Analyses Multivariable linear regression models. Results Among parents, nutrition label use was associated with lower total cholesterol (B[SE] = −.53 [.20]; P = .009), lower low-density lipoprotein (B[SE] = −.57 [.21]; P = .007), and lower total cholesterol/high-density lipoprotein cholesterol ratio (B[SE] = −.82 [.30]; P = .008) but was not associated with adiposity. Among children, greater parental nutrition knowledge was associated with lower body mass index percentiles (B[SE] = −3.6 [1.49]; P = .02), lower waist circumference (B[SE] = −1.27 [.55]; P = .02), and lower percent body fat (B[SE] = −1.28 [.47]; P = .008). Parental nutrition label use or nutrition knowledge was not associated with children's lipids. Conclusions and Implications Parents with greater nutrition label use had more favorable lipids, but children's lipids were unaffected. Children of parents with greater nutrition knowledge had lower adiposity. Further research on the correlates of label use and health is needed. [ABSTRACT FROM AUTHOR]