Impact of prehypertension on left ventricular mass and QT dispersion in adult black Nigerians

Prevalence of Increased QTc Dispersion Among Hypertensive Patients and Its Correlation to Clinical Risk Factors: A Hospital-Based Case-Control Study

Background In Ghana and other sub-Saharan African countries, hypertension (HTN) prevalence is rapidly increasing. Hypertensive left ventricular hypertrophy (LVH) is associated with excess fibrous tissue deposition throughout the myocardium. This could lead to ventricular arrhythmias and sudden cardiac death. Increased corrected QT dispersion (QTcd) can cause ventricular repolarization and be used to identify patients at risk of ventricular tachyarrhythmia. The measurement of increased QTcd among hypertensive patients is a simple screening tool to stratify patients at cardiovascular risk. Methods A case-control hospital-based study was conducted on 200 consecutive hypertensive patients. Age- and sex-matched control groups of 200 normotensive individuals who gave informed consent were also recruited. The baseline clinical and demographic characteristics of participants were acquired using structured questionnaires. A physical examination and a resting 12-lead ECG were performed. Increased QTcd and LVH were determined. Results The mean age of hypertensive patients was 50.99±6.73 and 48.19±7.17 for the controls (p-value 0.63). The study population was predominantly female (1:2.4 male:female ratio). Higher mean values for QTcd and LVH (Sokolow-Lyon) were observed among hypertensive patients compared to controls. The prevalence of increased QTcd was 45.0% among hypertensive patients compared to 16.5% in controls (χ2 =38.14, p-value <0.0000001, odds ratio = 4.14). Conclusion Increased QTcd is prevalent among hypertensive Ghanaians. Its measurement can be an effective non-invasive screening tool to risk-stratify hypertensive patients.

Echocardiographic Assessment of the Left Ventricle in Young Prehypertensive Nigerians

BACKGROUND

 Prehypertension is associated with an increased risk of cardiovascular morbidity and mortality. This risk could partly be explained by the early compromise in left ventricular (LV) structure and function. This study investigated the LV geometry and function in young black prehypertensive subjects.

METHODS AND RESULTS

This cross-sectional descriptive study was conducted at the Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria. Echocardiography-derived LV geometry and function were assessed using standardized methods. Prehypertensive subjects had higher mean systolic blood pressure (BP) (130.78 ± 3.57 mmHg vs 111.42 ± 3.54 mmHg, P<0.001), diastolic BP (79.32 ± 4.13 mmHg vs 66.39 ± 4.42 mmHg, P<0.001), body mass index (BMI) (26.24 ± 3.45 kg/m2 vs 22.20 ± 2.21 kg/m2, P<0.001), waist circumference (WC) (86.93 ± 8.73 cm vs 76.73 ± 6.66 cm, P<0.001), fasting blood glucose (FBG) (93.84 ± 7.28 mg/dl vs 90.08 ± 6.26 mg/dl, P<0.001), and dyslipidemia (21.5% vs 6%. P<0.001) compared to normotensive subjects. LV mass index (LVMI) was greater in prehypertensive subjects compared to normotensive subjects {male (106.84 ± 12.34 g/m2 vs 76.07 ± 10.25 g/m2, P<0.001); female (92.06 ± 8.80 g/m2 vs 66.53 ± 7.21 g/m2, P<0.001)}, with abnormal LV geometry recorded in 17.5%. Linear regression analysis showed that waist circumference, systolic BP, serum creatinine level, and urea level were determinants of LVMI. The prevalence of LV diastolic dysfunction was higher in prehypertensive subjects than in normotensive subjects (14.5% vs. 0.5%, P<0.001), with systolic BP {odds ratio (OR) 0.928, confidence interval (CI) 0.834 - 0.969; P=0.016)} and diastolic BP (OR 0.832, CI 0.722 - 0.958; P=0.011) being independent predictors.

CONCLUSION

 This study showed that prehypertension in young Black subjects was associated with altered LV geometry and impaired diastolic function, and these changes demonstrated linear progression with increasing systolic BP.

Efficacy of Khār-i-khasak (Tribulus terrestris Linn.) in prehypertension: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Prehypertension is a state of above-normal blood pressure that does not meet the criteria for the diagnosis of hypertension and its prevalence estimated in population-based samples ranges from 22 to 52%. It conveys potentially many deleterious consequences such as high risk of progression to hypertension and cardiovascular disease later in life.

OBJECTIVES

The present study was conducted to evaluate the blood pressure-lowering effect of Khār-i-khasak (Tribulus terrestris Linn.) in prehypertensive individuals.

METHODS

This randomized, double-blind, placebo-controlled, clinical trial was conducted at the National Institute of Unani Medicine, Hospital, Bengaluru, after approval by the Institutional Ethics Committee. Prehypertensive individuals over 18 years of age were enrolled after obtaining their written informed consent and were randomly allocated to the test or placebo group. The test and placebo groups were administered powdered dried fruits of Khār-i-khasak (6g) and matched placebo (6g) in three divided doses for two months respectively. The efficacy assessment was determined by changes in systolic and diastolic blood pressures.

RESULTS

Both systolic and diastolic blood pressure showed a significant decline in the test group (p<0.001) as compared to the placebo group. The average decline in systolic/diastolic blood pressure was -7.7/5.5 mmHg in the test group and -1.9/0.2 mmHg in the placebo group. During the post-therapy follow-up period, no prehypertensive developed full-blown hypertension in either group. Safety parameters were found to be within normal limits.

CONCLUSIONS

The test drug Khār-i-khasak (T. terrestris Linn.) was found to be effective and safe in lowering blood pressure compared to placebo in prehypertensive individuals.

Lifestyle modification and hypertension: prescription patterns of Nigerian general practitioners

Introduction

Implementation of lifestyle modification (LM), a cornerstone of hypertension control has been reported to be more challenging than pharmacotherapy. We studied the LM prescription patterns of general medical practitioners (GPs) in Lagos, Nigeria for blood pressure control.

Methods

GPs were assessed using anonymous self-administered questionnaire on the prescription of salt restriction, weight management, cessation of tobacco use, physical exercise, and consumption of DASH-like diet for blood pressure control. Chi-square, Fisher's exact and Student t-test were used to test for differences as appropriate. Logistic regression model was constructed to identify the determinants of adequate LM prescription.

Results

A total of 213 GPs (38% females) participated in the survey. LM prescription was over 90% for the following: salt restriction (96.7%), tobacco cessation (94.8%), weight management (94.4%). The remaining were 81.2% and 75.1% for healthy diet and physical activity respectively. The median LM prescription score (of the GPs) was 18.0 [15.0-50.0]. The single significant predictor of adequate LM prescription was total patient load of the GPs (AOR:0.98, 95% CI: 0.97-0.99, p=0.006). Eleven (5.2%), 190 (89.2%), and 12 (5.6%) GPs initiated LM prescription at blood pressure values >140/90mmHg, =140/90mmHg and <140/90mmHg respectively. LM initiation at BP <140/90mmHg was associated with female gender, shorter work experience, working in tertiary care facility and ignorance about hypertension prevention (p<0.05).

Conclusion

LM is widely prescribed for the treatment of hypertension, but rarely prescribed for its prevention in Nigeria. Interventions to reduce physician's patient load may engender improved LM prescription.

Blood pressure-related electrocardiographic findings in healthy young individuals

Purpose: Elevated blood pressure induces electrocardiographic changes and is associated with an increase in cardiovascular disease later in life compared to normal blood pressure levels. The purpose of this study was to evaluate the association between normal to high normal blood pressure values (90-139/50-89 mmHg) and electrocardiographic parameters related to cardiac changes in hypertension in healthy young adults.Methods: Data from 1449 volunteers aged 18-30 years collected at our centre were analyzed. Only subjects considered healthy by a physician after review of collected data with systolic blood pressure values between 90 and 139 mmHg and diastolic blood pressure values between 50 and 89 mmHg were included. Subjects were divided into groups with 10 mmHg systolic blood pressure increment between groups for analysis of electrocardiographic differences. Backward multivariate regression analysis with systolic and diastolic blood pressure as a continuous variable was performed.Results: The mean age was 22.7 ± 3.0 years, 73.7% were male. P-wave area, ventricular activation time, QRS-duration, Sokolow-Lyon voltages, Cornell Product, J-point-T-peak duration corrected for heart rate and maximum T-wave duration were significantly different between systolic blood pressure groups. In the multivariate model with gender, body mass index and cholesterol, ventricular rate (standardized coefficient (SC): +0.182, p < .001), ventricular activation time in lead V6 (SC= +0.065, p = .048), Sokolow-Lyon voltage (SC= +0.135, p < .001), and Cornell product (SC= +0.137, p < .001) were independently associated with systolic blood pressure, while ventricular rate (SC= +0.179, p < .001), P-wave area in lead V1 (SC= +0.079, p = .020), and Cornell product (SC= +0.091, p = .006) were independently associated with diastolic blood pressure.Conclusion: Blood pressure-related electrocardiographic changes were observed incrementally in a healthy young population with blood pressure in the normal range. These changes were an increased ventricular rate, increased atrial surface area, ventricular activation time and increased ventricular hypertrophy indices on a standard 12 lead electrocardiogram.

Prevalence and Clinical Correlates of Left Ventricular Hypertrophy in Black Africans

INTRODUCTION

African-Americans present higher prevalence of left ventricular hypertrophy (LVH) when compared with white populations. However, there is a lack of information about the prevalence and determinants of LVH in black individuals living in Africa.

METHODS

A cross-sectional study was performed with a non-probabilistic sample comprised of 609 University workers from Angola/Africa, describing the prevalence of LVH and the determinants of left ventricular mass. Echocardiographic measurements were performed and left ventricular mass was indexed to body surface area. Systolic and diastolic blood pressures were measured, along with anthropometric and clinical variables.

RESULTS

Chamber diameter and wall thickness were higher in men compared to women. Additionally, LVM was higher in men (114.2 ± 36 vs 98.4 ± 31.9, P < 0.001), and the overall prevalence of LVH in black Angolans was 41.1%, which tended to be higher in women (44.5 vs 37.4%, P = 0.096). In men, systolic blood pressure and BMI were independently associated with LVM, while age, systolic blood pressure and waist circumference were associated with LVM in women.

CONCLUSIONS

In summary, blood pressure levels were the main determinants of LVH in black Africans, although different anthropometric variables showed mild influence in LVM. Our data suggests that LVH prevalence and determinants in black Africans are similar to that reported for African-Americans.