Mechanisms of initial heart rate response to postural change

1982 ◽  
Vol 243 (5) ◽  
pp. H676-H681 ◽  
Author(s):  
C. Borst ◽  
W. Wieling ◽  
J. F. van Brederode ◽  
A. Hond ◽  
L. G. de Rijk ◽  
...  
Keyword(s):  
Heart Rate ◽  
Time Course ◽  
Heart Rate Response ◽  
Cardiovascular Effects ◽  
Plasma Catecholamine ◽  
Catecholamine Level ◽  
Free Standing ◽  
Leg Muscles ◽  
Plasma Catecholamine Level ◽  
Head Up Tilt

We explored in 43 healthy subjects the afferent mechanisms of the initial heart rate response to standing by comparing free standing, 70 degrees head-up tilt, handgrip, and contraction of abdominal and leg muscles. The results indicate the following. 1) Standing evokes an immediate, large, bimodal increase of heart rate (HR) of about 20 s duration that far exceeds the gradual HR rise induced by 70 degrees head-up tilt. 2) The immediate HR increase with active standing is due to the exercise reflex and results in a first peak about 3 s after standing briskly. 3) The secondary, more gradual HR increase after 5 s of standing and the subsequent rapid decrease of HR between about 12 and 20 s corresponds through the baroreceptor reflex with a striking fall, recovery, and sometimes overshoot of arterial pressure. 4) The maximum HR increase found after about 12 s of standing is augmented and delayed after rest. 5) The time course of the initial HR response is not modified by physical training. We conclude that active and passive changes of posture result in fundamentally different cardiovascular effects for about 20 s and that "central command," muscle receptors, high-pressure receptors, low-pressure receptors, and the plasma catecholamine level are probably all involved in the initial HR response to standing.

Circulatory adaptation to orthostatic stress in healthy 10–14-year-old children investigated in a general practice

1991 ◽  
Vol 81 (1) ◽  
pp. 51-58 ◽  
Author(s):  
J. H. A. Dambrink ◽  
B. P. M. Imholz ◽  
J. M. Karemaker ◽  
W. Wieling
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Steady State ◽  
Initial Phase ◽  
Time Course ◽  
Free Standing ◽  
Postural Tachycardia ◽  
Circulatory Control ◽  
Head Up Tilt ◽  
Blood Pressures

1. The magnitude and time course of circulatory adaptation to active standing were investigated in healthy premenarchic girls and boys (n = 24; 10–14 years old) by non-invasive measurement of heart rate and continuous finger blood pressure (Finapres). 2. Four subjects (two girls, two boys) showed presyncopal symptoms after 4–9 min of free standing. 3. In the 20 non-fainting subjects, changes in blood pressure and heart rate upon standing did not differ between girls (n = 10) and boys (n = 10). In the initial phase of standing (first 30 s) systolic and diastolic blood pressures dropped by 22 ± 14 (mean ± sd) and 16 ± 7 mmHg, respectively, at 8 ± 2 s. Blood pressure subsequently recovered and showed an overshoot in all subjects. The transient drop in blood pressure was accompanied by an increase in heart rate of 40 ± 7 beats/min. These characteristic transient changes were not observed with passive head-up tilt. During the early steady-state phase (2 min), systolic blood pressure was similar to the supine value and diastolic blood pressure rose by 11 ± 5 mmHg. Heart rate increased by 25 ± 11 beats/min. In six of the subjects (three girls, three boys) the increase in heart rate exceeded 30 beats/min (postural tachycardia). Little further changes were observed during prolonged (10 min) standing. 4. Typical findings in the four near-fainting subjects were higher supine heart rates, no blood pressure overshoot in the initial phase (in three out of four subjects), postural tachycardia in the early steady-state phase and progressive decreases in blood pressure and heart rate afterwards. 5. In conclusion, for investigation of orthostatic circulatory adaptation in childhood it is important to pay attention to the dynamics of the circulatory response. No important differences appear to exist in orthostatic circulatory control between premenarchic girls and boys: orthostatic tachycardia and fainting appear to be common in both.

Sensitivities of cardiac O2 consumption and contractility to catecholamines in dogs

1991 ◽  
Vol 261 (1) ◽  
pp. H196-H205 ◽  
Author(s):  
Y. Ohgoshi ◽  
Y. Goto ◽  
S. Futaki ◽  
H. Yaku ◽  
H. Suga
Keyword(s):  
Mechanical Energy ◽  
Plasma Catecholamines ◽  
Systolic Pressure ◽  
Plasma Catecholamine ◽  
Catecholamine Level ◽  
Oxygen Cost ◽  
O2 Consumption ◽  
Total Mechanical Energy ◽  
Plasma Catecholamine Level ◽  
Stimulation Of

We studied the effects of plasma catecholamines from the adrenal gland on systolic pressure-volume area (PVA)-independent O2 consumption (VO2) and contractility index (Emax) in the left ventricle of excised cross-circulated dog hearts. PVA is a measure of the total mechanical energy of contraction. Under baseline conditions, the PVA-independent VO2 correlated with plasma catecholamine level in the hearts (r = 0.84). Plasma epinephrine and norepinephrine levels increased gradually from 0.3 and 0.4 ng/ml to 10.3 and 2.7 ng/ml on average during adrenal sympathetic nerve stimulation of support dogs. Simultaneously, Emax and PVA-independent VO2 increased by 240 +/- 127 (SD) and 75 +/- 24%. Although their increases were monotonic in a given heart, their sensitivities to catecholamines were considerably variable among hearts. However, these two sensitivities were correlated (r = 0.96) with each other in the hearts, and the interheart variation of the sensitivity of the PVA-independent VO2 to Emax (i.e., oxygen cost of Emax) was smaller. We conclude that the oxygen cost of Emax is less variable among hearts despite large interheart variations of Emax and VO2 responses to plasma catecholamines.

Plasma catecholamine level and portal venous pressure as guides to prognosis in patients with cirrhosis

1988 ◽  
Vol 6 (3) ◽  
pp. 350-358 ◽  
Author(s):  
U. Tage-Jensen ◽  
J.H. Henriksen ◽  
E. Christensen ◽  
A. Widding ◽  
H. Ring-Larsen ◽  
...  
Keyword(s):  
Venous Pressure ◽  
Portal Venous Pressure ◽  
Plasma Catecholamine ◽  
Catecholamine Level ◽  
Plasma Catecholamine Level

Orthostatic Circulatory Control in the Elderly Evaluated by Non-Invasive Continuous Blood Pressure Measurement

1990 ◽  
Vol 79 (1) ◽  
pp. 73-79 ◽  
Author(s):  
B. P. M. Imholz ◽  
J. H. A. Dambrink ◽  
J. M. Karemaker ◽  
W. Wieling
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Time Course ◽  
Blood Pressure Measurement ◽  
Elderly Subjects ◽  
Postural Changes ◽  
Significant Difference ◽  
Head Up Tilt ◽  
Blood Pressures

1. Continuous orthostatic responses of blood pressure and heart rate were measured in 40 healthy and active elderly subjects over 70 years of age in order to assess the time course and rapidity of orthostatic cardiovascular adaptation in old age. 2. During the first 30 s (initial phase) the effects of active standing and passive head-up tilt closely resembled those observed earlier in younger age groups. Standing up was accompanied by a drop (mean ± SD) in systolic and diastolic blood pressures of 26 ± 13 mmHg and 12 ± 18 mmHg, respectively, at around 10 s, and a subsequent rise up to 11 ± 17 mmHg and 8 ± 6 mmHg above supine values at around 20 s. The drop in blood pressure upon standing was accompanied by a transient increase in heart rate with a maximum of 13 beats/min, followed by a gradual decrease to 7 beats/min above supine levels. These characteristic transient changes were absent upon a passive head-up tilt. 3. After 1–2 min of standing (early steady-state phase) diastolic blood pressure and heart rate increased significantly after active and passive postural changes. On average, for all subjects systolic blood pressure tended to increase from control during 5–10 min standing, reaching a significant difference at 10 min. During standing, the largest increases in systolic blood pressure were found in subjects with the lowest supine blood pressures. 4. In conclusion, for the investigation of orthostatic circulatory responses in elderly subjects the following factors have to be taken into account: active versus passive changes in posture, the timing of the blood pressure reading, and the level of supine blood pressure.

Change of Hemodynamic Parameters and Plasma Catecholamine Level during Laparoscopic Cholecystectomy

1992 ◽  
Vol 25 (3) ◽  
pp. 515
Author(s):  
Young In Kim ◽  
Mi Ae Shur ◽  
Hee Soon Kim ◽  
Sung Jin Hong ◽  
Se Ho Moon ◽  
...  
Keyword(s):  
Laparoscopic Cholecystectomy ◽  
Plasma Catecholamine ◽  
Catecholamine Level ◽  
Hemodynamic Parameters ◽  
Plasma Catecholamine Level

Neuronal mediation of cardiovascular effects of food arousal in aplysia

1984 ◽  
Vol 51 (1) ◽  
pp. 126-135 ◽  
Author(s):  
U. T. Koch ◽  
J. Koester ◽  
K. R. Weiss
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Motor Neurons ◽  
Digestive System ◽  
Heart Rate Response ◽  
Pressor Response ◽  
Cardiovascular Effects ◽  
Cyclic Activity ◽  
Pressor Responses ◽  
Protraction Phase

Previous studies have demonstrated that heart rate and blood pressure increase in Aplysia during an arousal state elicited by food stimuli. In addition, during biting, blood flow is routed alternately to the head (during protraction of the buccal mass) and to the digestive system (during retraction). In this study, cutting the pleuroabdominal connectives eliminated 75% of the heart rate response during food arousal, and cutting the pleuroabdominal connectives eliminated 20-50% of the pressor response. Recording in the abdominal ganglion from the RBHE heart excitor and the three LBVC vasoconstrictor motor neurons in a reduced preparation showed that activity in these neurons was increased 50 and 100%, respectively, during food arousal. Activity of the LBVC cells was maximal during the protraction phase of biting. The LBVC vasoconstrictor motor neurons, when fired at the rates recorded during food arousal, can occlude the abdominal aorta completely. We conclude that the RBHE and LBVC neurons mediate, in part, the heart rate and pressor responses recorded during food arousal and that cyclic activity in LBVC contributes significantly to the cyclic alternation of blood flow between the head and the gut during rhythmic biting behavior.

HEART RATE RESPONSE TO VALSALVA MANEUVER AND HEAD-UP TILT IN SEDENTARY AND ENDURANCE TRAINED CYCLISTS

2003 ◽  
Vol 35 (Supplement 1) ◽  
pp. S119
Author(s):  
F S. Martinelli ◽  
M P. T. Chacon-Mikahil ◽  
V A. M. Forti ◽  
R Golfetti ◽  
L E. B. Martins ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Response ◽  
Valsalva Maneuver ◽  
Head Up Tilt

Cardiovascular effects of peptide kinin B2 receptor antagonists in rats

2002 ◽  
Vol 80 (4) ◽  
pp. 310-322 ◽  
Author(s):  
F Carini ◽  
M Guelfi ◽  
A Lecci ◽  
M Tramontana ◽  
S Meini ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Time Course ◽  
Cardiovascular Effects ◽  
Receptor Antagonists ◽  
Indwelling Catheter ◽  
Induced Hypotension ◽  
Conscious Rats ◽  
Anaesthetized Rats ◽  
The Right

Bradykinin (BK) is a vasoactive peptide reputed to play an important role in cardiovascular homeostasis. In this study, we describe the cardiovascular changes (mean blood pressure (BP) and heart rate (HR)) induced by the i.v. administration (left jugular vein) of two selective kinin B2 receptor antagonist, namely icatibant (0.1–1 µmol/kg as a bolus) and MEN11270 (0.1–1 µmol/kg as a bolus or 1 µmol/kg infused in 15 or 60 min), in urethane-anaesthetized or conscious rats with an indwelling catheter implanted in the right carotid artery for BP measurements. In conscious rats, icatibant at 0.1 or 0.3 µmol/kg did not change BP but at 0.1 µmol/kg increased HR at 30 min from administration. MEN11270 at 0.1 or 0.3 µmol/kg induced a dose-related increase in BP and a concomitant bradycardia (significant at 0.3 µmol/kg) lasting for 5 or 30 min, respectively. Icatibant at 1 µmol/kg induced a slight (P < 0.05) increase in BP that resolved in 5 min and a biphasic tachycardia (peaks at 30 and 90 min from administration). MEN11270 at 1 µmol/kg induced a triphasic change in HR (tachycardia in the first 5 min, bradycardia at 30 min, and tachycardia at 90 and 120 min) and a biphasic change in BP (hypotension at 15 min and hypertension at 30 min). The i.v. infusion of MEN11270 (1 µmol/kg in 15 or 60 min) produced hypertension, whereas HR was increased only following the 15-min infusion. In urethane-anaesthetized rats, both icatibant and MEN11270 (0.1 µmol/kg as a bolus) increased BP and the onset for this effect was correlated with the time course of the antagonism of BK-induced hypotension, where the effect of MEN11270 was more rapid than that of icatibant. These results indicate that kinin B2 receptor antagonists can induce acute cardiovascular effects, and the reason for the different haemodynamic profile between icatibant and MEN11270 could be putatively attributed to kinetic characteristics.Key words: icatibant, MEN11270, bradykinin, blood pressure, heart rate.

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