Effect of antihypertensive drug therapy on short-term heart rate variability in newly diagnosed essential hypertension.

1. Abnormalities of cardiac autonomic regulation are a potential mechanism for morbidity despite blood pressure (BP) lowering in hypertension. Analysis of short-term (5 min) heart rate variability (HRV) provides a non-invasive probe of autonomic regulation of sino-atrial (SA) node automaticity. 2. We hypothesized that antihypertensive drug therapy would be associated with an increase in 5 min overall HRV, along with a decrease in blood pressure (BP), at 8 weeks follow up in subjects with newly diagnosed, never-treated essential hypertension. 3. One hundred and fifty patients (84 men and 66 women; mean (+/-SD) age 48 +/- 10 years) with newly diagnosed essential hypertension were divided to five groups of 30 patients each to receive one of the following antihypertensive drugs (or drug combinations): 5 mg/day amlodipine; 50 mg/day atenolol; 5 mg/day enalapril; 25 mg/day hydrochlorothiazide; or a combination of 5 mg/day amlodipine and 50 mg/day atenolol. 4. The only significant change in HRV indices was an increase in total variability of RR intervals and an increase in high-frequency (HF) RR interval spectral power in the amlodipine + atenolol-treated group (P < 0.05). 5. The results indicate that there is a dissociation between changes in short-term HRV and mean RR interval and BP lowering in patients with newly diagnosed hypertension. 6. We interpret the increase in HF RR interval spectral power in the amlodipine + atenolol-treated group as being due to an increase in vagal modulation of RR intervals and/or diminution in sympathetic restraint of respiratory sinus arrhythmia.

Effect of antihypertensive therapy on serum lipids in newly diagnosed essential hypertensive men.

The effect of antihypertensives on serum lipids in newly diagnosed male essential hypertensive patients was studied. The participants (n = 99) were randomly allocated to receive amlodipine, atenolol, enalapril, hydrochlorothiazide, and a combination of amlodipine and atenolol. Lipid parameters were estimated before and after 8 weeks of therapy. The atenolol and thiazide group showed a significant increase in triglycerides (TGs) and very-low-density lipoprotein cholesterol (VLDL-C). High-density lipoprotein cholesterol (HDL-C) and HDL-C to low-density lipoprotein cholesterol (LDL-C) ratio were significantly increased and TC to HDL-C ratio was significantly decreased in the amlodipine and amlodipine- atenolol combination groups. In the enalapril group, we found a significant reduction in TC, TGs, VLDL-C, non-HDL-C, and TG to HDL-C ratio after treatment. It can be concluded from the present study that some drugs have beneficial effects on the lipid status, whereas others adversely affect the lipid status in hypertension.

Heart rate variability in middle-aged men with new-onset hypertension.

BACKGROUND: It has been well established that hypertension is associated with autonomic dysregulation. Studies investigating HRV have established that hypertension is characterized by sympathetic overactivity and or attenuation of parasympathetic modulation of the heart. METHODS: We examined short-term heart rate variability (HRV) as well as conventional indices of cardiovascular autonomic function including heart rate variation during deep breathing (HRVdb), 30: 15 ratio, pressor response to quiet standing and isometric handgrip in 35 male subjects (39 +/- 7 year, mean +/- SD) with new-onset hypertension (resting BP 155 +/- 17/101 +/- 8 mm Hg) and 17 age-matched normotensive men (resting BP: 111 +/- 7/71 +/- 5 mmHg). RESULTS: HRVdb was significantly lower in hypertensives (21 +/- 8) compared to normotensives (mean age 36 +/- 7, P = 0.03). Differences in mean RR were insignificant, logarithm of high-frequency (HF) spectral power of RR intervals was significantly lower in hypertensives compared to normotensives in the supine position (P = 0.02). CONCLUSIONS: Our data suggest that new-onset hypertension is characterized by diminished short-term HRV, possibly due to an increase in cardiovascular sympathovagal balance.

Association between protein-bound sialic acid and high-sensitivity C-reactive protein in essential hypertension: a possible indication of underlying cardiovascular risk.

The aim of this study was to examine the possible alteration in the levels of C-reactive protein, protein-bound sialic acid, and other lipid risk factors in newly diagnosed essential hypertensive subjects. In all, 56 hypertensive and 33 normotensive male subjects were enrolled in the study. Lipid profile, C-reactive protein, apolipoprotein-B, and protein-bound sialic acid were estimated in both the groups. Total cholesterol, triglyceride, low-density lipoprotein-cholesterol, C-reactive protein, apolipoprotein-B, and protein-bound sialic acid were significantly increased in patients with essential hypertension. Correlation analysis revealed a significant association between the protein-bound sialic acid with mean arterial pressure, C-reactive protein, and low-density lipoprotein-cholesterol. The findings of the present study suggest that in essential hypertension there is an association between protein-bound sialic acid and C-reactive protein, which reflects the clustering of cardiovascular risk factors in these patients.

Sex differences in short-term heart rate variability in patients with newly diagnosed essential hypertension.

The authors report the results of the analysis of heart rate variability (HRV) indices during 5 minutes of supine rest and 5 minutes of standing and conventional indices of autonomic function in 69 men and 51 women with untreated newly diagnosed hypertension matched for body mass index and resting blood pressure. Mean RR interval, standard deviation of normal-to-normal RR intervals, low-frequency RR spectral power, HRV during deep breathing at 6 breaths per minute, and the 30:15 ratio (maximum RR interval 30th beat/minimum RR interval 15th beat) were significantly lower in women (P=.01, .02, .001, .04, .01, respectively) compared with men. Low frequency RR in normalized units was lower in women in the supine position alone (P=.03). HRV was significantly lower in women with untreated newly diagnosed hypertension compared with men. The authors interpret these results as indicating an increase in baseline cardiac sympathovagal balance in female hypertensive patients.

Enhanced glycation of hemoglobin and plasma proteins is associated with increased lipid peroxide levels in non-diabetic hypertensive subjects.

BACKGROUND: Accumulating evidences indicate that lipid peroxidation and protein glycation play a vital role in the pathogenesis of cardiovascular disease. The purpose of the present study was to evaluate the levels of lipid peroxides and glycated proteins in non-diabetic hypertensive patients and to assess the possible nexus between them, among these subjects. METHODS: Thirty hypertensive patients and 25 normotensive subjects were enrolled in the present study. Lipid peroxides, glycated hemoglobin, and fructosamine levels were estimated in both groups. RESULTS: Lipid peroxides, glycated hemoglobin, and fructosamine levels were significantly increased in hypertensive subjects in comparison with normotensive subjects. When partial correlation analysis was performed, malondialdehyde was significantly associated with glycated hemoglobin and fructosamine. CONCLUSIONS: An increased glycation of proteins was found in non-diabetic hypertensive subjects. These data also support the premise that lipid peroxidation per se plays a role in glycation of hemoglobin and plasma proteins.

Increased glycation of hemoglobin and plasma proteins in normotensive, non-diabetic obese Indian subjects: putative role of lipid peroxides.

BACKGROUND: Glycation and lipid peroxidation are spontaneous reactions believed to contribute to the pathogenesis of many clinical disorders. The purpose of the present study was to evaluate the levels of lipid peroxides and glycated proteins in normotensive, non-diabetic obese Indian subjects and to assess possible associations between them. METHODS: A total of 28 obese male subjects and 20 non-obese subjects were included in the present study. Whole blood glycated hemoglobin, plasma lipid peroxides and fructosamine levels were estimated in both groups. RESULTS: Lipid peroxides, glycated hemoglobin and fructosamine levels were significantly higher in obese subjects in comparison with non-obese subjects. We also found a significant association between malondialdehyde and body mass index (r=0.424, p=0.025). Partial correlation analysis revealed that malondialdehyde was significantly correlated with glycated hemoglobin (r=0.590, p=0.01) and fructosamine (r=0.442, p=0.021) after controlling for glucose. CONCLUSIONS: Increased glycation of proteins was found in normotensive, non-diabetic obese Indian subjects. These data also support the premise that lipid peroxides per se play a role in the glycation of hemoglobin and plasma proteins.

Insulin resistance and enhanced protein glycation in men with prehypertension.

BACKGROUND: Insulin resistance and hyperinsulinemia have been reported among patients with hypertension. However, little is known about insulin sensitivity in subjects with prehypertension. The aim of this study was to assess whether the metabolic characteristics of insulin resistance syndrome are present in prehypertensive subjects. METHODS: Plasma fasting glucose, lipid profile, glycated hemoglobin, fructosamine and insulin concentrations were evaluated in 35 prehypertensive subjects and in 30 healthy controls. RESULTS: Prehypertensive subjects had significantly higher levels of plasma insulin and triglycerides compared with normotensive subjects. The level of high-density lipoprotein cholesterol was significantly lower in prehypertensive subjects compared with controls. There was no significant difference in total cholesterol and low-density lipoprotein cholesterol levels. The levels of glycated hemoglobin and fructosamine were also significantly higher in prehypertensive subjects compared with controls. Plasma insulin levels were positively correlated with systolic and diastolic blood pressure in prehypertensive subjects. Similarly, plasma insulin was significantly positively correlated with triglyceride and negatively correlated with high-density lipoprotein cholesterol. CONCLUSIONS: The present study indicates that prehypertensive non-diabetic subjects have higher insulin resistance and protein glycation compared to normotensive subjects, which may contribute to the pathogenesis of prehypertension.