G. K. Pal

Assessment of sympathovagal imbalance by spectral analysis of heart rate variability in prehypertensive and hypertensive patients in Indian population.

Though the incidence of hypertension has increased considerably in recent years, the pathophysiologic mechanism that causes progression from stage of prehypertension to hypertension has not been fully elucidated. Therefore, the present study was conducted to assess the sympathovagal imbalance in prehypertensives and hypertensives by spectral analysis of heart rate variability (HRV) to understand the nature of change in autonomic balance in this common dysfunction of mankind. Body mass index (BMI), basal heart rate (BHR), blood pressure (BP), and spectral indices of HRV such as total power (TP), normalized low frequency power (LFnu), normalized high frequency power (HFnu), ratio of low frequency power to high frequency power (LF-HF ratio), mean heart rate (mean RR), square root of the mean squared differences of successive normal to normal intervals (RMSSD), the number of interval differences of successive NN intervals greater than 50 ms (NN50), and the proportion derived by dividing NN50 by the total number of NN intervals (pNN50) were assessed in three groups of subjects: normotensives (n = 32), prehypertensives (n = 28), and hypertensives (n = 31). Sympathovagal balance was analyzed and correlated with BMI, BHR, and BP in all the groups. It was observed that autonomic imbalance in prehypertensives was due to proportionate increased sympathetic activity and vagal inhibition, whereas in hypertensives, vagal withdrawal was more prominent than sympathetic overactivity. The LF-HF ratio, the sensitive indicator of sympathovagal balance, was significantly correlated with BMI, BHR, and BP. It was concluded that vagal inhibition plays an important role in the critical alteration of sympathovagal balance in the development of clinical hypertension in prehypertensive subjects.

Spectral analysis of heart rate variability (HRV) may predict the future development of essential hypertension

Presently, essential hypertension (EH) is among the most common morbid disorders of mankind. The fundamental pathophysiology of EH is sympathetic overactivity. It has been observed that the people having common risk factors for hypertension such as obesity, insulin resistance and stress generally have increased sympathetic activity. Therefore, it is presumed that patients suffering from EH develop some degree of increased sympathetic activity much before they clinically develop hypertension. Spectral analysis of heart rate variability (HRV) has been demonstrated to accurately assess change in sympathovagal balance (autonomic activity) even when the alteration is in its minimal form. Therefore, in the present paper we hypothesize that spectral analysis of HRV could be utilized for early prediction of EH. We also suggest that the predictive knowledge of sympathovagal imbalance in the development of EH should be employed in elucidating the mechanisms for prevention of this dysfunction.

Spectral Analysis of Heart Rate Variability for Early Prediction of Pregnancy-Induced Hypertension

The early prediction of pregnancy-induced hypertension (PIH), a common morbid disorder of pregnancy is unsatisfactory. Therefore, in the present study we have investigated the role of spectral analysis of heart rate variability (HRV) in the early prediction of PIH. Spectral analysis of HRV was performed in three groups of subjects (Group I: normal pregnant women; Group II: pregnant women with risk factors, but did not develop PIH; Group III: pregnant women with risk factors and developed PIH). It was observed that the LF-HF ratio, the most sensitive indicator of sympathovagal balance, was significantly high (p < 0.01) since early pregnancy in group III compared to other groups, which was significantly correlated with heart rate and blood pressure. It was suggested that the predictive knowledge of sympathovagal imbalance should be utilized in designing the prevention and management of PIH.

Association of sympathovagal imbalance with obesity indices, and abnormal metabolic biomarkers and cardiovascular parameters

PROBLEM Pathophysiological mechanisms contributing to abnormal cardiovascular (CV) parameters in obesity have not been fully elucidated. Role of sympathovagal imbalance (SVI) in the prediction of abnormalities in CV functions in obesity has not been studied. METHODS Anthropometric indices, CV parameters, autonomic function tests (AFTs) such as spectral heart rate variability (HRV) analysis, heart rate and blood pressure response to standing, deep breathing, and isometric-handgrip, and biochemical parameters like insulin resistance (HOMA-IR), lipid risk factors and inflammatory marker [high-sensitive C-reactive protein (hsCRP)] were assessed in control group (non-obese, n=43) and obese group (n=45). Association of anthropometric indices and abnormal CV parameters with low-frequency to high-frequency ratio (LF-HF) of HRV was performed by Pearsons correlation. Independent contribution of anthropometric indices and abnormal CV parameters to LF-HF was assessed by using a multiple regression analysis. LF-HF prediction of rate-pressure product (RPP), the indicator of CV dysfunction was assessed by logistic regression. RESULTS LF-HF, the marker of SVI was more in obese group compared to control group. AFTs of sympathetic activity were increased and of parasympathetic activity were reduced in obese group. Anthropometric indices, HOMA-IR, lipid risk factors and hsCRP were correlated with LF-HF. These metabolic biomarkers had independent contribution to SVI. Among, anthropometric indices, waist-to-height ratio (WHtR) had maximum association with LF-HF. LF-HF had significant prediction of RPP in obese group. CONCLUSION SVI in obesity is due to both increased sympathetic and decreased vagal activity. Abnormal CV parameters in obesity are linked to SVI, which is contributed by insulin resistance, dyslipidaemia and low-grade inflammation. LF-HF predicts abnormal CV parameters in obesity.

Sympathovagal Imbalance in Prehypertensive Offspring of Two Parents versus One Parent Hypertensive

Objective. Though prehypertension has strong familial predisposition, difference in pathophysiological mechanisms in its genesis in offspring of both parents and single parent hypertensive have not been elucidated. Methods. Body mass index (BMI), waist-hip ratio (WHR), basal heart rate (BHR), blood pressure (BP), HR and BP response to standing, deep breathing difference, BP response to handgrip and spectral indices of heart rate variability (HRV) were analyzed in normotensive offspring of two parents hypertensive (Group I), normotensive offspring of one parent hypertensive (Group II), prehypertensive offspring of two parents hypertensive (Group III) and prehypertensive offspring of one parent hypertensive (Group IV). Results. Sympathovagal imbalance (SVI) in prehypertensive offspring was observed due to increased sympathetic and decreased vagal activity. In group III, SVI was more prominent with greater contribution by vagal withdrawal. LF-HF ratio, the marker of SVI was correlated more with diastolic pressure, 30 : 15 ratio and E : I ratio in prehypertensives and the degree of correlation was more in group III prehypertensives. Conclusion. Vagal withdrawal plays a critical role in development of SVI in prehypertensive offspring of hypertensive parents. The intensity of SVI was more in offspring of two parents hypertensive compared to single parent hypertensive.

A Randomized Controlled Trial to Study the Effect of Yoga Therapy on Cardiac Function and N Terminal Pro BNP in Heart Failure

AIMS The purpose of this study was to evaluate whether yoga training in addition to standard medical therapy can improve cardiac function and reduce N terminal pro B-type natriuretic peptide (NT pro BNP) in heart failure (HF). METHODS 130 patients were recruited and randomized into two groups: Control Group (CG) (n = 65), Yoga Group (YG). In YG, 44 patients and in CG, 48 patients completed the study. Cardiac function using left ventricular ejection fraction (LVEF), myocardial performance index (Tei index), and NT pro BNP, a biomarker of HF, was assessed at baseline and after 12 weeks. RESULT Improvement in LVEF, Tei index, and NT pro BNP were statistically significant in both the groups. Furthermore, when the changes in before and after 12 weeks were in percentage, LVEF increased 36.88% in the YG and 16.9% in the CG, Tei index was reduced 27.87% in the YG and 2.79% in the CG, NT pro BNP was reduced 63.75% in the YG and 10.77% in the CG. The between group comparisons from pre to post 12 weeks were significant for YG improvements (LVEF, P < 0.01, Tei index, P < 0.01, NT pro BNP, P < 0.01). CONCLUSION These results indicate that the addition of yoga therapy to standard medical therapy for HF patients has a markedly better effect on cardiac function and reduced myocardial stress measured using NT pro BNP in patients with stable HF.

Vagal Withdrawal and Sympathetic Overactivity Contribute to the Genesis of Early-Onset Pregnancy-Induced Hypertension

Objective. In this study, we have assessed sympathovagal imbalance (SVI) by spectral analysis of heart rate variability (HRV) that contributes to the genesis of early-onset PIH. Methods. Body mass index (BMI), basal heart rate (BHR), blood pressure (BP) and HRV indices such as LFnu, HFnu, LF-HF ratio, mean RR, SDNN and RMSSD were assessed in normal pregnant women (Control group) and pregnant women having risk factors for PIH (Study group) at all the trimesters pregnancy. Retrospectively, those who did not develop PIH (Study group I) were separated from those who developed PIH (Study group II). Study group II was subdivided into early-onset and late-onset PIH. Sympathovagal balance (LF-HF ratio) was correlated with BMI, BHR and BP. Results. LF-HF ratio was significantly high in study group II compared to study group I and control group, and in early-onset PIH group compared to the late-onset category at all the trimesters of pregnancy, which was significantly correlated with BHR and BP. Alteration in HFnu in early-onset category was more prominent than the alteration in LFnu. Conclusion. Though the SVI in PIH is contributed by both sympathetic overactivity and vagal withdrawal, especially in early-onset type, SVI is mainly due to vagal inhibition.

Study of Interaction of Estrogen and Dopamine Injected Into Ventromedial Hypothalamus on Control of Obesity in Ovariectomized Albino Rats

Dopamine and estrogen are known anorectic and body weight inhibiting agents. However, at their anorectic doses they also produce widespread metabolic actions. No study has been conducted till now to assess the interaction of these two anorectic neurotransmitters in brain to suggest whether they can be used in combination at low doses without causing significant side effects. Therefore, this study was conducted to assess the interaction of anorectic and body weight inhibiting effects of dopamine and estrogen injected into ventro-medial hypothalamus (VMH), through stereotaxically implanted cannula. Pre- and post-ovariectomy basal 24 h measurements of food intake, water intake and body weight were recorded in 24 female albino rats. Estrogen and dopamine were injected into VMH at different doses (0.5,1, 2 and 4 mg) separately in two different groups of rats to find out their minimum effective dose for production of significant anorexia and body weight loss. Then, they were co-injected at their minimum effective doses into VMH in another group of rats. Ovariectomy resulted in significant increase in food and water intake and body weight, which was reversed by intra-nuclear administration of dopamine and estrogen separately. The minimum dose for both was found to be 1 mg. Combined injection at this dose produced significant anorexia and body weight loss, which was similar to their individual highest effective dose. Thus, this preliminary study indicates that dopamine and estrogen can potentiate their effects even at a lower dose when administered in combination indicating a future implication of these two chemicals in obesity management. doi: 10.5214/ans.0972.7531.2007.140103

Decreased baroreflex sensitivity is linked to sympathovagal imbalance, low-grade inflammation, and oxidative stress in pregnancy-induced hypertension.

ABSTRACT Pregnancy-induced hypertension (PIH) has been reported as a cardiovascular (CV) risk. We assessed the sympathovagal imbalance (SVI) and the association of inflammation and oxidative stress (OS) with CV risks in PIH. A total of 125 pregnant women having a risk factor for PIH were followed till term and the incidence of PIH was observed. Retrospectively, they were divided into two groups: Group I (those who did not develop PIH, n = 82) and Group II (those who developed PIH, n = 43). Blood pressure variability (BPV) parameters including baroreflex sensitivity (BRS), spectral heart rate variability (HRV), autonomic function tests (AFTs), inflammatory markers (interleukin-6, TNF-α, interferon-γ), and OS markers were measured in both the groups. Alterations in parasympathetic and sympathetic components of AFTs were analyzed. Link of various parameters to BRS was assessed by correlation and multiple regression analysis. Parasympathetic components of AFTs were decreased from the early part of pregnancy and sympathetic components were increased toward the later part of pregnancy. Decreased BRS, the marker of CV risk, was more prominent in Group II subjects. Independent contribution of interleukin-6 (β = 0.276, P = 0.020), TNF-α (β = 0.408, P = 0.002), interferon-γ (β = 0.355, P = 0.008), and thiobarbituric-acid reactive substance (β = 0.287, P = 0.015) to BRS was found to be significant. It was concluded that sympathetic overactivity that develops more in the later part (third trimester) of pregnancy contributes to SVI and genesis of PIH. In PIH women, CV risks are present from the beginning of pregnancy that intensifies in the later part of pregnancy. Retrograde inflammation and oxidative stress contribute to the decreased BRS in PIH.

Nuts can prevent diabetes mellitus

IntroductIon Diabetes mellitus is primarily the metabolic and endocrine disorder in the entire globe and India is the capital of it.[1] On the one hand, it is still a disease that is preventable following a disciplined lifestyle at prediabetes stage, and on the other hand, its ill effects can still be controlled by modifying diet and lifestyle. Therefore, if diabetes is at bay, one should not go nuts rather may consider going for nuts. Yes this editorial, we will discuss some interesting facts regarding nuts and how it would be useful in a planning a balanced diet.