Relias Dysrhythmia Basic A Exam – 250 Practice Questions with ECG Strips, Answers & Rationales

Relias Dysrhythmia Basic A Exam – 250
Practice Questions with ECG Strips, Answers
& Rationales

NEW SET – Questions 1 to 50 (Better ECG Art & Clearer
Figures)

Legend for all strips:
| = 1 small box (0.04 sec)
P = P wave, QRS = QRS complex, T = T wave
_ = flat baseline
^ = pacemaker spike
~ = fibrillatory wave
/\/\/\ = flutter wave
[ ] = abnormal/widened complex
Numbers below = seconds (each | = 0.04s, 25 boxes = 1 sec)




Question 1

6-second strip (150 small boxes):
| | | | P | QRS | T | | | P | QRS | T | | | P | QRS | T | | | P | QRS | T | |

(12 QRS complexes in 6 sec → rate 120 bpm)
Description: Regular rhythm, rate 120. Normal P before each QRS, PR 0.16, QRS 0.08.
Choices:
A) Sinus bradycardia
B) Normal sinus rhythm
C) Sinus tachycardia
D) Atrial flutter
Correct Answer: C) Sinus tachycardia – Rate 120 (>100), sinus origin.

,Question 2

6-second strip:
| | | | | P | QRS | T | | | | | P | QRS | T | | | | | P | QRS | T | |

(6 QRS in 6 sec → rate 60 bpm)
Description: Regular, rate 60. Normal P, PR 0.16, QRS 0.08.
Choices:
A) Normal sinus rhythm
B) Sinus bradycardia
C) Junctional rhythm
D) First-degree AV block
Correct Answer: A) Normal sinus rhythm – Rate 60-100, normal intervals.




Question 3

6-second strip:
| | | | | | P | QRS | T | | | | | | P | QRS | T | | | | | | P | QRS | T |

(5 QRS in 6 sec → rate 50 bpm)
Description: Regular, rate 50. Normal P, PR 0.18.
Choices:
A) Sinus tachycardia
B) Sinus bradycardia
C) Junctional bradycardia
D) 2nd degree block
Correct Answer: B) Sinus bradycardia – Rate <60, normal P waves.




Question 4

,6-second strip:
| P | QRS | T | P | QRS | T | P | ____ | P | QRS | T | (one dropped QRS)
Description: Irregular. PR interval progressively lengthens (0.16 → 0.20 → 0.24) then
a QRS is dropped.
Choices:
A) First-degree AV block
B) 2nd degree type I (Wenckebach)
C) 2nd degree type II
D) 3rd degree AV block
Correct Answer: B) 2nd degree type I (Wenckebach) – Progressive PR
lengthening then dropped beat.




Question 5

6-second strip:
| P | QRS | T | P | QRS | T | P | ____ | P | QRS | T | P | QRS |

Description: PR interval constant at 0.18, but a QRS is dropped suddenly without
warning.
Choices:
A) Wenckebach
B) 2nd degree type II
C) 3rd degree
D) First-degree
Correct Answer: B) 2nd degree type II – Fixed PR, dropped QRS.




Question 6

6-second strip:
| P | ____ | P | ____ | P | ____ | QRS | ____ | P | ____ | P | ____ | (P's regular,

, QRS slow)
Description: Atrial rate 100, ventricular rate 40. No relationship between P and QRS.
Choices:
A) 2nd degree type I
B) 2nd degree type II
C) 3rd degree AV block
D) Junctional rhythm
Correct Answer: C) 3rd degree AV block – Complete AV dissociation.




Question 7

6-second strip:
| | | ~ | QRS | ~ | | | ~ | QRS | ~ | | | ~ | QRS | ~ | | |

(irregularly irregular, no P waves)
Description: Irregularly irregular, rate 90. No discernible P waves, chaotic baseline.
Choices:
A) Atrial flutter
B) Atrial fibrillation
C) MAT
D) Sinus arrhythmia
Correct Answer: B) Atrial fibrillation – Irregularly irregular, no P waves.




Question 8

6-second strip:
| /\/\/\ | QRS | /\/\/\ | QRS | /\/\/\ | /\/\/\ | QRS | (sawtooth)
Description: Regular sawtooth flutter waves at 300 bpm, ventricular rate 75 (4:1
block).
Choices: