Atrial fibrillation, stroke, and cognition: a longitudinal population-based study of people aged 85 and older.

BACKGROUND AND PURPOSE: The aim of this study was to investigate the association between atrial fibrillation (AF), stroke, dementia, and their correlation with brain pathology in subjects aged 85 years or older. METHODS: This is a prospective 9-year follow-up population based study in Vantaa, a town in Southern Finland; 553 subjects (92% of the total population) aged 85 years or older were clinically examined by a neurologist. The presence of AF was collected from the medical records or examined by ECG or ambulatory ECG. Neuropathological examination was conducted in more than half of the clinically examined subjects. RESULTS: AF was significantly associated with stroke at baseline; 32% of patients with AF had clinical evidence of stroke compared with 16.7% of those without such evidence (P<0.001). Dementia at baseline was significantly associated with age, clinical stroke, and the presence of apolipoprotein E epsilon4 allele, but not with sex, education, or vascular risk factors. Multiple regression analysis including neuropathological results showed that dementia was significantly associated with education (OR, 0.89; 95% CI, 0.80 to 0.98; P=0.019), the beta-amyloid load in the brain (OR, 1.26; 95% CI, 1.13 to 1.39; P<0.001) and with the vascular pathology (OR, 2.03; 95% CI, 1.14 to 3.62; P=0.016), but not with sex, age at death, apolipoprotein E epsilon4 allele, or vascular risk factors. CONCLUSIONS: AF is a significant and preventable risk factor for stroke but not for dementia in the very old. The etiology of dementia syndrome in the very old is multifactorial. Both Alzheimer disease pathology and vascular pathology, particularly multiple small infarcts, contribute to cognitive decline.

Effects of cellular phone use on ear canal temperature measured by NTC thermistors.

The earlier studies using phantom models and human subjects concerning warming effects during cellular phone use have been controversial, partly because radiofrequency (RF) exposures have been variable. In this randomized, double-blind, placebo-controlled crossover trial, 30 healthy subjects were submitted to 900 MHz (2W) and 1800 MHz (1W) cellular phone RF exposure, and to sham exposure in separate study sessions. Temperature signals were recorded continuously in both ear canals before, during and after the 35-min RF exposure and the 35-min sham exposure sessions. Temperature was measured by using small-sized NTC thermistors placed in the ear canals through disposable ear plugs. The mean temperature changes were determined during a set cardiovascular autonomic function studies: during a 5-min controlled breathing test, during a 5-min spontaneous breathing test, during 7-min head-up tilting, 1-min before, during and after two consecutive Valsalva manoeuvres and during a deep breathing test. Temperatures in the exposed ear were significantly higher during RF exposures compared with sham exposure in both 900 and 1800 MHz studies with maximum differences of 1 x 2 +/- 0 x 5 degrees C (900 MHz exposure) and 1 x 3 +/- 0 x 7 degrees C (1800 MHz exposure). Temperatures in the RF-exposed ear were also significantly higher during the postexposure period compared with post-sham exposure period with maximum differences of 0 x 6 +/- 0 x 3 degrees C for 900 MHz and 0 x 5 +/- 0 x 5 degrees C for 1800 MHz. The results of this study suggest that RF exposure to a cellular phone, either using 900 or 1800 MHz with their maximal allowed antenna powers, increases the temperature in the ear canal. The reason for the ear canal temperature rising is a consequence of mobile phone battery warming during maximal antenna power use. The earlier published articles do not indicate that temperature rising in the ear canal has any significant contribution from the RF fields emitted from mobile phones.

Association between blood pressure and survival over 9 years in a general population aged 85 and older.

OBJECTIVES: To investigate the association between blood pressure and mortality in people aged 85 and older. DESIGN: Population-based prospective study with 9-year follow-up. SETTING: Department of Neuroscience and Neurology and Department of Public Health and General Practice, University of Kuopio, and Department of Clinical Neurosciences, Helsinki University Hospital. PARTICIPANTS: Of all 601 people living in the city of Vantaa born before April 1, 1906, whether living at home or in institutions and alive on April 1, 1991, 521 were clinically examined and underwent blood pressure measurement. MEASUREMENTS: Blood pressure was measured using a standardized method in the right arm of the subject after resting for at least 5 minutes. Information on medical history for each participant was verified from a computerized database containing all primary care health records. Death certificates were obtained from the National Register; the collection of death certificates was complete. RESULTS: After adjusting for age, sex, functional status, and coexisting diseases (earlier-diagnosed myocardial infarction, congestive heart failure, dementia, cancer, stroke, or hypertension), low systolic blood pressure (BP) was associated with risk of death. CONCLUSION: Low systolic BP may be partially related to poor general health and poor vitality, but the very old may represent a select group of individuals, and the use of BP-lowering medications needs to be evaluated in this group.

Recording of dynamic arterial compliance changes during hand elevation.

Finger arterial compliance has been studied on the beat-to-beat basis by using the digital arterial pressure and volume waveforms and performing measurements at zero transmural pressure during arm elevation in 11 volunteers. Continuous non-invasive finger blood pressure was measured by applying the Finapres monitor and the finger volume pulses were recorded by the UT9201 physiograph by using the photoplethysmographic principle of registration. Estimation of the beat-to-beat finger arterial compliance is based on (i) the recorded volume and pressure wave amplitudes (Vpulse and Ppulse) and (ii) on the calculation of the slope of the pressure-volume relationship from the first derivatives dV/dt and dP/dt of the recorded volume and pressure pulses near the point of the maximum slope. The results of the study demonstrate that the applied two methods similarly (correlation coefficient r = 0.97) describe the changes of the beat-to-beat compliance during hand elevation test. At the same time the second estimate was 18% higher than the first one (P = 0.003).

Age dependency of cardiovascular autonomic responses to head-up tilt in healthy subjects.

In elderly subjects, heart rate responses to postural change are attenuated, whereas their vascular responses are augmented. Altered strategy in maintaining blood pressure homeostasis during upright position may result from various cardiovascular changes, including age-related cardiovascular autonomic dysfunction. This exploratory study was conducted to evaluate impact of age on cardiovascular autonomic responses to head-up tilt (HUT) in healthy subjects covering a wide age range. The study population consisted of 63 healthy, normal-weight, nonsmoking subjects aged 23-77 yr. Five-minute electrocardiogram and finger blood pressure recordings were performed in the supine position and in the upright position 5 min after 70 degrees HUT. Stroke volume was assessed from noninvasive blood pressure signals by the arterial pulse contour method. Heart rate variability (HRV) and systolic blood pressure variability (SBPV) were analyzed by using spectral analysis, and baroreflex sensitivity (BRS) was assessed by using sequence and cross-spectral methods. Cardiovascular autonomic activation during HUT consisted of decreases in HRV and BRS and an increase in SBPV. These changes became attenuated with aging. Age correlated significantly with amplitude of HUT-stimulated response of the high-frequency component (r = -0.61, P < 0.001) and the ratio of low-frequency to high-frequency power of HRV (r = -0.31, P < 0.05) and indexes of BRS (local BRS: r = -0.62, P < 0.001; cross-spectral baroreflex sensitivity in the low-frequency range: r = -0.38, P < 0.01). Blood pressure in the upright position was maintained well irrespective of age. However, the HUT-induced increase in heart rate was more pronounced in the younger subjects, whereas the increase in peripheral resistance was predominantly observed in the older subjects. Thus it is likely that whereas the dynamic capacity of cardiac autonomic regulation decreases, vascular responses related to vasoactive mechanisms and vascular sympathetic regulation become augmented with increasing age.

Gender influence on vasoactive hormones at rest and during a 70 degrees head-up tilt in healthy humans.

To evaluate the influence of age and gender on the neuroendocrine control of blood pressure in normal subjects, a 13-min 70 degrees head-up tilt (HUT) was applied after 3 h of recumbency to 109 healthy men and women aged 23-50 yr (age group I) and 51-77 yr (age group II). We found that age and gender had a significant influence on plasma norepinephrine (PNE) concentration at baseline and in the upright position. PNE was significantly higher in older men compared with the younger men and women of both age groups, suggesting a divergent age-related activation of the sympathetic nervous system between genders at baseline as well as during a sustained orthostatic challenge. There was no significant influence of age or gender on plasma epinephrine at baseline or during HUT. Plasma renin activity was significantly higher at baseline as well as in the upright position during HUT in elderly men than in women. Age or gender had no influence on plasma vasopressin (PAVP), and, regardless of age, nonhypotensive HUT induced an extremely modest increase in PAVP. The syncopal subjects displayed a hormonal pattern associating increased PNE and a surge in plasma epinephrine and PAVP minutes before syncope during HUT. The orthostatic intolerance appears not to be a feature of healthy aging per se. In healthy subjects, both age and gender modulate markedly the cardiovascular and neuroendocrine responses to an orthostatic challenge and must be taken into consideration, particularly when catecholamine responses are studied.

Determinants of bronchial responsiveness to methacholine at school age in twin pairs.

The methacholine inhalation challenge test (MIC) was used to evaluate bronchial responsiveness in 67 children who were the products of multiple pregnancies when they were 7-15 years old. At birth, 30 (45%) infants had intrauterine growth retardation (IUGR; birth weight <2 SD below normal birth weight, or birth weight difference >1.3 SD between twin-pairs), and 59 (88%) were born before 37 weeks of gestation. None of the children had doctor-diagnosed asthma. The provocative dose of methacholine causing a 20% fall in Wright's peak expiratory flow (WPEF) (PD20) was below 1,000 microg in 10 (15%) children, and they were classified as MIC responders. There were no differences in perinatal or neonatal factors between MIC responders and nonresponders; in particular, MIC responses did not differ between IUGR infants, and children with appropriate growth for gestational age (AGA) at birth. There were seven discordant pairs in which one child was a MIC responder and the other was not; 5 responders were IUGR, and 2 were AGA children (ns). Respiratory tract infections after the neonatal period were equally common in IUGR and AGA children. However, these infections were associated with later bronchial hyperresponsiveness. Doctor-diagnosed respiratory infections, numbers of antibiotic courses, episodes of otitis media, and the need for adenoidectomy, tonsillectomy, and tympanostomy were more common in MIC responders than in nonresponders. We conclude that IUGR was not associated with subsequent bronchial hyperresponsiveness in twin pairs assessed by the MIC test. A significant relationship was seen between bronchial hyperresponsiveness and infections after the neonatal period.

Effect of deep breathing test on finger blood pressure.

BACKGROUND: The deep breathing test (DB) is a simple method to measure heart rate variability. However, in most studies the amplitude of blood pressure oscillations has not been considered and little is known about the influence of the deep breathing test on the blood pressure level. DESIGN: The aim of this study is to investigate the effect of DB on finger blood pressure (FBP). METHODS: Continuous beat-to-beat FBP was recorded by the volume clamp method (Portapres model 2 monitor). RESULTS: Thirteen volunteers were studied before, during and after DB at a fixed rate of six breaths/min. After DB, systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP) were lower than before DB by 9.1, 4.3 and 5.9 mmHg, respectively. There was no significant correlation between the reduction in the BP level and the amplitudes of induced oscillations in blood pressure and heart rate during the deep breathing test. CONCLUSIONS: Deep breathing might be used to reduce blood pressure.

Association of apolipoprotein E genotypes, blood pressure, blood lipids and ECG abnormalities in a general population aged 85+.

BACKGROUND: Several studies have linked apolipoprotein E (ApoE) epsilon4 allele with elevated cholesterol and blood pressure levels. Data on the association of APOE genotypes with blood pressure, lipids, atrial fibrillation and ECG abnormalities in individuals aged 85 years and over is sparse. METHODS: This cross sectional study consisted of all residents of the city of Vantaa (N = 601) aged 85 years or over of whom 505 participated in the study. Blood pressure was measured by using mercury sphygmomanometer. 12-Lead ECG, short ambulatory ECG, or both were taken from all study subjects to diagnose atrial fibrillation (AF). Ambulatory ECG was carried out home or in the institute. APOE genotyping was performed using a combination of the polymerase chain reaction (PCR) and solid-phase minisequencing technique. Statistical analysis was made by using Kruskall-Wallis-test (continuous data) and chi2-test (rates and proportions). RESULTS: In these very elderly individuals, APOE 4 allele was significantly associated with elevated cholesterol and low-density lipoprotein (LDL) levels. Blood pressure or cardiac arrhythmias did not differ between APOE genotypes. CONCLUSIONS: These observations suggest that the important role of APOE genotype still influences cardiovascular risk profile even among the very elderly people.

Pre- and post-discharge feeding of very preterm infants: impact on growth and bone mineralization.

In this prospective study we examined (1) how the nutritional status of very preterm infants, judged by growth measures and biochemical values, evolved during the initial hospitalization; (2) the effect of feeding on growth after discharge from hospital; and (3) the risk factors associated with low lumbar bone mineral content (BMC) later in infancy. Sixty-four former preterm infants had their lumbar spine (L2-L4) BMC assessed by dual energy X-ray absorptiometry when they weighed between 5 and 7 kg. Predicted BMC values were calculated based on our previously reported reference lumbar BMC data. These values were used to convert the preterm infants' BMC values into percentages. The extremely preterm group (gestational age < or =28 weeks) had significantly more respiratory morbidity and longer duration of hospital stay than the more mature infants. Both groups developed growth retardation and malnutrition during the hospital stay. Exclusive breastfeeding after discharge from hospital supported linear catch-up growth and weight gain but was associated with a 7.0 (1.2-41.7)-fold risk of having low BMC values. The other factors associated with the risk of having low BMC values later in infancy were low serum phosphate levels at 6 weeks, with a 7.8 (1.6-37.0)-fold risk, and male gender, with a 4.3 (1.2-16.1)-fold risk. Appropriately designed interventional studies are needed to improve the growth and nutrition of these infants during initial hospitalization. In order to improve the postdischarge nutrition, we suggest that the amount and duration of multicomponent human milk fortification should be studied further to provide individualized nutrition throughout the catch-up growth period until the end of the first year of life.

Lumbar bone mineral content and density measured using a Lunar DPX densitometer in healthy full-term infants during the first year of life.

This cross-sectional study provides values for lumbar spine bone mineral content (BMC) and density (BMD) in 41 healthy full-term born Finnish infants, 19 boys and 22 girls, during the first year of life measured by dual energy X-ray absorptiometry (DXA) using the Lunar DPX densitometer. Lumbar BMC correlated with the weight (r=0.733; P=0.000), length (r=0.677; P=0.000), standardized length (r=0.315; r=0.045) and age at examination (r=0.314; P=0.045), and with the bone area (r=0.736; P=0.000). Infants with < or =-1 SD scores for lengths at examination had significantly lower BMC values [mean (SD); 1.79 (0.66) g] than infants with SD scores above -1 SD [2.27 (0.46) g] (P=0.011). Exclusive breast feeding did not correlate with the lumbar BMC values (r=-0.039; P=0.811). No differences were found in lumbar spine BMC (P=0.097), BMD (P=0.254) and bone area (P=0.094) values between boys and girls. In order to determine the predictive value of the anthropometric measurements on lumbar BMC, stepwise multiple regression analysis were performed, bone area and present weight were the only independent variables which explained 67.6% of the variance in the BMC values. The present cross-sectional data imply that, in healthy term infants, patterns of relative linear growth during the first year of life are related to the lumbar BMC values. In future, careful longitudinal measurements of linear growth are needed to study connections between growth patterns and bone mineral status in infancy.

Portapres and differential oscillometric finger blood pressure changes during deep breathing test in the assessment of BRS index.

The aim of this study was to investigate changes in the finger blood pressure during a deep breathing test (DB) and to find out whether the mean blood pressure might be used as a substitute for the systolic pressure in calculations of baroreflex sensitivity from data derived from the DB test. Continuous beat-to-beat finger pressure was recorded by the volume clamp method (Portapres model 2 monitor). In addition, the mean arterial pressure was recorded by the modified oscillometric method (UT9201 beat-to-beat monitor, University of Tartu, Estonia). Fifteen healthy volunteers, aged 25-56 years, were studied. The amplitude of respiration-linked oscillations in the Portapres systolic (Psyst) and mean blood pressure (Pmean) was 22.2 +/- 8.8 and 16.6 +/- 5.8 mmHg, respectively. There was no significant difference between the amplitudes of induced changes in Pmean recorded by the two devices: the amplitude of oscillations in the mean blood pressure recorded by the differential oscillometric monitor was 16.0 +/- 5.9 mmHg. The amplitude of oscillations in Psyst correlated significantly with the amplitude of oscillations in Pmean recorded either by Portapres or by UT9201 (r=0.95 and 0.98, respectively). The high correlation between the amplitudes of oscillations in mean and systolic blood pressure allows to conclude that mean arterial pressure changes during a DB test might be used instead of systolic pressure changes in calculation of the ratio of changes in pulse interval to changes in blood pressure, which is considered to reflect baroreflex sensitivity.

Taichiquan acutely increases heart rate variability.

A group of 15 elderly men and 14 young male students of physical education made twice a series of Taichiquan (TCQ) practices. Their electrocardiograms were recorded on tape-recorder and heart rates and heart rate variability (HRV) were calculated from digitized data. Here we report the results of recordings in supine positions before and after the first and second series of TCQ. Intervals between heart beats (RRIs) and their standard deviation (SDNN) increased in older men from recordings before the exercise to postexercise. In young subjects the SDNN and total variance (TV) of RRIs increased. HRV increases immediately after TCQ-exercise in young and old male healthy subjects. Whether these practices have permanent effects and effects in patients need controlled and prospective studies.

Effects of endurance training on heart rate and blood pressure variability.

PURPOSE: To study the influences of a 1-year controlled, randomized endurance exercise training period on heart rate (HR) and blood pressure variability in a representative sample of Finnish men in their late middle age. METHODS AND RESULTS: Subjects were 140 sedentary men aged 53-63 years. The men were randomized into two identical groups: an intervention (EX) and a reference (CO) group. One hundred and twelve of them remained in the final analysis (EX: n=59, CO: n=53). EX trained for 30-60 min three to five times a week with the intensity of 40-60% of maximal oxygen consumption. In EX, 1 year of regular exercise training increased oxygen consumption at respiratory compensation threshold by 11% (P < or = 0.001) in a maximal cardiorespiratory test. Total power and very low frequency power of R-R interval variability (ms2) tended to increase in the EX group by 26 and 42% and to decrease in the CO group by 13 and 10% (interaction P<0.05 and P<0.01), respectively. There were no significant changes in blood pressure variability. CONCLUSION: Regular low- to moderate-intensity exercise training could retard the declining tendency in cardiac autonomic nervous function in older men during 1 year.

Cerebral blood flow during acceleration in flight measured with SPECT.

INTRODUCTION: Positive pressure breathing for G-protection (PBG) reduces the need for fighter pilots to use the fatiguing anti-G straining maneuver (AGSM) so that they can better endure high acceleration (+Gz). The aim of the study was to determine the differences in cerebral blood flow during flight with an extended-coverage anti-G suit (ECGS) with AGSM or with PBG. METHODS: Subjects were eight male members of the Finnish Air Force. Each was studied in the laboratory at +1 Gz and then during two identical flights in the back seat of the BAe Hawk Mk 51 jet trainer at +6 Gz, first with AGSM and second with PBG (24 mmHg). Regional cerebral blood flow (rCBF) was measured by injecting (99 m) Tc-ECD for deposition at +6 Gz, then scanning the subject in the laboratory an hour later using single photon emission computed tomography (SPECT). RESULT: The rCBF was 30% below baseline for both the AGSM and PBG. CONCLUSIONS: PBG maintained CBF at +6 Gz without the need for the fatiguing AGSM.

Vascular risk factors and dementia in the general population aged >85 years: prospective population-based study.

The aim of this study was to evaluate the association between dementia and common vascular risk factors including blood pressure, blood lipids, homocysteine and diabetes mellitus in a population of very old people. This study is a 9-year follow-up prospective population-based study monitoring 339 non-demented subjects aged 85 years or over in the city of Vantaa, Southern Finland. During the follow-up, those individuals with diabetes mellitus at the baseline and new incident stroke had a higher probability for developing dementia. History of hypertension or higher level of education were associated with a lower probability of dementia. It seems that the contribution of vascular risk factors to the risk of dementia may be age-dependent and their role in the very old subjects may be mediated through their influence on cerebrovascular morbidity. Thus, prevention of stroke and diabetes mellitus may reduce the risk of cognitive decline in the very old.

Evaluation of informed consent: a pilot study.

AIM: This paper is a report of a study to describe and analyse the use of informed consent in clinical research, from the point of view of voluntary adult research participants, in order to develop and test an interview schedule for the evaluation of informed consent. BACKGROUND: Informed consent is one of the central ethical research principles in healthcare research, but empirical research on this topic is still scarce. To evaluate and develop the ethical quality of scientific research, there is a need to explore the meaning and implications of informed consent for research participants. METHOD: The data were collected in 2004 by interviews using an interview schedule created for this study by the first author and discussed in a multidisciplinary group. The response rate was 81%. The sample consisted of 32 patients with a metabolic syndrome who were participants in a project evaluating the effects of betaine on cardiovascular risk factors. FINDINGS: Participants stated that the key elements of informed consent are information, understanding and decision-making, and that competence is an essential factor in the reception and understanding of information and making an independent decision about participation. Our interview schedule was found to be useful in the investigation of informed consent. CONCLUSION: This study strengthened the perception that more extensive research about research participants is needed.

Assessment of attitudes towards assisted reproduction: a survey among medical students and parous women.

BACKGROUND: The present paper explores attitudes towards different aspects of assisted reproductive technologies among parous women and future doctors (third- and fourth-year medical students). METHODS: We anonymously surveyed 200 parous women who had at least three infants and had given birth at Kuopio University Hospital, and 200 medical students of Kuopio University. RESULTS: The overall response rate was 45%. Most of the medical students were childless (95.7%), unmarried (63.8%), and younger (24 vs. 35 years) compared with the parous women (p < 0.001). Medical students were liberal in questions of who has the right to get infertility treatment: 49% of them would allow the possibility to lesbian couples, 43% to homosexual couples and over 50% to single women. Over 40% of medical students would allow the use of a surrogate mother for lesbian and homosexual couples; the number was under 20% in the group of parous women. Their setting of priorities within the field of reproductive health also showed differences in prostate cancer screening, doctor's appointments for contraception, abortion and menopausal hormone replacement therapy. CONCLUSIONS: Medical students take a rather liberal stance on reproductive issues. On the other hand, baseline attitudes among medical students reveal some degree of subjectivism when it comes to allocation of scarce healthcare resources within the field of reproductive health. Medical education faces a challenge in ensuring that future physicians are able to set priorities and balance resources between preventive medicine and management of specific medical conditions, and to base their attitudes on evidence.

A survey of the attitudes of infertile and parous women towards the availability of assisted reproductive technology.

OBJECTIVE: The aim of the study was to assess differences in attitudes towards aspects of assisted reproduction technology between infertile and parous women. DESIGN: Case-control study. SETTING: University-based tertiary care clinic. POPULATION/SAMPLE: Three hundred and ninety-two women with fertility problems and 200 parous controls. METHODS: A questionnaire was sent out to 392 the members of Childless Support Association and 200 parous women who had at least three infants and had given birth at Kuopio University Hospital. The questionnaire consisted of 46 questions: demographic information, fertility history, different aspects of assisted reproduction technology and prioritisation issues. MAIN OUTCOME MEASURES: Attitudes towards assisted reproduction technology. RESULTS: The overall response rate was 46%. Infertile women were highly educated (P < 0.01) and had lower parity (mean 0.83 vs 4.76, P < 0.01) than parous women. We recorded four major differences in attitudes between the two groups (OR >2 or <0.5) including provision of infertility treatment to lesbian (46.9% vs 16.7%) and homosexual couples (28.4% vs 11.4%), the opportunity for homosexual couples to use surrogate mothers (30.6% vs 15.2%) and limitations in the number of infertility treatment cycles (28.4% vs 61.4%). For 11 questions, we recorded minor, but statistically significant, differences. In the prioritisation questions, the women set the order according to their own interests, probably because the women were at fertile age and they had or would like to have a child. Maternity services and screening for cancer in women (Papanicolaou's test and mammography) were at the top of the list. CONCLUSION: These results reflect a split attitude that was influenced by the wish of infertile women to help childless couples and to be able to recruit suitable sperm/oocyte donors. Parous women were motivated by their concern for children's rights.

Baroreflex sensitivity in essential and secondary hypertension.

Baroreceptor reflex regulation has been shown to reset towards a higher blood pressure level and to operate with reduced sensitivity in hypertension. Whether this is secondary to elevated blood pressure or whether it plays a role in the development of hypertension is not known. In addition, only limited data exist on baroreflex sensitivity (BRS) in patients with long-lasting medically treated essential hypertension and in patients who have blood pressure elevation with similar severity, but of different etiology. The purpose of this study was to examine BRS in patients with different severity and forms of chronic, medically treated hypertension. Patients with renovascular hypertension (RVHT, n = 14), severe essential hypertension (SEHT, n = 36) and mild essential hypertension (MEHT, n = 29) as well as healthy age- and sex-matched control subjects were studied. BRS was measured with the phenylephrine method.BRS in the RVHT (3.7 +/- 0.6 ms/mmHg) and SEHT (7.6 +/- 0.8 ms/mmHg) groups did not differ from each other after age, gender and left ventricular mass index were taken into consideration. On the contrary, BRS in the RVHT (p = 0.008) and SEHT (p = 0.016) groups were lower than in the MEHT (8.5 +/- 1.2 ms/mmHg) group. BRS was also significantly reduced in the RVHT (P = 0.004) and SEHT groups (P = 0.006) when compared to the healthy age- and sex-matched controls. BRS in the MEHT group did not differ from the control subjects. In conclusion, BRS was equally impaired in patients with renovascular and severe essential hypertension, which was similar in severity but different in etiology. BRS in patients with long-lasting medically treated mild essential hypertension did not differ from the healthy subjects. Our study suggests that baroreflex dysfunction in hypertensive patients is related to the clinical severity of hypertension, rather than its etiology.