ECG Pharmacology and Cardiac Medications Flashcards

Which ECG change is most commonly associated with digoxin toxicity?

Answer: Prolonged PR interval and ST scooping

Digoxin toxicity characteristically causes a prolonged PR interval and a 'scooped' or sagging ST segment depression.

A patient taking amiodarone is most likely to show which ECG finding?

Answer: Prolonged QT interval

Amiodarone prolongs ventricular repolarization, resulting in a prolonged QT interval on the ECG.

Which class of antiarrhythmic drugs primarily works by blocking sodium channels and may widen the QRS complex?

Answer: Class I

Class I antiarrhythmics (e.g., lidocaine, flecainide) block sodium channels, slowing depolarization and widening the QRS complex.

A patient receiving IV adenosine for SVT would most likely show which transient ECG finding immediately after the dose?

Answer: Complete heart block or brief asystole

Adenosine transiently blocks AV node conduction, often producing a brief period of complete heart block or asystole before normal rhythm resumes.

Hyperkalemia caused by potassium-sparing diuretics (e.g., spironolactone) would first appear on the ECG as:

Answer: Peaked, narrow T waves

The earliest ECG manifestation of hyperkalemia is tall, peaked (tented) T waves due to altered ventricular repolarization.

Which beta-blocker effect on the ECG helps an ECG technician recognize its therapeutic use?

Answer: Prolonged PR interval and slower heart rate

Beta-blockers slow AV node conduction, producing a prolonged PR interval, and reduce heart rate by decreasing SA node automaticity.

A patient on a calcium channel blocker (e.g., verapamil) is expected to show which ECG change?

Answer: Prolonged PR interval

Calcium channel blockers slow conduction through the AV node, prolonging the PR interval on the ECG.