Cardiac Rhythm Interpretation & ECG Analysis Flashcards
7 cards from real CCS 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 Rhythm Interpretation & ECG Analysis flashcards as text
What is the normal PR interval on a standard 12-lead ECG?
Answer: 0.12–0.20 seconds
The normal PR interval is 0.12–0.20 seconds, representing the time for an impulse to travel from the SA node through the AV node to the ventricles.
Which ECG finding is characteristic of first-degree AV block?
Answer: Consistently prolonged PR interval greater than 0.20 seconds with all P waves conducted
First-degree AV block is defined by a PR interval consistently >0.20 seconds, with every P wave still successfully conducted to the ventricles.
What heart rate range defines sinus bradycardia in an adult?
Answer: Less than 60 bpm
Sinus bradycardia is defined as a sinus rhythm with a heart rate less than 60 beats per minute originating from the SA node.
On a standard ECG, what physiologic event does the QRS complex represent?
Answer: Ventricular depolarization
The QRS complex represents ventricular depolarization, which triggers the mechanical contraction of both ventricles.
What is the normal QRS duration on an ECG?
Answer: 0.06–0.10 seconds
Normal QRS duration is 0.06–0.10 seconds (60–100 ms); a duration ≥0.12 seconds suggests a bundle branch block or ventricular origin.
Which rhythm is characterized by an irregularly irregular ventricular response with no discernible P waves?
Answer: Atrial fibrillation
Atrial fibrillation presents with an irregularly irregular ventricular rhythm and absent or chaotic P waves due to disorganized atrial electrical activity.
What does the T wave on a surface ECG represent?
Answer: Ventricular repolarization
The T wave represents ventricular repolarization, the electrical recovery phase of the ventricles in preparation for the next contraction.