A dysrhythmia can arise from abnormal automaticity, the ability of cardiac cells to generate impulses on their own.
Missing Word
automaticity
Automaticity is the ability of pacemaker cells to fire spontaneously. When it is abnormal, the SA node may pace too slowly or too quickly, or other cells may begin firing on their own.
Category: Dysrhythmia Basics
Question 2
In ablation, radiofrequency energy creates scar tissue that cannot conduct impulses, eliminating the source of a dysrhythmia.
Missing Word
ablation
Ablation is a nonpharmacologic treatment that destroys the small area of tissue causing a dysrhythmia. The resulting scar does not conduct electrical impulses.
Category: Dysrhythmia Basics
Question 3
Ventricular fibrillation is treated at once with defibrillation, an unsynchronized electrical shock that stops the chaotic rhythm so the SA node can take over.
Missing Word
defibrillation
Defibrillation delivers an unsynchronized shock to the whole heart and is the immediate treatment for ventricular fibrillation and pulseless ventricular tachycardia, alongside CPR and advanced cardiac life support drugs. It differs from cardioversion, which is timed to the QRS complex and used for rhythms that still have a pulse.
Category: Dysrhythmia Basics
Question 4
A flat line with no electrical activity on the cardiac monitor indicates asystole.
Missing Word
asystole
Asystole is the absence of all electrical activity, so the heart does not pump. It requires advanced cardiac life support.
Category: Dysrhythmia Basics
Question 5
Quinidine can cause a low platelet count, called thrombocytopenia, so it is avoided when the platelet count is already low.
Missing Word
thrombocytopenia
Thrombocytopenia is a low platelet count. Quinidine can cause it, so a complete blood count is monitored and baseline thrombocytopenia is a reason to avoid the drug.
Category: Class I Sodium Blockers
Question 6
Clients taking oral mexiletine should report jaundice, a yellowing of the skin and eyes that can signal liver injury.
Missing Word
jaundice
Jaundice is yellowing from bilirubin buildup. Mexiletine carries a boxed warning for abnormal liver function, so clients report this sign promptly.
Category: Class I Sodium Blockers
Question 7
Atrial fibrillation can be restored to sinus rhythm with a shock timed to the QRS complex, a procedure called cardioversion.
Missing Word
cardioversion
Cardioversion is a synchronized shock, timed to the QRS complex so it does not land during ventricular repolarization, used for atrial fibrillation, atrial flutter and unstable tachycardias that still have a pulse. Before elective cardioversion of atrial fibrillation, clients are assessed for atrial clots and anticoagulated, because restoring rhythm can dislodge a clot.
Category: Dysrhythmia Basics
Question 8
Clients taking amiodarone are taught to avoid grapefruit and its juice, which can raise the drug's blood level.
Missing Word
grapefruit
Grapefruit inhibits the CYP3A enzyme that helps break down amiodarone, so eating it or drinking its juice can raise drug levels and toxicity risk. Clients are taught to avoid it for the whole course of therapy.
Category: Class III Potassium Blockers
Question 9
Class III antidysrhythmics block channels that carry potassium out of cardiac cells during repolarization, prolonging the action potential.
Missing Word
potassium
Potassium outflow repolarizes cardiac cells. Blocking it lengthens the action potential and refractory period, which also prolongs the QT interval and raises the risk of torsade de pointes.
Category: Class III Potassium Blockers
Question 10
Amiodarone contains iodine, so hypersensitivity to this element is a contraindication to the drug.
Missing Word
iodine
Iodine is part of the amiodarone molecule. That iodine content also explains why amiodarone can cause both hyperthyroidism and hypothyroidism.
Category: Class III Potassium Blockers
Question 11
Besides diltiazem, the other nondihydropyridine calcium channel blocker used as a class IV antidysrhythmic is verapamil.
Missing Word
verapamil
Verapamil and diltiazem are the two class IV drugs. Both slow the heart rate and AV node conduction, unlike dihydropyridines, which act mainly on arteries.
Category: Class IV Calcium Blockers
Question 12
Diltiazem is contraindicated in a client with hypotension, a blood pressure that is already abnormally low.
Missing Word
hypotension
Hypotension is abnormally low blood pressure. Diltiazem dilates blood vessels and slows the heart, which can lower blood pressure further, so heart rate and blood pressure are checked before each dose and the drug is avoided when the pressure is already low.
Category: Class IV Calcium Blockers
Question 13
Within seconds of an adenosine bolus, the client may have flushing, a sudden warm redness of the face.
Missing Word
flushing
Flushing is a brief, warm reddening of the skin. It is one of the immediate effects of adenosine, along with sweating, dyspnea and a sense of impending doom, and it fades quickly because the drug is cleared within seconds.
Category: Unclassified Antidysrhythmics
Question 14
Right after giving adenosine as a rapid IV bolus, the nurse pushes a rapid flush of normal saline.
Missing Word
saline
Normal saline is used to flush adenosine into the circulation immediately. Adenosine has a half-life of seconds, so a rapid flush is needed for the drug to reach the heart.
Category: Unclassified Antidysrhythmics
Question 15
Clients taking a class III drug seek emergency care for palpitations or syncope, the medical term for fainting, because either can signal torsade de pointes.
Missing Word
syncope
Syncope is a brief loss of consciousness from reduced blood flow to the brain. Class III drugs prolong the QT interval, and torsade de pointes can cause dizziness, palpitations or syncope, so clients are taught to get emergency help for these symptoms.
Category: Class III Potassium Blockers