The influence of antihypertensive agents on circadian rhythms of blood pressure and heart rate in patients with essential hypertension.

The effects of once-daily administration of calcium (Ca) channel blockers, beta-blockers and and angiotensin-converting enzyme (ACE) inhibitors on circadian rhythms of blood pressure (BP) and heart rate (HR) were studied using the cosinor method. Sixty-two recruited patients with essential hypertension (WHO stage I or II) were divided into three groups based on the class of administered drugs. In the Ca channel blocker group (n = 37, age 54 +/- 9.0 years), 18 patients were given YM 730 at a mean dose of 11 +/- 4.0 mg/day (mean +/- S.D.), 8 were given nitrendipine (11 +/- 6.7 mg/day), and 11 were given nisoldipine (8 +/- 6.4 mg/day). In the beta-blocker group (n = 15, age 42 +/- 13.5 years), 13 patients were given atenolol (44 +/- 11.0 mg/day), 1 was given nadolol (30 mg/day), and 1 was given sustained-release propranolol (60 mg/day). In the ACE inhibitor group (n = 10, age 56 +/- 8.7 years), 7 patients were given enalapril (6 +/- 2.8 mg/day), and 3 were given lisinopril (20 mg/day). Ambulatory BP monitoring (ABPM) was performed before and during treatment. Mean arterial pressure (MAP) and HR were monitored under ambulatory conditions every five minutes for 24 hr with a finger volume oscillometric device. In all three groups, the mesor of MAP decreased significantly, while the amplitude and acrophase did not change during treatment. beta-Blockers reduced the amplitude as well as the mesor of HR. Ca channel blockers increased the amplitude of HR without influencing the mesor. ACE inhibitors had no effect on the circadian rhythm parameters of HR. These results suggest that Ca channel blockers, beta-blockers and ACE inhibitors lowered BP throughout the day without changing the circadian BP rhythm. However, the three drug classes may have different influences on the autonomic nervous system that regulates circadian cardiac rhythm.     

Effects of Atrial Tachypacing on Symptoms and Blood Pressure in Severe Orthostatic Hypotension

The treatment of severe orthostatic hypotension (OH) is currently unsatisfactory and usually includes various pharmaceuticals to expand the blood volume and promote peripheral vasoconstriction. This study examined the short- and intermediate-term effects of atrial tachypacing (ATP) in patients with severe OH. We implanted dual chamber pacemakers in five patients (mean age 64 ± 7 years; four men), presenting with drug refractory, recurrent syncope, and OH due to panautonomic failure with severe chronotropic incompetence and absence of rate acceleration upon assuming the upright posture. The blood pressure (BP) was measured in the supine and passive upright postures, during sinus rhythm, and during atrial pacing at 90, 100, and 110 ppm, at 1 week and at discharge and/or 3 months after pacemaker implantation. Alleviation of symptoms and a delay in the fall in upright BP were observed in a single patient at 1 week, while at discharge and/or 3 months, all patients were markedly improved. The mean fall in systolic/diastolic BP between supine and upright position decreased from 73 ± 17/46 ± 13 mmHg before, to 56 ± 27/41 ± 30 mmHg during ATP. Although these changes did not reach statistical significance, the time required for the fall in BP lengthened significantly from 2.1 ± 0.2 minutes during sinus rhythm to 9.3 ± 1.5 minutes during ATP (P < 0.001).
Conclusions: At discharge and/or 3 months of follow-up, ATP conferred beneficial effects on orthostatic BP and alleviated symptoms in patients with severe OH. The short-term effects of ATP did not reflect its longer-term effects in four of the five patients.     

Circadian rhythm of blood pressure in normotensive NIDDM subjects. Its relationship to microvascular complications

OBJECTIVE: To investigate the relationship between circadian rhythm of mean blood pressure (MBP) and microvascular complications in non-insulin-dependent diabetes mellitus (NIDDM) subjects. RESEARCH DESIGN AND METHODS: Seventy-six normotensive NIDDM subjects without azotemia were studied under ordinary hospital conditions with a noninvasive ambulatory blood pressure monitoring device. Time series data were analyzed by the cosinor method. RESULTS: Fifty-four subjects had a circadian MBP rhythm similar to that of 34 age-matched nondiabetic control subjects, with a peak value in the afternoon (group 1). In contrast, 22 had a reversed circadian MBP rhythm, with a peak value during the night (group 2). Obvious complications were found in 65% of group 1 and in all of group 2. The prevalence of retinopathy and somatic neuropathy and the degree of retinopathy were similar in the two groups. The prevalence and degree of autonomic neuropathy (postural hypotension and reduced beat-to-beat heart-rate variation) and nephropathy were greater in group 2 than group 1. Linear discriminant analysis revealed a correlation between the reversed circadian MBP rhythm and postural hypotension (F = 32.2, P less than 0.001) and overt nephropathy (F = 5.1, P less than 0.05) but not with beat-to-beat heart-rate variation (F = 0.17, NS). CONCLUSIONS: These results suggest that in the hospitalized normotensive NIDDM subjects, there are normal and reversed circadian MBP rhythms and that the reversal of normal circadian MBP rhythm may be related to the degree of postural hypotension and/or nephropathy.     

不同给药时间对非勺型高血压患者降压效果的影响

目的对高血压患者不同服药时间进行研究和护理干预,观察给药时间与血压昼夜节律是否相关,以探讨合理的高血压患者给药时间。方法选择高血压病住院患者共58例,随机分为两组,分别在6：00～7：00、20：00～21：00服药,监测24h动态血压。结果清晨或夜间服药均能有效降低24h平均血压。夜间给药组夜间SBP和夜间DBP显著低于清晨给药组,清晨时段SBP或DBP显著低于清晨服药组。结论通过选择恰当的给药时间,可逆转异常的昼夜血压节律,有效抑制清晨时段血压的迅速上升,降低心脑事件的发生率。     

The validity of a hyperventilation test for an investigation of autonomic failure: assessment in patients with multiple system atrophy and Parkinson's disease

Although heart rate (HR) responses to hyperventilation (HV) have been used as a cardiovascular autonomic function test, autonomic involvement during HV remains uncertain. To clarify the relationship between autonomic activity and cardiovascular changes during HV, we compared cardiovascular responses during HV among subjects with different autonomic function, namely 16 patients with probable multiple system atrophy (MSA), 16 with possible MSA, 28 with Parkinson's disease (PD) and 28 healthy controls. Abnormalities of cardiovascular responses to head-up postural change and the Valsalva maneuver were definitely present in the order of probable MSA, possible MSA and PD, and abnormal HR and blood pressure (BP) responses during HV were observed in probable MSA and possible MSA, but not in PD. Unlike the significant difference in standard cardiovascular autonomic function tests, the HR and BP responses during HV were equivalent between probable and possible MSA. These findings suggest that cardiovascular control during HV may be affected not only by autonomic activity but also by other factors.     

The circadian variation of blood pressure and heart rate in patients with hyperthyroidism

The circadian variation of blood pressure (BP) and heart rate (HR) was examined in 18 normal subjects, 15 patients with essential hypertension treated with beta-blockers and 21 patients with hyperthyroidism. Most of the patients with hyperthyroidism were also treated with beta-blockers. The 24 hr BP was measured with an ambulatory blood pressure monitoring device (UBP-100) every 5 min. A nocturnal fall in BP and HR was observed in the patients with essential hypertension treated with beta-blockers and the patients with mild to moderate hyperthyroidism as well as normal subjects. On the other hand, in patients with severe hyperthyroidism the nocturnal fall was observed in HR alone, and the fall was small in its amplitude. There was a significant negative correlation between triiodothyronine (T3) level and percentage amplitude of the nocturnal fall in systolic BP (n = 21, r = -0.5, p less than 0.01). However, this relation was not significant in diastolic BP and HR. These results indicate that excess thyroid hormone may modulate the circadian variation of BP and HR.     

Daily variation of blood pressure in patients with Cushing's syndrome

The circadian rhythm of blood pressure (BP) was compared between patients with Cushing's syndrome and those with essential hypertension. In patients with essential hypertension, clear nocturnal falls in systolic and diastolic BP and heart rate (HR) were observed, and there was a positive correlation between HR and systolic or diastolic BP. On the other hand, in patients with Cushing's syndrome, there was no nocturnal fall in BP and instead a rise in some cases. In all cases with Cushing's syndrome there was a nocturnal fall in HR, and consequently no significant correlation between HR and BP in these patients. The present results imply that the normal circadian rhythm of blood pressure may be regulated at least in part by the hypothalamo-pituitary-adrenal system.     

Cosinor analysis of changes in circadian blood pressure rhythm with aging in spontaneously hypertensive rats

Evolution of circadian rhythm of blood pressure with age in male spontaneously hypertensive rats (SHR) was compared with that in male Wistar Kyoto rats (WKY). Three different age groups (5-6 week old, 19-22 week old, 29-31 week old) were provided for each strain. Chronogram and cosinor method were used for time series analyses. In all age groups of WKY, a diurnal fall and a nocturnal rise in blood pressure (BP) as well as in heart rate (HR) were observed. There was no significant difference in acrophase between BP and HR in each age group of WKY. Regarding SHR, however, each age group demonstrated a different relation between circadian BP rhythm and HR rhythm. In 5-6 week old SHR, a difference in acrophase between BP and HR (about 6.9 hr, p less than 0.1) was observed, which became more conspicuous with the increase in age, eventually presenting an inverted relation between BP and HR in 19-22 week old SHR. The relation between circadian BP rhythm and circadian HR rhythm in 29-31 week old SHR was almost identical with that in 19-22 week old SHR. In other words, a phase lag of acrophase of BP from that of HR already observed in young SHR increased with aging. The results indicate that parasympathetic periodicity remained unchanged even in SHR since circadian HR rhythm was similar in all groups, while the periodicity of sympathetic neural tone relating to the regulation of circadian BP rhythm seems to be disturbed. The mechanism responsible for development and maintenance of high BP in SHR may be linked to a disturbance in the sympathetic mechanism which regulates BP periodicity.     

100 or 30 years after Janeway or Bartter,Healthwatch helps avoid ‘flying blind’

Longitudinal records of blood pressure (BP) and heart rate (HR) around the clock for days, weeks, months, years, and even decades obtained by manual self-measurements (during waking) and/or automatically by ambulatory monitoring reveal, in addition to well-known large within-day variation, also considerable day-to-day variability in most people, whether normotensive or hypertensive. As a first step, the circadian rhythm is considered along with gender differences and changes as a function of age to derive time-specified reference values (chronodesms), while reference values accumulate to also account for the circaseptan variation. Chronodesms serve for the interpretation of single measurements and of circadian and other rhythm parameters. Refined diagnoses can thus be obtained, namely MESOR-hypertension when the chronome-adjusted mean value (MESOR) of BP is above the upper limit of acceptability, excessive pulse pressure (EPP) when the difference in MESOR between the systolic (S) and diastolic (D) BP is too large, CHAT (circadian hyper-amplitude tension) when the circadian BP amplitude is excessive, DHRV (decreased heart rate variability) when the standard deviation (SD) of HR is below the acceptable range, and/or ecphasia when the overall high values recurring each day occur at an odd time (a condition also contributing to the risk associated with ‘non-dipping’). A non-parametric approach consisting of a computer comparison of the subject's profile with the time-varying limits of acceptability further serves as a guide to optimize the efficacy of any needed treatment by timing its administration (chronotherapy) and selecting a treatment schedule best suited to normalize abnormal patterns in BP and/or HR. The merit of the proposed chronobiological approach to BP screening, diagnosis and therapy (chronotheranostics) is assessed in the light of outcome studies. Elevated risk associated with abnormal patterns of BP and/or HR variability, even when most if not all measurements lie within the range of acceptable values, becomes amenable to treatment as a critical step toward prevention (prehabilitation) to reduce the need for rehabilitation (the latter often after costly surgical intervention).     

Cardiopulmonary Responses to Exercise in Children with Activity Sensing Rate Responsive Ventricular Pacemakers

The physiological benefits of activity sensing rate responsive ventricular pacing)VVIR) over fixed rate pacing)VVI) were investigated in 14 children during incremenlal cycle exercise. Based on their heart rhythm response during exercise, children were divided into two groups. Group I patients)13 ± 4 years) remained in a paced-only rhythm when exercised. Group II patients)16 ± 7 years) were paced at rest but converted to sinus rhythm with exercise. In Group I patients, the significant physioJogicol benefits of VVIR over VVI pacing were evidenced hy a 51% increase in peak heart rate)HRmax) and a 16% increase in exercise duration and maximum oxygen uptake)VO₂max). Additionally, a 27% reduction in peak oxygen pulse)O₂Pmax) was found, reflecting a similar decrease in stroke volume. The cardiorespiraiory responses of Group I and 11 patients were compared in terms of percent of predicted normal values. Although Group I patients in the VVIR mode attained a better exercise performance than in the VVI mode and a normal O₂Pmax)108% pred). their HRmax)62% pred) and VO₂max)70% pred) fell far below normal values. In comparison. Group II patients, who went into sinus rhythm, achieved normal values for HRmax)84% pred), VO₂max)90% pred), and O₂Pmax)97% pred). The higher pacing rates attained by Group I patients in the VVIR mode may have allowed them to reach not only a higher cardiac output but also a more normal stroke volume at peak exercise than in the VVI mode. However, the overall exercise performance of children paced in the VVI and VVIR modes were significantly diminished compared to the performance of children who went into sinus rhythm with exercise.)     

Frequency and Variability of Ventricular Premature Contractions—The Influence of Heart Rate and Circadian Rhythms

Present knowledge about arrhythmias is still too limited to prevent sudden cardiac death Long-term ambulatory ECG monitoring should be the method of choice in further investigating and evaluating the possible relationships between the frequency of arrhythmias and heart rate (MR), circadian patterns, and effects of drugs Using a computer-supported, semiautomatic anaiysis system, 77 patients with a mean premature ventricuiar contraction (PVC)-rate of over 1% were monitored for 24 hours (group A). Ten other patients with PVC's of over 1% were monitored for up to 96 hrs each, continuousiy, to demonstrate the reproducibility of possible circadian PVC's and HR patterns (group B) Another group of 44 patients (group C) underwent long-term ECG monitoring of 24 hrs before and during drug therapy with disopyramide (n = 15 pts, 200 mg tid), mexiletine (n = 13 pts, 200 mg t.i.d.), acebutoiol (n = 9 pts, 200 mg bid) and propafenon (n = 7 pts, 300 mg t i.d.) to judge the drug effects in relation to their specific chronotropic properties. In group A patients there was a significant correlation (r = -0 602) between mean PVC frequency and respective PVC variabilities The latter increase with a reduction of the PVC rate and vice versa A circadian pattern of HR and PVC's can be demonstrated in the majority of group A and B patients. By using Scheffe's test to determine the required PVC reduction, the statistical PVC reduction curve (p < 0 05) does not conform to the PVC-aboiition curve (PVC beiow 1%) in group B patients If patients without circadian PVC/HR patterns are under antiarrhythmic therapy, they need a much higher mean PVC-reduotion rate to reach the statistical significance level than patients without such a PVC and HR behavior. Drugs administered in Group C patients had different chronotropic effects Heart rate spectra were demonstrated for each antiarrhythmic drug used The distribution of arrhythmias, their variability, HR, circadian rhythm and the activity of antiarrhythmic drugs should be taken into account to narrow the gap between current antiarrhythmic treatment and the prevention of sudden cardiac death     

Ventricular Parasystole: A Chronobiologic Study

Previous works have reported circadian rhythms for several cardiovascular parameters. A chronobiologic rhythm is characterized by: mesor (a rhythm-determined average), amplitude (half difference between the highest and lowest values), and acrophase (timing of high point in degrees and/or in hours) along with 95% confidence limits. We performed 24-hour ECG Holler monitoring in seven patients (mean age, 50.6 years) with ventricular parasystole (VP) in order to determine whether the chronotropic activity of parasystolic foci has a circadian rhythm similar to that of the sinus node. For each Holter recording parasystolic rates (PRs) and heart rates (HRs) were calculated every hour. Furthermore, a mean hourly PR and a mean hourly HR were calculated from the hourly PRs and HRs of the patients. The statistic chronobiologic analysis was done by single and mean cosinor methods. Correlation between mean hourly PR and HR was evaluated by Pearson's V coefficient. A statistically significant rhythm (P < 0.05) was found for the single and mean rhythms both of HR and PR. In our patients, HR had acrophase at 1.27 P.M., mesor at 73.28 beats/min, and amplitude at 9.53 beats/min, whereas PR had acrophase at 1.42 P.M., mesor al 38.31 beats/min, and amplitude at 3.64 beats/ min. Chronobiological data and the high direct correlation between mean hourly HRs and mean hourly PRs (r = 0.96, P < 0.001) indicate a similar circadian variability of the chronotropic activity of sinus nodes and parasystolic foci. Although several hypotheses can be made, responsiveness of parasystolic foci to circadian variations of the autonomic nervous system tone (sympathetic and/or vagal) and/or circulating substances (particularly catecholamines) seems the more probable one for explaining our findings.     

Characteristics of 100 consecutive patients presenting with orthostatic hypotension

OBJECTIVE: To elucidate the demographic and clinical characteristics of a consecutive series of patients who presented for evaluation of orthostatic hypotension. PATIENTS AND METHODS: From January 1, 1997, through September 30, 2001, we assessed retrospectively the demographic and clinical characteristics, antihypertensive medication use, and blood pressure variability in 100 consecutive patients with orthostatic hypotension who underwent 24-hour ambulatory blood pressure monitoring (OH group) and in a convenience sample of 100 age-matched patients who underwent 24-hour ambulatory blood pressure monitoring for evaluation of hypertension (HTN group). RESULTS: The OH group had a mean +/- SD age of 71.6 +/- 9.4 years, and 42% were women. The most common symptoms were light-headedness and weakness. Comorbid conditions included neurologic diseases (38%), preexisting hypertension (36%), hyperlipidemia (31%), cardiac arrhythmias and coronary artery disease (45%), and neoplasm (28%). During ambulatory blood pressure monitoring, postprandial decreases in blood pressure were noted in 83% of the OH group, supine or sleep hypertension in 84%, and noncompensatory heart rate variability in 75%. Findings on autonomic testing were abnormal in 99% of patients, serum creatinine value was increased in 30%, proteinuria was present in 27%, and left ventricular hypertrophy was present in 20%. CONCLUSIONS: Orthostatic hypotension is present in a heterogeneous group of disease states, is usually symptomatic, and is often associated with an abnormal blood pressure profile of reversal of circadian pattern, postprandial hypotension, and noncompensatory heart rate variability. Consequent target organ (kidney) damage can be as frequent as in patients who undergo 24-hour ambulatory blood pressure monitoring for evaluation of hypertension.     

Measurement and clinical evaluation of blood pressure in the management of hypertension

It has been increasingly recognized that, for the reliable assessment of blood pressure (BP) and the accurate diagnosis of hypertension, not only office-BP but out-of-office BP measurement with ambulatory BP monitoring (ABPM) or self BP measurement at home is useful and important. Although office-BP should be used as reference, ABPM and home BP monitoring improves the prediction of cardiovascular risk in untreated and treated hypertensive patients. In this article, we reviewed the methodology for measuring BP by these procedures, its diagnostic and therapeutic thresholds, and its clinical applications in the management of hypertension. We also mentioned the abnormal circadian rhythm of BP and related conditions diagnosed by the implementation of these procedures.     

Effects of chronic cetamolol therapy on resting, ambulatory, and exercise blood pressure and heart rate

We studied blood pressure (BP) and heart rate (HR) responses in 12 patients with hypertension who were receiving cetamolol, a cardioselective beta-blocker with intrinsic sympathomimetic activity. The BP and HR parameters were evaluated at rest (casual, office readings), with ambulatory BP monitoring, and after treadmill exercise testing. At a mean (+/- SD) dose of 46 +/- 21 mg/day, casual supine BP decreased by 10/12 mm Hg (P less than 0.05 for systolic; P less than 0.01 for diastolic) compared with placebo, while HR decreased 4 bpm. Cetamolol resulted in a significant reduction in the mean 24-hour systolic BP. The most striking reduction occurred in the BP at work (23 mm Hg), with almost no decrease in the BP during sleep. Ambulatory HR reductions occurred while the subjects were at work (9 bpm; P less than 0.05) but not while at home (awake) or during sleep. The mean duration of exercise was the same during cetamolol and placebo phases, but both HR and BP fell significantly at peak performance after cetamolol. These data suggest that cetamolol reduces BP without lowering HR at rest. During periods of increased adrenergic activity such as work and dynamic exercise, both HR and BP are reduced.     

护理干预对糖尿病患者血压昼夜节律和自主神经功能的影响

目的观察糖尿病患者的血压昼夜节律和心脏自主神经功能变化,以及护理干预对其的影响。方法以55例糖尿病患者作为实验组,50例健康人群作为对照组,通过对两组研究对象进行24h动态血压监测和心电图描记,分析糖尿病患者血压昼夜节律和心脏自主神经功能变化;对实验组患者进行自主神经功能和改善夜间睡眠的针对性护理干预,并于干预1周后观察患者的血压昼夜节律和自主神经功能变化。结果糖尿病患者的夜间血压下降不明显,昼夜平均动脉压差和杓型节律比例低于对照组;且前者乏氏动作反应指数和站立后第30次与第15次心搏R-R间期比值（30／15比值）也低于正常人群（P〈0．05）;护理干预后,糖尿病患者的昼夜平均动脉压差和杓型节律比例增大（P〈0．05）,但自主神经功能变化无统计学意义。结论以纠正血压昼夜节律为目的的护理干预对改善糖尿病患者的心脏自主神经功能有实际意义。     

Differentiating the Ligament of Marshall from the Pulmonary Vein Musculature Potentials in Patients with Paroxysmal Atrial Fibrillation: Electrophysiological Characteristics and Results of Radiofrequency Ablation

TAI, C.-T., et al. : Differentiating the Ligament of Marshall from the Pulmonary Vein Musculature Potentials in Patients with Paroxysmal Atrial Fibrillation: Electrophysiological Characteristics and Results of Radiofrequency Ablation. It was reported that paroxysmal atrial fibrillation (PAF) can be initiated by ectopic atrial beats originating from the pulmonary vein (PV) or left atrial tract (LAT) within the ligament of Marshall (LOM). The aim of this study was to differentiate the LAT from the PV potentials, and to investigate the results of radiofrequency ablation guided by these potentials. Ten patients (  age 60 ± 12 years  ) with PAF who had a recording of double potentials (DPs) in or around the left PV were included. Group I had five patients with the second deflection of DPs (D2) due to activation of the LAT, and Group II had five patients with D2 due to activation of the PV musculature. There were no significant difference in the isoelectric interval between DPs, the activation time, and amplitude of D2 between Groups I and II. During distal coronary sinus (CS) pacing, the CS ostium (CSO) to D2 interval was shorter compared with that during sinus rhythm in Group I (  39 ± 19 vs 71 ± 25 ms, P = 0.04  ), but was longer in Group II (  96 ± 16 vs 44 ± 19 ms, P = 0.04  ). During ectopic activation, three patients in Group I, but no Group II patients, had transformation of recorded DPs into triple potentials. Radiofrequency ablation guided by the earliest activation of the LAT potential was performed with transient suppression of PAF, but ablation guided by the earliest activation of the PV potentials had a high success rate in eliminating PAF. In conclusion, differentiating the LAT from the PV potentials for initiation of PAF is feasible by an electrophysiological approach, and may be important for radiofrequency ablation of PAF.     

Blood pressure variation and cardiovascular risk in hypertension

Disruption of circadian rhythm of blood pressure (BP) is associated with advanced target organ damage and poor cardiovascular prognosis. We studied silent cerebrovascular disease and stroke events in older Japanese patients with different nocturnal BP dipping. There was a J-shaped relationship of nocturnal dipping status with silent cerebral infarcts detected by brain MRI at baseline, and with stroke incidence during the follow-up period. The extreme-dippers (with marked nocturnal BP dipping) and risers (with higher nocturnal BP than awake BP) had a higher prevalence of silent cerebral infarcts and poorer stroke prognosis than those with appropriate nocturnal BP dipping (dippers). Extreme-dippers tended to have predominant systolic hypertension and increased BP variability. Several factors are affecting the diurnal BP variation pattern. The non-dipping pattern is associated with autonomic nervous dysfunction and poor sleep quality due to nocturnal behavior and sleep apnea. Extreme-dippers might have increased arterial stiffness with reduced circulating blood volume in addition to an excessive morning surge due to alpha-adrenergic hyperactivity. Morning BP surge, which is partly associated with nocturnal BP dipping status, was a predictor of stroke event independently for ambulatory BP level and silent cerebral infarcts. Antihypertensive medication that normalize the disrupted circadian BP variation might improve cardiovascular prognosis in high-risk hypertensive patients.     

The effects of the long-acting angiotensin-converting enzyme inhibitor cilazapril on casual, exercise, and ambulatory blood pressure

We assessed blood pressure (BP) and heart rate (HR) responses in a double-blind, randomized study comparing cilazapril, a long-acting, nonsulfhydryl-group converting enzyme inhibitor, with placebo in 18 patients with mild to moderate (sitting diastolic BP, 95 to 114 mm Hg) essential hypertension. The BP and HR parameters were evaluated at rest (casual, 24 hours after administration), during treadmill exercise testing (Bruce protocol), and with 24-hour noninvasive ambulatory BP monitoring. These assessments were made after a 4-week drug washout period and after 8 to 12 weeks of therapy. After 8 weeks of therapy with cilazapril (mean dose 3.6 +/- 0.9 mg/day), casual BP decreased 19/11 mm Hg (p less than 0.01), whereas placebo lowered BP by 4/5 mm Hg (difference not significant) compared with the baseline period. The casual HR was modestly (7 beats/min) but significantly (p less than 0.05) lowered by cilazapril monotherapy. Exercise BP was reduced by cilazapril (reduction at peak HR, 23/11 +/- 10/5 mm Hg; p less than 0.05), and exercise HR was unchanged. Compared with baseline, the duration of exercise was improved with cilazapril but not with placebo (1.0 minute vs -0.2 minute; p less than 0.05). Twenty-four-hour mean, awake, and sleep BPs were reduced with cilazapril with the most impressive reduction occurring during the awake period (19/12 mm Hg; p less than 0.01). These data demonstrate that cilazapril lowers casual, exercise, and ambulatory BP with a modest but significant improvement in exercise time. Thus cilazapril may be particularly effective in the physically active hypertensive patient.     

正常人和急性心肌梗死患者心率震荡斜率的昼夜变化及与心率的相关性

目的观察正常人和急性心肌梗死（AMI）患者心率震荡（HRT）的昼夜变化规律,探讨不同人群心率与震荡斜率（TS）的相关性。方法选择100例AMI患者,平均年龄（60.87±13.72）岁,男66例,女34例;82例正常对照者,平均年龄（59.23±13.31）岁,男54例,女28例。两组均进行24h动态心电图检查,定量测定一昼夜中每小时的平均心率（HR）与TS的均值,采用圆形分布统计分析方法,计算两组TS值在昼夜分布中的高峰时点及集中时段。结果（1）正常对照组TS值在24h分布上有明显的集中趋势,高峰时点为04：34（P〈0.05）,集中时段为21：25～11：41;AMI组TS值在24h分布上无明显集中趋势（P〉0.05）。（2）正常对照组HR与TS呈负相关关系（r=-0.771,P〈0.01）;AMI组HR与TS不存在直线相关关系（r=-0.312,P〉0.05）。结论正常人TS值有昼夜节律性,明显受HR的影响。作为心脏的一个基本生物节律,其主要受自主神经的调控。而AMI患者的这种生物节律性消失,可能与自主神经功能紊乱有关。