Comparison of once-daily nifedipine controlled-release with twice-daily nifedipine retard in the treatment of essential hypertension

AIMS: Nifedipine is a short-acting calcium antagonist formulated into several different oral preparations, each of which may have different effects on haemodynamics and autonomic nervous function. We compared the effects of nifedipine controlled-release (CR) and nifedipine retard on 24-h blood pressure, heart rate, rate-pressure product, and power spectral measures of heart rate variability in patients with essential hypertension. METHODS: After 4 weeks of a drug-free period, 25 patients were randomized to receive either once-daily treatment with nifedipine CR (20-40 mg daily; 12 patients) or twice-daily treatment with nifedipine retard (20-40 mg daily; 13 patients) for 12 weeks. The ambulatory blood pressure, heart rate, and ECG R-R intervals were measured during a 24-h period using a portable recorder (TM-2425) at the end of the drug-free and the treatment periods. A power-spectral analysis of R-R intervals was performed to obtain the low-frequency (LF) and high-frequency (HF) components. RESULTS: Nifedipine CR and nifedipine retard reduced 24-h blood pressure significantly by 15.9 +/- 3.2 (SE)/8.7 +/- 1.4 mmHg and by 10.9 +/- 2.8/9.4 +/- 1.7 mmHg, respectively, after the 12-week treatment. Nifedipine CR did not change the 24-h heart rate significantly, while nifedipine retard increased it significantly by 3.9 +/- 2.1 beats min(-1). Nifedipine CR produced a significant reduction in rate-pressure product throughout a 24-h period, while nifedipine retard did not change the rate-pressure product significantly. In addition, nifedipine retard significantly decreased the 24-h and daytime average values of the LF and HF components, while nifedipine CR affected the nighttime LF component alone and did not change the HF component throughout a 24-h period. CONCLUSIONS: These results demonstrate that both nifedipine CR and nifedipine retard are effective as antihypertensive agents, but nifedipine CR has less influence on the autonomic nervous system and heart rate than nifedipine retard.     

Effects of angiotensin converting enzyme inhibitor,perindopril, on autonomic reflexes

Summary The effect of the angiotensin converting enzyme inhibitor, perindopril, on autonomic function was assessed in a double blind, placebo controlled, crossover study in 10 normotensive males. Eight milligram of perindopril given orally lowered blood pressure without a change in heart rate. Perindopril enhanced the vagally mediated heart rate variation with deep breathing. There was no impairment of the responses to either bicycle exercise at 175 W for 5 min or isometric handgrip. The pressor response to cold was not changed and the response to the Valsalva manoeuvre was unaltered. These results suggest that the absence of tachycardia after perindopril may be in part related, as has been reported with other converting enzyme inhibitors, to enhanced cardiac parasympathetic tone. Vagomimetic action may be a property of converting enzyme inhibitors in general.     

Effect of morning and bedtime dosing with cilnidipine on blood pressure, heart rate, and sympathetic nervous activity in essential hypertensive patients

Cilnidipine has a blocking action against N-type calcium channels as well as L-type calcium channels. We studied the effect of morning and bedtime dosing on circadian variation of blood pressure (BP), heart rate (HR), and activity of the autonomic nervous system, using an open randomized crossover study in 13 essential hypertensive patients. An automated device allowed 24-hour monitoring of ambulatory BP and HR and the power spectrum of the R-R interval, at the observation period, the morning dosing regimen, and the bedtime dosing regimen. Morning dosing and bedtime dosing with cilnidipine reduced the average systolic BP over 24 hours, during daytime, and during nighttime. The average HR and the average LF/HF ratio over 24 hours, during daytime, and during nighttime, were similar for the three periods. Both morning and bedtime dosing reduced the maximum systolic BP in the early morning and suppressed the morning rise of BP, which were accompanied by partial inhibition of the increase in LF/HF ratio. Our results show that cilnidipine administered once daily is an efficient antihypertensive drug regardless of the time of dosing, without reflex tachycardia and increase in sympathetic nervous activity, and with partial inhibition of the morning activation of the sympathetic nervous system.     

Heart rate control in hypertensive patients treated by captopril

1 The effect of captopril on autonomic reflex functions has been investigated in fifteen patients with essential hypertension by examining their responses to tests of baroreceptor function (Valsalva's manoeuvre and upright posture), sympathetic nervous system reactivity (cold pressor and mental stress tests) and parasympathetic reactivity (diving test) before and after 3 weeks' treatment with captopril. 2 Captopril significantly reduced arterial blood pressure and resting heart rate but did not affect cardiovascular responses to Valsalva's manoeuvre, upright posture, cold pressor and mental stress tests. 3 The bradycardia associated with the diving reflex test was significantly enhanced by captopril (P less than 0.01). 4 These results indicate that treatment with captopril is associated with increased parasympathetic tone but without inhibition of baroreceptor or sympathetic reflexes.     

The effects of rilmenidine and atenolol on mental stress, dynamic exercise and autonomic function in mild to moderate hypertension.

1. The effects of 4 week treatment with rilmenidine or atenolol on tests of mental stress, dynamic exercise, autonomic function and psychometric tests were evaluated in a randomized, double-blind, placebo-controlled, cross-over study. 2. After a 4 week placebo run-in, 12 patients with essential hypertension (blood pressure [BP] 160/95 +/- 15/7 mmHg) received rilmenidine 1-2 mg day-1, and atenolol 50-100 mg day-1, each for 4 weeks, with a 4 week placebo wash-out between drug treatments. 3. Both agents produced a comparable reduction in supine and erect BP. During the mental arithmetic test, BP and heart rate (HR) responses were similar for rilmenidine and atenolol. 4. During bicycle exercise, the increase in HR was significantly greater after rilmenidine (+50 vs 41 beats min-1, P = 0.04). During recovery, the areas under the curve for diastolic BP (46,450 vs 51,400 mmHg s, P = 0.02) and HR (49,445 vs 63,597 beats min-1 s, P = 0.001) were significantly less with atenolol than rilmenidine. 5. Neither rilmenidine nor atenolol affected mental performance as judged by arithmetic and psychomotor tests. Physiological responses to autonomic function tests (deep breathing, facial immersion, isometric handgrip and cold pressor) were preserved with both drugs. The standing to lying ratio was higher on atenolol (P = 0.01) and Valsalva ratio was higher on rilmenidine (P = 0.03). 6. In conclusion, rilmenidine and atenolol exerted comparable antihypertensive effects both at rest and during mental and dynamic stress. Atenolol attenuated HR responses to dynamic exercise and the Valsalva manoeuvre; rilmenidine did not interfere with the physiological responses of BP and HR during autonomic function tests.     

Effect of UK-52,046, an alpha 1-adrenoceptor antagonist, on baroreflex function in man.

1. In a placebo controlled study (six healthy male subjects), the effects of UK-52,046 (0.4 microgram kg-1 i.v.) and prazosin (0.25 mg i.v.) on baroreflex function were compared, at doses which produced antagonism to phenylephrine, but which had no effect on supine blood pressure. 2. Baroreflex function [delta R-R interval ms mm Hg-1 change in SBP] was assessed following increases in systolic blood pressure (SBP) with phenylephrine and during the Valsalva manoeuvre. 3. At these doses neither UK-52,046 nor prazosin had an effect on supine SBP or heart rate; however following prazosin, standing SBPs at 5 s (69.7 +/- 7.6 mm Hg) and at 3 min (65.5 +/- 11.7 mm Hg) were less than the respective pre-treatment (P less than 0.05) values (96.0 +/- 2.9, 110.3 +/- 6.2 mm Hg) and placebo (82.7 +/- 5.6, 98.7 +/- 11.1 mm Hg). UK-52,046 had no significant effects on standing SBP at 5 s or 3 min. At 5 s, pre- and post-treatment R-R intervals (584 +/- 26, 541 +/- 27 ms respectively) were not significantly different with prazosin, but at 3 min the post-treatment R-R interval following prazosin (519 +/- 17 ms) was less (P less than 0.05) than the pre-treatment value (658 +/- 36 ms). 4. UK-52,046 had no effect on baroreflex sensitivity (12.7 +/- 1.3 ms mm Hg-1) compared with placebo (17.9 +/- 2.7 ms mm Hg-1).(ABSTRACT TRUNCATED AT 250 WORDS)     

西尼地平胶囊治疗原发性高血压双盲双模拟随机对照多中心研究

目的:评价国产西尼地平胶囊治疗轻度至中度高血压的临床疗效及安全性。方法:以国产西尼地平片为对照药,在252例轻度至中度高血压病人中进行多中心、随机、双盲、平行、活性药物对照的临床试验。结果:治疗8wk后,西尼地平胶囊组平均坐位收缩压和舒张压分别下降(18±s 11)mmHg (11．9％)和(12±8)mmHg(12．6％),西尼地平片组平均坐位收缩压和舒张压分别下降(19±13)mmHg (12．5％)和(12±8)mmHg(12．9％),2药的总有效率分别为80．3％和82．9％。西尼地平胶囊和西尼地平片对心率无明显影响,与药物有关的不良反应分别为6例和4例,主要表现为轻到中度的头晕、头痛、面红、心悸等。2药的疗效和不良反应比较无统计学差异(P＞0．05)。结论:国产西尼地平胶囊与国产西尼地平片相似,治疗轻中度原发性高血压具有明确的降压疗效与良好的安全性。     

西尼地平与非洛地平治疗高血压病疗效及对自主神经功能的影响

目的 比较原发性高血压患者使用西尼地平与非洛地平的降压效果及对自主神经功能的影响。方法 轻中度原发性高血压患者随机分为西尼地平组(n=38，西尼地平10mg，每日1次)与非洛地平组(n=36，非洛地平5mg，每日1次)，治疗3个月后，比较两组血压与心率的改变，用动态心电图进行能量光谱分析。结果 西尼地平与非洛地平均有良好降压作用，但西尼地平对心率无明显的影响，而非洛地平增加心率，并使白天与夜晚R-R间期低频／高频(LF/HF)比率明显增加，西尼地平仅在白天有增加。结论 西尼地平对轻中度原发性高血压有良好降压疗效，且不增加交感神经活性，为有利于防止心脏事件发生的新型钙通道阻滞剂。     

Contrasting effects of verapamil and amlodipine on cardiovascular stress responses in hypertension

AIMS: To compare the effects of two long-acting calcium antagonists of different types on cardiovascular stress responses in hypertension. METHODS: One-hundred and forty-five patients with mild to moderate hypertension and a mean (+/- s.e.mean) age of 51 +/- 0.9 years received for 8 weeks the phenylalkylamine verapamil sustained release (240 mg) and the dihydropyridine amlodipine (5 mg) in a double-blind cross-over design, both after 4 weeks of placebo. Blood pressure, heart rate and plasma noradrenaline were monitored during 3 min of sustained isometric handgrip and 2 min of cold pressor. RESULTS: Blood pressure was equally reduced by both drugs. After 3 min handgrip, systolic blood pressure, heart rate and rate-pressure product were lower with verapamil compared with amlodipine. Verapamil attenuated the increases in systolic blood pressure (25 +/- 2 vs 30 +/- 2 mmHg, difference 4.6, 95% CI (1.0, 8.1), P < 0.01) and rate-pressure product (3.1 +/- 0.2 vs 3.6 +/- 0.3 x 10(3) mmHg x beats min(-1), difference 0.5, 95% CI (0.1, 0.9), P < 0.01) during handgrip compared with amlodipine. Similar results were observed during cold pressor. Plasma noradrenaline levels were lower with verapamil compared with amlodipine at rest and after both tests, but the increases in plasma noradrenaline were not significantly different. CONCLUSIONS: Verapamil is more effective in reducing blood pressure and rate-pressure product responses to stress compared with amlodipine. Although plasma noradrenaline is lower with verapamil at rest and after stress, the increase during stress is not different.     

针刺治疗对原发性高血压患者血压变异性和心率变异性的影响

目的：探讨针刺治疗对原发性高血压患者血压变异性和心率变异性的影响。方法选择符合条件的60例原发性高血压患者进行针刺治疗,疗程为30 d,采用自身前后对照,分别于治疗前后完善24 h动态血压及24 h动态心电图检查。结果针刺治疗后血压变异性各指标（24 h平均收缩压、24 h平均舒张压、24 h收缩压标准差、24 h舒张压标准差、白昼收缩压标准差、白昼舒张压标准差、夜间收缩压标准差、夜间舒张压标准差）均较治疗前降低,差异具有统计学意义（ P＜0．05）;心率变异性各指标（连续RR间期标准差、平均5 min RR间期标准差、平均5 min RR间期标准差的平均值、连续RR间期差值的均方根值、相邻RR间期大于50 ms的百分数）均较治疗前有所改善,差异具有统计学意义（ P＜0．05）。结论针刺治疗能显著降低原发性高血压患者的血压变异性,改善心率变异性,从而可能改善高血压患者的靶器官损害。     

Cardiovascular autonomic regulation in subjects with normal blood pressure, high-normal blood pressure and recent-onset hypertension

1. In the present study, we tested the hypothesis that heart rate variability (HRV) is reduced in recent-onset hypertension and that pressor responses to standard autonomic reflex tests are not any different in hypertensives compared with normotensives. We also hypothesized that subjects with high-normal blood pressure (BP) would be distinguishable from normotensives on the basis of short-term HRV indices. 2. Three groups of subjects, each consisting of 15 men and 10 women, were examined. The first group consisted of subjects with recent-onset hypertension who were not taking antihypertensive medication (mean (+/-SD) age 50 +/- 12 years; BP >/= 140/90 mmHg), the second group consisted of subjects with high-normal BP (mean age 46 +/- 13 years; BP 130-139/85-89 mmHg) and the third group consisted of subjects with normal BP (mean age 48 +/- 12 years; BP < 120/80 mmHg). The aim was to characterize the autonomic state in each group. 3. Blood pressure, heart rate (HR), indices of short-term HRV during supine rest and quiet standing, HR variation during timed deep breathing (HRVdb) and pressor responses to the cold pressor test and sustained isometric handgrip were compared between the groups. 4. Although the three groups were comparable (P > 0.1) in terms of mean HR and low-frequency (LF) power expressed in normalized units at rest and during quiet standing, the standard deviation of normal-to-normal RR intervals (SDNN) during supine rest, LF and high-frequency spectral powers during supine rest and HRVdb were lowest in hypertensives (P 相似文献   

缬沙坦对高血压及心率变异性影响的研究

目的:研究缬沙坦对高血压心率变异性的影响。方法:选择80例原发性高血压患者服用缬沙坦,分别在治疗前与治疗14周后进行动态心电图(DCG)及心率变异性(HRV)检查,并与对照组(40例)进行比较。结果:治疗后连续R-R间期标准差(SDNN),相邻R-R均方差(RMSSD),相邻R-R间期大于50ms百分数(PNN50)、高频功率(HF)值均明显上升;低频功率与高频功率比值(LF/HF)显著降低(P<0.01),结论:原发性高血压患者存在HRV下降,而缬沙坦在降压的同时,可提高HRV,改善自主神经功能失调。     

AUTONOMIC BLOCKADE AMPLIFIES CORTISOL-INDUCED HYPERTENSION IN MAN

1. We investigated the role of the autonomic nervous system (ANS) in Cortisol induced hypertension using the technique of total autonomic blockade (AB). 2. Four healthy young males were given 50 mg Cortisol 6 hourly for 6 days. On the day prior to, and the last day of, Cortisol treatment, AB was produced using oral prazosin 1 mg, intravenous clonidine 300 μg, propranolol 0.2 mg/kg and atropine 2 mg. The adequacy of blockade was assessed using the haemodynamic response to Valsalva manoeuvre. 3. Cortisol produced a significant rise in systolic blood pressure (130 ± 2 vs 110 ± 1 mmHg, pre vs post Cortisol; P<0.01). On the final treatment day, AB augmented the increase in diastolic blood pressure (ΔDBP), mean arterial pressure (ΔMAP) and heart rate (ΔHR) compared to the pre-treatment day, ΔDBP: 43 ± 6 vs 17 ± 4 mmHg, post vs pre Cortisol, P<0.005, ΔMAP: 39 ± 4 vs 14 ± 4 mmHg, P<0.001, ΔHR: 45 ± 5 vs 26 ± 4 b.p.m., P<0.05. The change in systolic blood pressure (ΔSBP) was not statistically significant (32 ± 4 vs7 ± 3 mmHg, P= 0.065). 4. These results suggest that the ANS exerts a modulating influence on the hypertensive effect of Cortisol.     

Effect of calcium antagonists on stress-induced rise in blood pressure and heart rate: a double-blind, placebo-controlled study

OBJECTIVE: The current study was designed to evaluate the effect of treatment with calcium antagonists on stress-induced increases in blood pressure and heart rate. SUBIECTS, MATERIAL AND METHODS: Two models of stress were chosen, cold stress and isometric handgrip exercise. Six healthy volunteers were randomized to receive amlodipine (5 mg), lacidipine (4 mg) for a two-day period in a double-blind, crossover design. Thirty hypertensive patients received the same treatment for a period of one week in a double-blind, parallel design. The effects of stress on blood pressure and heart rate were taken at baseline and after drug treatment. RESULTS: Cold stress and handgrip exercise significantly increased the systolic and diastolic blood pressure as well as the heart rate. In normotensive volunteers, the resting heart rate and blood pressure were not altered by the drugs. The increase in systolic and diastolic blood pressure produced by cold stress and isometric exercise were unchanged by amlodipine and lacidipine. In hypertensive patients, both drugs reduced the resting blood pressure (p < 0.05). As in normotensive individuals, the pressor response to stress was not altered by the drugs. CONCLUSION: Cold stress and handgrip exercise produced a significant rise in blood pressure and heart rate in normotensive volunteers and patients with hypertension. Cardiovascular reactivity to cold stress and handgrip exercise is not altered by the administration ofamlodipine and lacidipine.     

西尼地平与尼群地平治疗高血压病的疗效比较

目的:比较西尼地平与尼群地平治疗高血压病的疗效及安全性。方法:86例原发性高血压病患者随机均分为西尼地平组和尼群地平组,西尼地平组给予西尼地平,起始剂量为5mg,qd,根据血压可调整至10mg,qd;尼群地平组给予尼群地平,起始剂量为10mg,qd,根据血压可调整至20mg,bid。比较2组的降压疗效及药品不良反应。结果:西尼地平组与尼群地平组的总有效率分别为90.7%和88.4%,2组比较差异无统计学意义(P>0.05);西尼地平组和尼群地平组收缩压的最大降幅分别为(34.2±3.8)和(29.2±2.2)mmHg,舒张压最大降幅分别为(23.8±2.6)和(19.4±2.3)mmHg,差异有统计学意义(P<0.05)。尼群地平组治疗后心率明显快于治疗前及西尼地平组治疗后(P<0.05),但西尼地平组患者心率治疗前、后无显著变化(P>0.05)。治疗过程中2组均未见明显不良反应发生。结论:西尼地平用于治疗高血压疗效与尼群地平相近,但其对患者的心率影响较小。     

Antihypertensive effect of a new formulation of slow release oxprenolol in essential hypertension

To test whether a new formulation of a slow release oxprenolol (SLOx) can produce a steady 24-h antihypertensive effect, we recorded 24-h intraarterial blood pressure (Oxford technique) in eight ambulant inpatients (age 44.5 +/- 3.0 years, mean +/- SE) with a mild or moderate hypertension who were untreated since three weeks. The study was started seven days after hospitalization and was conducted according to a randomized doubleblind cross-over design. Blood pressure recordings were made after (a) a 7-day administration of SLOx in a single evening dose, and (b) a 7-day administration of placebo. This design allowed to determine the effect of SLOx without interference from nonspecific blood pressure lowering factors. Blood pressure effects of handgrip, submaximal cyclette exercise, and cold pressor test 20-24 h after the administration of SLOx and placebo were also evaluated. The blood pressure tracing was analyzed beat-to-beat by a computer which provided also the analysis of the heart rate data. The 24-h mean systolic and diastolic blood pressure measured during placebo were 144.6 +/- 6.4 and 81.1 +/- 3.9 mm Hg, the corresponding heart rate being 76.9 +/- 3.5 beats/min. SLOx reduced these values by 6.2, 10.6, and 4.8%, respectively, all effects being similarly evident throughout the blood pressure recording. The pressor responses to handgrip, cyclette exercise, and cold pressor test were not affected by SLOx. By contrast, the small tachycardic response to handgrip and the large tachycardic response to submaximal cyclette exercise were significantly reduced by the drug.(ABSTRACT TRUNCATED AT 250 WORDS)     

国产西尼地平治疗原发性高血压的多中心随机双盲双模拟临床研究

目的 对西尼地平治疗原发性高血压患者的疗效与安全性进行临床评价。方法 用多中心双盲双摸拟随机平行对照的试验方法,研究国产西尼地平与对照药苯磺酸氨氯地平对233例轻中度原发性高血压患者的降压疗效及药物不良反应。结果 治疗8周后,西尼地平组平均坐位收缩压(SBP)及舒张压(DBP)下降幅度分别为16.2,1 2.7 mmHg,苯磺酸氨氯地平组分别下降23.1,15.1 mmHg;两药总有效率分别为76.6％和87.7％,与治疗前比较有显著性差异(P<0.01);两药对心率无明显影响;两组药物不良反应的发生率分别为16.7％和12.9％。长期服用西尼地平疗效能持续,并有良好的耐受性。结论 西尼地平治疗轻中度原发性高血压具有明确的降压疗效与良好的安全性。     

冠心病患者心率变化、血压与心肌缺血改变的相关性研究

目的根据监测清晨血压变化参数与对应时域的缺血ST段演变相关性,探讨冠心病合并高血压患者心率变化、血压是否与心肌缺血改变存在相关性。方法对2010年2月～2011年2月90例冠心病合并高血压患者（高血压组）及66例单纯冠心病患者（对照组）,行24h动态心电图及同步动态血压监测,获得的心率、清晨血压波动值和ST段压低持续时间进行相关性统计学分析及研究结论。结果高血压组的清晨血压升值与对应时域的ST段压低有正相关性关系;尤以清晨血压回升差值（收缩压、平均脉压、舒张压）和心率与对应ST段压低有显著正相关性,而对照组无明显相关性。结论清晨清醒前后血压升高与心肌缺血的发生呈正相关关系,且多为无痛性心肌缺血。     

The dose–response effects of terbutaline on the variability, approximate entropy and fractal dimension of heart rate and blood pressure

Aims To study the dose-response effects of intravenous terbutaline on the cardiovascular and respiratory autonomic nervous regulation.
Methods The study followed a randomized, placebo-controlled crossover design in six healthy adult volunteers. The terbutaline dose ranged from 10 to 30  μg  min⁻¹. We continuously measured electrocardiogram, finger systolic arterial pressure (SAP) and flow-volume spirometry in supine and upright positions at baseline and during 3  h drug infusion. The periodic variability components of R-R intervals (time between successive heart beats) and SAP in relation to respiration were assessed using spectral analysis techniques. The regularity of the time series was assessed by approximate entropy (ApEn) and the convolutedness by fractal dimension (FD).
Results Terbutaline dose-dependently decreased total variability of R-R intervals, low frequency (LF) variability of R-R intervals (10  s waves), high frequency (HF) variability of R-R intervals (respiratory variability), total variability of SAP, HF variability of SAP, baroreflex sensitivity, plasma potassium concentration, approximate entropy of R-R interval and of SAP as well as fractal dimension of R-R interval. Terbutaline dose-dependently increased heart rate, LF/HF ratios of R-R intervals and of SAP, LF variability of SAP, minute ventilation and plasma terbutaline concentration.
Conclusions Terbutaline infusion decreases parasympathetic cardiovascular reactivity, baroreflex sensitivity, dimensionality of heart rate and plasma potassium concentration; it increases sympathetic dominance in cardiovascular autonomic balance, minute ventilation, and the regularity of heart rate and blood pressure time series.     

Correlation between short-term heart rate variability indices and heart rate, blood pressure indices, pressor reactivity to isometric handgrip in healthy young male subjects

The purpose of the present study was to determine whether readily measured blood pressure (BP) indices and, responses to autonomic reflex tests could be used as surrogates of short-term heart rate variability (HRV), which is an established marker of autonomic regulation of SA node. Therefore, we examined the correlation between short-term HRV and heart rate (HR), BP indices viz. systolic pressure, diastolic pressure, pulse pressure (PP), and rate-pressure product (RPP), during supine rest and head-up tilt in 17 young healthy normotensive subjects, aged 19.8 +/- 1 yr (mean +/- SD). Three classic autonomic indices viz. Valsalva ratio, HR response to deep breathing and pressor response to isometric handgrip were also determined. We noted two interesting and statistically significant (P < 0.05 in both cases) correlations viz. i) a positive correlation (r = 0.6) between change in RPP during tilt and change in low frequency (LF) RR spectral power expressed in normalized units (LF nu) during tilt, and ii) a negative correlation (r = -0.6) between change in PP during isometric handgrip and LF nu during tilt. The possible physiologic significance of these and other correlations is discussed in this paper. In conclusion, the presence of a statistically significant correlation between RPP, PP and spectral measures of short-term HRV supports a simplistic approach to autonomic assessment, in that, easily measurable BP indices could be used as surrogates of HRV when it is not feasible to determine HRV indices directly. However, the same have to be tested in healthy subjects belonging to various age groups and in patients with conditions known to be associated with autonomic dysregulation.