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Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice
Published on: September 17, 2015
Left ventricular contractility varies directly with blood ionized calcium
R M Lang1, S K Fellner, A Neumann
1Department of Medicine, University of Chicago Medical Center, Illinois.
Annals of Internal Medicine
|April 1, 1988
Summary
Blood ionized calcium (Ca2+) levels directly impact heart muscle contractility. Lowering Ca2+ reduced contractility, while increasing it improved function in hemodialysis patients.
Area of Science:
- Cardiology
- Nephrology
- Biochemistry
Background:
- Myocardial contractility is crucial for cardiac function.
- Ionized calcium (Ca2+) plays a vital role in cardiac muscle contraction.
- Understanding the independent effect of Ca2+ on contractility is important for managing patients with renal failure.
Purpose of the Study:
- To investigate the direct effect of varying blood ionized calcium (Ca2+) levels on myocardial contractility.
- To isolate the impact of Ca2+ from changes in loading conditions and other biochemical factors.
Main Methods:
- A randomized, double-blind hemodialysis study was conducted.
- Dialysates with varying calcium concentrations were used.
- Left ventricular contractility was assessed using load- and heart rate-independent measures (end-systolic wall stress and rate-corrected velocity of fiber shortening).
Main Results:
- Statistically significant changes in myocardial contractility were observed with different Ca2+ levels.
- Lowering Ca2+ (1.02 mmol/L) decreased contractility (Vcfc = 0.89 cir/sec).
- Increasing Ca2+ (1.68 mmol/L) enhanced contractility (Vcfc = 1.10 cir/sec) compared to medium levels (1.34 mmol/L, Vcfc = 1.01 cir/sec).
Conclusions:
- Blood ionized calcium (Ca2+) levels are directly correlated with myocardial contractility.
- Clinical management of Ca2+ levels may be important for optimizing cardiac function in patients undergoing hemodialysis.
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