ECG ECG Pharmacology and Cardiac Medications 2

Question 1

Hypokalemia from loop diuretic use (e.g., furosemide) produces which characteristic ECG change?

Accepted Answer

Flat or inverted T waves and prominent U waves

Answer

Hypokalemia flattens or inverts the T wave and causes prominent U waves (deflection after the T wave) due to delayed ventricular repolarization.

Question 2

A patient receiving IV procainamide (Class IA) for ventricular arrhythmia may develop which dangerous ECG pattern?

Accepted Answer

QRS widening greater than 50% of baseline

Answer

Procainamide can widen the QRS by more than 50% of the baseline width, signaling toxicity and increased risk of proarrhythmia.

Question 3

Which ECG finding would suggest a patient has received too much atropine?

Accepted Answer

Sinus tachycardia with shortened PR interval

Answer

Atropine blocks muscarinic receptors, increasing SA node automaticity and speeding AV conduction, resulting in sinus tachycardia with a shortened PR interval.

Question 4

Tricyclic antidepressant (TCA) overdose is classically recognized on the ECG by:

Accepted Answer

Widened QRS, right axis deviation, and prolonged QT

Answer

TCA overdose causes sodium channel blockade (widened QRS), potassium channel blockade (prolonged QT), and rightward axis shift, which is a life-threatening combination.

Question 5

Heparin and warfarin are anticoagulants that do NOT directly alter the ECG. Which ECG change may appear indirectly if anticoagulation reverses a pulmonary embolism?

Accepted Answer

Resolution of the S1Q3T3 pattern

Answer

A pulmonary embolism can produce the S1Q3T3 pattern; successful anticoagulation and clot resolution can lead to normalization and disappearance of this pattern.

ECG (Electrocardiogram) Practice Test

ECG (Electrocardiogram) Practice Test

ECG ECG Pharmacology and Cardiac Medications 2