A nurse is caring for a client admitted to the intensive care unit for a cardiac dysrhythmia. The nurse understands the prescribed calcium channel blocker has which of the following mechanisms of action?
Acts on the beta cells within the heart and lungs to regulate cardiac rhythm
Increases heart rate and increases myocardial contractility
Reduces the contractility and conductivity of the heart
Increase oxygen to the systemic circulation
The Correct Answer is C
A) "Acts on the beta cells within the heart and lungs to regulate cardiac rhythm.": This statement is incorrect because calcium channel blockers do not primarily act on beta cells. Instead, they block calcium channels in cardiac and smooth muscle, which affects heart contractility and conductivity.
B) "Increases heart rate and increases myocardial contractility.": Calcium channel blockers typically do the opposite; they decrease heart rate and myocardial contractility by inhibiting calcium entry into the heart muscle cells. Therefore, this statement does not accurately describe their mechanism of action.
C) "Reduces the contractility and conductivity of the heart.": This statement accurately reflects the action of calcium channel blockers. By blocking calcium entry, these medications decrease myocardial contractility and slow down electrical conduction through the heart, which can help manage dysrhythmias.
D) "Increase oxygen to the systemic circulation.": While calcium channel blockers can improve blood flow and reduce myocardial oxygen demand by decreasing heart workload, their primary action does not directly focus on increasing oxygen delivery to systemic circulation. Their primary role is in managing heart contractility and rhythm.
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Correct Answer is ["D","E"]
Explanation
A) Aspirin: While aspirin is an antiplatelet medication that can help prevent further clot formation, it does not have thrombolytic properties and does not directly lyse existing clots. Therefore, it is not appropriate for this purpose.
B) Heparin: Heparin is an anticoagulant used to prevent the extension of existing clots and reduce the risk of new clots forming, but it does not dissolve existing clots. It helps manage deep vein thrombosis but does not have thrombolytic activity.
C) Warfarin (Coumadin): Warfarin is an oral anticoagulant that is used to prevent new clot formation and the growth of existing clots. However, like heparin, it does not actively lyse or dissolve existing clots.
D) Alteplase (Activase): This medication is a thrombolytic agent that actively dissolves blood clots by activating plasminogen to plasmin, leading to clot breakdown. It is appropriate for use in cases of deep vein thrombosis when clot lysis is indicated.
E) Anistreplase (Eminase): Similar to alteplase, anistreplase is another thrombolytic agent used to lyse existing clots. It acts by converting plasminogen to plasmin, effectively breaking down fibrin in clots, making it suitable for the treatment of deep vein thrombosis.
Correct Answer is C
Explanation
A) "Acts on the beta cells within the heart and lungs to regulate cardiac rhythm.": This statement is incorrect because calcium channel blockers do not primarily act on beta cells. Instead, they block calcium channels in cardiac and smooth muscle, which affects heart contractility and conductivity.
B) "Increases heart rate and increases myocardial contractility.": Calcium channel blockers typically do the opposite; they decrease heart rate and myocardial contractility by inhibiting calcium entry into the heart muscle cells. Therefore, this statement does not accurately describe their mechanism of action.
C) "Reduces the contractility and conductivity of the heart.": This statement accurately reflects the action of calcium channel blockers. By blocking calcium entry, these medications decrease myocardial contractility and slow down electrical conduction through the heart, which can help manage dysrhythmias.
D) "Increase oxygen to the systemic circulation.": While calcium channel blockers can improve blood flow and reduce myocardial oxygen demand by decreasing heart workload, their primary action does not directly focus on increasing oxygen delivery to systemic circulation. Their primary role is in managing heart contractility and rhythm.