What question did this study set out to answer?

To examine the cardiovascular effects of acute insulin-induced hypoglycemia in humans and identify the autonomic receptor pathways responsible for these responses.

June 1, 1990AJP Heart and Circulatory Physiology

Cardiac responses to acute insulin-induced hypoglycemia in humans

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Why the study?

What are the mechanisms mediating the cardiovascular responses to acute insulin-induced hypoglycemia in humans?

Population

Humans

Comparison

Acute insulin-induced hypoglycemia, evaluated… vs Baseline state prior to hypoglycemia

Design

Other

Authors

BFB. M. FisherUniversity of Iowa AGAnthony J. GillThe University of Sydney DHDavid HepburnUniversity of Hull

Discussion

Member takes

Implication

Beta-blockade may blunt acute hypoglycemia-induced tachycardia and hypercontractility; extends mechanistic understanding but leaves clinical relevance open.

Key Points

To examine the cardiovascular effects of acute insulin-induced hypoglycemia in humans and identify the autonomic receptor pathways responsible for these responses.
Assessed cardiovascular hemodynamics and left ventricular ejection fraction during acute hypoglycemia using radioisotopic techniques, heart rate monitoring, and blood pressure measurements.
Administered pharmacological autonomic inhibitors to evaluate mechanisms: propranolol (parenteral nonselective beta-adrenergic blockade), phentolamine (alpha-adrenergic blockade), and atropine (cholinergic blockade).
Acute hypoglycemia increased heart rate from 62 ± 3 to 87 ± 3 beats/min and left ventricular ejection fraction from 47 ± 3% to 72 ± 5%, alongside increased systolic blood pressure and decreased diastolic blood pressure with no change in mean arterial pressure.
Beta-adrenergic blockade with propranolol completely abolished the increases in heart rate and ejection fraction, whereas alpha-adrenergic blockade (phentolamine) and cholinergic blockade (atropine) had no effect on these metrics.
Diastolic and mean arterial blood pressure rose during beta-blockade, whereas systolic, diastolic, and mean arterial blood pressure all fell significantly under alpha-blockade in response to hypoglycemia.

Structured PICO

What are the mechanisms mediating the cardiovascular responses to acute insulin-induced hypoglycemia in humans?

Population

Humans

Intervention

Acute insulin-induced hypoglycemia, evaluated with and without pharmacological blockades (propranolol, phentolamine, atropine)

Comparator

Baseline state prior to hypoglycemia

Outcome

Changes in heart rate, blood pressure, and left ventricular ejection fractionsurrogate

The increases in ejection fraction and heart rate during acute hypoglycemia are mediated by beta-adrenoreceptors, while blood pressure responses involve both alpha- and beta-adrenoreceptors.

Cite This Study

Fisher et al. (1990) studied this question.

synapsesocial.com/papers/6a7167518031ec7bb1dcf414 https://doi.org/10.1152/ajpheart.1990.258.6.h1775

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Implication

Beta-blockade may blunt acute hypoglycemia-induced tachycardia and hypercontractility; extends mechanistic understanding but leaves clinical relevance open.

Cardiac responses to acute insulin-induced hypoglycemia in humans

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Cardiac responses to acute insulin-induced hypoglycemia in humans

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider