Parental hypertension and cardiac alterations in normotensive children and adolescents

Physical exercise and cardiovascular response: design and implementation of a pediatric CMR cohort study

To examine feasibility and reproducibility and to evaluate the cardiovascular response to an isometric handgrip exercise in low-risk pediatric population using Cardiovascular Magnetic Resonance measurements. In a subgroup of 207 children with a mean age of 16 years participating in a population-based prospective cohort study, children performed an isometric handgrip exercise. During rest and exercise, continuous heart rate and blood pressure were measured. Cardiovascular magnetic resonance (CMR) measurements included left ventricular mass, aortic distensibility and pulse wave velocity at rest and left ventricular end-diastolic and end-systolic volumes, ejection fraction, stroke volume and cardiac output during rest and exercise. 207 children had successful CMR measurements in rest and 184 during exercise. We observed good reproducibility for all cardiac measurements. Heart rate increased with a mean ± standard deviation of 42.6% ± 20.0 and blood pressure with 6.4% ± 7.0, 5.4% ± 6.1 and 11.0% ± 8.3 for systolic, diastolic and mean arterial blood pressure respectively (p-values < 0.05). During exercise, left ventricular end-diastolic and end-systolic volumes and cardiac output increased, whereas left ventricular ejection fraction slightly decreased (p-values < 0.05). Stroke volume did not change significantly. A sustained handgrip exercise of 7 min at 30-40% maximal voluntary contraction is a feasible exercise-test during CMR in a healthy pediatric population, which leads to significant changes in heart rate, blood pressure and functional measurements of the left ventricle in response to exercise. This approach offers great novel opportunities to detect subtle differences in cardiovascular health.

Effects of Race, Cardiac Mass, and Cardiac Load on Myocardial Function Trajectories from Childhood to Young Adulthood: The Augusta Heart Study

Background

The overall goal of this longitudinal study was to determine if the Black population has decreased myocardial function, which has the potential to lead to the early development of congestive heart failure, compared with the White population.

Methods and Results

A total of 673 subjects were evaluated over a period of 30 years including similar percentages of Black and White participants. Left ventricular systolic function was probed using the midwall fractional shortening (MFS). A longitudinal analysis of the MFS using a mixed effect growth curve model was performed. Black participants had greater body mass index, higher blood pressure readings, and greater left ventricular mass compared with White participants (all P<0.01). Black participants had a 0.54% decrease of MFS compared with White participants. As age increased by 1 year, MFS increased by 0.05%. As left ventricular mass increased by 1 g, MFS decreased by 0.01%. As circumferential end systolic stress increased by 1 unit, MFS decreased by 0.04%. The MFS trajectories for race differed from early age to young adulthood.

Conclusions

Changes in myocardial function mirror the race‐dependent variations in blood pressure, afterload, and cardiac mass, suggesting that myocardial function depression occurs early in childhood in populations at high cardiovascular risk such as Black participants.

The Cardiovascular Stress Response as Early Life Marker of Cardiovascular Health: Applications in Population-Based Pediatric Studies-A Narrative Review

Stress inducement by physical exercise requires major cardiovascular adaptations in both adults and children to maintain an adequate perfusion of the body. As physical exercise causes a stress situation for the cardiovascular system, cardiovascular exercise stress tests are widely used in clinical practice to reveal subtle cardiovascular pathology in adult and childhood populations with cardiac and cardiovascular diseases. Recently, evidence from small studies suggests that the cardiovascular stress response can also be used within research settings to provide novel insights on subtle differences in cardiovascular health in non-diseased adults and children, as even among healthy populations an abnormal response to physical exercise is associated with an increased risk of cardiovascular diseases. This narrative review is specifically focused on the possibilities of using the cardiovascular stress response to exercise combined with advanced imaging techniques in pediatric population-based studies focused on the early origins of cardiovascular diseases. We discuss the physiology of the cardiovascular stress response to exercise, the type of physical exercise used to induce the cardiovascular stress response in combination with advanced imaging techniques, the obtained measurements with advanced imaging techniques during the cardiovascular exercise stress test and their associations with cardiovascular health outcomes. Finally, we discuss the potential for cardiovascular exercise stress tests to use in pediatric population-based studies focused on the early origins of cardiovascular diseases.

Left Ventricular Myocardial Performance in Normotensive Offspring of Hypertensive Parents

INTRODUCTION

Early alterations in the cardiovascular system have been described in offspring of hypertensive parents, but with conflicting results.

AIM

To evaluate the influence of genetic predisposition to hypertension on left ventricular (LV) geometry and function, 30 normotensive male offspring of hypertensive parents (EH+) and 30 matched offspring of normotensive families (EH-), were studied.

METHODS

All subjects underwent office and 24-h ambulatory blood pressure monitoring (ABPM), conventional and Tissue Doppler Echocardiography (TDE), including assessment of myocardial performance index (MPI).

RESULTS

EH+ showed an increase in office BP with statistical significance in diastolic BP (84 ± 7 vs 73 ± 6 mmHg; p < 0.05). Relative wall thickness (RWT) was greater in EH+ (0.37 ± 0.05 vs 0.31 ± 0.03; p < 0.05) and significantly related to the EH+ condition at the univariate analysis (p < 0.003), whilst the LV mass index was unchanged (84.3 ± 14 vs 80 ± 17 g/m²; p = NS), suggesting a trend towards concentric remodeling. Systolic and diastolic function, in both ventricles, were superimposable in the two groups. The MPI was higher in EH+ (0.49 ± 0.10 vs 0.45 ± 0.08; p = NS) and significantly correlated to RWT (r = 0.47, p < 0.01). However, at the stepwise multiple regression analysis, only the condition of EH + was independently associated with RWT (p <0.006). RWT, according to ROC curves analysis, predicted the condition of EH+ (cutoff 0.359, specificity 89%, sensitivity 82%).

CONCLUSION

Current results provide information about LV myocardial performance in EH+ subjects, related to a LV concentric remodeling and to endothelial dysfunction.

Renin gene polymorphisms in bangladeshi hypertensive population

Objective: Linkages of renin gene polymorphisms with hypertension have been implicated in several populations with contrasting results. Present study aims to assess the pattern of renin gene polymorphisms in Bangladeshi hypertensive individuals.

Methodology: Introns 1, 9 of renin gene and 4063 bases upstream of promoter sequence of renin gene were amplified from the genomic DNA of the total 124 (hypertensive and normotensive) subjects using respective primers. Polymerase chain reaction-based restriction fragment length polymorphisms were performed using BglI, MboI and TaqI restriction enzymes.

Results: Homozygosity was common in renin gene regarding BglI (bb=48.4%, Bb=37.9%, BB=13.7%, χ² =1.91, P>0.05), TaqI (TT=81.5%, Tt=14.5%, tt=4.0%, χ² =7.50, P<0.01) and MboI (mm=63.7%, Mm=32.3%, MM=4.0%, χ²=0.00, P>0.05) polymorphisms among total study population. For BglI and TaqI genotype distribution, hypertensive subjects (BglI: χ² =6.66, P<0.05; TaqI: χ² = 10.28, P<0.005) significantly deviate from Hardy-Weinberg Equilibrium law compared to normotensive subjects (BglI: χ²=0.51, P>0.05; TaqI: χ²=0.20, P>0.05). On the other hand, with respect to MboI polymorphisms of renin gene, only normotensive subjects deviate from the law (patients: χ²=1.28, P>0.05; vs controls: χ²=6.81, P<0.01). In the context of allelic frequency, common T allele was clearly prevalent (T frequency=0.86, t frequency = 0.14) for TaqI, but rare alleles b and m were more frequent for both BglI (b frequency=0.69, B frequency=0.31) and MboI (m frequency=0.80 M frequency=0.20) polymorphisms, respectively.

Conclusion: Thus, we report that Bangladeshi hypertensive subjects did not show any distinct pattern of renin gene polymorphisms compared to their healthy control subjects with regard to their genotypic and allelic frequencies.

High blood pressure response to stress ergometry could predict future hypertension

BACKGROUND

Previous studies have shown that exaggerated blood pressure (BP) during exercise is a valid risk predictor for future hypertension in most men and women, yet the use of ergometry as a means of early detection of incipient hypertension still requires confirmation.

OBJECTIVES

To assess the clinical utility of exercise BP measurement for the evaluation of risk for developing new-onset hypertension.

METHODS

Thirty individuals with normal BP were enrolled in this study and were subsequently divided into two groups: 13 persons with in-exercise hypertension were compared with 17 matched persons who were normotensive during ergometry. Their blood pressure was monitored during follow-up of two years.

RESULTS

More individuals in the exercise-hypertensive group developed hypertension after one or two years than those normotensive during the exercise (respectively, one year: 3 vs.0, p=0.03, two years: 10 vs. 1, p<0.0001). Both the systolic and diastolic BPs significantly differed between the two groups. Eighty four percent of those with exaggerated BP (>or=210 mm Hg) during the treadmill exercise developed hypertension after 2 years. The sensitivity and specificity of in-exercise hypertension for predicting its 2 year occurrence were, respectively, 91% and 84%.

CONCLUSION

Even in the absence of hypertension, its development during stress ergometry could be considered a predictive marker for the future development of hypertension, and can be a potential tool for identifying normotensive individuals at high risk. These individuals should be followed up and their BP controlled for a long time.

Childhood hypertension. An update on etiology, diagnosis, and treatment

In the general population, an estimated 70% or more of premature morbidity can be attributed to tobacco use, undertreatment of hypertension, and obesity. From a public health perspective, health-related behaviors that reduce the risk for cardiovascular disease should be encouraged for all children and their families. Pediatricians are obligated to accurately and frequently monitor patients' blood pressures. When discovered, elevated blood pressure should be appropriately investigated, with the evaluation being tailored to the age of the child and to the severity of the blood pressure elevation. Investigation should focus on not only a search for a cause but also target organ effects. Timely recognition of abnormal blood pressure and appropriate interventions are necessary to affect the future development of cardiovascular and renal morbidity and mortality.

The application of molecular genetic techniques to the study of hypertensive diseases

The techniques of modern molecular genetics are shedding new light on hypertension and its sequelae. This article discusses techniques which have identified genes associated with hypertension and have pointed the way toward identifying the full cohort of genes operative in all forms of human hypertension. These techniques have expanded understanding of the pathophysiology of hypertension as well as its prevention.