How cardiac output is regulated: August Krogh's proto-Guytonian understanding of the importance of venous return

Joyce, William; Wang, Tobias

doi:10.1016/j.cbpa.2020.110861

Cited by 15 publications

(7 citation statements)

References 20 publications

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“…A second explanation for the increase in CO could be due to an increase in preload secondary to phenylephrine induced constriction of capillaries, peripheral veins, and central veins with a subsequent increase in stroke volume [ 37 ]. In a study in pigs that were experimentally treated to be adjusted on the Frank-Starling curve to make CO preload independent or preload dependent, phenylephrine increased CO in pigs on the preload dependent part of the curve but decreased CO in pigs on the preload independent part of the curve.…”

Section: Discussionmentioning

confidence: 99%

Ultrasound dilution cardiac output and echocardiography findings in anesthetized mature alpacas (Vicugna pacos) during normotension, hypotension and hypertension

et al. 2023

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Alpacas (Vicugna pacos) have physiologic adaptations to live at high altitude. These adaptations may result in unexpected responses to changes in cardiac performance and blood pressure during general anesthesia. There are few studies evaluating cardiovascular variables in anesthetized alpacas. The purpose of this study was to report cardiovascular performance in anesthetized mature alpacas during normotension, hypotension, and hypertension using ultrasound dilution and echocardiography. Six adult alpacas, 3 females and 3 castrated males, weighing 62.6 to 88.7 kg were anesthetized and maintained with isoflurane and placed in right lateral recumbency. Each alpaca underwent ultrasound dilution and echocardiography measurements during three cardiovascular phases, normotension, hypotension via increased isoflurane concentration, and hypertension via phenylephrine infusion. Variables were analyzed with a Friedman test and a post hoc Dunn’s test when significant. A p < 0.05 was used for significance. Cardiac output, cardiac index, systemic vascular resistance, stroke volume, total ejection fraction, left ventricular internal diameter during diastole, and total stroke volume indexed to body weight were greater for hypertension compared to hypotension. Total ejection fraction, stroke volume, and left ventricular ejection time were greater for hypertions compared to normotension. There was no difference between ultrasound dilution and echocardiography determined cardiac output measurements within each cardiovascular phase. Phenylephrine appeared to have increased ventricular performance and/or increased preload in anesthetized, mature alpacas. For detecting change in cardiovascular status in anesthetized alpacas, ultrasound dilution and echocardiography may be useful.

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Section: Discussionmentioning

confidence: 99%

Ultrasound dilution cardiac output and echocardiography findings in anesthetized mature alpacas (Vicugna pacos) during normotension, hypotension and hypertension

et al. 2023

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“…The most notable alterations in SV in reptiles and amphibians occur as decreases associated with apnea. The greatest decrease in SV seen in these animals is associated with the apnea required during their physical effort in the water [7,17,53,66,69,86,123].…”

Section: Adjustment Of the Sv To Exercise In Vertebratesmentioning

confidence: 99%

“…SV is determined by contractility and the characteristics of the ventricle, mainly regarding its filling capacity. Similarly, the control of the SV is accomplished by two different pathways, nervous and hormonal [7,17,69].…”

mentioning

confidence: 99%

Cardiovascular Response to Exercise in Vertebrates: Update

López-Román,

Gómez-Lucas,

Jiménez-Herranz

et al. 2024

Preprint

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Physical exercise is the greatest stress on the cardiovascular system, not only in humans but also in all vertebrates. Consequently, the cardiovascular response cannot be thought of as having only one "anthropocentric" interpretation. The modulation of cardiac output (Q) in response to exercise in the five major groups of vertebrates exhibits considerable variability. Moreover, the response of the heart rate (HR) and the stroke volume (SV), the fundamental factors that cause the rise in Q, is also highly variable. The difference in the range of HR is difficult to determine in many vertebrates, both at rest and at maximal effort. Additionally, the increase in SV varies among vertebrates. For example, while rainbow trout and leopards increase their SV by increasing end diastolic volume (EDV), humans do so at the expense of both increasing EDV and reducing end systolic volume (ESV). The variation in arterial pressure that arises during exercise varies notably among vertebrates, such as amphibians, whose blood pressure values do not increase as significantly as in mammals. Such differences in cardiovascular response among vertebrates may be linked to their habitat or living environment. This review aims to analyze the cardiovascular response of vertebrates to physical exercise as the most common stressor.

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“…Increased adrenergic stimulation during exercise or stress (2,14) induces PKA phosphorylation of Ser23/24, thereby abolishing the TnI-TnC protein-protein interaction (11,15) and decreasing myofilament Ca 2+ affinity (16). Accordingly, this process accelerates dissociation of Ca 2+ during diastole and increases the rate of cardiomyocyte relaxation (13,17,18), which is essential for preserving adequate cardiac filling at elevated heart rates concomitantly driven by adrenergic stimulation (13,19,20). Deletion of the cTnI N-terminal extension in transgenic mice has been shown to mimic the effect of PKA phosphorylation (21)(22)(23) and benefit diastolic cardiac performance, particularly during aging (10) and deficient ß-adrenergic signaling (24).…”

Section: Main Textmentioning

confidence: 99%

Genetic excision of the regulatory cardiac troponin I extension in high heart rate mammal clades

Joyce

Bogomolny

et al. 2023

Preprint

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Cardiac troponin I (cTnI) contains a N-terminal extension harboring protein kinase A targets (Ser23/24), which are phosphorylated during β-adrenergic stimulation to increase cardiomyocyte relaxation rate. Here, we show that exon 3 of TNNI3, encoding most of the cTnI N-terminal extension including Ser23/24, was pseudoexonized multiple times in shrews and moles to mimic Ser23/24 phosphorylation without adrenergic stimulation, thus facilitating the evolution of exceptionally high resting heart rates (>1100 beats/minute). Cardiac transcriptomes further reveal alternative splicing of TNNI3 exon 3 in two distantly related bat families, thereby representing an intermediate state preceding the genomic assimilation of exon 3 skipping. As human TNNI3 may similarly be amenable to exon 3 alternative splicing, our results offer a new approach to restore diastolic function in chronic heart failure patients.

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How cardiac output is regulated: August Krogh's proto-Guytonian understanding of the importance of venous return

Cited by 15 publications

References 20 publications

Ultrasound dilution cardiac output and echocardiography findings in anesthetized mature alpacas (Vicugna pacos) during normotension, hypotension and hypertension

Ultrasound dilution cardiac output and echocardiography findings in anesthetized mature alpacas (Vicugna pacos) during normotension, hypotension and hypertension

Cardiovascular Response to Exercise in Vertebrates: Update

Genetic excision of the regulatory cardiac troponin I extension in high heart rate mammal clades

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