Weel 10: Cardiovascular Sys P2 (ECG)

Question 1

What is an ECG?

Answer 1

A picture of the electrical conduction of the heart

Question 2

The normal pacemaker of the heart is the?

Answer 2

SA node

Question 3

The P wave represents what? This sets the heart to beat at what rate?

Answer 3

The SA nodes, also known as the pacemaker
- Sets heart to beat at rate of 60-100BPM

Question 4

The end of the P wave (straight line ish) represents what? This sets the heart to beat at what rate?

Answer 4

The AV node “resistor node” as it slows down the electrical impulse b/w atria and ventricles
- Sets rate of 40-60 BPM
- Creates flat baseline after P wave

Question 5

Purkinje Fibers sets heart rate at what?

Answer 5

20-40BPM

Question 6

The QRS complex represents what?

Answer 6

Ventricular depolarization which cause ventricular contraction

Question 7

The T wave represents what?

Answer 7

Ventricular Relaxation and Repolarization

Question 8

The T wave represents what?

Answer 8

Ventricular Relaxation and Repolarization

Question 9

Describe the steps of the heart contracting in relation to the ECG wave and the SA/AV nodes

Answer 9

1. Atrial depolarization occurs initiated by the SA node: causing the P wave
2. With atrial depolarization complete, the impulse is delayed at the AV node: causing the “flatline” right before the Q
3. Ventricular depolarization begins at the apex, causing heart contraction and the QRS complex, and then atrial repolarization occurs
4. Ventricular depolarization is complete: “Flatline” right before T
5. Ventricular repolarization begins at apex, causing T wave
6. Ventricular repolarization is complete: end of T wave

Question 10

What are the 5 Leads on the ECG?

Answer 10

RA placement: White (Right)
LA placement: Black (Left)
RL placement: Green (middle to right)
LL placement: Red (Left)
V placement: Green (Right)

Question 11

Why is a five lead better than a 12 lead? If there is concern should you switch to a 12 lead?

Answer 11

A 5 lead provides lot’s of information, and when put on torso allows for better reading then on limbs (where coldness and other things may interfere with the readings)
- But if something is concering a 12-lead ECG is ordered to provide more information

Question 12

Limb vs. precordial leads?

Answer 12

Limb leads are placed on arms and legs of the individual
Precordial are placed on torso (precordium)

Question 13

What are the six limb leads called?

Answer 13

Lead I, II, III, aVL, aVR, AVF
- letter A stands for augmented as these leads are calculated as a combination of leads I, II, and III

Question 14

What are the six precordial leads called?

Answer 14

Leads V1, V2, V3, V4, V5, V6

Question 15

How many seconds should the PR interval be?

Answer 15

Between 0.12-0.20

Question 16

How many seconds should the QRS interval be?

Answer 16

0.08-0.1 seconds

Question 17

How long should the QT interval be?

Answer 17

Less than 0.44 seconds

Question 18

A depressed ST segment may indicate what?

Answer 18

Myocardial ischemia or digoxin toxicity

Question 19

An ST segment elevation may indicate what?

Answer 19

Myocardial injury

Question 20

How do you make sure an ECG’s rate and rhythm is regilar?

Answer 20

Make sure space between each r wave is equal (count the boxes)

Question 21

Arrythmias are defined by what?

Answer 21

The speed of the heartbeats: slow and fast, or bradycardia and tachycardia

Question 22

Bradycardia can be defined as what in relation to ECG / conduction

Answer 22

Malfunction of SA node (sick sinus syndrome), slowing down of the electrical signal to the ventricles (heart block)

Question 22

Bradycardia can be defined as what in relation to ECG / conduction

Answer 22

Malfunction of SA node (sick sinus syndrome), slowing down of the electrical signal to the ventricles (heart block)

Question 23

Tachycardia above the ventricle causes what?

Answer 23

an extra or early electrical impulse travels around and around the atria causing the atria to “flutter” ( atrial flutter); electrical activity in atria is disorganized and rapid causing very rapid contractions of the atria (A fib)

Question 24

What are symptoms of bradycardia?

Answer 24

Hypotension
Pale, cool skin
Weakness
Angina
Dizziness or syncope
Confusion or disorientation
SOB

Question 25

What are treatments for bradycardia?

Answer 25

Atropine
Pacemaker may also be required

Question 26

Bradycardia can occur in response to?

Answer 26

Carotid sinus massage
Valsalva’s manoeuvre
Hypothermia
Increased intraocular pressure
Increased vagal tone
Administration of parasympathomimetic drugs

Question 27

Bradycardia can occur in what disease states?

Answer 27

Hypothyroidism
Increased intracranial pressure
Obstructive jaundice
Inferior wall MI

Question 28

What can tachycardia be associated with/

Answer 28

Exercise
Fever, Pain
Hypotension
Hypovolemia
Anemia
Hypoxia
Hypoglycemia
MI
Heart failure
Hyperthyroidism
PE
Anxiety, fear

Question 29

What are treatments for tachycardia?

Answer 29

Adrenergic blockers to reduce HR and myocardial oxygen consumption
Antipyretics to treat fever
Analgesics to treat pain

Question 30

If an ECG is sawtooth-shaped flutter waves what condition is it indicating?

Answer 30

Atrial flutter
- Atrial tachydysrhythmias

Question 31

Atrial flutter usually occurs with?

Answer 31

CAD
Hypertension
Mitral valve disorders
Pulmonary embolus
Chronic lung disease
Cor pulmonale
Cardiomyopathy
Hyperthyroidism
Drugs: digoxin, quinidine, epinephrine
High ventricular rates (>100) and loss of the atrial “kick” can decrease CO and precipitate HF, angina
Risk for stroke due to risk of thrombus formation in the atria

Question 32

What is the primary goal for treatment of atrial flutter?

Answer 32

Slow ventricular reponse by increasing AV block

Drugs to slow HR: calcium channel blockers, -adrenergic blockers

Electrical cardioversion may be used to convert the atrial flutter to sinus rhythm emergently and electively.

Antidysrhythmic drugs (e.g., amiodarone, propafenone) to convert atrial flutter to sinus rhythm or to maintain sinus rhythm

Radiofrequency catheter ablation can be curative therapy for atrial flutter.