Brain natriuretic hormone predicts stress-induced alterations in diastolic function.

BACKGROUND: Mental stress (MS) reduces diastolic function (DF) and may lead to congestive heart failure with preserved systolic function. Whether brain natriuretic hormone (brain natriuretic peptide [BNP]) mediates the relationship of MS with DF is unknown. METHODS: One hundred sixty individuals aged 30 to 50 years underwent 2-hour protocol of 40-minute rest, videogame stressor and recovery. Hemodynamics, pro-BNP samples and DF indices were obtained throughout the protocol. Separate regression analyses were conducted using rest and stress E/A, E' and E/E' as dependent variables. Predictor variables were entered into the stepwise regression models in a hierarchical fashion. At the first level, age, sex, race, height, body mass index, pro-BNP and left ventricular mass (LVM) were permitted to enter the models. The second level consisted of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR). The final level contained cross-product terms of race by SBP, DBP and HR. RESULTS: E/A ratio was lower during stress compared to rest and recovery (P < 0.01). Resting E/A ratio was predicted by a regression model of age (-0.31), pro-BNP (0.16), HR (-0.40) and DBP (-0.23) with an R² = 0.33. Stress E/A ratio was predicted by age (-0.24), pro-BNP (0.08), HR (-0.38) and SBP (-0.21) with total R² = 0.22. Resting E' model consisted of age (-0.22), pro-BNP (0.26), DBP (-0.27) and LVM (-0.15) with an R² = 0.29. Stress E' was predicted by age (-0.18), pro-BNP (0.35) and LVM (-0.18) with an R² = 0.18. Resting E/E' was predicted by race (0.17, B > W) and DBP (0.24) with an R² = 0.10. Stress E/E' consisted of pro-BNP (-0.36), height (-0.26) and HR (-0.21) with an R² = 0.15. CONCLUSIONS: pro-BNP predicts both resting and stress DF, suggesting that lower BNP during MS may be a marker of diastolic dysfunction in apparently healthy individuals.

Does the relationship between natriuretic hormones and diastolic function differ by race?

INTRODUCTION: Heart failure develops earlier and is more prevalent in blacks than whites because of their higher incidence of hypertension and diabetes and likely subsequent diastolic dysfunction. Natriuretic peptides (NP) prevent cardiac malfunction through pressure, natriuresis action. However, whether race affects the relationships of NP action with cardiac function is unknown. METHODS: To assess this, 55 (21 whites and 27 males) normotensive adults underwent a 2-hour protocol of 40 minutes rest, video game stressor and recovery. Mitral inflow and myocardial velocities (tissue Doppler) were recorded every 20 minutes. Blood pressure and heart rate were obtained at 10-minute intervals. Blood samples for pro-atrial NP and pro-brain NP (pro-BNP) were collected every 40 minutes. RESULTS: There were differences in the association between (1) the changes from rest to stress for E/A ratio and double product (whites, r = -0.42; blacks, r = 0. 10; P = 0.034 for difference between correlations); (2) stress E(m) and pro-atrial NP (whites, r = 0.59; blacks, r = -0.25; P = 0.025); (3) rest E(m) and BNP (whites, r = 0.83; blacks r = -0.17; P = 000); (4) rest E(m)/A(m) and pro-BNP (whites, r = 0.70; blacks, r = -0.42; P = 0.003); (5) rest E/E(m) and pro-BNP (whites, r = -0.61; blacks, r = 0.31; P = 0.015) and (6) stress E and pro-BNP (whites, r = 0.56; blacks, r = -0.18; P = 0.043). CONCLUSION: The higher correlations between levels of NP and diastolic function indices both at rest and stress suggest that NP protective action is more pronounced in whites than in blacks.

Early markers of cardiovascular disease.

Vascular endothelium function plays a pivotal role in cardiovascular pre-clinical markers. Nitric oxide secreted by the vascular endothelium has a vasodilatory effect that reduces blood pressure which, in turn, prevents increases of left ventricular mass and intima-media thickness and improves left ventricular relaxation. Modern ultrasound technique allows noninvasive assessment of endothelial function and permits identification of functional alteration prior to manifestation of anatomical changes in the cardiovascular system. However, effort is needed to improve the reliability and reproducibility of ultrasound derived measure of endothelial function. This article provides an overview of challenges of clinical determination of endothelium-dependent arterial dilatation. In addition, we highlight the necessity of targeting the pediatric population in studies aimed at preventing and treating cardiovascular disease.

Anger suppression and adiposity modulate association between ADRB2 haplotype and cardiovascular stress reactivity.

OBJECTIVES: The purpose of this study was to examine how variation in the beta-2 adrenergic receptor gene (ADRB2), in combination with the moderating influences of race, body mass index (BMI), and anger expression style (anger-in, anger-out), affects blood pressure (BP) at rest and in response to acute laboratory stress. METHODS: Four hundred fifty adolescents (mean age = 18.5 +/- 2.7 years; 228 [124 males] whites and 222 [110 males] blacks completed two stressors (video game challenge, forehead cold pressor). Hemodynamic measures were taken before, during, and after each stressor. Stressors were separated by a 20-minute rest period. RESULTS: Frequency of detrimental haplotype (Gly16/Glu27) carrier status was greater among whites than blacks (p < .05). A significant three-way interaction among haplotype, BMI, and race for resting systolic blood pressure (SBP) found the highest BP level to be among high BMI carriers, but only for whites. A separate three-way interaction was found to be significant for haplotype, anger-in and race such that high anger-in carriers showed the highest level of resting SBP (p < .05) and total peripheral resistance (TPR) (p < .05) and the greatest TPR reactivity to the cold pressor task (p < .01). Post hoc analyses revealed these interactions with anger-in were only present among blacks. No significant interactions with anger-out for either ethnic group were observed. CONCLUSIONS: This study demonstrates modulating influences of BMI and anger expression styles on ADRB2 gene associations with hemodynamic function at rest and in response to laboratory stress. These findings support the hypothesis that consideration of gene-environment interactions may better characterize the role of ADRB2 variation in the development of stress-induced essential hypertension.

Impact of meditation on resting and ambulatory blood pressure and heart rate in youth.

OBJECTIVE: The purpose of this study was to evaluate the impact of a meditation program on resting and ambulatory blood pressure and heart rate in youth. METHODS: Data from 73 middle school students (age 12.3 +/- 0.6 years) randomly assigned by classroom to either meditation (N = 34) or health education control (N = 39) groups were analyzed. The meditation groups engaged in 10-minute sessions at school and at home after school each day for 3 months. Resting (seated) systolic blood pressure, diastolic blood pressure, and heart rate measurements were obtained pretest and posttest on three consecutive school days using Dinamap 1846SX monitors. Ambulatory systolic blood pressure, ambulatory diastolic blood pressure, and ambulatory heart rate were recorded over 24-hour periods at pretest and posttest every 20 minutes during self-reported normal waking hours and every 30 minutes during self-reported normal sleep hours using Spacelabs 90207 monitors. RESULTS: Significant (p < .05) differences in average change from pretest to posttest were found between the meditation and health education control groups for resting systolic blood pressure (-2.7 vs. 1.1 mm Hg), daytime ambulatory systolic blood pressure after school (-2.0 vs. 3.6 mm Hg), daytime ambulatory diastolic blood pressure after school (0.1 vs. 4.3 mm Hg), and daytime ambulatory heart rate after school (-5.3 vs. 0.3 bpm). CONCLUSION: These findings demonstrate the potential beneficial impact of meditation on blood pressure and heart rate in the natural environment in healthy normotensive youth.

Relationships among socioeconomic status, stress induced changes in cortisol, and blood pressure in African American males.

The inverse relation between socioeconomic status (SES) and cardiovascular disease (CVD) risk has been posited to be partially due to exaggerated cardiovascular reactivity (CVR) to stress. Stress elicits hypothalamic-pituitary-adrenal axis activation (e.g., increased cortisol secretion), which may contribute to subsequent blood pressure (BP) elevation. Univariate associations among SES, cortisol secretion, and aggregated change scores to stressors (i.e., video game and forehead cold) for systolic BP (SBP) and diastolic BP (DBP) were assessed in a sample of 24 African American males (M age = 18.8, +/- 2.7 years). Circadian variability of cortisol level was taken into account by partialling out collection time. Family SES was inversely related to initial cortisol level (partial r = -.46, p < .03). Neighborhood SES was inversely related to DBP reactivity (r = -.41, p < .05). The change in cortisol level during the stressor protocol was related to SBP reactivity (partial r = .44, p < .05). These results suggest that SES may be linked to CVD via BP and cortisol reactivity to stress, but prospective studies are needed to clarify whether such is the case.

A longitudinal study of ethnic differences in ambulatory blood pressure patterns in youth.

BACKGROUND: Many studies demonstrated an ethnic difference in ambulatory blood pressure (BP) patterns. We examined: 1) the stability of this difference; 2) demographic and anthropometric characteristics that predict the difference over 2 years; and 3) the clinical significance of the difference. METHODS: Recordings were performed 2 years apart on 94 African American and 92 European American youths with a positive family history of hypertension, aged 14 +/- 2 years at initial testing. RESULTS: African Americans had higher nighttime systolic BP (SBP) on the initial (109 +/- 9 v 105 +/- 8 mm Hg; P < .001) and follow-up (110 +/- 10 v 105 +/- 8 mm Hg; P < .0001) visits despite similar daytime SBP. This was associated with greater left ventricular mass/height2.7 (LVM/height2.7) during the initial (31 +/- 8 v 28 +/- 6 g/height2.7; P < .01) and follow-up (32 +/- 8 v 28 +/- 8 g/height2.7; P < .02) visits. Sex accounted for 17% (P < .0001) of the variance of follow-up daytime SBP in African Americans, and age for an additional 10% (P < .001). In comparison, initial height accounted for 11% (P < .001) of the variance in European Americans. Sex accounted for 18% (P < .0001) of the variance of follow-up nighttime SBP in African Americans, age for an additional 12% (P < .0001), and initial LVM/height2.7 an additional 6% (P < .02). In contrast, sex accounted for 13% of the variance of follow-up nighttime SBP in European Americans, and initial height accounted for an additional 8% (P < .004). CONCLUSIONS: The pattern of higher nighttime BP despite similar daytime BP in African Americans is stable over time, with sex as the most important predictor of nighttime BP in both groups. This study provides confirmatory data on the clinical significance of the differences.