Author Question: A nurse is reviewing a journal article about class IA antiarrhythmics. The article describes a drug ... (Read 54 times)

tatyanajohnson · **on:** Jul 23, 2018

A nurse is reviewing a journal article about class IA antiarrhythmics. The article describes a drug that decreases depolarization and prolongs the refractory period. The nurse is most likely reading an article about which drug?

A) Quinidine
B) Lidocaine
C) Disopyramide
D) Flecainide

Question 2

A client is diagnosed with an arrhythmia that involves irregular and rapid atrial contraction and an irregular and inefficient ventricular contraction. The nurse interprets this arrhythmia as which of the following?

A) Atrial flutter
B) Atrial fibrillation
C) Ventricular tachycardia
D) Ventricular fibrillation

kaykay69 · **Reply #1 on:** Jul 23, 2018

Answer to Question 1

Ans: C
Feedback:
Disopyramide (Norpace) decreases depolarization of myocardial fibers, prolongs the refractory period, and increases the action potential duration of cardiac cells. Lidocaine (Xylocaine) decreases diastolic depolarization, decreases automaticity of ventricular cells, and raises the threshold of the ventricular myocardium. Quinidine depresses myocardial excitability or the ability of the myocardium to respond to an electrical stimulus. Flecainide (Tambocor) depresses fast sodium channels, decreases the height and rate of rise of action potentials, and slows conduction of all areas of the heart.

Answer to Question 2

Ans: B
Feedback:
Atrial fibrillation is characterized by irregular and rapid atrial contraction, resulting in a quivering of the atria and causing an irregular and inefficient ventricular contraction. Atrial flutter is the rapid contraction of the atria at a rate too rapid for the ventricle to pump efficiently. Ventricular tachycardia is a rapid heartbeat with a rate greater than 100 bpm. Ventricular fibrillation is rapid, disorganized contractions of the ventricles, resulting in the inability of the heart to pump any blood to the body.