Information AboutContractility |
| CATEGORIES ABOUT CONTRACTILITY | |
| cardiology | |
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It is often defined in the following roundabout way: The determinants of myocardial performance are:
If myocardial performance changes while preload, afterload and heart rate are all constant, then the change in performance must be due to the change in contractility. It might be thought that a better definition would be that ''Contractility'' is the property that represents the strength of myocardial contraction. However, this definition does not separate ''contractility'' from the other loading factors that affect the strength of myocardial contraction. In particular, an increase in preload results in an increased force of contraction - this is Starling's Law Of The Heart - but this does not require a change in contractility. The concept of Contractility was necessary to explain why some interventions (e.g. an Adrenaline infusion) could cause an increase in myocardial performance even if, as could be shown in experiments, the preload, afterload and heart rate were all held constant. Experimental work controlling the other factors was necessary because a change in contractility is generally not an isolated effect. For example:
All factors that cause an increase in contractility work by causing an increase in intracellular {Link without Title} during contraction. |
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