Hyperdynamic beta-adrenergic circulatory state. Increased beta-receptor responsiveness

Ed, Frohlich; Rc, Tarazi; Hp, Dustan

doi:10.1001/archinte.123.1.1

Cited by 122 publications

(26 citation statements)

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“…Tachycardia in hypertension has been shown to be a strong marker of a widespread autonomic control abnormality of the circulatory system, suggesting abnormal -adrenergic receptor function. 22 An autonomic control abnormality has been found not only in patients with hypertension or other Relation between frequency of high heart rate and the number of risk factors. Risk factors: hypertension, diabetes mellitus, hypertriglyceridemia.…”

Section: Discussionmentioning

confidence: 99%

High Heart Rate Relates to Clustering of Cardiovascular Risk Factors in a Screened Cohort.

et al. 2001

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lustering of cardiovascular risk factors is significantly associated with hypertension 1 and increased risk of cardiovascular events. [2][3][4] Several epidemiological studies have reported that a high heart rate (HHR) is a predictor of cardiovascular and non-cardiovascular mortality, [5][6][7][8][9][10][11] and HHR has been associated with several cardiovascular risk factors, especially hypertension. 12 However, it is not certain whether the clustering of risk factors increases the risk for a higher HR or whether an accumulation of these risk factors is associated with HR even with a low HR (LHR). Our aim was to evaluate the association of HR with laboratory and clinical parameters and lifestyle factors such as smoking, drinking, and exercise habits in a screened cohort in Okinawa, Japan. Furthermore, we examined whether the clustering of cardiovascular risk factors increased the risk for HHR. Methods SubjectsIn 1997, the Okinawa General Health Maintenance Association (OGHMA) in Okinawa, Japan, held a one-day 'dry doc' clinic, in which 9,914 individuals participated, all of whom were over 18 years of age. The population of Okinawa at that time was 1,273,440 of whom 931,376 were over the age of 18 (Census, 1995). Thus the clinic particiJapanese Circulation Journal Vol. 65, November 2001 pants were about 1% of the general population aged 18 years or over. We excluded as subjects anyone who had been prescribed drugs for hypertension or heart disease, anyone who had not had an ECG recording, and anyone who had a record of ectopic beats or atrial fibrillation. Thus, a total of 8,508 subjects (5,299 men, 3,209 women; age range, 18-89 years) were examined. OGHMA operates the largest examination center in Okinawa, Japan 13 and the 'dry doc' program provides both a thorough physical examination for individuals and the health maintenance programs of companies and public organizations. About 10,000 people participate in this program each year. Individual histories of hypertension, diabetes mellitus, hyperlipidemia, smoking habits, drinking habits, and exercise habits are determined by self-administered questionnaires and physician interviews. Blood sampling is performed after overnight fasting. Trained nurses measure blood pressure twice using a standard sphygmomanometer after having the subject sit for 15 min. In the present study, the lower blood pressure value was used. An ECG was recorded after 2 min in the supine position. Height, body weight, fasting blood glucose, hemoglobin A1c (HbA1c), total cholesterol, triglyceride, and high-density lipoprotein cholesterol were measured for all subjects. Body mass index (BMI) was calculated as body weight (kg) divided by the square of the height (m 2 ). HR was calculated from the average of consecutive RR intervals in 5 s from the ECG recording.Hypertension was defined as systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, or antihypertensive drug use. Obesity was defined as BMI ≥25 kg/m 2 . Diabetes mellitus was defined as fasting blood glucose concentrati...

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Section: Discussionmentioning

confidence: 99%

High Heart Rate Relates to Clustering of Cardiovascular Risk Factors in a Screened Cohort.

et al. 2001

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“…1,2 Increased sympathetic nervous system activity has been noted in several prior studies. These observations include high plasma norepinephrine levels, 4 decreased norepinephrine clearance, 5 increased adrenoreceptor sensitivity, 5,6 increased low-frequency/high-frequency ratio of RR-interval variability and low-frequency power of systolic blood pressure (putative measures of sympathetic modulation of RR interval and vascular tone, respectively), 7 and norepinephrine-transporter deficiency. 8 In contrast to these studies, there are also reports of reduced cardiovascular sympathetic activity, including impairment of late phase II of the Valsalva maneuver.…”

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confidence: 99%

Sympathetic Nerve Activity in Response to Hypotensive Stress in the Postural Tachycardia Syndrome

Bonyhay

Freeman

2004

Circulation

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Background-Increased central sympathetic activity and/or deficient peripheral sympathetic nerve function are among the proposed pathophysiological changes in patients with the postural tachycardia syndrome (POTS). Little is known about sympathetic nerve outflow and its role in hemodynamic control in this disorder. Methods and Results-We recorded peroneal muscle sympathetic nerve activity in 9 POTS patients and 9 control subjects at rest and during a nitroprusside-induced hypotensive stimulus. Baseline blood pressure (BP) and heart rate were significantly higher in POTS patients than in controls. At rest, the burst frequency was similar in POTS patients and controls (18.1Ϯ6.2 and 20.1Ϯ7.9 bursts/min, respectively; PϭNS), whereas the burst incidence was significantly lower (23.1Ϯ6.8 versus 32.2Ϯ11.4 bursts/100 heartbeats, PϽ0.05). Nitroprusside increased sympathetic outflow significantly more in POTS patients than in controls despite a similar BP decrease (burst frequency 20.4Ϯ7.5 versus 12.1Ϯ4.1 bursts/min, Pϭ0.008, and burst incidence 21.8Ϯ8.4 versus 14.4Ϯ5.2 bursts/100 heartbeats, Pϭ0.03). The change in mean burst area, a measure of the number of actively firing sympathetic neurons, was similar in patients and controls (117Ϯ15% versus 114Ϯ21%, PϭNS). Conclusions-At rest, the tachycardia and normal burst frequency result in normal or even elevated BP in POTS patients.During a hypotensive stimulus, cardiovascular homeostasis is maintained by the increased sympathetic outflow and normal heart rate response despite the lack of concomitant increase in mean burst area that is most likely due to sympathetic denervation.

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“…1 The pathophysiology of this disorder, which mainly affects women in the second or third decade of life, is still imperfectly understood. 2 It has been suggested that hypovolemia, 3,4 excessive venous pooling in the lower extremities, 5 partial dysautonomia involving the vasculature of the legs, [6][7][8] or hypersensitivity of ␤-adrenoreceptors 9,10 can contribute to the hemodynamic abnormalities of IOI. The unifying feature of patients with IOI is the presence of symptoms suggestive of cerebral hypoperfusion (eg, presyncope, visual changes, altered mentation) associated with standing despite largely sustained systemic arterial pressure.…”

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Raised Cerebrovascular Resistance in Idiopathic Orthostatic Intolerance

Jordan¹,

Shannon²,

Black³

et al. 1998

Hypertension

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Abstract-Patients with idiopathic orthostatic intolerance (IOI) exhibit symptoms suggestive of cerebral hypoperfusion and an excessive decrease in cerebral blood flow associated with standing despite sustained systemic blood pressure. In 9 patients (8 women and 1 man aged 22 to 48 years) with IOI, we tested the hypothesis that volume loading (2000 cc normal saline) and ␣-adrenoreceptor agonism improve systemic hemodynamics and cerebral perfusion and that the decrease in cerebral blood flow with head-up tilt (HUT) could be attenuated by ␣-adrenoreceptor blockade with phentolamine. At 5 minutes of HUT, volume loading (Ϫ20Ϯ3.2 bpm) and phenylephrine (Ϫ18Ϯ3.4 bpm) significantly reduced upright heart rate compared with placebo; the effect was diminished at the end of HUT. Phentolamine substantially increased upright heart rate at 5 minutes (20Ϯ3.7 bpm) and at the end of HUT (14Ϯ5 bpm). With placebo, mean cerebral blood flow velocity decreased by 33Ϯ6% at the end of HUT. This decrease in cerebral blood flow with HUT was attenuated by all 3 interventions. We conclude that in patients with IOI, HUT causes a substantial decrease in cerebrovascular blood flow velocity. The decrease in blood flow velocity with HUT can be attenuated with interventions that improve systemic hemodynamics and therefore decrease reflex sympathetic activation. Moreover, ␣-adrenoreceptor blockade also blunts the decrease in cerebral blood flow with HUT but at the price of deteriorated systemic hemodynamics. These observations may suggest that in patients with IOI, excessive sympathetic activity contributes to the paradoxical decrease in cerebral blood flow with upright posture. (Hypertension. 1998;32:699-704.)Key Words: cerebral blood flow Ⅲ receptors, adrenergic Ⅲ phentolamine Ⅲ phenylephrine Ⅲ intolerance, orthostatic Ⅲ tachycardia I diopathic orthostatic intolerance (IOI) is commonly defined as a Ͼ30 bpm increase in heart rate (HR) with standing associated with orthostatic symptoms but without significant orthostatic hypotension.1 The pathophysiology of this disorder, which mainly affects women in the second or third decade of life, is still imperfectly understood.2 It has been suggested that hypovolemia, 3,4 excessive venous pooling in the lower extremities, 5 partial dysautonomia involving the vasculature of the legs, 6-8 or hypersensitivity of ␤-adrenoreceptors 9,10 can contribute to the hemodynamic abnormalities of IOI. The unifying feature of patients with IOI is the presence of symptoms suggestive of cerebral hypoperfusion (eg, presyncope, visual changes, altered mentation) associated with standing despite largely sustained systemic arterial pressure. Recently, an excessive decrease in cerebral blood flow velocity with upright posture as well as stable mean arterial pressure (MAP) was reported in a single patient with a history and physical findings suggestive of IOI.11 Similarly, in a larger group of well-characterized IOI patients, mean middle cerebral blood flow velocity (mean MCA vel ) decreased by 28% with 75°HUT; age-and gender-mat...

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Hyperdynamic beta-adrenergic circulatory state. Increased beta-receptor responsiveness

Cited by 122 publications

References 0 publications

High Heart Rate Relates to Clustering of Cardiovascular Risk Factors in a Screened Cohort.

High Heart Rate Relates to Clustering of Cardiovascular Risk Factors in a Screened Cohort.

Sympathetic Nerve Activity in Response to Hypotensive Stress in the Postural Tachycardia Syndrome

Raised Cerebrovascular Resistance in Idiopathic Orthostatic Intolerance

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