EKG Ch. 5

Question 1

What is the first critical point to master after calculating the heart rate?

Answer 1

Evaluation of the rhythm

Question 2

How can you determine if the rhythm is regular or irregular?

Answer 2

Evaluate if QRS complexes march out at even intervals

Question 3

What are the two classifications of irregular rhythms?

Answer 3

• Regularly irregular * Irregularly irregular

Question 4

What role does the autonomic nervous system play in heart rate variation?

Answer 4

It influences normal heart rate variation

Question 5

What does sympathetic stimulation do to vagal tone?

Answer 5

Decreases vagal tone

Question 6

What is the effect of parasympathetic stimulation on heart rate?

Answer 6

Increases vagal tone, allowing for slow resting heart rates

Question 7

What can increased vagal tone appear as on an EKG?

Answer 7

• Sinus bradycardia * Sinus pauses * AV block

Question 8

What can overstimulation of the vagus nerve lead to?

Answer 8

Vasovagal syncope

Question 9

What is sinus arrhythmia and its most common cause?

Answer 9

A common nonpathologic irregular rhythm caused by normal respiration

Question 10

How does heart rate change during inspiration and expiration in sinus arrhythmia?

Answer 10

• Increases with inspiration * Decreases with expiration

Question 11

What is a premature atrial contraction (PAC)?

Answer 11

An early conduction triggered by an area of excitable cells in the atrium

Question 12

What is atrial bigeminy?

Answer 12

When every other beat is a PAC

Question 13

What defines atrial tachycardia?

Answer 13

Three or more consecutive PACs

Question 14

What distinguishes unifocal atrial tachycardia from multifocal atrial tachycardia?

Answer 14

Unifocal has one ectopic focus; multifocal has multiple foci with differing P wave morphology

Question 15

What is atrial fibrillation?

Answer 15

A disorganized irregularly irregular rhythm with chaotic electrical activity in the atria

Question 16

What is the significance of differentiating atrial tachycardia from atrial fibrillation?

Answer 16

Due to the difference in treatment and stroke risk

Question 17

What does the AV node do during atrial fibrillation?

Answer 17

Prevents excessively fast ventricular rates through decremental conduction

Question 18

What are the characteristics of multifocal atrial tachycardia?

Answer 18

• Slightly irregular rhythm * Different P wave morphology

Question 19

What is a wandering atrial pacemaker?

Answer 19

Beat-to-beat variance in P wave morphology at slower rates

Question 20

What should be considered when treating PACs?

Answer 20

• Lifestyle limiting symptoms * Progression to sustained atrial arrhythmias

Question 21

What medications are commonly used to treat symptomatic PACs?

Answer 21

• Beta blockers * Calcium channel blockers

Question 22

What are premature ventricular contractions (PVCs)?

Answer 22

Early beats originating from excitable tissue in the ventricles

Question 23

How can you distinguish PACs from PVCs?

Answer 23

Evaluate for the presence of a P wave and its association with a QRS complex

Question 24

What does a PVC look like compared to a sinus beat?

Answer 24

Wide and bizarre looking QRS complex

Question 25

What is the clinical relevance of frequent PACs?

Answer 25

Higher PAC burden is associated with increased incidence of atrial fibrillation

Question 26

What lifestyle modifications should be encouraged for PACs?

Answer 26

* Caffeine restriction * Hydration * Stress reduction * Good sleep hygiene

Question 27

What does a PVC QRS complex look like?

Answer 27

Wide and often bizarre looking

Question 28

What is the most accurate method to calculate heart rate in an irregular rhythm strip?

Answer 28

Count the total number of QRS complexes in a 10-second rhythm strip and multiply by 6

Question 29

What is the clinical relevance of PVCs in patients with a left ventricular ejection fraction less than 50%?

Answer 29

Associated with more frequent PVCs and increased risk of congestive heart failure and sustained ventricular arrhythmias

Question 30

What percentage of PVC burden may increase the risk of new cardiomyopathy?

Answer 30

Greater than 20% over a 24-hour period

Question 31

What does a wide PVC indicate?

Answer 31

Ventricular contraction that occurs at a distance from normal septal activation

Question 32

What is the first-line therapy for PVCs?

Answer 32

Beta blockers or calcium channel blockers

Question 33

Name two alternative agents for suppression of PVCs.

Answer 33

* Flecainide * Sotalol

Question 34

What are contraindications for using Class Ic and III antiarrhythmic medications?

Answer 34

* Cardiomyopathy * Congestive heart failure * Structural heart disease

Question 35

What is a treatment option for PVCs reserved for patients refractory to medical therapy?

Answer 35

Radiofrequency ablation

Question 36

What common factors can lead to PACs?

Answer 36

* Increased automaticity * Anxiety * Caffeine or other stimulants * Poor sleep patterns * Dehydration * Obstructive sleep apnea * Hypertension * Pulmonary disease * Structural heart disease (less commonly)

Question 37

What conditions are associated with atrial fibrillation?

Answer 37

* Structural heart disease * Obstructive sleep apnea * Hypertension * Obesity * Advanced age

Question 38

What abnormalities are associated with PVCs?

Answer 38

* Increased automaticity * Anxiety * Caffeine or other stimulants * Poor sleep patterns * Dehydration * Obstructive sleep apnea * Hypertension * Structural heart disease * Ischemic heart disease * Electrolyte abnormalities

Question 39

True or False: PVCs are always a sign of serious heart disease.

Answer 39

False

Question 40

Fill in the blank: The QRS complex will have the same appearance throughout the _______.

Answer 40

strip

Question 41

What do PVCs cause in the heart?

Answer 41

Electromechanical dyssynchrony