Cardiac Rhythm Recognition & Interpretation Flashcards
7 cards from real ECC 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 Recognition & Interpretation flashcards as text
In complete (third-degree) heart block, what is the relationship between P waves and QRS complexes?
Answer: P waves and QRS complexes occur completely independently with no fixed relationship
Complete heart block (third-degree AV block) features total AV dissociation — the atria and ventricles are controlled by separate independent pacemakers.
Which combination of ECG findings is pathognomonic for Wolff-Parkinson-White (WPW) syndrome?
Answer: Short PR interval (< 0.12 s) with a delta wave
WPW syndrome is defined by a short PR interval and a delta wave (slurred QRS upstroke) caused by ventricular pre-excitation via an accessory bypass tract.
An ECG shows a regular rhythm with sawtooth-shaped negative deflections at 300 bpm and a ventricular rate of 150 bpm. What is the most likely rhythm?
Answer: Atrial flutter with 2:1 AV conduction
Atrial flutter produces regular sawtooth flutter waves at approximately 300 bpm; with 2:1 AV conduction, the ventricular rate is 150 bpm.
Which ECG change is most characteristic of hyperkalemia in an emergency setting?
Answer: Peaked (tall, narrow) T waves with progressive QRS widening
Hyperkalemia first produces peaked T waves (tall, narrow, symmetric), and as levels rise further the QRS widens, which can progress to a sine-wave pattern and cardiac arrest.
Pulseless electrical activity (PEA) is best described as which of the following?
Answer: Organized electrical activity on ECG with no palpable pulse
PEA is defined as any organized cardiac rhythm on ECG without a palpable pulse, indicating mechanical failure despite preserved electrical activity.
In a wide-complex regular tachycardia, which ECG feature most strongly suggests ventricular tachycardia over SVT with aberrancy?
Answer: AV dissociation (independent P waves and QRS complexes)
AV dissociation — independent atrial and ventricular activity — is the most specific ECG criterion for ventricular tachycardia in a wide-complex tachycardia.
A new left bundle branch block (LBBB) in a patient presenting with ischemic chest pain should be managed how?
Answer: Treated as a STEMI equivalent requiring emergent reperfusion evaluation
New or presumed new LBBB in the setting of ischemic symptoms is a STEMI equivalent per ACC/AHA guidelines and warrants emergent coronary reperfusion therapy.