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Contractility

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-intrinsic ability of the heart to pump
-related to shortening of the myocardial fiber muscle
-dependant on intracellular calcium during systole

Contractility is affected by:
-neural influence
-humoral influence
-pharmacological influence

Sympathetic nervous system
-usually most important effect on cardiac contractility
-affects the atrium, ventricle and nodal tissue

Factors which may decrease myocardial contractility:

-anoxia
-hypoxia
-catecholamine storage depletion
-ischemia
-infarction
-anesthetic agents
-antiarrhythmic agents