Demonstration of a Remote Optical Measurement Configuration That Correlates With Breathing, Heart Rate, Pulse Pressure, Blood Coagulation, and Blood Oxygenation

This study compared the effects of self-selected exercise intensity (SEI) versus predetermined exercise intensity (PEI) on blood pressure (BP) and arterial stiffness in adolescents with obesity. A total of 37 adolescents, 14.7 (1.6) years old, body mass index ≥95th percentile were randomly allocated into SEI (n = 18; 12 boys) or PEI (n = 19; 13 boys). Both groups exercised for 35 minutes on a treadmill, 3 times per week, for 12 weeks. The SEI could set the speed at the beginning of the sessions and make changes every 5 minutes. The PEI adolescents were trained at an intensity set at 60% to 70% of heart rate reserve. Brachial and central BP, pulse pressure, augmentation index, and carotid–femoral pulse wave were determined at baseline and after 12 weeks. Both groups reduced brachial systolic BP (SEI, Δ = −9 mm Hg; PEI, Δ = −4 mm Hg; P < .01), central systolic BP (SEI, Δ = −4 mm Hg; PEI, Δ = −4 mm Hg; P = .01), and central pulse pressure (SEI, Δ = −4 mm Hg; PEI, Δ = −3 mm Hg; P = .02) without differences between groups. No changes in the augmentation index and carotid–femoral pulse wave were observed in either group. The SEI induced similar changes in various cardiovascular outcomes compared with PEI in adolescents with obesity.

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Effects of pacing modality on noninvasive assessment of heart rate dependency of indices of large artery function

Journal of Applied Physiology ◽

10.1152/japplphysiol.00445.2016 ◽

2016 ◽

Vol 121 (3) ◽

pp. 771-780 ◽

Cited By ~ 10

Author(s):

Isabella Tan ◽

Hosen Kiat ◽

Edward Barin ◽

Mark Butlin ◽

Alberto P. Avolio

Keyword(s):

Heart Rate ◽

Arterial Stiffness ◽

Pulse Pressure ◽

Wave Reflection ◽

Pulse Wave ◽

Augmentation Index ◽

Large Artery ◽

Rate Dependency ◽

Wave Reflections

Studies investigating the relationship between heart rate (HR) and arterial stiffness or wave reflections have commonly induced HR changes through in situ cardiac pacing. Although pacing produces consistent HR changes, hemodynamics can be different with different pacing modalities. Whether the differences affect the HR relationship with arterial stiffness or wave reflections is unknown. In the present study, 48 subjects [mean age, 78 ± 10 (SD), 9 women] with in situ cardiac pacemakers were paced at 60, 70, 80, 90, and 100 beats per min under atrial, atrioventricular, or ventricular pacing. At each paced HR, brachial cuff-based pulse wave analysis was used to determine central hemodynamic parameters, including ejection duration (ED) and augmentation index (AIx). Wave separation analysis was used to determine wave reflection magnitude (RM) and reflection index (RI). Arterial stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV). Pacing modality was found to have significant effects on the HR relationship with ED ( P = 0.01), central aortic pulse pressure ( P = 0.01), augmentation pressure ( P < 0.0001), and magnitudes of both forward and reflected waves ( P = 0.05 and P = 0.003, respectively), but not cfPWV ( P = 0.57) or AIx ( P = 0.38). However, at a fixed HR, significant differences in pulse pressure amplification ( P < 0.001), AIx ( P < 0.0001), RM ( P = 0.03), and RI ( P = 0.03) were observed with different pacing modalities. These results demonstrate that although the HR relationships with arterial stiffness and systolic loading as measured by cfPWV and AIx were unaffected by pacing modality, it should still be taken into account for studies in which mixed pacing modalities are present, in particular, for wave reflection studies.

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Reflex sympathetic activation in humans is accompanied by inhibition of gastric HCO3- secretion

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1988.255.6.g752 ◽

1988 ◽

Vol 255 (6) ◽

pp. G752-G758 ◽

Cited By ~ 2

Author(s):

H. Sjovall ◽

H. Forssell ◽

J. Haggendal ◽

L. Olbe

Keyword(s):

Heart Rate ◽

Vascular Resistance ◽

Pulse Pressure ◽

Negative Pressure ◽

Sympathetic Activity ◽

Plasma Catecholamine ◽

Series Of Experiments ◽

Plasma Catecholamine Concentrations ◽

Peripheral Sympathetic Activity ◽

Forearm Vascular Resistance

The study was performed to determine whether the sympathetic nervous system contributes to the reflex control of gastric HCO3- secretion in humans. Gastric HCO3- secretion was registered by a computerized technique based on measurements of pH and PCO2 in gastric effluent. To minimize formation of CO2 in the stomach, subjects were pretreated with the H2-receptor blocker ranitidine. Compensations were made for HCO3- of nongastric origin. As indicators of cardiovascular sympathetic activity, we measured heart rate, forearm vascular resistance, and plasma catecholamine concentrations. In one series of experiments, peripheral sympathetic activity was enhanced by the application of a negative pressure around the lower part of the body (lower body negative pressure, LBNP), at a rate sufficient to induce a slight decrease in systemic arterial pressure. In another series of experiments, peripheral sympathetic activity was inhibited by elevation of the legs, a procedure that simulates volume loading by redistributing blood volume toward the central circulation. LBNP at -20 mmHg decreased systolic pressure and pulse pressure and significantly increased heart rate, forearm vascular resistance, and plasma catecholamine levels. All these effects were observed in the first 15-min period of LBNP and were well maintained throughout the 45-min observation period. LBNP also inhibited basal gastric HCO3- secretion rate in seven of eight individuals, but this response was slower in onset with a latency of at least 15 min. Elevation of the legs increased pulse pressure and decreased forearm vascular resistance. Catecholamines were not measured in these experiments. Gastric HCO3- secretion tended to increase, but the magnitude of the response was highly variable.(ABSTRACT TRUNCATED AT 250 WORDS)

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Alteration in heart rate response to hemorrhage in conscious dogs with volume overload

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1978.235.4.h422 ◽

1978 ◽

Vol 235 (4) ◽

pp. H422-H428

Author(s):

M. M. LeWinter ◽

J. S. Karliner ◽

J. W. Covell

Keyword(s):

Heart Rate ◽

Central Venous Pressure ◽

Pulse Pressure ◽

Pressure Pulse ◽

Heart Rate Response ◽

Parasympathetic Nervous System ◽

Venous Pressure ◽

Volume Overload ◽

Conscious Dogs ◽

Central Venous

The heart rate response to hemorrhage was studied in conscious dogs before and up to 2 mo after the establishment of volume overload due to systemic arteriovenous (a-v) fistulas. Before a-v fistula, heart rate increased markedly during hemorrhage. When hemorrhage was preceded by dextran infusion, bleeding resulted in a gradual reduction in heart rate. The a-v fistula caused marked increases in resting heart rate, central venous pressure, pulse pressure, and blood volume. During hemorrhage, heart rate initially remained constant, but then declined abruptly from the resting value of 121 +/- 3.7 beats/min to a nadir of 89 +/- 6.5 beats/min (P less than 0.01). Although mean arterial pressure decreased markedly, there was no significant change in pulse pressure, and central venous pressure tended to stabilize with the heart rate decline. The abrupt heart rate decline was prevented by atropine but unaltered by propranolol. The response was observed as early as 5 days after a-v fistula. We conclude that an alteration in the heart rate response to hemorrhage appears early during volume overload. This alteration appears to be reflex in nature and to be mediated by the parasympathetic nervous system.

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Relation between pulse pressure and the pulsation strength in camera-based photoplethysmograms

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2017-0184 ◽

2017 ◽

Vol 3 (2) ◽

pp. 489-492 ◽

Cited By ~ 5

Author(s):

Alexander Trumpp ◽

Stefan Rasche ◽

Daniel Wedekind ◽

Matthias Rudolf ◽

Hagen Malberg ◽

...

Keyword(s):

Heart Rate ◽

Pulse Pressure ◽

Vital Signs ◽

Measuring Technique ◽

Video Cameras ◽

Medical Factors ◽

Two Measures

AbstractCamera-based photoplethysmography (cbPPG) is an innovative measuring technique that enables the remote extraction of vital signs using video cameras. Most studies in the field focus on heart rate detection while other physiological quantities are often ignored. In this work, we analyzed the relation between the pulse pressure and the pulsation strengths of cbPPG signals for 70 patients after surgery. Our results show a high correlation between the two measures (r = 0.54). Furthermore, the influence of technical and medical factors was tested. The controlled impact of these factors proved to enhance the correlation by between 9 and 27 %.

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Mesenteric Blood Flow as Influenced by Progressive Hypercapnia

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1956.184.2.275 ◽

1956 ◽

Vol 184 (2) ◽

pp. 275-281 ◽

Cited By ~ 18

Author(s):

Eugene W. Brickner ◽

E. Grant Dowds ◽

Bruce Willitts ◽

Ewald E. Selkurt

Keyword(s):

Heart Rate ◽

Blood Flow ◽

Arterial Pressure ◽

Oxygen Content ◽

Vascular Resistance ◽

Pulse Pressure ◽

Venous Pressure ◽

Mesenteric Blood Flow ◽

Initial Tendency ◽

Elevated Heart Rate

The influence of hypercapnia on mesenteric blood flow was studied in dogs subjected to progressive increments in CO2 content of inspired air produced by rebreathing from a large spirometer. Oxygen content was maintained above 21 volumes %. Although some animals showed an initial tendency for mesenteric blood flow to decrease and arterial pressure to increase in the range 0–5 volumes % of CO2, the usual hemodynamic change in the range 5–16 volumes % was an increase in mesenteric blood flow resulting from decrease in intestinal vascular resistance, accompanied by a decline in arterial pressure. Portal venous pressure was progressively elevated. Heart rate slowed in association with an increase in pulse pressure. The observations suggest that in higher ranges of hypercapnia, CO2 has a direct dilating action on the mesenteric vasculature.

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