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Contractility; By this model, if myocardial performance changes while preload, afterload, heart rate, and conduction velocity are all held constant, then the change in performance must be due to a change in contractility. However, changes in contractility alone generally do not occur. [citation needed] Other examples:
The FDA approved the OPTIMIZER Smart System, which delivers cardiac contractility modulation therapy, as indicated to improve 6-minute hall walk distance, quality of life, and functional status of NYHA Class III heart failure patients who remain symptomatic despite guideline directed medical therapy, who are in normal sinus rhythm, are not indicated for cardiac resynchronization therapy, and ...
An increase in contractility is manifested as an increase in dP/dt max during isovolumic contraction. However, dP/dt max is also influenced by preload, afterload, heart rate, and myocardial hypertrophy. Hence, the relationship between ventricular end-diastolic volume and dP/dt is a more accurate index of contractility than dP/dt alone.
The Anrep effect describes the rapid increase in myocardial contractility in response to the sudden rise in afterload, the pressure the heart must work against to eject blood. [ 1 ] [ 2 ] This adaptive mechanism allows the heart to sustain stroke volume and cardiac output despite increased resistance.
Pages for logged out editors learn more. Contributions; Talk; Cardiac contractility
Contractility refers to the ability for self-contraction, especially of the muscles or similar active biological tissue Contractile ring in cytokinesis; Contractile vacuole; Muscle contraction. Myocardial contractility; See contractile cell for an overview of cell types in humans.
Lusitropy or lucitropy is the rate of myocardial relaxation. The increase in cytosolic calcium of cardiomyocytes via increased uptake leads to increased myocardial contractility (positive inotropic effect), but the myocardial relaxation, or lusitropy, decreases.
Myocardial cells possess the property of automaticity or spontaneous depolarization. This is the direct result of a membrane which allows sodium ions to slowly enter the cell until the threshold is reached for depolarization. Calcium ions follow and extend the depolarization even further.