Heart Rate and Rhythm: A Comprehensive Guide for Medical Assistants

Question 1

An EKG strip displays a consistent pattern of P waves before QRS complexes, with each P wave followed by a QRS complex and T wave. Which rhythm is most likely present?

Accepted Answer

Normal sinus rhythm

Answer

Atrial flutter

Answer

Ventricular tachycardia

Answer

Bradycardia

Question 2

To determine the heart rate using an EKG, you should measure the interval between which two consecutive events occur?

Accepted Answer

QRS complexes

Answer

P waves

Answer

T waves

Answer

PR segments

Question 3

Identify the EKG rhythm characterized by consistent, narrow QRS complexes occurring at a rate of 60-100 beats per minute (bpm).

Accepted Answer

Sinus rhythm

Answer

Atrial flutter

Answer

Ventricular tachycardia

Answer

Atrioventricular block

Question 4

Which of the following EKG rhythms exhibits irregular, wide QRS complexes with varying rates?

Accepted Answer

Ventricular tachycardia

Answer

Atrial fibrillation

Answer

Premature ventricular contractions

Answer

Supraventricular tachycardia

Question 5

Identify the EKG rhythm characterized by regular, narrow QRS complexes occurring at a rate of 30 bpm.

Accepted Answer

Sinus bradycardia

Answer

Atrial fibrillation

Answer

Ventricular tachycardia

Answer

Junctional escape rhythm

Question 6

An ECG rhythm strip shows a regular pattern of repeating waveforms with a heart rate of 120 beats per minute and clear P-QRS-T complexes. Which rhythm is this most likely to be?

Accepted Answer

Normal sinus rhythm

Answer

Ventricular tachycardia

Answer

Atrial fibrillation

Answer

Bradycardia

Question 7

On an EKG, which interval measures the time from the start of one QRS complex to the start of the next?

Accepted Answer

RR interval

Answer

PR interval

Answer

QT interval

Answer

ST segment

Question 8

Which of the following is the hallmark feature of third-degree heart block on an EKG?

Accepted Answer

P waves are absent or unrelated to QRS complexes

Answer

PR interval progressively lengthens

Answer

QRS duration is greater than 0.12 seconds

Answer

T waves are inverted

Question 9

Which arrhythmia involves rapid, irregular atrial depolarizations?

Accepted Answer

Atrial flutter

Answer

Ventricular tachycardia

Answer

Supraventricular tachycardia

Answer

Pulseless electrical activity

Question 10

On an EKG, what does a QT interval longer than 0.44 seconds potentially indicate?

Accepted Answer

Increased risk of torsades de pointes

Answer

Slow heart rate

Answer

Normal finding

Answer

Conduction defect

Question 11

Which heart sound corresponds to the closure of the atrioventricular valves?

Accepted Answer

S2

Answer

S1

Answer

S3

Answer

S4

Question 12

Which heart rhythm is defined by irregular atrial activity and a ventricular rate usually between 100 and 150 beats per minute (bpm)?

Accepted Answer

Atrial fibrillation

Answer

Sinus tachycardia

Answer

Ventricular tachycardia

Answer

Bradycardia

Question 13

The normal heart rate for an adult at rest is approximately:

Accepted Answer

60-80 bpm

Answer

50-60 beats per minute (bpm)

Answer

80-100 bpm

Answer

100-120 bpm

Question 14

Which of the following is the electrical impulse that initiates each heartbeat?

Accepted Answer

P wave

Answer

QRS complex

Answer

T wave

Answer

U wave

Question 15

What is the term for a heart rate greater than 100 bpm?

Accepted Answer

Tachycardia

Answer

Bradycardia

Answer

Arrhythmia

Answer

Asystole

Question 16

Which of the following arrhythmias is characterized by an irregular, chaotic heart rhythm?

Accepted Answer

Atrial fibrillation

Answer

Sinus tachycardia

Answer

Ventricular tachycardia

Answer

Premature ventricular contractions (PVCs)

Question 17

What is the primary method used to calculate heart rate from an EKG?

Accepted Answer

Measuring the distance between QRS complexes

Answer

Measuring the distance between P waves

Answer

Counting the number of T waves in a minute

Answer

Counting the number of U waves in a minute

Question 18

Which of the following is NOT a typical characteristic of normal sinus rhythm?

Accepted Answer

Inverted T waves

Answer

P waves preceding each QRS complex

Answer

Regular R-R intervals

Answer

Heart rate between 60-100 bpm

Question 19

What is the name of the EKG lead that is placed on the left leg?

Accepted Answer

Lead III

Answer

Lead I

Answer

Lead II

Answer

Lead aVL

Question 20

Which of the following is a sign of premature ventricular contractions (PVCs)?

Accepted Answer

Wide QRS complex

Answer

Absence of a compensatory pause

Answer

Regular heart rhythm

Answer

Heart rate over 100 bpm

Question 21

What is the term for a heart rate less than 60 bpm?

Accepted Answer

Bradycardia

Answer

Tachycardia

Answer

Arrhythmia

Answer

Asystole

Question 22

Which of the following heart rates is considered to be a medical emergency?

Accepted Answer

160 bpm

Answer

55 bpm

Answer

80 bpm

Answer

120 bpm

Question 23

To calculate heart rate from an EKG, count the number of QRS complexes in a:

Accepted Answer

10-second interval

Answer

5-second interval

Answer

15-second interval

Answer

20-second interval

Question 24

An EKG showing a heart rate of 150 bpm and an irregular rhythm is most likely indicative of:

Accepted Answer

Atrial fibrillation

Answer

Bradycardia

Answer

Tachycardia

Answer

Ventricular fibrillation

Question 25

Which of the following is a sign of a heart attack on an EKG?

Accepted Answer

ST segment elevation

Answer

Inverted T waves

Answer

Bundle branch block

Answer

Prolonged QT interval

Question 26

When analyzing an EKG, the electrical axis of the heart is determined by:

Accepted Answer

T wave direction in leads I and aVF

Answer

QRS complex amplitude

Answer

P wave polarity

Answer

ST segment elevation

Question 27

Which of the following lead pairs is used to assess the inferior leads?

Accepted Answer

III and aVF

Answer

I and aVL

Answer

II and III

Answer

V1 and V6

Question 28

The QT interval on an EKG represents:

Accepted Answer

ventricular depolarization and repolarization

Answer

atrial systole

Answer

atrioventricular delay

Answer

ventricular systole

Question 29

A narrow QRS complex (less than 0.12 seconds) usually indicates:

Accepted Answer

supraventricular rhythm

Answer

ventricular hypertrophy

Answer

bundle branch block

Answer

atrioventricular block

Question 30

Which formula accurately calculates heart rate from an EKG?

Accepted Answer

Heart rate = 1500 / RR interval

Answer

Heart rate = 300 / RR interval

Answer

Heart rate = RR interval / 1500

Answer

Heart rate = RR interval x 300

Question 31

What is the typical heart rate range for adults at rest?

Accepted Answer

60-100 bpm

Answer

50-100 beats per minute (bpm)

Answer

70-120 bpm

Answer

80-140 bpm

Question 32

Which EKG pattern is characteristic of sinus tachycardia?

Accepted Answer

Regular P waves and heart rate greater than 100 bpm

Answer

Irregular P waves and heart rate greater than 100 bpm

Answer

Regular P waves and heart rate less than 60 bpm

Answer

Irregular P waves and heart rate less than 60 bpm

Question 33

How is atrial fibrillation typically represented on an EKG?

Accepted Answer

Irregular P waves and irregular QRS complexes

Answer

Regular P waves and irregular QRS complexes

Answer

Regular P waves and regular QRS complexes

Answer

Irregular P waves and regular QRS complexes

Question 34

Which type of arrhythmia is most common in children?

Accepted Answer

Supraventricular tachycardia

Answer

Ventricular tachycardia

Answer

Atrial fibrillation

Answer

Ventricular fibrillation

Question 35

What is the typical range for normal sinus rhythm heart rate?

Accepted Answer

60-100 beats per minute (bpm)

Answer

40-80 bpm

Answer

80-120 bpm

Answer

100-140 bpm

Question 36

Which method is commonly used to manually calculate heart rate?

Accepted Answer

Radial pulse

Answer

Blood pressure cuff

Answer

Stethoscope

Answer

EKG

Question 37

What does the QRS complex on an EKG represent?

Accepted Answer

Electrical impulse traveling through the ventricles

Answer

Electrical impulse passing through the SA node

Answer

Electrical impulse originating in the atria

Question 38

Which arrhythmia is characterized by a heart rate exceeding 100 bpm?

Accepted Answer

Tachycardia

Answer

Fibrillation

Answer

Asystole

Answer

Bradycardia

Question 39

What is the primary distinction between atrial fibrillation and ventricular fibrillation?

Accepted Answer

Atrial fibrillation originates in the atria, while ventricular fibrillation originates in the ventricles.

Answer

Atrial fibrillation typically presents with a slower heart rate than ventricular fibrillation.

Question 40

Which of the following is a characteristic of pulseless electrical activity (PEA)?

Accepted Answer

No palpable pulse despite electrical activity visible on the EKG

Answer

Very slow heart rate

Answer

Irregular heart rate

Question 41

What is the initial step in managing asystole?

Accepted Answer

Initiate cardiopulmonary resuscitation (CPR)

Answer

Defibrillate

Answer

Call for emergency assistance

Answer

Administer epinephrine

Question 42

What is the primary role of a medical assistant in EKG interpretation?

Accepted Answer

Preparing patients, assisting in interpretation, and monitoring patients during EKG procedures.

Answer

Interpreting EKGs without supervision

Answer

Independently diagnosing and treating arrhythmias

Question 43

Which action demonstrates a professional responsibility in EKG interpretation?

Accepted Answer

Maintaining patient confidentiality and seeking consultation when necessary.

Answer

Overinterpreting EKGs to provide comprehensive information

Answer

Ignoring abnormal findings to prevent patient anxiety