24-hour Variability Research Articles

24-hour blood pressure profile and systemic inflammation in patients with stable coronary artery disease with obstructive sleep apnea

Aim. To evaluate 24-hour blood pressure (BP) profile and systemic inflammation in patients with coronary artery disease (CAD) depending on the presence of obstructive sleep apnea (OSA).Material and methods. This cross-sectional cohort study included 132 patients with CAD aged 62,3±6,9 years. Depending on OSA, all patients were divided into 2 groups: group 1 (n=60) — without OSA, group 2 (n=72) — with OSA. Systemic inflammation was assessed using neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), monocyte/lymphocyte ratio (MLR), Systemic immune-inflammation index (SII) — platelets´neutrophils/lymphocytes. Blood pressure was monitored with assessment of average daily values, circadian rhythm, and variability.Results. Patients with OSA had higher nighttime blood pressure values (p<0,05) and 24-hour variability (p<0,05). In group 2 patients, a pathological blood pressure profile was detected in 66,7% of cases, while in group 1 — in 36,7%. The systemic inflammation indices were significantly higher in patients with OSA than in the group without OSA — NLR by 18,8% (p<0,01), PLR by 22,5% (p<0,01), MLR by 19,0% (p<0,01), SII by 41,0% (p<0,001).Conclusion. We established that patients with coronary artery disease and OSA have more pronounced systemic inflammation, more often have a pathological 24-hour BP profile ("non-dipper", "night-peaker"), BP variability, higher values of average 24-hour, daytime and nighttime BP compared with patients without OSA.

Day-night patterns in heart rate variability and complexity: differences with age and cardiopulmonary disease.

Heart rate variability (HRV) measures provide valuable insights into physiology; however, gaps remain in understanding circadian patterns in heart rate dynamics. We aimed to explore day-night differences in heart rate dynamics in patients with chronic cardiopulmonary disease compared with healthy controls. Using 24-hour heart rate data from patients with chronic obstructive pulmonary disease (COPD) and/or heart failure (n = 16) and healthy adult controls (older group: ≥50 years, n = 42; younger group: 20-49 years, n = 136), we compared day-night differences in conventional time and frequency domain HRV indices and a multiscale-entropy-based complexity index (CI1-20) of HRV among the 3 groups. Twenty-four-hour HRV showed significant day-night differences (marked with "△") among younger healthy (mean age: 34.5 years), older healthy (mean age: 61.6 years), and cardiopulmonary patients (mean age: 68.4 years), including change in percentage of adjacent intervals that differ > 50 ms (△pNN50), high frequency (△HF), normalized low frequency (△nLF), ratio (△LF/HF), and △CI1-20. Among these, △LF/HF (2.13 ± 2.35 vs 1.1 ± 2.47 vs -0.35 ± 1.25; P < .001) and △CI1-20 (0.15 ± 0.24 vs 0.02 ± 0.28 vs -0.21 ± 0.27; P < .001) were significant in each pairwise comparison following analysis of variance tests. Average CI1-20 was highest in younger healthy individuals and lowest in cardiopulmonary patients (1.37 ± 0.12 vs 1.01 ± 0.27; P < .001). Younger healthy patients showed a heart rate complexity dipping pattern (night < day), older healthy patients showed nondipping, and cardiopulmonary patients showed reverse dipping (night > day). As measures of 24-hour variability, traditional and complexity-based metrics of HRV exhibit large day-night differences in healthy individuals; these differences are blunted, or even reversed, in individuals with cardiopulmonary pathology. Measures of diurnal dynamics may be useful indices of reduced adaptive capacity in patients with cardiopulmonary conditions. Ma Y, Chang M-C, Litrownik D, Wayne PM, Yeh GY. Day-night patterns in heart rate variability and complexity: differences with age and cardiopulmonary disease. J Clin Sleep Med. 2023;19(5):873-882.

24-HOUR CENTRAL BLOOD PRESSURE

Objective: Central systolic blood pressure (cSBP) differs from peripheral SBP (pSBP) and may have higher prognostic relevance, but the normal values in ambulatory conditions are unknown. We present reference values for 24-hour central BP profiles, obtained in apparently healthy adult individuals from 20 centers in 14 countries and 5 continents, and compare the findings with peripheral BP. Design and method: 24-hour ambulatory BP monitoring, using a validated oscillometric device (Mobilograph, I.E.M, Stolberg, Germany), was performed in 2527 individuals (1206 men, 1321 women). Central pressures were assessed, using brachial waveforms, calibrated with mean/diastolic BP, and a transfer function. Participants were divided into 6 age groups (18–29, 30–39, 40–49, 50–59, 60–69, 70–99 years). Nighttime/daytime difference (N/D) was defined as nighttime (01.00 - 06.00) minus daytime (09.00 - 21.00) values / daytime values. Results: Averaged 24-hour central BP across all individuals was 128/79 mm Hg (daytime 128/81 mm Hg, nighttime 125/72 mm Hg), with slightly higher BP in men, compared to women. In contrast, central pulse pressure (PP; mean value 48 mm Hg, daytime 46 mm Hg, nighttime 52 mm Hg) was higher in women, compared to men. Mean values for cSBP, diastolic BP, and heart rate were highest in middle age, whereas mean values for cPP were highest in old age. Peripheral SBP N/D was −11% in the youngest age group, and decreased with increasing age, reaching −6% in the oldest age group. In contrast, cSBP N/D was less pronounced, even inverse (1 %) in the youngest age group, reaching −2 % in the oldest age group. Peripheral PP N/D was negligible across all age groups, and central PP N/D was inverse and highest (31 %) in the youngest age group. Conclusions: We provide reference values for apparently healthy individuals across the adult life span for central SBP and PP, comprising 24-hour mean BPs and 24-hour variability. Both differ from peripheral BP. These data may serve for comparison in various diseases and have potential implications for refining hypertension diagnosis and management.

PULSE WAVE VELOCITY AND CIRCADIAN VARIABILITY IN WELL CONTROLLED HYPERTENSIVE PATIENTS

Objective: Pulse wave velocity (PWV) is the gold standard for measuring large artery stiffness. A PWV >10m/s is considered a conservative estimate of significant alterations of aortic function in middle-aged hypertensive patients. Although commonly used, there are only a few reports investigating the 24-hour variability in PWV measurements, the determination of which is important when using PWV as a clinical marker of target organ damage. The aim of this study was to investigate the variability in PWV measurements and factors that may influence PWV variability during 24 hours. Design and method: A prospective study was conducted in 55 well controlled hypertensive patients (mean age 65.8 ± 11.8 years) and 21 healthy control subjects (mean age 55.6 ± 18.9 years). In all subjects, complete blood chemistry (including SUA determination), echocardiographic examination, office and 24 h ambulatory blood pressure (BP) as well as 24 h ambulatory PWV and central (BP) measurement were performed Results: 24 hours systolic BP, central BP and PWV (p < 0.001) were significantly higher in hypertensive patients in confront to health subjects, but not diastolic BP (p = 0.140) levels. Specifically, the mean of PWV, SBP and cBP during 24 h was 9.7 (±0.3) vs 7.7 (± 0.3); 131.6 (±4.6) vs 122.8 (±5.9) and 137.7 (±4.3) vs 125.6 (± 4.2) for hypertensives and controls respectively. However, the mean of DBP during 24 h was 78.7 (±4.1) for patients and 79.4 (±5.6) for controls. Moreover, PWV of patients was significantly correlated with SBP, DBP (r = 0.411) and cBP (r = 0.717) levels (p < 0.001). Significant correlations were found between PWV of controls and SBP (r = 0.616), DBP (r = 0.499) and cBP (r = 0.579) levels (p < 0.001). PWV levels presented a small variability during the whole 24 hours (±0,3) suggesting that measurement and reproducibility of this marker are not influenced by a circadian rhythm. Conclusions: PWV assessment may be performed any time during 24 hours in an outpatient clinic. In our study, we didn’t find a circadian variability that may influence the reproducibility of PWV.

Influence of age and gender on 24-hour variability of central blood pressure: Findings from the International 24-hour Ambulatory Aortic Blood Pressure Consortium (i24ABC)

BackgroundConventional brachial cuff BP is known to vary according to age and gender, but the influence of these factors on 24-hour ambulatory central BP is unknown. We sought to determine this in a large healthy population from 11 centers in Europe and Asia.Methods24-hour ambulatory BP using a validated oscillometric device (Mobilo-graph, I.E.M, Stolberg, Germany) was performed in 1645 individuals free from anti-hypertensive drugs. Participants were categorized as young (Y: 13–39 years; M/F:219/112), middle-aged (MA: 40–66 years; M/F:545/553), and older (O: 67–104 years; M/F:86/130). Nighttime/daytime difference (N/D) was defined as nighttime (01.00–06.00) minus daytime (09.00–21.00) values / daytime values.ResultsAveraged 24-hour brachial BP was 125/79 (Y), 128/83 (MA), and 127/77 (O) mmHg. N/D for brachial SBP was -10.3% (Y), -6.4% (MA), and -4.7% (O), but was significantly less pronounced for central SBP: -1% (Y), -3.1% (MA), and -1.9% (O). Men, compared to women, had higher brachial and central SBPs, mainly in younger participants. Brachial pulse pressure (PP) displayed limited and age-dependent circadian variations, whereas central PP was substantially higher at nighttime: N/D was 24% (Y), 9% (MA), and 5.9% (O). Brachial and central PPs were higher in men in the younger group, but higher in women in middle-aged and older groups.ConclusionBoth age and gender each have a significant influence on 24hour variability of central BP, but is different than variability in brachial BP. These data have potential implications for refining hypertension diagnosis and management.

PP.26.09] 24-HOUR AMBULATORY BLOOD PRESSURE VARIABILITY AND CARDIOVASCULAR RISK

Objective: The correlation of antithrombin III (ANT-III) levels to 24-hour blood pressure variability in hypertensive patients. Design and method: 137 hypertensive patients both treated and untreated (average age: 63.3 yrs, average SBP/DBP: 140/85 mmHg, average heart rate: 73 bpm, average BMI: 29.2), were subjected to 24-hour ambulatory blood pressure monitoring and measurement of their antithrombin III plasma levels. The degree of SBP/DBP 24-hour variability >15 mmHg or <15 mmHg was correlated against them.Conclusions: In hypertensive patients the higher degree of 24-hour diastolic pressure variability relates to lower plasma levels of antithrombin III, thus suggesting a greater risk of thrombotic events in this group of patients.

Variability of arterial pressure in acute stroke - a modern approach to the problem

The question of prospects of using the data of variability of arterial pressure as a base of predictor of development, course and consequences of brain stroke is considered on the base of studied literature.Methods of research: E-data base Medline and PubMed was used for thorough searching for literature on studied questions.Results. The results of scientific literature analysis testify to the connection between variability of arterial pressure and hypertrophy of left ventricle, endothelial dysfunction, development of new cases of auricles fibrillation. According to AP day monitoring, the direct positive connection between the mass index of myocardium of left ventricle and SAP and DAP variability was found. It is indicated, that SAP variability in childhood is a predicator of arterial hypertension development in adulthood. It is shown, that VAP growth can be a predicator of both first and secondary stroke. There are also the data about independent prognostic value of 24-hour variability of arterial pressure as to cardio-vascular events. The duration of study of 24-hour variability of arterial pressure and the number of publications on this question is underlined and insufficiency of information about long-term variability of arterial pressure is noted. It is accented, that in modern assessment of clinical importance of different parameters of arterial pressure variability the change of priority from 2-hour to long-term monitoring of arterial pressure “from visit to visit” is observed.The urgent need in elaboration of accessible methods of assessment of long-term variability of arterial pressure (VAP) that would supply the doctors-practicians with additional information as to the stroke risk and possible consequences is felt.Conclusions. Long-term variability of arterial pressure can be considered as a predictor of stroke development and as independent factor of influence on consequences of undergone brain stroke. It is shown, that the problem of arterial pressure variability is polyhedral and needs further deep study

Short-term effects of air temperature and mitochondrial DNA lesions within an older population

BackgroundPrevious studies have linked both extreme and sub-optimal air temperature to cardiopulmonary morbidity and mortality, especially in older individuals. However, the underlying mechanisms are yet to be determined. ObjectivesWe hypothesized that short-term increases in air temperature may induce blood mitochondrial DNA (mtDNA) lesions in older individuals, which could contribute to temperature-related pathogenesis. MethodsWe repeatedly measured mtDNA lesions in blood samples from 654 participants in the Normative Aging Study from 1999 to 2013 (1142 observations) by quantitative long-amplicon polymerase chain reaction assay. Hourly temperature data were obtained from the Boston Logan Airport weather station (located approximately 12km from the clinical site). We calculated 2-, 7-, and 14-day moving averages of 24-hour mean and 24-hour variability of temperature. We fit covariate-adjusted linear-mixed models accounting for repeated measures to evaluate the association between short-term increases in mean and variability of temperature with mtDNA lesions within each season. ResultsInterquartile increases in 7- and 14-day moving averages of 24-hour mean temperature in summer were associated with a 0.17 (95% CI: 0.07, 0.27; p=0.0007) and 0.21 (95% CI: 0.10, 0.32; p=0.0001) increase in the number of mtDNA lesions per 10kb, respectively. Results were similar when we further adjusted for temperature variability. We also observed significant associations between increases in temperature variability and mtDNA lesions independent of mean air temperature. An interquartile range increase in the 7-day moving average of 24-hour standard deviation in summer was associated with a 0.19 (95% CI: 0.07, 0.31; p=0.0023) increase in the number of mtDNA lesions per 10kb. ConclusionsShort-term exposure to higher mean air temperature was associated with increased mtDNA lesions in older adults, supporting the hypothesis that sub-optimal meteorological conditions may induce pathophysiological responses among susceptible populations.

PP.15.06] BLOOD PRESSURE VARIABILITY IN HYPERTENSIVE PATIENTS AND DIASTOLIC/ SYSTOLIC FUNCTION OF THE LEFT VENTRICLE

Objective: Our aim was to study any possible correlation between indices of diastolic/ systolic function of the left ventricle to the 24-hour blood pressure (BP) variability among hypertensive patients. Design and method: 845 hypertensive patients (438 males), treated (N = 222) or newly diagnosed untreated (N = 623), mean age of 52 years, body mass index: 27 kg/m2, mean systolicBP/ diastolicBP: 143/91 mmHg and mean heart rate of 76 beats per minute, underwent 24-hour ambulatory BP recording and transthoracic echocardiographic/Doppler exam. The early-diastolic and end-diastolic velocities of the transmitral valve flow were recorded. In a subgroup of 105 patients, indices of diastolic and systolic function of the left ventricle were measured using Tissue Doppler Imaging (TDI). The aforementioned parameters were correlated on the 24-hour BP variability and possible correlations between them was examined for values of 24-hour SBP variability >15 mmHg or <15 mmHg.Conclusions: In hypertensive patients, treated or newly diagnosed untreated, the 24-hour variability of the SBP significantly correlates principally with indices of left ventricle's diastolic function and its filling pressures, as well as with indices of its systolic function.

Assessing Efficacy of Canaloplasty Using Continuous 24-Hour Monitoring of Ocular Dimensional Changes.

We investigated whether 24-hour monitoring of corneoscleral limbus area (CSLA) with the Sensimed Triggerfish contact lens sensor (CLS) can be used clinically to assess midterm efficacy of canaloplasty and to assess the relationships of CSLA changes with the heart rhythm. Ten eyes of 10 patients, with POAG, which were qualified either to canaloplasty or canaloplasty and phacoemulsification, were included in this study. Eyes were washed out before the surgery and control visits were done at days 1, 7, and 3, 6, 12 months postoperatively, at which subjects were examined. We performed 24-hour monitoring of CSLA changes and Holter ECG at washout, and at 3- and 12-month postop visits. Raw CLS signals were processed to lead two parameters describing short-term 24-hour variability of CSLA (VAR, â). Heart activity parameters from CLS were compared to those acquired from Holter ECG. Mean post washout IOP was 20.6 ± 4.7 and decreased to 14.2 ± 3.0 mm Hg 1 year after surgery (P < 0.01). A decreasing trend in VAR and â parameters were noted. Statistically significant differences were found between the washout and 3-month postop visit for VAR and â (P = 0.014 and P = 0.027, respectively) as well as between the washout and 12-month postop result for the parameter â (P = 0.031). No statistically significant differences were found between the 3- and 12-month postop results for both considered parameters. Canaloplasty alone or combined with cataract surgery is a successful surgical method of lowering IOP in glaucoma patients. Canaloplasty decreases 24-hour CSLA fluctuation pattern measured with CLS.

Blood Pressure, Heart Rate Variability, and Renal Function in Nonsmoker and Smoker Hypertensive Patients.

Blood Pressure, Heart Rate Variability, and Renal Function in Nonsmoker and Smoker Hypertensive Patients.

The relationship between blood pressure variability and cardiovascular risk factors in patients with primary hypertension

Abstract Objective: The aim of the study is to assess 24-hour blood pressure variability, circadian blood pressure profile and its relation to 24-hour blood pressure and cardiovascular risk factors in primary hypertension without any associated disease versus associated with a disease such as diabetes or chronic kidney disease. Methods: This observational study included 90 hypertensive patients, 49 with primary hypertension without associated disease and 41 patients with primary hypertension and diabetes or chronic kidney disease. Circadian blood pressure profile and 24-hour variability were assessed using ambulatory monitoring. Laboratory data regarding cardiovascular risk factors and demographic data were collected in a questionnaire. Results: The number of dipper patients was higher in the group without associated disease, but the difference was not statistically significant (p=0.27). In both groups a positive correlation was found between 24-hour systolic blood pressure variability and 24-hour systolic blood pressure (p=0.029) and was related to age (p=0.031). In the second group, systolic variability showed a positive correlation with serum triglycerides (p=0.006, r=0.416, CI: 0.1252 to 0.6422). Conclusion: Our findings suggest that systolic blood pressure variability is related to age, systolic blood pressure values and serum lipid levels. To prevent end organ damage in hypertension, the assessment of ambulatory monitoring derived 24-hour systolic blood pressure variability and its reduction may be at least as important as blood pressure lowering.

IMPROVEMENT OF AMLODIPINE CONTROL EFFICACY OVER HYPERTENSION USING FIXED COMBINATION OF PERINDOPRIL ARGININE AND AMLODIPINE

Aim. To evaluate possibilities of hypertension control improvement using fixed combination of perindopril arginine and amlodipine. Material and methods. Totally 46 patients studied (25 men, 21 women of the age 53,6±4,3y.)with arterial hypertension 2-3 grade. All patients underwent ABPM with analysis of the following: mean 24-hour BP, velocity of morning SBP and DBP rise, BP variability of Ps BP (VPsBPd, VPsBPn). The criteria of inclusion were insufficient control over hypertension while using free combinations of ACE inhibitor or angiotensin II receptor blockers and diuretic or calcium channel blocker. To control arterial hypertension all patients were prescribed the fixed combination of perindopril arginine/amlodipine it standard dosage 10/5 mg (Prestans, Les Laboratories Servier, France) with further possible increase of dosage up to 10/10 mg. Results. While receiving the therapy 84,7% patients reached BP. Mean 24-hour SBP decreased from 139,24±1,8to 121,13+1,22 mmHg (p<0,05), DBP decreased from 84,51±2,08 to 73,14±1,4 (p<0,05), mean BP decreased from 103,07±1,56 to 87,66±1,13 (p<0,05). 24-hour variability of SBP significantly decreased from 15,28±0,72 to 10,21±0,42 (p<0,05), DBP from 13,46±0,72 to 10,72±0,31 (p<0,001). Values of VMR after the treatment also decreased. Before treatment VMR of SBP was 27±3,26 mmHg/hour, on therapy — 15,3±5,04 mmHg/hour, (p<0,01); the same for DBP — VMR decreased from 23,6±2,37 mmHg/hour to 11±1,62mmHg, (p<0,01). Conclusion. The usage of combined perindopril arginine/amlodipine in patients with former uncontrolled arterial hypertension at the background of free chosen antihypertensive drugs combinations succeeded in the target BP values achievement in 84,7% cases. The reached control over BP was successful daily and during the night, as over variability of BP and velocity of morning BP rise. Usage of fixed combination of perindopril arginine/amlodipine was marked with good tolerability and high patients' compliance.

Twenty-four-hour intraocular pressure related changes following adjuvant selective laser trabeculoplasty for normal tension glaucoma.

To investigate intraocular pressure (IOP) related patterns before and after selective laser trabeculoplasty (SLT) for normal tension glaucoma (NTG).In this prospective cohort study, 18 NTG patients underwent SLT. Success was defined as IOP reduction ≥20% by Goldmann applanation tonometry. 24-hour IOP-related pattern recording with a contact lens sensor (CLS) (SENSIMED Triggerfish®, Sensimed, Switzerland) was done before (baseline) and 1 month after SLT. A cosine function was fitted to the mean CLS patterns for each individual in the SLT success and non-success groups and the amplitude before and after SLT was calculated. Diurnal, nocturnal, and 24-hour CLS pattern local variability was determined for pre- and post-SLT sessions. Cosine amplitude and variability were compared before and after SLT by group using paired t-tests, with α = 0.05.Patients (11 women, 7 men) had a mean age of 65.1 ± 13.7 years. Mean IOP was 15.3 ± 2.2 mm Hg at baseline and was reduced by 17.0% to 12.7 ± 1.8 mm Hg 1 month after SLT (P = 0.001). SLT was successful in 8 patients (44%). The amplitude of the fitted cosine was reduced by 24.6% in the success group, but displayed an amplitude increase of 19.2% post-SLT in the non-success group. Higher diurnal local variability of the CLS pattern was observed after SLT in non-success subjects (P = 0.002), while nocturnal variability showed no significant change. The increase in diurnal variability in the non-success group led to an increase in 24-hour variability in this group (P = 0.001). No change in local variability (diurnal, nocturnal, and 24-hour) was seen in the success group.The IOP-related pattern cosinor amplitude was reduced in NTG patients with a successful SLT treatment whereas the non-success group exhibited an increase of cosine amplitude. Higher diurnal and 24-hour CLS pattern variability was observed in non-success patients 1 month post-SLT.

9 LOW CORRELATION BETWEEN VISIT-TO-VISIT VARIABILITY AND 24-HOUR VARIABILITY OF BLOOD PRESSURE

Background: Higher visit-to-visit variability (VVV) and 24-hour variability of systolic blood pressure (SBP) have been associated with increased cardiovascular disease risk. Few data are available on the correlation of VVV and 24-hour variability. Design and methods: We assessed the correlation between VVV and 24-hour SBP variability using data from 146 untreated, mostly normotensive participants (mean age 47.9 years; 64% women) in the Masked Hypertension Study who attended 6 study visits and had ambulatory BP monitoring (ABPM) performed. VVV was estimated by the standard deviation (SDvvv) and average real variability (ARVvvv). We used ABPM data to calculate the day-night SD (SDdn) and the ARV over 24 hours (ARV24). Results: The average SDvvv and SDdn were 6.3 ± 2.5 and 8.8 ± 1.8 mmHg, respectively, and the ARVvvv and ARV24 were 7.2 ± 3.2 and 7.0 ± 2.2 mmHg, respectively. The Spearman correlation coefficient between SDvvv and SDdn was rs = 0.25 and between ARVvvv and ARV24 was rs = -0.02. Participants in the lowest quartile of SDdn and ARV24 were 1.33 (95% CI: 0.69 – 2.33) and 0.67 (95% CI: 0.24 – 1.45) times as likely to be in the lowest versus upper three quartiles of SDvvv and ARVvvv, respectively. Also, participants in the highest quartile of SDdn and ARV24 were 1.66 (95% CI: 0.93 – 2.75) and 1.22 (95% CI: 0.61 – 2.19) times as likely to be in the highest versus lowest three quartiles of SDvvv and ARVvvv of BP. Conclusion: In the current study, the correlation between VVV and 24-hour variability was low. These data suggest that VVV and 24-hour variability are not interchangeable.

THE EFFECT OF ANTIHYPERTENSIVE THERAPY ON RETINAL VASCULAR CALIBER IN HYPERTENSION: PP.22.387

Objective: Peripheral arteriolar constriction, increased vascular resistance and structural remodeling are classic features of essential hypertension. Design: To estimate how treatment of patients suffering from HA influences retinal vessels and to evaluate correlation between diameter of arterioles (DA) and venules (DV) and BP parametres. Methods: 49 patients at the age of 57,3 ± 10,3 with mild or moderate HA were qualified for a study (group I). The duration of HA was 5,6 ± 2,4 years. Control group (group II) included 25 clinically healthy people at the age of 51,8 ± 8,6. First group was systematically treated for over a year and for last 3 months they were taken perindopril (10 mg/24 h), amlodipine (5–10 mg /24 h), 20 mg/24 h of simvastatine (43,3%) and 75 mg/24 h of ASA (31,7%). The DA, DV and arteriolar-to-venule ratio (AVR) were estimated, and next clinical parameters of BP were correlated with DA, DV and AVR values. Results: In the first group comparing to control, values of 24-hour SBP was 135 ± 14,8 vs 109 ± 8,9 (p < 0,000), DBP was 79 ± 13,3 vs 64 ± 6,3 (p < 0,000), mean BP 98 ± 13,1 vs 79 ± 6,4 (p < 0,000), HR 72 ± 10,0 vs 65 ± 10,4 per minute. DA was 91,9 ± 8,6 vs 86,8 ± 8,6um (p < 0,0221), DV was 118,5 ± 14,3 vs 121,9 ± 11,6um (p > 0,05) and AVR was 0,78 ± 0,08 vs 0,72 ± 0,09 (p < 0,000). After separating patiens with good control of BP (24-hour BP <125/80, day-time BP <135/85 and night-time BP <120/70) from the first group, it occurred that there were no significant differences in DA and DV between new group and control. We found negative correlation between 24-hour, day and night BP, day and night load of SBP and DBP, and 24-hour variability of SBP and AVR. Conclusions: Good 24-hour blood pressure control in HA patients causes normalization of retinal vascular diameter. Patients with HA have negative correlation between BP parameters, load of HA and 24-hour variability of BP and AVR.

Intracranial and Blood Pressure Variability and Long-Term Outcome After Aneurysmal Sub-arachnoid Hemorrhage

Care of brain-injured patients in intensive care units has focused on maintaining arterial blood pressure and intracranial pressure within prescribed ranges. Research suggests, however, that the dynamic variability of these pressure signals provides additional information about physiological functioning and may reflect adaptive capacity. To see if long-term outcomes can be predicted from variability of arterial blood pressure and intracranial pressure in patients with aneurysmal subarachnoid hemorrhage. Arterial blood pressure and intracranial pressure were monitored continuously for 4 days in 90 patients (74% women; mean age, 53 years) in an intensive care unit after subarachnoid hemorrhage. Variability of arterial blood pressure and intracranial pressure signals was calculated on 4 timescales: 24 hours, 1 hour, 5 minutes, and the difference of sequential 5-second means. The Extended Glasgow Outcome Scale was used to assess functional outcome 6 months after subarachnoid hemorrhage. Pressure variability was better than mean pressure levels for predicting 6-month functional outcome. When initial neurological condition was controlled for, greater faster variability (particularly 5-second) was associated with better outcomes (typical P<.001), whereas greater 24-hour variability was associated with poorer outcomes (typical P<.001). The relationship between long-term functional outcome and variability of arterial blood pressure and intracranial pressure levels depends on the timescale at which the variability is measured. Because it is associated with better outcome, greater faster variability may reflect better physiological adaptive capacity.

Short-term vs. 24-hour variability of atrial fibrillatory wave characteristics: a surface ecg study in clinical stable patients

Short-term vs. 24-hour variability of atrial fibrillatory wave characteristics: a surface ecg study in clinical stable patients

Circadian variations in cardiovascular function and their relation to the occurrence and timing of cardiac events.

Circadian patterns of risk for cardiac events and their implications for prevention and treatment of cardiovascular conditions are discussed. Sympathovagal tone, a major biological determinant of circadian variation in cardiovascular function, is modulated through circadian patterns of sleep-wake activity. The influence of neurohumoral activity on cardiovascular function is manifested by 24-hour variability in heart rate, blood pressure, and vasomotor tone. Platelet aggregation and plasminogen-activator inhibitor-1 activity peak around the time of awakening. Conversely, endogenous plasminogen activator exhibits a nadir around the time of awakening. Studies of patterns of occurrence of cardiac disorders such as acute myocardial infarction, sudden cardiac death, stroke, and ventricular arrhythmia show an increased occurrence during the period surrounding awakening. These patterns are consistent with observed circadian patterns in cardiovascular function. Diabetes, left ventricular dysfunction, and congestive heart failure may contribute to alterations in patterns of occurrence of cardiac events. Factors such as race, sex, and age may lead to alterations in circadian variation in cardiovascular function. Unusual physical exertion, stress, and anger may act as triggers of an event at any time of day. The circadian patterns of cardiac events follow the natural fluctuations in endogenous physiological processes, with a vulnerable period consistently observed in the early morning; dynamic assessment of markers of cardiovascular function may assist in determining the extent of disease progression and in selecting cardiovascular therapies.

Reduced beat-to-beat changes of heart rate: an important risk factor after acute myocardial infarction.

The prognostic significance of heart rate variability derived from 24-hour electrocardiographic recordings was investigated in 250 patients with acute myocardial infarction. During a follow-up of 6 months 15 patients experienced a serious arrhythmic event. These patients showed a significantly reduced beat to beat variability (p = 0.006), a slightly reduced 5-min variability (p = 0.04) and no significant differences in the 24-hour variability compared to the patients free of arrhythmic events. Based on Cox proportional hazard analysis, beat to beat variability remained an independent risk factor (p = 0.0036) in addition to the presence or absence of ventricular late potentials (p = 0.0004) and history of previous infarction (p = 0.04).