EKG Strip Quiz
Questions: 16 · 10 minutes
1. A patient develops sudden palpitations. The tracing shows a regular narrow-complex rhythm at 180 beats per minute, and P waves are not clearly visible. Which interpretation best fits?
Sinus bradycardia
Supraventricular tachycardia
Idioventricular rhythm
Atrial fibrillation
2. During an otherwise regular sinus rhythm, one beat occurs early, has a wide and unusual QRS complex, and has no clearly preceding P wave. What does this beat most likely represent?
A premature ventricular contraction
A blocked sinus beat
A premature atrial contraction
A junctional escape beat
3. Which rhythm is classically associated with repeating sawtooth-like atrial waves, often with a fixed or variable conduction ratio?
First-degree AV block
Ventricular fibrillation
Sinus arrhythmia
Atrial flutter
4. Every P wave is followed by a QRS complex, but the PR interval is consistently 0.24 seconds. Which conduction pattern is present?
Second-degree AV block type II
First-degree AV block
Third-degree AV block
Atrial fibrillation
5. A tracing shows regular P waves with occasional nonconducted P waves. For the conducted beats, the PR interval stays constant rather than lengthening. Which pattern best fits?
Second-degree AV block type II
First-degree AV block
Second-degree AV block type I
Sinus arrhythmia
6. The PR interval becomes progressively longer over several beats until a P wave is not followed by a QRS complex. The pattern then repeats. What is this?
First-degree AV block
Second-degree AV block type II
Complete heart block
Second-degree AV block type I, or Wenckebach
7. A tracing shows a regular rate of 72 beats per minute, one upright P wave before every QRS, a constant normal PR interval, and narrow QRS complexes. Which rhythm best fits?
Sinus arrest
Atrial fibrillation
Normal sinus rhythm
Junctional rhythm
8. At the standard paper speed of 25 mm/second, which PR interval is generally considered normal in an adult?
0.22-0.30 seconds
0.06-0.10 seconds
0.12-0.20 seconds
Less than 0.06 seconds
9. P waves and QRS complexes occur regularly but at different rates, with no consistent relationship between them. Which rhythm does this describe?
Third-degree AV block
First-degree AV block
Sinus rhythm with premature atrial contractions
Atrial flutter with fixed conduction
10. A patient’s tracing has an irregularly irregular ventricular rhythm, no consistent distinct P waves, and narrow QRS complexes. What is the most likely rhythm?
Sinus tachycardia
Second-degree AV block type I
Atrial flutter with fixed 2:1 conduction
Atrial fibrillation
11. A markedly prolonged QT interval is most closely associated with increased susceptibility to which rhythm?
Atrial fibrillation
Atrial flutter
Torsades de pointes
First-degree AV block
12. An adult with a previous myocardial infarction has a regular rhythm at 160 beats per minute with three or more consecutive wide QRS complexes and no clear preceding P waves. What is the most concerning interpretation?
Ventricular tachycardia
Accelerated idioventricular rhythm
Atrial flutter with 2:1 conduction
Sinus tachycardia with normal ventricular conduction
13. Which method is most appropriate for estimating the ventricular rate of a clearly irregular rhythm on a six-second strip?
Divide 300 by the number of large boxes between one pair of R waves
Count the QRS complexes in six seconds and multiply by 10
Divide 1,500 by the number of small boxes between one pair of R waves
Count the P waves in six seconds and multiply by 10
14. A regular rhythm has four large boxes between consecutive R waves. What is the approximate heart rate?
60 beats per minute
100 beats per minute
75 beats per minute
150 beats per minute
15. A monitor suddenly displays a chaotic-looking waveform, but the patient is awake, speaking normally, and has a stable palpable pulse. What is the best initial response?
Label the rhythm ventricular fibrillation based only on the monitor
Assume the patient’s pulse assessment must be incorrect
Increase the monitor gain until regular complexes appear
Assess the patient and verify electrodes and connections before identifying the rhythm
16. A patient with acute chest pressure has new ST-segment elevation in contiguous, anatomically related leads. How should this finding be regarded?
As proof of an old, fully healed myocardial infarction
As possible acute myocardial injury requiring urgent clinical evaluation
As a finding that identifies first-degree AV block
As a normal consequence of a slow heart rate