CMT Cardiac Dysrhythmias and Arrhythmias 2 — Questions and Answers
Question 1: Which arrhythmia is characterized by a sawtooth flutter wave pattern at a rate of 250-350 bpm?
- Atrial fibrillation
- Atrial flutter (Correct answer)
- Supraventricular tachycardia
- Multifocal atrial tachycardia
Correct answer: Atrial flutter
Atrial flutter produces a characteristic sawtooth flutter wave pattern (F waves) at 250-350 bpm, best seen in leads II, III, and aVF.
Question 2: A patient's ECG shows no discernible P waves, an irregularly irregular rhythm, and a ventricular rate of 110 bpm. What is the most likely diagnosis?
- Atrial flutter with variable block
- Ventricular tachycardia
- Atrial fibrillation (Correct answer)
- Junctional tachycardia
Correct answer: Atrial fibrillation
Atrial fibrillation is characterized by the absence of distinct P waves, a chaotic baseline, and an irregularly irregular ventricular response.
Question 3: What is the typical ventricular rate in untreated atrial flutter with 2:1 conduction?
- 75-100 bpm
- 125-175 bpm
- 150 bpm (Correct answer)
- 300 bpm
Correct answer: 150 bpm
With an atrial rate of 300 bpm and 2:1 AV conduction, exactly half the atrial impulses conduct, yielding a ventricular rate of approximately 150 bpm.
Question 4: Which arrhythmia is most commonly associated with Wolff-Parkinson-White (WPW) syndrome?
- Atrial fibrillation
- Atrioventricular reentrant tachycardia (AVRT) (Correct answer)
- Ventricular flutter
- Complete heart block
Correct answer: Atrioventricular reentrant tachycardia (AVRT)
WPW syndrome involves an accessory pathway that creates a reentrant circuit, most commonly manifesting as AVRT.
Question 5: On a rhythm strip, premature beats with wide, bizarre QRS complexes and a fully compensatory pause are characteristic of:
- Premature atrial contractions
- Premature junctional contractions
- Premature ventricular contractions (Correct answer)
- Aberrantly conducted supraventricular beats
Correct answer: Premature ventricular contractions
PVCs arise from ventricular foci, producing wide and bizarre QRS complexes (>0.12 sec) followed by a fully compensatory pause.
Question 6: A rhythm showing P waves that change morphology and PR intervals that vary, with a rate between 60-100 bpm, is called:
- Multifocal atrial tachycardia
- Wandering atrial pacemaker (Correct answer)
- Sick sinus syndrome
- First-degree AV block
Correct answer: Wandering atrial pacemaker
Wandering atrial pacemaker is identified by at least three different P-wave morphologies with varying PR intervals at a normal heart rate.
Question 7: Which of the following best describes Mobitz Type I (Wenckebach) second-degree AV block?
- Constant PR interval with occasional dropped QRS
- Progressively lengthening PR interval until a QRS is dropped (Correct answer)
- Alternating conducted and non-conducted P waves
- Complete dissociation of P waves and QRS complexes
Correct answer: Progressively lengthening PR interval until a QRS is dropped
Mobitz Type I shows progressive PR interval lengthening with each beat until one P wave is not conducted and the cycle repeats.
CMT Cardiac Dysrhythmias and Arrhythmias 2
Which arrhythmia is characterized by a sawtooth flutter wave pattern at a rate of 250-350 bpm?