Electrocardiography

Question 1

On 25 mm/s paper, one box is how many seconds?

Answer 1

.04sec

Question 2

On 50 mm/s paper, one box is how many seconds?

Answer 2

.02sec

Question 3

What is dromotropy?

Answer 3

Conduction velocity

Question 4

What lead is used to monitor rhythm in SAM?

Answer 4

Lead II

Question 5

How is rhythm monitored in LAM?

Answer 5

Base-apex lead

Question 6

What area does lead I measure?

Answer 6

RA to LA

Question 7

What area does lead II measure?

Answer 7

RA to LL

Question 8

What area does lead III measure?

Answer 8

LA to LL

Question 9

When placing electrodes, what leads SHOULD be positive?

Answer 9

Leads II, III, and AVF

Question 10

A normal QRS wave in horses is ___ (positive/negative)

Answer 10

Negative

Question 11

What does the P wave represent?

Answer 11

Depolarization of the atria

Question 12

What does the PR interval represent?

Answer 12

Time from atrial depolarization to ventricular depolarization (AV node)

Question 13

What does the QRS wave represent?

Answer 13

Ventricular depolarization (His purkinje)

Question 14

What does the ST segment represent?

Answer 14

Early ventricular repolarization

Question 15

What does the T wave represent?

Answer 15

Ventricular repolarization

Question 16

Where are the leads placed?

Answer 16

White - front right
Green - back right (uncommon)
Black - front left
Red - back left

Question 17

How is instantaneous heart rate calculated for 25mm/s paper? 50mm/s paper?

Answer 17

1500/ # of boxes between QRS waves

3000/ # of boxes between QRS waves

Question 18

What is Mean Electrical Axis?

Answer 18

MEA is a tool used to measure the pattern of ventricular depolarization using QRS complexes

Question 19

How is MEA measured?

Answer 19

Isoelectric method (lead where waves equal out to 0)
Tallest R wave

Question 20

What are some primary cardiac diseases in dogs that cause arrhythmias?

Answer 20

Infectious (Chagas, endocarditis)
Inflammatory
Structural (valvular disease)
Cardiomyopathy (DCM, ARVC)

Question 21

What metabolic/endocrine disorders can cause arrhythmias in dogs?

Answer 21

Electrolyte imbalance (K, Ca, Mg)

Question 22

What are some drugs/toxins that cause arrhythmias in dogs?

Answer 22

Digoxin
Amphetamine
Theobromine

Question 23

What are “the usual suspects” for arrhythmias in dogs?

Answer 23

GDV
Sepsis
Splenic Dz
Hypoxia
Hypovolemia
Pain
Trauma

Question 24

What autonomic imbalance can cause arrhythmias in dogs?

Answer 24

Pheochromocytoma

Question 25

What primary cardiac diseases cause arrhythmias in cats?

Answer 25

Cardiomyopathy (HCM, ARVC, restrictive, DCM)

Question 26

What metabolic/endocrine disorders can cause arrhythmias in cats?

Answer 26

``` Electrolyte imbalance (K, Ca, Mg) Hyperthyroidism ```

Question 27

What drugs and toxins can cause arrhythmias in cats?

Answer 27

Anesthesia

Question 28

What are "the usual suspects" that cause cat arrhythmias?

Answer 28

``` Sepsis Hypoxia Hypovolemia Pain Trauma ```

Question 29

T/F: arrhythmias in cats are more likely to be due to primary cardiac disease than in dogs

Answer 29

True

Question 30

What are 5 hemodynamic consequences of arrhythmias?

Answer 30

``` Decreased cardiac function Drop in blood pressure Reduced tissue perfusion Limited exercise capacity Syncope ```

Question 31

What are 3 electrical instabilities arising from arrhythmias?

Answer 31

Myocardial fibrillation Asystole Sudden cardiac death

Question 32

When do you treat an arrhythmia?

Answer 32

If there are clinical signs or an increased risk for sudden death

Question 33

What breeds are predisposed to arrhythmias?

Answer 33

Boxers, dobermans

Question 34

What are DADs?

Answer 34

Delayed after depolarizations related to abnormal Ca influx

Question 35

What are EADs?

Answer 35

Early after depolarizations related to the prolongation of the action potential