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New nurses on the telemetry unit have been paired with preceptors. One new nurse asks her preceptor to explain depolarization. What would be the best answer by the preceptor?
- A. Depolarization is the mechanical contraction of the heart muscles.
- B. Depolarization is the electrical stimulation of the heart muscles.
- C. Depolarization is the electrical relaxation of the heart muscles.
- D. Depolarization is the mechanical relaxation of the heart muscles.
Correct Answer: B
Rationale: The electrical stimulation of the heart is called depolarization, and the mechanical contraction is called systole. Electrical relaxation is called repolarization, and mechanical relaxation is called diastole.
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A nurse is providing health education to a patient scheduled for cryoablation therapy. The nurse should describe what aspect of this treatment?
- A. Peeling away the area of endocardium responsible for the dysrhythmia
- B. Using electrical shocks directly to the endocardium to eliminate the source of dysrhythmia
- C. Using high-frequency sound waves to eliminate the source of dysrhythmia
- D. Using a cooled probe to eliminate the source of dysrhythmia
Correct Answer: D
Rationale: Cryoablation therapy involves using a cooled probe to create a small scar on the endocardium to eliminate the source of the dysrhythmias. Endocardium resection involves peeling away a specified area of the endocardium. Electrical ablation involves using shocks to eliminate the area causing the dysrhythmias. Radio frequency ablation uses high-frequency sound waves to destroy the area causing the dysrhythmias.
A cardiac care nurse is aware of factors that result in positive chronotropy. These factors would affect a patients cardiac function in what way?
- A. Exacerbating an existing dysrhythmia
- B. Initiating a new dysrhythmia
- C. Resolving ventricular tachycardia
- D. Increasing the heart rate
Correct Answer: D
Rationale: Stimulation of the sympathetic system increases heart rate. This phenomenon is known as positive chronotropy. It does not influence dysrhythmias.
A patient is scheduled for catheter ablation therapy. When describing this procedure to the patients family, the nurse should address what aspect of the treatment?
- A. Resetting of the hearts contractility
- B. Destruction of specific cardiac cells
- C. Correction of structural cardiac abnormalities
- D. Clearance of partially occluded coronary arteries
Correct Answer: B
Rationale: Catheter ablation destroys specific cells that are the cause or central conduction route of a tachydysrhythmia. It does not reset the hearts contractility and it does not address structural or vascular abnormalities.
A patient is brought to the ED and determined to be experiencing symptomatic sinus bradycardia. The nurse caring for this patient is aware the medication of choice for treatment of this dysrhythmia is the administration of atropine. What guidelines will the nurse follow when administering atropine?
- A. Administer atropine 0.5 mg as an IV bolus every 3 to 5 minutes to a maximum of 3.0 mg.
- B. Administer atropine as a continuous infusion until symptoms resolve.
- C. Administer atropine as a continuous infusion to a maximum of 30 mg in 24 hours.
- D. Administer atropine 1.0 mg sublingually.
Correct Answer: A
Rationale: Atropine 0.5 mg given rapidly as an intravenous (IV) bolus every 3 to 5 minutes to a maximum total dose of 3.0 mg is the medication of choice in treating symptomatic sinus bradycardia. By this guideline, the other listed options are inappropriate.
The nurse caring for a patient whose sudden onset of sinus bradycardia is not responding adequately to atropine. What might be the treatment of choice for this patient?
- A. Implanted pacemaker
- B. Trancutaneous pacemaker
- C. ICD
- D. Asynchronous defibrillator
Correct Answer: B
Rationale: If a patient suddenly develops a bradycardia, is symptomatic but has a pulse, and is unresponsive to atropine, emergency pacing may be started with transcutaneous pacing, which most defibrillators are now equipped to perform. An implanted pacemaker is not a time-appropriate option. An asynchronous defibrillator or ICD would not provide relief.