Cardiac Rhythm Interpretation and Management Flashcards
7 cards from real CCRN 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 and Management flashcards as text
An ICU patient's monitor shows a regular rhythm at 150 bpm with narrow QRS complexes and a classic sawtooth baseline pattern. What is the most likely rhythm?
Answer: Atrial flutter with 2:1 block
Atrial flutter typically fires at 300 bpm; with 2:1 block the ventricular rate is 150 bpm, and the sawtooth (flutter) waves are the hallmark finding.
Which ECG change is the earliest indicator of hyperkalemia in a critically ill patient?
Answer: Peaked (tall, narrow) T waves
Peaked T waves are the earliest ECG manifestation of hyperkalemia, appearing before PR prolongation, QRS widening, or the sine wave pattern seen in severe cases.
Which ECG characteristic definitively identifies a third-degree (complete) AV block?
Answer: Completely independent atrial and ventricular rates with no relationship
In complete heart block, the atria and ventricles fire independently because no impulses conduct through the AV node, producing dissociated P waves and QRS complexes.
A normal PR interval on a standard ECG measures:
Answer: 0.12–0.20 seconds
The normal PR interval ranges from 0.12 to 0.20 seconds (3–5 small boxes); values above 0.20 indicate first-degree AV block.
A patient's rhythm strip shows an irregularly irregular ventricular response, absent distinct P waves, and an estimated atrial activity rate of 400–600 bpm. What is this rhythm?
Answer: Atrial fibrillation
Atrial fibrillation is characterized by chaotic atrial activity at 400–600 bpm, absent organized P waves, and an irregularly irregular ventricular response.
What is the normal range for QRS complex duration in an adult?
Answer: 0.06–0.12 seconds
A normal QRS duration is 0.06–0.12 seconds; a QRS wider than 0.12 seconds indicates intraventricular conduction delay such as bundle branch block or ventricular origin.
Which ECG finding most strongly differentiates ventricular tachycardia from supraventricular tachycardia with aberrant conduction?
Answer: AV dissociation visible on the rhythm strip
AV dissociation — independent P waves unrelated to QRS complexes — is pathognomonic for ventricular tachycardia and cannot occur with SVT.