The role of heart rate in the left ventricular twist response to increased arterial blood pressure: a ‘stiff’ challenge?

We exposed fetuses to high-altitude (3,820 m) hypoxemia from 30 to 130 days gestation, when we measured fetal heart rate, right and left ventricular outputs with electromagnetic flow probes, and arterial blood pressure during an isoproterenol dose-response infusion. We also measured the distribution of cardiac output with radiolabeled microspheres during the maximal isoproterenol dose. Baseline fetal arterial blood pressure was higher in long-term hypoxemic fetuses (50.1 +/- 1.3 vs. 43.4 +/- 1.0 mmHg) but fell during the isoproterenol infusion to 41.3 +/- 1.4 and 37.5 +/- 1.4 mmHg, respectively, at the highest dose. Heart rate was the same in both groups and did not differ during isoproterenol infusion. Baseline fetal cardiac output was lower in the hypoxemic group (339 +/- 18 vs. 436 +/- 19 ml.min-1.kg-1) due mainly to a reduction in right ventricular output. During the isoproterenol infusion, right ventricular output increased to the same extent in both hypoxemic and normoxic fetuses (approximately 35%); however, left ventricular output increased only approximately 15% in the hypoxemic group compared with approximately 40% in the normoxic group. The percent change in individual organ blood flows during isoproterenol infusion in the hypoxemic groups was not significantly different from the normoxic group. All of the mechanisms that might be responsible for the differential response of the fetal left and right ventricles to long-term hypoxia are not understood and need further exploration.

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Role of oral gabapentin in attenuating cardiovascular response to laryngoscopy and tracheal intubation.

The Professional Medical Journal ◽

10.29309/tpmj/2020.27.07.4373 ◽

2020 ◽

Vol 27 (07) ◽

pp. 1470-1475

Author(s):

Mohsin Riaz Askri ◽

Shumyala Maqbool ◽

Kausar Abbas Shah ◽

Shahbaz Ahmad

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Tracheal Intubation ◽

Arterial Blood Pressure ◽

Mean Arterial Blood Pressure ◽

Cardiovascular Response ◽

Arterial Blood ◽

Group I ◽

Group Ii

Objectives: To determine the role of 800 mg oral gabapentin in attenuating cardiovascular response to laryngoscopy and tracheal intubation. Study Design: Double Blind Randomized Control Trial. Setting: Independent University Hospital/Independent Medical College, Faisalabad, Pakistan. Period: Six months from January1st 2019 to June 30th 2019. Material & Methods: This study included 60 patients which were divided into two equal groups. 800 mg oral gabapentin was given to group I while capsule placebo was administrated to group II patients in pre-operative area one hour prior to surgery. Heart rate, systolic, diastolic and mean arterial blood pressure were taken after induction of anesthesia at base line and then 1,2,3,4,5,10 and 15 minutes after endotracheal intubation. SPSS version 11 was used to analyze the data. Heart rate systolic, diastolic and mean arterial blood pressure were dependent variables while placebo and gabapentin were independent variables. Results: Out of total 60 patients there were 36 (60 %) males and 24 (40 %) females. In group I mean age was 37.1 while in group II it was 36.3. As compare to group II there was decreased cardiovascular response in group I. There was a significant decrease in systolic blood pressure at 1,2 and 10 minutes; diastolic blood pressure at 3 minutes; heart rate at 10 and 15 minutes and mean arterial blood pressure at 3 minutes after induction in group I. Conclusion: Cardiovascular response to laryngoscopy and intubation is significantly reduced with oral gabapentin.

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Left ventricular filling: relationship with arterial blood pressure, left ventricular mass, age, heart rate and body build

Journal of Hypertension ◽

10.1097/00004872-199104000-00006 ◽

1991 ◽

Vol 9 (4) ◽

pp. 345-353 ◽

Cited By ~ 13

Author(s):

Alberto Genovesi-Ebert ◽

Claudio Marabotti ◽

Carlo Palombo ◽

Stefano Giaconi ◽

Sergio Ghione

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Left Ventricular Mass ◽

Arterial Blood Pressure ◽

Left Ventricular ◽

Left Ventricular Filling ◽

Body Build ◽

Arterial Blood ◽

Ventricular Mass ◽

Ventricular Filling

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Reflex inhibition of plasma renin activity by increased left ventricular pressure in conscious dogs

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1989.256.6.r1299 ◽

1989 ◽

Vol 256 (6) ◽

pp. R1299-R1307

Author(s):

A. J. Gorman ◽

J. S. Chen

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Plasma Renin Activity ◽

Arterial Blood Pressure ◽

Left Atrial ◽

Plasma Renin ◽

Left Ventricular ◽

Renin Activity ◽

Conscious Dogs ◽

Arterial Blood

The purpose of the present study was to determine the effects of left ventricular (LV) outflow obstruction on plasma renin activity (PRA) and the contribution from afferent receptors located in the LV myocardium. In chronically instrumented, conscious dogs (n = 12), changes in PRA during a 15- to 20-mmHg decrease in arterial blood pressure were assessed during 1) intravenous infusions of nitroprusside (NP) alone and 2) infusions of NP while peak systolic LV pressure was elevated by acute ascending aortic occlusion (AAO + NP). Infusions of NP alone elicited significant increases in heart rate (24.9 +/- 5.1 beats/min; P less than 0.01) and in PRA [3.31 +/- 0.53 ng angiotensin I (ANG I).ml-1.h-1; P less than 0.01]. These were accompanied by decreases in both LV pressure (-13.8 +/- 3.6 mmHg; P less than 0.05) and left atrial pressure (-3.0 +/- 0.7 mmHg; P less than 0.05). During AAO + NP, LV pressure was elevated to an absolute level of 169.2 +/- 4.6 mmHg (+53.3 +/- 4.2 mmHg; P less than 0.001), whereas left atrial pressure was not changed. Both the hypotension-induced rise in PRA and tachycardia were significantly inhibited during AAO + NP (+0.59 +/- 0.29 ng ANG I.ml-1.h-1 and +6.3 +/- 4.6 beats/min, respectively; NS). The topical application of a local anesthetic in the region of the main coronary artery, sufficient to block the heart rate and arterial blood pressure responses to selective LV receptor stimulation by intracoronary veratridine (0.1-0.4 microgram/kg), resulted in significant increases in PRA and heart rate during AAO + NP.(ABSTRACT TRUNCATED AT 250 WORDS)

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Effects of isoflurane versus halothane on myocardial contractility in rabbits: assessment with transthoracic two-dimensional echocardiography

Laboratory Animals ◽

10.1258/002367797780600161 ◽

1997 ◽

Vol 31 (2) ◽

pp. 144-150 ◽

Cited By ~ 14

Author(s):

Giuseppe Marano ◽

Roberto Formigari ◽

Mauro Grigioni ◽

Alessandro Vergari

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Nitrous Oxide ◽

Arterial Blood Pressure ◽

Myocardial Contractility ◽

Left Ventricular ◽

Two Dimensional ◽

Arterial Blood ◽

Nitrous Oxide Anaesthesia ◽

Oxide Anaesthesia

The effects of isoflurane versus halothane on cardiac contractility were evaluated by two-dimensional (2D) transthoracic echo cardiography in rabbits. The relationship between the left ventricular end-systolic wall stress (LVESWS) and the velocity of heart rate corrected circumferential fibre shortening (Vcfc) was used. Arterial blood pressure, heart rate, left ventricular pressure and transthoracic 2D echocardiographic data were determined at 1 MAC (minimum alveolar concentration) of halothane or isoflurane, both with 50% nitrous oxide. Drug-induced changes in pre-and afterload were performed in all study animals to assess the left ventricular contractile response over a wide range. LVESWS and Vcfc Were calculated on videotape recorded M-mode tracings. Mean heart rate and arterial blood pressure were not significantly different between the two groups. Myocardial contractility under isoflurane/nitrous oxide anaesthesia was significantly higher than under halothane/nitrous oxide anaesthesia at 1 MAC. The results of the present study confirm data obtained from humans and other animal species and suggest that, in rabbits, myocardial contractility is best preserved by inhalation of isoflurane. Isoflurane should therefore be preferred over halothane, especially in cases of prolonged anaesthetic procedures.

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Compression Stocking Length Effects on Arterial Blood Pressure and Heart Rate Following Head-Up Tilt in Healthy Volunteers

Nursing Research ◽

10.1097/nnr.0000000000000062 ◽

2014 ◽

Vol 63 (6) ◽

pp. 435-438 ◽

Cited By ~ 3

Author(s):

Kunihiko Tanaka ◽

Shiori Tokumiya ◽

Yumiko Ishihara ◽

Yumiko Kohira ◽

Tetsuro Katafuchi

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Healthy Volunteers ◽

Arterial Blood Pressure ◽

Compression Stocking ◽

Arterial Blood ◽

Head Up Tilt ◽

Length Effects

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Sex- and age-based differences in the effect of central serotonin on arterial blood pressure regulation

Journal of Applied Physiology ◽

10.1152/japplphysiol.00414.2020 ◽

2020 ◽

Vol 129 (6) ◽

pp. 1310-1323

Author(s):

Jennifer L. Magnusson ◽

Craig A. Emter ◽

Kevin J. Cummings

Keyword(s):

Blood Pressure ◽

Arterial Blood Pressure ◽

Nrem Sleep ◽

Blood Pressure Regulation ◽

Pressure Regulation ◽

Adult Rats ◽

Arterial Blood ◽

Serotonin Neurons ◽

Older Males

The role of serotonin in arterial blood pressure (ABP) regulation across states of vigilance is unknown. We hypothesized that adult rats devoid of CNS serotonin (TPH2−/−) have low ABP in wakefulness and NREM sleep, when serotonin neurons are active. However, TPH2−/− rats experience higher ABP than TPH2+/+ rats in wakefulness and REM only, a phenotype present only in older males and not females. CNS serotonin may be critical for preventing high ABP in males with aging.

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