What question did this study set out to answer?

To investigate the mechanism of beta-agonist refractoriness and evaluate the dependency of myocardial contractility on extracellular ionized calcium in end-stage heart failure.

May 1, 1983Annals of Internal Medicine

Myocardial Performance and Extracellular Ionized Calcium in a Severely Failing Human Heart

View Full Paper

Ask AI

Bookmark

Authors

RGRobert GinsburgUniversity of Colorado Hospital

Discussion

Member takes

Implication

Case study demonstrates myocardial contractility dependence on ionized calcium in severe heart failure, highlighting calcium's role during beta-adrenergic desensitization.

Key Points

To investigate the mechanism of beta-agonist refractoriness and evaluate the dependency of myocardial contractility on extracellular ionized calcium in end-stage heart failure.
Monitored in vivo myocardial performance in a 16-year-old patient with end-stage congestive heart failure receiving CaCl2 infusions to correct low serum ionized calcium.
Conducted in vitro pharmacological and biochemical analyses on explanted myocardial tissue following heart transplantation, testing papillary muscle and adenylate cyclase responsiveness to isoproterenol, calcium, fluoride, and histamine.
In vivo myocardial performance correlated directly with serum ionized calcium levels during calcium chloride administration.
Explanted cardiac membranes exhibited severe beta-adrenergic receptor down-regulation, with papillary muscles and adenylate cyclase showing marked subsensitivity to isoproterenol.
Isolated papillary muscles retained normal contractile responses to calcium, and adenylate cyclase activity remained normally responsive to fluoride and histamine.

Cite This Study

Robert Ginsburg (1983) studied this question.

synapsesocial.com/papers/6aa3d58f229fb590e7c61b71 https://doi.org/10.7326/0003-4819-98-5-603

View Full Paper

Ask AI

Bookmark

Implication

Case study demonstrates myocardial contractility dependence on ionized calcium in severe heart failure, highlighting calcium's role during beta-adrenergic desensitization.

Myocardial Performance and Extracellular Ionized Calcium in a Severely Failing Human Heart

Discussion

Member takes

Implication

Key Points

Cite This Study

Myocardial Performance and Extracellular Ionized Calcium in a Severely Failing Human Heart

Discussion

Member takes

Implication

Key Points

Cite This Study

Also Consider

Also Consider