BCEN Cardiac Emergencies 3 — Questions and Answers
Question 1: A patient presents with palpitations and the ECG shows a narrow-complex tachycardia at 160 bpm with no visible P waves. Vagal maneuvers are ineffective. What is the next treatment?
- Amiodarone 150 mg IV over 10 minutes
- Adenosine 6 mg rapid IV push (Correct answer)
- Diltiazem 0.25 mg/kg IV
- Synchronized cardioversion at 50 J
Correct answer: Adenosine 6 mg rapid IV push
For stable SVT unresponsive to vagal maneuvers, adenosine 6 mg IV rapid push is the first pharmacological treatment per ACLS.
Question 2: Which ECG finding is most consistent with right ventricular infarction complicating an inferior STEMI?
- ST elevation in V1-V4
- ST elevation in right-sided lead V4R (Correct answer)
- New left bundle branch block
- ST depression in leads I and aVL
Correct answer: ST elevation in right-sided lead V4R
ST elevation in right-sided lead V4R is the most sensitive and specific indicator of right ventricular infarction.
Question 3: A patient with inferior STEMI and RV infarction develops hypotension. Which intervention is contraindicated?
- Normal saline 500 mL IV bolus
- Norepinephrine infusion
- Dopamine infusion
- Nitroglycerin administration (Correct answer)
Correct answer: Nitroglycerin administration
Nitroglycerin is contraindicated in RV infarction because the RV is preload-dependent, and reducing venous return can precipitate severe hypotension.
Question 4: Torsades de pointes is most commonly associated with which electrolyte abnormality?
- Hypernatremia
- Hypomagnesemia (Correct answer)
- Hyperkalemia
- Hypercalcemia
Correct answer: Hypomagnesemia
Hypomagnesemia is the most common electrolyte cause of Torsades de pointes, and IV magnesium sulfate is the treatment of choice.
Question 5: A patient with a history of Wolff-Parkinson-White (WPW) syndrome develops atrial fibrillation with a rapid ventricular response. Which drug is contraindicated?
- Procainamide
- Ibutilide
- Amiodarone
- Diltiazem (Correct answer)
Correct answer: Diltiazem
AV nodal blocking agents like diltiazem, verapamil, digoxin, and adenosine are contraindicated in WPW with AF as they can accelerate conduction through the accessory pathway.
Question 6: A patient presents 2 hours after cocaine use with chest pain and diaphoresis. ECG shows ST elevation in V1-V4. Which medication should be avoided?
- Aspirin
- Nitroglycerin
- Non-selective beta-blockers (Correct answer)
- Morphine
Correct answer: Non-selective beta-blockers
Non-selective beta-blockers are contraindicated in cocaine-induced coronary spasm because they can cause unopposed alpha-adrenergic stimulation, worsening vasospasm.
Question 7: Which finding on a 12-lead ECG indicates posterior MI?
- ST elevation in V5-V6
- ST elevation in leads I, aVL, and V6
- Tall R waves and ST depression in V1-V2 (Correct answer)
- ST elevation in leads II, III, and aVF
Correct answer: Tall R waves and ST depression in V1-V2
Posterior MI presents as a mirror image on standard leads, showing tall R waves, ST depression, and upright T waves in V1-V2, which represents posterior ST elevation when viewed from the back.
BCEN Cardiac Emergencies 3
A patient presents with palpitations and the ECG shows a narrow-complex tachycardia at 160 bpm with no visible P waves.
Vagal maneuvers are ineffective.
What is the next treatment?