scholarly journals Sildenafil enhances central hemodynamic responses to exercise, but not V̇o2peak, in people with diabetes mellitus

2019 ◽  
Vol 127 (1) ◽  
pp. 1-10
Author(s):  
Timothy J. Roberts ◽  
Andrew T. Burns ◽  
Richard J. MacIsaac ◽  
Andrew I. MacIsaac ◽  
David L. Prior ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Heart Rate ◽  
Cardiac Output ◽  
Pulmonary Vascular Resistance ◽  
Exercise Capacity ◽  
Vascular Resistance ◽  
Exercise Performance ◽  
Exercise Echocardiography ◽  
Cardiopulmonary Exercise ◽  
Central Hemodynamic

Exercise capacity is frequently reduced in people with diabetes mellitus (DM), and the contribution of pulmonary microvascular dysfunction remains undefined. We hypothesized that pulmonary microvascular disease, measured by a novel exercise echocardiography technique termed pulmonary transit of agitated contrast (PTAC), would be greater in subjects with DM and that the use of pulmonary vasodilator agent sildenafil would improve exercise performance by reducing right ventricular afterload. Forty subjects with DM and 20 matched controls performed cardiopulmonary exercise testing and semisupine exercise echocardiography 1 h after placebo or sildenafil ingestion in a double-blind randomized crossover design. The primary efficacy end point was exercise capacity (V̇o2peak) while secondary measures included pulmonary vascular resistance, cardiac output, and change in PTAC. DM subjects were aged 44 ± 13 yr, 73% male, with 16 ± 10 yr DM history. Sildenafil caused marginal improvements in echocardiographic measures of biventricular systolic function in DM subjects. Exercise-induced increases in pulmonary artery systolic pressure and pulmonary vascular resistance were attenuated with sildenafil, while heart rate (+2.4 ±1.2 beats/min, P = 0.04) and cardiac output (+322 ± 21 ml, P = 0.03) improved. However, the degree of PTAC did not change ( P = 0.93) and V̇o2peak did not increase following sildenafil as compared with placebo (V̇o2peak: 31.8 ± 9.7 vs. 32.1 ± 9.5 ml·min−1·kg−1, P = 0.42). We conclude that sildenafil administration causes modest acute improvements in central hemodynamics but does not improve exercise capacity. This may be due to the mismatch in action of sildenafil on the pulmonary arteries rather than the distal pulmonary microvasculature and potential adverse effects on peripheral oxygen extraction. NEW & NOTEWORTHY This is one of the largest and most comprehensive studies of cardiopulmonary exercise performance in people with diabetes mellitus and to our knowledge the first to assess the effect of sildenafil using detailed echocardiographic measures during incremental exercise. Sildenafil attenuated the rise in pulmonary vascular resistance while augmenting cardiac output and intriguingly heart rate, without conferring any improvement in exercise capacity. The enhanced central hemodynamic indexes may have been offset by reduced peripheral O2 extraction.

Monocrotaline model of noncardiogenic pulmonary edema in dogs

1978 ◽  
Vol 45 (6) ◽  
pp. 962-965 ◽  
Author(s):  
W. C. Miller ◽  
D. L. Rice ◽  
R. G. Kreusel ◽  
C. W. Bedrossian
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Pulmonary Edema ◽  
Pulmonary Vascular Resistance ◽  
Intravenous Injection ◽  
Vascular Resistance ◽  
Endothelial Damage ◽  
Lung Water

Monocrotaline, a plant alkaloid shown histologically to produce pulmonary endothelial damage and edema, was used in dogs to produce an acute model of noncardiogenic pulmonary edema. Following intravenous injection there was no change in pulmonary vascular pressures or heart rate; cardiac output fell and pulmonary vascular resistance increased. After 2 h measurement of lung water demonstrated modest pulmonary edema in all animals. The degree of edema produced was more consistent and reproducible than that following alloxan or alpha-naphthylthiourea.

Circulatory effects of prolonged hypoxia before and during antihistamine

1976 ◽  
Vol 40 (4) ◽  
pp. 549-558 ◽  
Author(s):  
J. E. Levasseur ◽  
H. A. Kontos ◽  
D. W. Richardson ◽  
J. L. Patterson
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Left Atrial ◽  
Blocking Agent ◽  
Circulatory Response ◽  
Receptor Blocking ◽  
Arterial Blood ◽  
Blood Ph

Five chronically instrumented healthy dogs were exposed to a 5-day period of breathing 10% oxygen in a chamber. The response to hypoxia was found to be time dependent. During the first 24 h of hypoxia the circulatory response was characterized by increases in cardiac output, heart rate, pulmonary and systemic arterial blood pressures, and pulmonary vascular resistance. Systemic vascular resistance increased; left atrial pressure decreased. During the early part of hypoxia the animals became hypocapnic; the arterial blood pH rose significantly. During the rest of the hypoxic period cardiac output, heart rate, and arterial blood pH returned to the control values; pulmonary and systemic arterial pressures and pulmonary vascular resistance remained significantly elevated. Systemic vascular resistance rose; left atrial pressure remained below control. This response to hypoxia was not substantially modified when the experiment was repeated during the administration of the antihistamine promethazine, an H1-receptor blocking agent, in a dose which blocked the pulmonary vasoconstrictor response to small doses of exogenous histamine. The circulatory response to acute hypoxia in five anesthetized dogs was not modified by intravenous administration of metiamide, an H2-receptor blocking agent.

Ghrelin and Obesity-An Update

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Gandhi M. ◽  
Swaminathan S.
Keyword(s):  
Diabetes Mellitus ◽  
Cardiac Output ◽  
Energy Balance ◽  
Vascular Resistance ◽  
The Body ◽  
Ghrelin Receptor ◽  
Type2 Diabetes ◽  
Type2 Diabetes Mellitus ◽  
Natural Hormones

Ghrelin as human natural hormones is involved in fundamental regulatory process of eating and energy balance. It is a stomach derived hormone that acts as at the ghrelin receptor in multiple tissues throughout to the body. Its properties includes increasing appetite, decreasing systemic inflammation, decreasing vascular resistance ,increasing cardiac output, increasing glucose and IGF-1 levels, Hence it may play a significant role in Diabetes mellitus. Many studies have linked ghrelin to obesity and this paper is an attempt to bring out recent findings on the role of ghrelin in Diabetes Mellitus, particularly type2 Diabetes mellitus.

scholarly journals Hemodynamic abnormalities during muscle metaboreflex activation in patients with type 2 diabetes mellitus

2019 ◽  
Vol 126 (2) ◽  
pp. 444-453 ◽  
Author(s):  
Silvana Roberto ◽  
Raffaele Milia ◽  
Azzurra Doneddu ◽  
Virginia Pinna ◽  
Girolamo Palazzolo ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Blood Pressure ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Cardiac Output ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Blood Pressure Response ◽  
Pressure Response

Metaboreflex is a reflex triggered during exercise or postexercise muscle ischemia (PEMI) by metaboreceptor stimulation. Typical features of metaboreflex are increased cardiac output (CO) and blood pressure. Patients suffering from metabolic syndrome display hemodynamic abnormalities, with an exaggerated systemic vascular resistance (SVR) and reduced CO response during PEMI-induced metaboreflex. Whether patients with type 2 diabetes mellitus (DM2) have similar hemodynamic abnormalities is unknown. Here we contrast the hemodynamic response to PEMI in 14 patients suffering from DM2 (age 62.7 ± 8.3 yr) and in 15 age-matched controls (CTLs). All participants underwent a control exercise recovery reference test and a PEMI test to obtain the metaboreflex response. Central hemodynamics were evaluated by unbiased operator-independent impedance cardiography. Although the blood pressure response to PEMI was not significantly different between the groups, we found that the SVR and CO responses were reversed in patients with DM2 as compared with the CTLs (SVR: 392.5 ± 549.6 and −14.8 ± 258.9 dyn·s−1·cm−5; CO: −0.25 ± 0.63 and 0.46 ± 0.50 l/m, respectively, in DM2 and in CTL groups, respectively; P < 0.05 for both). Of note, stroke volume (SV) increased during PEMI in the CTL group only. Failure to increase SV and CO was the consequence of reduced venous return, impaired cardiac performance, and augmented afterload in patients with DM2. We conclude that patients with DM2 have an exaggerated vasoconstriction in response to metaboreflex activation not accompanied by a concomitant increase in heart performance. Therefore, in these patients, blood pressure response to the metaboreflex relies more on SVR increases rather than on increases in SV and CO. NEW & NOTEWORTHY The main new finding of the present investigation is that subjects with type 2 diabetes mellitus have an exaggerated vasoconstriction in response to metaboreflex activation. In these patients, blood pressure response to the metaboreflex relies more on systemic vascular resistance than on cardiac output increments.

scholarly journals Effect of Repeated Exposure to Contrasting Temperatures on the Body of Working Age Men with Different Types of Autonomic Regulation

2021 ◽  
pp. 394-404
Author(s):  
Tat’yana A. Fisher ◽  
◽  
Svetlana S. Kolyvanova
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Vascular Resistance ◽  
Autonomic Regulation ◽  
Repeated Exposure ◽  
The Body ◽  
Biological Research ◽  
Adaptive Potential ◽  
Different Types ◽  
Working Age

The aim of this paper was to study changes in the haemodynamic and psychophysiological parameters of working age men as a result of repeated exposure to contrasting temperatures, depending on the type of autonomic regulation. Materials and methods. The research involved 14 men (aged 34.77 ± 5.66 years; office workers) divided into two groups according to Kérdö index: those with the sympathetic (n = 8) and parasympathetic (n = 6) types of self-regulation. Cold conditioning followed a certain plan of exposure to contrasting temperatures. The haemodynamic and psychophysiological parameters as well as adaptive potential were assessed 20 minutes before and 20 minutes after the exposure (alternating temperature cycles). We examined the following parameters: heart rate, systolic and diastolic blood pressure, pulse and mean arterial pressure, stroke volume, cardiac output, vascular resistance, and adaptive potential according to Baevsky. Integral psychophysiological parameters were determined using the Lüscher express method. Results. Subjects with predominance of sympathetic regulation both before and after the exposure to contrasting temperatures had higher values of heart rate and cardiac output and lower vascular resistance than the parasympathicotonic group. Individuals with predominance of parasympathetic regulation showed decreased cardiac output and a significant increase in vascular resistance after the exposure compared with the initial data. We found statistically significant differences in the integral parameters “heteronomy/autonomy” and “balance of personal traits” between the groups under study before the conditioning procedures. The research indicates that repeated exposure to contrasting temperatures not only affects the haemodynamic parameters, but also changes the psychophysiological parameters, motivated behaviour in particular. For citation: Fisher T.A., Kolyvanova S.S. Effect of Repeated Exposure to Contrasting Temperatures on the Body of Working Age Men with Different Types of Autonomic Regulation. Journal of Medical and Biological Research, 2021, vol. 9, no. 4, pp. 394–404. DOI: 10.37482/2687-1491-Z077

Increased pulmonary vascular resistance and reduced stroke volume in association with CO2retention and inferior vena cava dilatation

2006 ◽  
Vol 101 (3) ◽  
pp. 866-872 ◽  
Author(s):  
Darija Baković ◽  
Davor Eterović ◽  
Zoran Valic ◽  
Žana Saratlija-Novaković ◽  
Ivan Palada ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Inferior Vena Cava ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Inferior Vena ◽  
Vena Cava ◽  
Arterial Oxygen ◽  
Breath Holding ◽  
Oxygen Saturation Level ◽  
The Impact

Changes in cardiovascular parameters elicited during a maximal breath hold are well described. However, the impact of consecutive maximal breath holds on central hemodynamics in the postapneic period is unknown. Eight trained apnea divers and eight control subjects performed five successive maximal apneas, separated by a 2-min resting interval, with face immersion in cold water. Ultrasound examinations of inferior vena cava (IVC) and the heart were carried out at times 0, 10, 20, 40, and 60 min after the last apnea. The arterial oxygen saturation level and blood pressure, heart rate, and transcutaneous partial pressures of CO2and O2were monitored continuously. At 20 min after breath holds, IVC diameter increased (27.6 and 16.8% for apnea divers and controls, respectively). Subsequently, pulmonary vascular resistance increased and cardiac output decreased both in apnea divers (62.8 and 21.4%, respectively) and the control group (74.6 and 17.8%, respectively). Cardiac output decrements were due to reductions in stroke volumes in the presence of reduced end-diastolic ventricular volumes. Transcutaneous partial pressure of CO2increased in all participants during breath holding, returned to baseline between apneas, but remained slightly elevated during the postdive observation period (∼4.5%). Thus increased right ventricular afterload and decreased cardiac output were associated with CO2retention and signs of peripheralization of blood volume. These results indicate that repeated apneas may cause prolonged hemodynamic changes after resumption of normal breathing, which may suggest what happens in sleep apnea syndrome.

Mechanism of circulatory responses to systemic hypoxia in the anesthetized dog

1965 ◽  
Vol 209 (2) ◽  
pp. 397-403 ◽  
Author(s):  
Hermes A. Kontos ◽  
H. Page Mauck ◽  
David W. Richardson ◽  
John L. Patterson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Vascular Resistance ◽  
The Other ◽  
Arterial Flow ◽  
Arterial Blood ◽  
Systemic Hypoxia ◽  
Anesthetized Dogs ◽  
Spontaneously Breathing

The possibility that mechanisms secondary to the increased ventilation may contribute significantly to the circulatory responses to systemic hypoxia was explored in anesthetized dogs. In 14 spontaneously breathing dogs systemic hypoxia induced by breathing 7.5% oxygen in nitrogen increased cardiac output, heart rate, mean arterial blood pressure, and femoral arterial flow, and decreased systemic and hindlimb vascular resistances. In 14 dogs whose ventilation was kept constant by means of a respirator pump and intravenous decamethonium, systemic hypoxia did not change cardiac output, femoral arterial flow, or limb vascular resistance; it significantly decreased heart rate and significantly increased systemic vascular resistance. In seven spontaneously breathing dogs arterial blood pCO2 was maintained at the resting level during systemic hypoxia. The increase in heart rate was significantly less pronounced but the other circulatory findings were not different from those found during hypocapnic hypoxia. Thus, mechanisms secondary to increased ventilation contribute significantly to the circulatory responses to systemic hypoxia. Hypocapnia accounts partly for the increased heart rate, but not for the other circulatory responses.

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