EKG Quiz
Questions: 16 · 10 minutes
1. A patient has a narrow-complex rhythm with unpredictable R-R intervals and no distinct, consistently repeating P waves. Which rhythm is most likely?
Sinus arrhythmia
Atrial flutter with fixed conduction
Atrial fibrillation
Monomorphic ventricular tachycardia
2. P waves and QRS complexes occur regularly but independently, with no consistent PR relationship and a slow ventricular escape rhythm. What is the best interpretation?
Third-degree AV block
First-degree AV block
Mobitz I second-degree AV block
Sinus rhythm with premature atrial contractions
3. An early beat has a wide, unusual QRS complex, no clearly preceding P wave, and is followed by a compensatory pause. What is the most likely explanation?
Premature ventricular contraction
Sinus pause
Premature junctional contraction
Premature atrial contraction
4. A person with pressure-like chest pain has new ST-segment elevation in anatomically contiguous leads. What should this pattern raise immediate concern for?
Hypokalemia without myocardial ischemia
Isolated first-degree AV block
A benign respiratory variation in sinus rate
Acute myocardial injury from a possible coronary occlusion requiring emergency evaluation
5. An adult's QRS duration is measured at 0.14 second. What does this most directly indicate?
Delayed conduction from the sinoatrial node to the atria
An abnormally shortened period of ventricular repolarization
Delayed or abnormal ventricular depolarization
A normal variation in atrioventricular nodal conduction
6. What does the PR interval primarily represent?
Ventricular depolarization and repolarization
Conduction through the ventricles only
The period from the end of ventricular depolarization to the end of repolarization
Conduction from the beginning of atrial depolarization to the beginning of ventricular depolarization
7. A pacing spike appears immediately before every wide QRS complex, and each spike is consistently followed by a QRS. What does this show?
Atrial pacing without capture
Successful ventricular pacing with capture
Failure of the pacemaker to capture the ventricles
Pacemaker undersensing
8. A regular rhythm has four large boxes between consecutive R waves at a paper speed of 25 mm/second. Using the 300 method, what is the approximate heart rate?
50 beats per minute
60 beats per minute
100 beats per minute
75 beats per minute
9. A tracing shows a regular rate of 72 beats per minute, one consistent P wave before every narrow QRS complex, and a stable PR interval of 0.16 second. Which rhythm best fits?
Atrial fibrillation
Normal sinus rhythm
Junctional rhythm
Second-degree AV block
10. A tracing contains continuous sawtooth-like atrial activity near 300 per minute and a regular ventricular response near 150 per minute. What is the best interpretation?
Sinus tachycardia with first-degree AV block
Atrial flutter with approximately 2:1 AV conduction
Atrial fibrillation with a rapid ventricular response
Supraventricular tachycardia without visible atrial activity
11. The PR interval becomes progressively longer with each beat until one P wave is not followed by a QRS complex. Which conduction disturbance is present?
Mobitz I second-degree AV block
Mobitz II second-degree AV block
Third-degree AV block
Right bundle branch block
12. An EKG reports a corrected QT interval of 520 milliseconds. Which arrhythmia is particularly associated with a markedly prolonged QT interval?
Atrial flutter
AV nodal reentrant tachycardia
Sinus bradycardia with respiratory variation
Torsades de pointes
13. A tracing has stable PR intervals in conducted beats, but some P waves are suddenly not followed by QRS complexes. Which finding best fits?
First-degree AV block
Mobitz I second-degree AV block
Mobitz II second-degree AV block
Sinus arrhythmia
14. A patient with kidney failure has tall, narrow, peaked T waves followed by progressive QRS widening. Which electrolyte disturbance is the leading concern?
Hypocalcemia
Hyperkalemia
Hypokalemia
Hypermagnesemia
15. At the standard paper speed of 25 mm/second, how much time does one small horizontal EKG box represent?
0.20 second
0.10 second
0.04 second
0.40 second
16. During exertion, a patient develops chest discomfort accompanied by horizontal ST-segment depression that resolves with rest. Which process is most consistent with this finding?
Myocardial ischemia
Benign early repolarization
Complete AV block
Acute hyperkalemia