Cardiovascular System: Part I

2019 ◽  
Author(s):  
Vanetta Levesque
Keyword(s):  
Blood Pressure ◽  
Cardiac Arrest ◽  
Cardiac Output ◽  
Cardiovascular System ◽  
Life Support ◽  
Advanced Cardiac Life Support ◽  
Ventricular Contractility ◽  
Fick Principle ◽  
Arterial Blood ◽  
Systolic And Diastolic Function

This chapter reviews the cardiovascular system in its entirety. It begins with the details of the cardiac cycle, a highly coordinated sequence of electrical and mechanical events that allows blood flow from the atria to the ventricles, which then pump blood out to pulmonary, and systemic circulations. There is an overview of basic ventricular physiology, assessment of ventricular contractility, and systolic and diastolic function. Cardiac output, its determinants, regulation, and its measurement according to the Fick principle and other methods are also extensively reviewed. The chapter moves on to describe the importance of blood pressure and its determinants. It follows with a description of how arterial blood pressure and other intracardiac pressures are measured. Finally, in the event of cardiac arrest, the chapter describes high quality CPR, and several algorithms used in managing patients in cardiac arrest. This review contains 5 figures, and 51 references. Keywords: electrocardiogram (ECG), Frank-Starling law, myocardial contractility, Fick principle, cardiac output, blood pressure, intracardiac pressures, advanced cardiac life support

scholarly journals Application of a self-designed inspiratory impedance threshold device in cardiopulmonary resuscitation in three porcine models of cardiac arrest

2019 ◽  
Author(s):  
Chao Li ◽  
Hai-Fei Gu ◽  
Xiao-Li He ◽  
Yu Zhang ◽  
Jie-Qing Min ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Arrest ◽  
Cardiac Output ◽  
The Self ◽  
Control Group ◽  
Blood Gas ◽  
End Diastolic Volume ◽  
Arterial Blood ◽  
Threshold Device ◽  
Impedance Threshold Device

Abstract Background: To evaluate and compare the efficiency of a self-designed inspiratory impedance threshold device in cardiopulmonary resuscitation (CPR) in the porcine models of cardiac arrest established by three approaches. Methods: Twenty healthy pigs were randomly assigned into the control group (n=5), model 1 (n=5), model 2 (n=5) and model 3 (n=5) groups. Following anesthesia induction, endotracheal tube was inserted and connected to the anesthesia machine. In the three model groups, pigs received intravenous injection of ketamine (model 1), MgSO4 (model 2) and KCl (model 3), and subsequently pig models of cardiac arrest were established. Manual closed-chest CPR was performed at 80 bpm with the self-designed inspiratory impedance threshold device in the model groups and without this device in the control group. After 2-, 6- and 10-min CPR, the heart rate and hemodynamic parameters including arterial blood pressure, blood oxygen saturation, end-diastolic volume and cardiac output were quantitatively measured. The Esophageal echocardiography and blood-gas analyses were performed. Results: After CPR, the mean arterial blood pressure, end-diastolic volume and cardiac output in three model groups were significantly higher compared with those in the control group (all P<0.05). In model 2 group, the stroke volume, cardiac output, end-diastolic volume, SPO2 and PCO2 levels and blood-gas parameters were the highest among three model groups (all P<0.05). Conclusions: The self-invented inspiratory impedance threshold device yields the highest efficiency in the porcine model of cardiac arrest established by intravenous infusion of MgSO4 by increasing the cardiac output during CPR compared with the remaining two pig models.

Cardiovascular Effects of Micromeria graeca (L.) Benth. ex Rchb in Normotensive and Hypertensive Rats

2020 ◽  
Vol 20 (8) ◽  
pp. 1253-1261
Author(s):  
Mourad Akdad ◽  
Mohamed Eddouks
Keyword(s):  
Blood Pressure ◽  
Cardiovascular System ◽  
Arterial Blood Pressure ◽  
Antihypertensive Activity ◽  
Computer Assisted ◽  
Hypertensive Rats ◽  
Vasorelaxant Effect ◽  
Arterial Blood

Aims: The present study was performed in order to analyze the antihypertensive activity of Micromeria graeca (L.) Benth. ex Rchb. Background: Micromeria graeca (L.) Benth. ex Rchb is an aromatic and medicinal plant belonging to the Lamiaceae family. This herb is used to treat various pathologies such as cardiovascular disorders. Meanwhile, its pharmacological effects on the cardiovascular system have not been studied. Objective: The present study aimed to evaluate the effect of aqueous extract of aerial parts of Micromeria graeca (AEMG) on the cardiovascular system in normotensive and hypertensive rats. Methods: In this study, the cardiovascular effect of AEMG was evaluated using in vivo and in vitro investigations. In order to assess the acute effect of AEMG on the cardiovascular system, anesthetized L-NAME-hypertensive and normotensive rats received AEMG (100 mg/kg) orally and arterial blood pressure parameters were monitored during six hours. In the sub-chronic study, rats were orally treated for one week, followed by blood pressure assessment during one week of treatment. Blood pressure was measured using a tail-cuff and a computer-assisted monitoring device. In the second experiment, isolated rat aortic ring pre-contracted with Epinephrine (EP) or KCl was used to assess the vasorelaxant effect of AEMG. Results: Oral administration of AEMG (100 mg/kg) provoked a decrease of arterial blood pressure parameters in hypertensive rats. In addition, AEMG induced a vasorelaxant effect in thoracic aortic rings pre-contracted with EP (10 μM) or KCl (80 mM). This effect was attenuated in the presence of propranolol and methylene blue. While in the presence of glibenclamide, L-NAME, nifedipine or Indomethacin, the vasorelaxant effect was not affected. Conclusion: This study showed that Micromeria graeca possesses a potent antihypertensive effect and relaxes the vascular smooth muscle through β-adrenergic and cGMP pathways.

scholarly journals Blood pressure reduction after gastric bypass surgery is explained by a decrease in cardiac output

2017 ◽  
Vol 122 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Peter M. van Brussel ◽  
Bas van den Bogaard ◽  
Barbara A. de Weijer ◽  
Jasper Truijen ◽  
C.T. Paul Krediet ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Gastric Bypass ◽  
Body Weight ◽  
Cardiac Output ◽  
Baroreflex Sensitivity ◽  
Bypass Surgery ◽  
Gastric Bypass Surgery ◽  
Left Ventricular ◽  
Ventricular Contractility ◽  
Left Ventricular Contractility

Blood pressure (BP) decreases in the first weeks after Roux-and-Y gastric bypass surgery. Yet the pathophysiology of the BP-lowering effects observed after gastric bypass surgery is incompletely understood. We evaluated BP, systemic hemodynamics, and baroreflex sensitivity in 15 obese women[mean age 42 ± 7 standard deviation (SD) yr, body mass index 45 ± 6 kg/m2] 2 wk before and 6 wk following Roux-and-Y gastric bypass surgery. Six weeks after gastric bypass surgery, mean body weight decreased by 13 ± 5 kg (10%, P < 0.001). Office BP decreased from 137 ± 10/86 ± 6 to 128 ± 12/81 ± 9 mmHg ( P < 0.001, P < 0.01), while daytime ambulatory BP decreased from 128 ± 14/80 ± 9 to 114 ± 10/73 ± 6 mmHg ( P = 0.01, P = 0.05), whereas nighttime BP decreased from 111 ± 13/66 ± 7 to 102 ± 9/62 ± 7 mmHg ( P = 0.04, P < 0.01). The decrease in BP was associated with a 1.6 ± 1.2 l/min (20%, P < 0.01) decrease in cardiac output (CO), while systemic vascular resistance increased (153 ± 189 dyn·s·cm−5, 15%, P < 0.01). The maximal ascending slope in systolic blood pressure decreased (192 mmHg/s, 19%, P = 0.01), suggesting a reduction in left ventricular contractility. Baroreflex sensitivity increased from 9.0 [6.4–14.3] to 13.8 [8.5–19.0] ms/mmHg (median [interquartile range]; P < 0.01) and was inversely correlated with the reductions in heart rate ( R = −0.64, P = 0.02) and CO ( R = −0.61, P = 0.03). In contrast, changes in body weight were not correlated with changes in either BP or CO. The BP reduction following Roux-and-Y gastric bypass surgery is correlated with a decrease in CO independent of changes in body weight. The contribution of heart rate to the reduction in CO together with enhanced baroreflex sensitivity suggests a shift toward increased parasympathetic cardiovascular control. NEW & NOTEWORTHY The reason for the decrease in blood pressure (BP) in the first weeks after gastric bypass surgery remains to be elucidated. We show that the reduction in BP following surgery is caused by a decrease in cardiac output. In addition, the maximal ascending slope in systolic blood pressure decreased suggesting a reduction in left ventricular contractility and cardiac workload. These findings help to understand the physiological changes following gastric bypass surgery and are relevant in light of the increased risk of heart failure in these patients.

A Comparison of the Acute Haemodynamic Effects of Propranolol and Pindolol at Rest and during Supine Exercise in Man

1980 ◽  
Vol 59 (s6) ◽  
pp. 465s-468s ◽  
Author(s):  
T. L. Svendsen ◽  
J. E. Carlsen ◽  
O. Hartling ◽  
A. McNair ◽  
J. Trap-Jensen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Pulmonary Artery ◽  
Pulmonary Artery Pressure ◽  
Response Curves ◽  
Receptor Blocking ◽  
Artery Pressure ◽  
Arterial Blood ◽  
Β Receptor

1. Dose-response curves for heart rate, cardiac output, arterial blood pressure and pulmonary artery pressure were obtained in 16 male patients after intravenous administration of three increasing doses of pindolol, propranolol or placebo. All patients had an uncomplicated acute myocardial infarction 6–8 months earlier. 2. The dose-response curves were obtained at rest and during repeated bouts of supine bicycle exercise. The cumulative dose amounted to 0.024 mg/kg body weight for pindolol and to 0.192 mg/kg body weight for propranolol. 3. At rest propranolol significantly reduced heart rate and cardiac output by 12% and 15% respectively. Arterial mean blood pressure was reduced by 9.2 mmHg. Mean pulmonary artery pressure increased significantly by 2 mmHg. Statistically significant changes in these variables were not seen after pindolol or placebo. 4. During exercise pindolol and propranolol both reduced cardiac output, heart rate and arterial blood pressure to the same extent. After propranolol mean pulmonary artery pressure was increased significantly by 3.6 mmHg. Pindolol and placebo did not change pulmonary artery pressure significantly. 5. The study suggests that pindolol may offer haemodynamic advantages over β-receptor-blocking agents without intrinsic sympathomimetic activity during low activity of the sympathetic nervous system, and may be preferable in situations where the β-receptor-blocking effect is required only during physical or psychic stress.

HAEMODYNAMIC CHANGES AND ADRENAL FUNCTION IN MAN DURING INDUCED HYPOGLYCAEMIA

1963 ◽  
Vol 44 (3) ◽  
pp. 430-442 ◽  
Author(s):  
B. Arner ◽  
P. Hedner ◽  
T. Karlefors ◽  
H. Westling
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Mean Arterial Blood Pressure ◽  
Peripheral Vascular ◽  
Adrenocortical Activity ◽  
Arterial Blood ◽  
Haemodynamic Changes ◽  
The Mean ◽  
Temporary Rise ◽  
Catechol Amines

ABSTRACT Observations were made on healthy volunteers during insulin induced hypoglycaemia (10 cases) and infusion of adrenaline (3 cases) or cortisol (1 case). In all cases a rise in the cardiac output was registered during insulin hypoglycaemia. The mean arterial blood pressure was relatively unchanged and the calculated peripheral vascular resistance decreased in all cases. A temporary rise in plasma corticosteroids was observed. After infusion of adrenaline similar circulatory changes were observed but no rise in plasma corticosteroids was found. Infusion of cortisol caused an increased plasma corticosteroid level but no circulatory changes. It is concluded that liberation of catechol amines and increased adrenocortical activity following hypoglycaemia are not necessarily interdependent.

scholarly journals Rhythmic Breath Holding and Its Effect on Arterial Blood Pressure and Its Correlation With Blood Gases

2020 ◽  
Author(s):  
Bharti Bhandari ◽  
Manisha Mavai ◽  
Yogendra Raj Singh ◽  
Bharati Mehta ◽  
Omlata Bhagat
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiovascular System ◽  
Arterial Blood Pressure ◽  
Blood Gases ◽  
Total Power ◽  
Breath Holding ◽  
Single Episode ◽  
Arterial Blood ◽  
Maximum Inspiration

A single episode of breath-holding (BH) is known to elevate the blood pressure, and regular breathing exercise lowers the blood pressure. This prompted us to investigate how a series of BH epochs would affect the cardiovascular system. To observe arterial blood pressure (ABP) and heart rate (HR) changes associated with a series of “BH epochs” following maximum inspiration and maximum expiration and find the underlying mechanisms for the change by autonomic activity. Thirty-five healthy young adults were instructed to hold their breath repetitively, for 5 minutes, in two patterns, one following maximum inspiration and other following maximum expiration. ABP and ECG (for Heart Rate Variability) were continuously recorded at rest and during both the maneuvers. Capillary blood gases (BG) were zanalyzed at baseline and at the breakpoint of the last epoch of BH. ABP rose significantly at the breakpoint during both the maneuvers. No change in HR was observed. There was significant fall in PO2 from 94.7 (4.1) mmHg at baseline to 79.1 (9.0) mmHg during inspiratory and 76.90 (12.1) mmHg during expiratory BH. Similarly, SPO2 decreased from 96.3 (1.9) % at baseline to 95.4 (1.5) % and 94.5 (2.7) % during inspiratory and expiratory BH, respectively. Rise in PCO2 from 39.5(3.1) mmHg at baseline to 42.9 (2.7) mmHg and 42.1 (2.8) mmHg during inspiratory and expiratory BH respectively was observed. There was no significant correlation between blood gases and arterial blood pressure. Among HRV parameters, a significant decrease in SDNN, RMSSD, HFnu, total power and SD1/SD2 and the significant increase in LFnu, LF/HF and SD2 were observed during both BH patterns. Rhythmic BH patterns affect the cardiovascular system in similar way as a single episode of BH. Sympathetic overactivity could be the postulated mechanism for the same. © 2019 Tehran University of Medical Sciences. All rights reserved. Acta Med Iran 2019;57(8):492-498.

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