Practice Test Geeks(CET) Certified Electrocardiogram Technician Practice Test
← All CET Flashcard Decks

Cardiac Pharmacology Effects on ECG Flashcards

7 cards from real CET practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Cardiac Pharmacology Effects on ECG flashcards as text

  1. A patient receiving IV heparin for pulmonary embolism shows right heart strain pattern on ECG (S1Q3T3). This ECG pattern is caused by:

    Answer: Acute right ventricular pressure overload from the PE, not heparin

    The S1Q3T3 pattern reflects acute right ventricular strain from pulmonary embolism; heparin treats the PE but does not directly cause or reverse ECG changes immediately.

  2. Tricyclic antidepressant (TCA) overdose characteristically produces which ECG pattern?

    Answer: Widened QRS > 100 ms with rightward terminal axis deviation

    TCAs block fast sodium channels, causing QRS widening (>100 ms) and rightward axis deviation (R wave in aVR >3 mm) — key markers of severe TCA toxicity.

  3. Dofetilide's ECG monitoring requirement focuses primarily on which measurement?

    Answer: QTc interval before each dose

    Dofetilide requires mandatory in-hospital QTc monitoring before each of the first 5-6 doses due to its potent QT-prolonging effect and Torsades risk.

  4. Atropine reverses symptomatic bradycardia by:

    Answer: Antagonizing muscarinic receptors to increase SA node firing rate

    Atropine blocks muscarinic (vagal) receptors at the SA and AV nodes, removing parasympathetic inhibition and increasing heart rate.

  5. A patient on phenytoin (an antiseizure drug with Class IB properties) overdoses. Which ECG finding is most expected?

    Answer: PR prolongation and widened QRS

    Phenytoin toxicity causes sodium channel blockade similar to Class IB drugs, slowing AV conduction (prolonged PR) and intraventricular conduction (wide QRS).

  6. Which electrolyte abnormality caused by loop diuretics can indirectly produce QT prolongation and U waves on ECG?

    Answer: Hypokalemia

    Loop diuretics cause potassium wasting; hypokalemia prolongs repolarization, manifesting as QT prolongation, flattened T waves, and prominent U waves on ECG.

  7. Epinephrine administered during cardiac arrest (ACLS) is expected to produce which ECG response if effective?

    Answer: Increased amplitude of fibrillatory waveforms making defibrillation more likely to succeed

    Epinephrine increases coronary perfusion pressure and can increase the amplitude/coarseness of VF waveforms, improving the likelihood of successful defibrillation.