CVT CVT Pharmacology & Cardiac Medications 2 — Questions and Answers
Question 1: Which medication is used to pharmacologically stress the heart during a nuclear stress test in patients who cannot exercise?
- Dobutamine or regadenoson (Correct answer)
- Nitroglycerin
- Metoprolol
- Atropine alone
Correct answer: Dobutamine or regadenoson
Pharmacologic stress agents such as regadenoson (vasodilator) or dobutamine (inotrope) are used to mimic exercise-induced coronary flow changes in non-exercising patients.
Question 2: Amiodarone is classified as which type of antiarrhythmic drug?
- Class I
- Class II
- Class III (Correct answer)
- Class IV
Correct answer: Class III
Amiodarone is a Class III antiarrhythmic that primarily blocks potassium channels, prolonging the action potential duration and effective refractory period.
Question 3: Which medication is the first-line treatment for ventricular fibrillation refractory to defibrillation?
- Lidocaine
- Amiodarone (Correct answer)
- Atropine
- Adenosine
Correct answer: Amiodarone
Current ACLS guidelines recommend IV amiodarone as the first-line antiarrhythmic for shock-refractory ventricular fibrillation.
Question 4: Atropine increases heart rate by:
- Stimulating beta-1 adrenergic receptors
- Blocking muscarinic acetylcholine receptors (Correct answer)
- Inhibiting the sinoatrial node
- Increasing vagal tone
Correct answer: Blocking muscarinic acetylcholine receptors
Atropine is an anticholinergic agent that blocks vagal (muscarinic) influence on the SA node, allowing intrinsic automaticity to increase heart rate.
Question 5: Which diuretic is most commonly used in heart failure management and acts primarily on the loop of Henle?
- Hydrochlorothiazide
- Spironolactone
- Furosemide (Correct answer)
- Acetazolamide
Correct answer: Furosemide
Furosemide (Lasix) is a loop diuretic that inhibits the Na-K-2Cl cotransporter in the ascending loop of Henle, producing potent diuresis to reduce volume overload.
Question 6: Heparin-induced thrombocytopenia (HIT) is a serious complication characterized by:
- Bleeding due to platelet destruction
- Paradoxical thrombosis despite low platelet count (Correct answer)
- Allergic rash without thrombosis risk
- Anemia from red cell destruction
Correct answer: Paradoxical thrombosis despite low platelet count
HIT is an immune-mediated reaction where antibodies against heparin-PF4 complexes activate platelets, causing thrombocytopenia and a paradoxical hypercoagulable, prothrombotic state.
CVT CVT Pharmacology & Cardiac Medications 2
Which medication is used to pharmacologically stress the heart during a nuclear stress test in patients who cannot exercise?