Lecture 12: ECG Assessing Cardiac Function

Question 0

What is the SA nodes rate in bpm?

Answer 0

60-80 bpm

Question 1

What is the goal of the conducting system?

Answer 1

To coordinate pumping of the cardiac muscle

Question 2

What is the AV nodes rate in bpm?

Answer 2

40 to 60bpm

Question 3

What are the ventricular nodes rate in bpm?

Answer 3

20 to 40 bpm

Question 4

What is an ectopic focus?

Answer 4

Any cardiac cell can depolarize on it’s own

Loner atrial cell

Question 5

What is the normal time of the PR interval?

Answer 5

0.12 to 0.2 seconds

Question 6

What is the PR interval?

Answer 6

The area between the p wave and the QRS complex

Question 7

What does a longer PR interval indicate?

Answer 7

If the pr interval is longer than 0.2 seconds then there is a delay in conduction between the SA node and the ventricle (AVblock)

Question 8

What is the normal time of the QRS complex?

Answer 8

0.04 to 0.12 seconds

Question 9

What position should the ST segment be?

Answer 9

Isoelectric or at baseline

Question 10

What is the beginning of the ST segment called?

Answer 10

The J point

Question 11

When is the ST segment significant?

Answer 11

Depression more than 1mm and at least 0.08 seconds (2 small boxes)

Question 12

What is a lead?

Answer 12

A combination of electrodes to give you a view of the heart (a combination of three electrodes)

Question 13

What are the chest leads in a 12 lead EKG? What part of the heart do they look at?

Answer 13

V1, V2 right side of the heart
V3,V4 inter ventricular septum
V5, V6 left side of the heart

Question 14

What should you start with when interpreting the ECG?

Answer 14

Determine the ventricular rate

Question 15

How do you determine the ventricular rate?

Answer 15

Look from R wave to R wave

Question 16

After looking at ventricular rate on an ECG, what is the next step in interpretation?

Answer 16

Look at the p wave. Is there a pave before each QRS?

Question 17

A QRS complex should have a duration of…

Answer 17

Less than 0.12 seconds or 3 small boxes

Question 18

What does ST segment elevation indicate?

Answer 18

Myocardial infarction

Question 19

What does ST segment depression indicate?

Answer 19

(>2 mm) myocardial ischemia

Question 20

What is a normal sinus rhythm?

Answer 20

Electrical conduction from the SA node through the normal conduction pathways
Sinus tachycardia is greater than 100
Sinus bradycardia is less than 60

Question 21

What is a sinus arrhythmia? What are the two kinds?

Answer 21

Normal conduction but irregular rhythm. Respiratory and non respiratory arrhythmia

Question 22

What are the characteristics of a sinus arrhythmia in order to be considered to be a respiratory sinus arrhythmia?

Answer 22

HR accelerates during inspiration and decelerates during expiration

Question 23

What is an atrial premature depolarization/contraction?

Answer 23

An atrial premature beat caused by an ectopic focus

Question 24

Will a PAC trigger the AV node?

Answer 24

Yes

Question 25

Does a PAC result in a normal CO?

Answer 25

Yes. It is considered a benign heart condition

Question 26

What is a saw tooth pattern?

Answer 26

An atrial flutter

Question 27

How many p waves per minute can occur in an atrial flutter?

Answer 27

250 - 300

Question 28

What are 2 possible causes of an atrial flutter?

Answer 28

(1) ischemic heart disease | (2) after surgery

Question 29

What feature on the ECG is missing when someone has atrial fibrillation?

Answer 29

P waves

Question 30

Will Afib disrupt cardiac output?

Answer 30

Yes

Question 31

What is the cause of Afib?

Answer 31

Multiple atrial cells depolarizing on their own

Question 32

What do the atria look like in an individual with Afib?

Answer 32

The atria quiver (looks like a bag of worms)

Question 33

What is a concern in someone with Afib?

Answer 33

Afib leads to blood stasis which may cause clot formation (which may lead to stroke)

Question 34

What are three clinical clues that someone may have AFib?

Answer 34

(1) irregular rhythm on palpation (2) weak pulse (3) clot risk increased

Question 35

What are junctional rhythms?

Answer 35

Tissue next to AV node (junctional tissue) taking over pacing and QRS depolarization

Question 36

Does the SA node fire in junctional rhythm?

Answer 36

No

Question 37

If the SA node doesn't fire in junctional rhythm, what is the heart rate?

Answer 37

40 - 60 bpm

Question 38

Ventricular premature depolarization or contraction is caused by...

Answer 38

One ectopic focus in the ventricles before atrial depolarization

Question 39

What is the result of PVC on the ECG?

Answer 39

The QRS will become wide and larger in magnitude

Question 40

Are PVCs considered normal?

Answer 40

Yes, until there are more than 6 per minute

Question 41

What is a unifocal PVC?

Answer 41

A PVC with one ectopic focus (the PVCs look the same)

Question 42

What is a multifocal PVC?

Answer 42

A PVC with different ectopic foci (so the PVCs look different)

Question 43

What is bigeminy?

Answer 43

When every other beat is a PVC.

Question 44

What is trigeminy?

Answer 44

Every third beat is a PVC

Question 45

What is a couplet?

Answer 45

When there are 2 PVCs in a row.

Question 46

What is a triplet?

Answer 46

3 PVCs in a row

Question 47

Can PT be done if the patient has a couplet? Triplet?

Answer 47

Yes- couplet | No- triplet

Question 48

If there are 3 PVCs in a row it greater than 6 PVCs in one minute what is the patient at risk for?

Answer 48

Ventricular tachycardia

Question 49

What is ventricular tachycardia?

Answer 49

(Can be sustained or not sustained) I don't know what it is

Question 50

V-Tach can become...

Answer 50

V Fib

Question 51

What is ventricular fibrillation?

Answer 51

When multiple ectopic foci are in the ventricle | No ventricular pumping

Question 52

What is a block?

Answer 52

I don't understand

Question 53

Atrioventricular blocks or (AV blocks) have 3 different kinds...

Answer 53

First degree AV block Second degree AV block -Type I (Mobitz Type I, Wenckebach phenomenon) -Type II (Mobitz Type II) Third degree AV block (Complete AV block)

Question 54

What is a First degree AV block?

Answer 54

Conduction delay in AV node PR interval > 0.20 sec (5 small boxes) and consistent benign

Question 55

What's a Second degree AV block, Type I (Mobitz Type I, Wenckebach phenomenon)?

Answer 55

PR intervals get progressively longer and longer until one P wave is not conducted through to ventricles (skipped QRS) usually benign

Question 56

What's a Second degree AV block, Type II (Mobitz Type II)?

Answer 56

Block in Bundle of His PR intervals tend to be long but of consistent duration conduction often does not go through to ventricles; may have P:QRS of 2:1, 3:1, 4:1, etc. Ventricular rate tends to be irregular; pacemaker often required. Pacemaker often required!

Question 57

What's a Third degree AV block (Complete AV block)?

Answer 57

Atrial and ventricular depolarization are independent (completely dissociated). P waves and QRS complexes are not coordinated, so PR intervals have no consistent duration. QRS may be wider than normal. Ventricular rate tends to be regular. Needs a pacemaker!!!

Question 58

What's a bundle branch block (BBB)?

Answer 58

Blockage between AV bundle (bundle of His) and Purkinje fibers leading throughout one ventricle. QRS > 0.12 sec

Question 59

What's a Right bundle branch block (RBBB)?

Answer 59

Left ventricle contracts first | Will be seen with leads V2 V3!

Question 60

What's a Left bundle branch block (LBBB)?

Answer 60

Will be seen with leads V5 V6!