摘要:

The incidence of most adverse cardiovascular events appears to follow a circadian pattern, reaching a peak in the morning shortly after wakening and arising. The activities of many physiologic parameters, including hemodynamic, hematologic and humoral factors, also fluctuate in a cyclical manner over the 24 h. It has been suggested that, during the post‐awakening hours, the phases of these cycles synchronize to create an environment that predisposes to atherosclerotic plaque rupture and thrombosis in susceptible individuals, thereby accounting for the heightened cardiovascular risk at this time of day. Blood pressure and heart rate are part of this physiologic process, following a clear circadian rhythm characterized by a fall during sleep and a sharp rise upon awakening. This so‐called ‘morning surge’ in blood pressure may act as a trigger for cardiovascular events, including myocardial infarction and stroke. The clinical implication of these observations is that antihypertensive therapy should provide blood pressure control over the entire interval between doses. For agents taken once daily in the morning, the time of trough plasma drug level (and lowest pharmacodynamic effect) will often coincide with the early morning surge in blood pressure and heart rate. For these reasons, chronotherapeutic formulations of drugs and intrinsically long‐acting antihypertensive agents provide the most logical approach to the treatment of hypertensive patients since they provide 24 h blood pressure control from a single daily dose as well as attenuating the early morning rise in blood pressure (and in some instances heart rate).

ISSN:1359-5237    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundMany studies have shown definite but weak correlations between 24 h blood pressure and left ventricular mass in hypertension.ObjectiveThe present study applied an original multivariate analysis of parameters from ambulatory blood pressure monitoring to predict left ventricular mass in hypertension.MethodsTwo hundred untreated hypertensive subjects (age = 51 ± 13 years, clinic blood pressure = 163/98 mmHg) had echocardiography and 24 h recording of blood pressure. Data from 102 subjects were used to construct a mathematical model for prediction of left ventricular mass. The remaining 98 subjects were used to validate the model.ResultsThe model included age, weight, height, 24 h systolic blood pressure, heart rate over 24 h, standard deviations of systolic blood pressure and of heart rate over 24 h. Using this model, we explained 63% of the variance of left ventricular mass. Moreover, the model was validated for the correlation (r = 0.70) between measured and the estimated left ventricular mass.ConclusionsSystolic blood pressure, heart rate and their standard deviations over 24 h contribute to left ventricular mass in hypertensive subjects. Thus, it is important to take into account not only blood pressure but also heart rate in clinical studies.

ISSN:1359-5237    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Heart failure is associated with a decreased variability in circadian systolic blood pressure. ACE inhibitors have been shown to be beneficial in CHF. However, the effect of the magnitude of the dose of ACE inhibitor on blood pressure variability has not been reported. The objective of this sub‐study of the ATLAS trial was to determine if there was a difference in effect on systolic blood pressure variability of two doses (35 mg,‘high’; and, 5 mg,‘low’) of the ACE inhibitor, lisinopril, in patients with heart failure (class II–IV; NYHA). Criteria for inclusion were: symptomatic heart failure (class II–IV; NYHA), left ventricular ejection fraction ≤ 30%, and 2 months of conventional therapy with diuretics with, or without, digoxin. Twenty‐four hour ambulatory blood pressure was recorded prior to randomization and after peak titration (4 weeks) of the study drug for analysis of variability of systolic blood pressure variability. The high dose of lisinopril was associated with greater variability of 24 h systolic blood pressure as noted by inspection of the 24 h recordings or calculation of the blood pressure variability index (P < 0.05). The greater variability in SBP was not associated with a difference in mean 24 h arterial blood pressure.ConclusionsVariation in circadian systolic blood pressure is useful in reflecting the influence of the magnitude of dose of the ACE inhibitor lisinopril on the pharmacodynamics of patients with heart failure.

ISSN:1359-5237    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundReduced distensibility of large arteries plays an important role in cardiovascular risk. Determination of the QKD interval during the ambulatory measurement of blood pressure enables calculation of an index of arterial distensibility. This index, the QKD100–60, is the theoretical value of QKD at systolic blood pressure of 100 mmHg and heart rate of 60 bpm obtained from the linear bivariate relationship linking QKD, systolic blood pressure and heart rate on a hundred successive values measured over 24 h. This study was designed to examine the relationship between QKD and QKD100–60on heart rate and systolic function of the left ventricle, the two parameters governing the pre‐ejection time which is part of the QKD interval.Methods and resultsIn a population of 203 untreated hypertensive patients having benefited from an ambulatory measurement of blood pressure over 24 h with QKD monitoring and an M‐mode echocardiographic recording of the left ventricle, we found that although mean QKD was linked to heart rate and systolic function of the left ventricle, QKD100–60was not. It fell significantly with age, and to a greater extent in the sustained hypertensives than in white‐coat hypertensives.ConclusionQKD100–60constitutes an index of arterial distensibility independent of the pre‐ejection time. As an adjunct to the ambulatory measurement of blood pressure, its determination is simple and completely automatic, thus eliminating observer bias.

ISSN:1359-5237    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveThis study was designed mainly to establish the rates of response to valsartan 80 mg once daily (qd) and to valsartan 160 mg qd given to non‐responders to 80 mg qd, as well as to determine the safety of valsartan and the blood pressure control achieved using valsartan over a period of 24 h or more, using ambulatory blood pressure monitoring (ABPM) devices.MethodsThis was a single‐blind, single‐arm, multicenter study involving 256 out‐patients with mild‐to‐moderate essential hypertension. After previous antihypertensive treatments had been ‘washed out’, the patients were entered into a 2‐week placebo run‐in period to confirm the diagnosis of mild‐to‐moderate hypertension. Patients who, at the end of the placebo run‐in period, had a mean sitting diastolic blood pressure of between 95 and 115 mmHg inclusive received valsartan 80 mg qd for 4 weeks. Non‐responders (those not demonstrating a diastolic blood pressure of less than 90 mmHg or a decrease in diastolic blood pressure of 10 mmHg or more compared with baseline) received valsartan 160 mg qd for another 4 weeks. In selected centers, patients who agreed also had their blood pressure monitored for 24 h, provided their blood pressure was shown to be controlled. Of these patients, half skipped one dose of valsartan and were monitored for an additional 24 h period.ResultsThe rate of response to valsartan 80 mg was 45.4%, and of those not responding to this dose, 36.3% responded to valsartan 160 mg. The response rate to one or other dose was 63.2%. The ambulatory blood pressure data support a consistent reduction of blood pressure with valsartan over a 24 h period and for up to 32 h after dosing in those who missed a dose. The overall incidence of adverse experiences per person–year, treatment related or otherwise, was 6.3 and 10.6 for the valsartan and placebo study periods respectively.ConclusionAntihypertensive treatment with valsartan for 8 weeks produced a significant decrease in diastolic blood pressure in hypertensive patients. In addition, the drug may be safely administered, and the results of 24 h/48 h ambulatory monitoring demonstrate that valsartan is a true once‐a‐day antihypertensive.

ISSN:1359-5237    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundAneroid manometers are frequently used to measure blood pressure. Aneroid manometers have moving parts that are subject to fatigue. The accuracy duration of the aneroid devices, like most digital devices, is unstudied. It has been accepted that if the aneroid device does not rest at ‘0’ it is inaccurate, but how often is the device inaccurate when it does rest at ‘0’?MethodsA Universal Biometer DPM‐III measuring unit was used for all of the measurements at 10 University of Michigan Health System sites. A total of 136 aneroid manometers were tested. Two additional aneroid devices were not tested, as the needle did not start within ‘0’. Static pressure measurements were made at nine levels for all devices: 50, 80, 90, 100, 120, 150, 200 and 250 mmHg.ResultsThe average difference of the nine pressure settings of the whole group was 0.2±0.31 (95% confidence interval 0.1–0.2) mmHg. The largest number of devices that were not calibrated within ±3 mmHg was seen at the 150 mmHg setting with six (4.4%) of the devices failing. If an accuracy standard of ±2 mmHg was used, the largest number of devices failed at 250 mmHg (22 devices, 16.2%). The largest number of devices that were inaccurate was manufactured 6 years prior to testing and was from two sites.ConclusionsAneroid devices were accurate. A yearly calibration programme should be performed and a ±2 mmHg standard should be used. Portable aneroid manometers may need to be more frequently calibrated due to the trauma associated with dropping.

ISSN:1359-5237    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundNon‐invasive self blood pressure monitoring has become increasingly popular. To assure the accuracy of devices used for this purpose, all need to be validated independently prior to marketing. The objective of this study was to assess the accuracy of the HEM‐907, a new semi‐automatic, non‐invasive, oscillometric blood pressure monitoring device specifically designed to be used in the clinic or physician's office setting.MethodsBlood pressure measurements taken employing this device were compared with the results obtained by two experienced observers using a mercury sphygmomanometer on 100 subjects and patients (384 measurements). The limits of agreement were calculated for the device compared with the results of the two observers according to the standards of the Association for the Advancement of Medical Instrumentation (AAMI).ResultsThe agreement between the two observers was –0.36 ± 2.32 mmHg for systolic blood pressure and 0.02 ± 2.42 mmHg for diastolic blood pressure. The agreement between the device and the observers was 1.56 ± 4.42 mmHg and 3.49 ± 4.61 mmHg for systolic and diastolic blood pressure respectively.ConclusionsThe Omron HEM‐907 satisfied the AAMI criteria for accuracy for a non‐invasive blood pressure monitoring device.

ISSN:1359-5237    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:1359-5237    

出版商:OVID    

年代:2001

数据来源: OVID