Basic ECG Concepts

Question 1

Explain the cycles of diastole & systole in the heart Hint: 7 steps

Answer 1

1) Ventricular diastole (early) → isovolumic/ isovolumetric relaxation
2) Ventricular diastole (late) → ventricular filling
3) Atrial systole begins → atrial contraction
4) Isovolumic/ isolvolumetric contraction
5) Ventricular systole (1st phase) → ventricular contraction
6) Ventricular systole (2nd phase) → ventricular ejection
7) Atrial diastole → for the process to start again

Question 2

What signals the end of diastole?

Answer 2

The mitral valve snapping shut

Question 3

What does the S1 sound or “lub” of lub dub indicate?

Answer 3

Systole

Question 4

Where is S1 heard best on auscultation?

Answer 4

The apex of the heart → where mitral valve closes

Question 5

What happens when aorta has more blood in it than the ventricle?

Answer 5

The aortic valve snaps shut signaling the end of systole & the cycle restarts with atrial diastole

Question 6

What does S2 sound or “dub” of lub dub indicate?

Answer 6

Diastole

Question 7

Where is S2 heard best on asucultation?

Answer 7

At the base → where aortic valve closes

Question 8

What is an atrial kick?

Answer 8

The big ejection where the blood gets pushed out into the ventricles; accounts for 30% of cardiac output

Question 9

What valve is louder when it closes & why?

Answer 9

The aortic valve b/c it has more pressure

Question 10

What valve is softer when it closes & why?

Answer 10

The pulmonic valve b/c it has less pressure

Question 11

What is a split S2 sound?

Answer 11

Audible separation of the second heart sound into 2 distinct components → typically heard as 2 separate sounds during inspiration

Question 12

Why does a split S2 sound occur? IS it safe?

Answer 12

B/c the aortic valve (A2) & pulmonic valve (P2) do not close simultaneously → it’s an okay (healthy) finding

Question 13

SA node

Answer 13

Primary pacemaker of heart fires 60-100 bpm

Question 14

AV node

Answer 14

Back up pacemaker fires 40-60 bpm

Question 15

Ventricle

Answer 15

Will fire 20-40 bpm if needed

Question 16

Explain electrical impulses from Sinus node

Answer 16

Impulses spread from sinus node throughout the left & right atria

Question 17

Explain electrical impulses from bundle of his

Answer 17

Impulses spread from bundle of his throughout left & right ventricles

Question 18

Explain what happens if SA node & AV nodes fail

Answer 18

SA node → AV node → bundle of his → right & left bundle branches → to the ventricles

Question 19

What does the P wave represent on an ECG?

Answer 19

Atria begins depolarizing (contracting) → blood moved down into ventricles

Question 20

What does it mean when the P wave returns to baseline on ECG strip?

Answer 20

Indicates the valve snapping shut & we are now in systole
Isoelectric

Question 21

What does the start of QRS complex indicate on ECG?

Answer 21

Ventricular depolarization begins at apex & progresses superiorly as the atria repolarizes

Question 22

How do we know when ventricular depolarization is complete?

Answer 22

When we see the full QRS complex on ECG strip

Question 23

What happens at the end of QRS complex?

Answer 23

The aortic valve snaps shut

Question 24

What does the T wave represent on ECG?

Answer 24

Ventricular repolarization begins at apex & progresses superiorly → short rest period before refiring

Question 25

What does the return to baseline indicate after T wave on ECG?

Answer 25

Ventricular repolarization is complete → heart is ready for the next cycle

Question 26

How can we tell if client is in diastole or systole when looking at ECG strip?

Answer 26

P & T waves → occur during diastole QRS complex → occurs during systole

Question 27

The basics: Electrodes

Answer 27

Electrical contacts on the patient

Question 28

The basics: Wires

Answer 28

Connect electrodes to the recording device

Question 29

The basics: Leads

Answer 29

Represent the heart from a specific viewpoint

Question 30

What are the 3 different wire systems?

Answer 30

Ten, five, or three

Question 31

What does each small box on ECG strip represent?

Answer 31

0.04 sec

Question 32

What does each big box on ECG strip represent?

Answer 32

0.20 sec

Question 33

What do every 5 big boxes on ECG strip represent?

Answer 33

1 second

Question 34

What do ECG strips measure?

Answer 34

Measurement of time (HR) & measurement of height (of complexes)

Question 35

Can you have ventricular contraction without atrial contraction?

Answer 35

NO

Question 36

When looking at an ECG what should precede the QRS complex?

Answer 36

P wave → should be upright & rounded

Question 37

What is the first negative deflection after the P wave on ECG?

Answer 37

The Q wave → may not always be a Q wave

Question 38

What is the first positive deflection after the P wave?

Answer 38

R wave

Question 39

What is the first positive or negative deflection after the T wave?

Answer 39

S wave

Question 40

What is a normal QRS interval?

Answer 40

Less than 0.10

Question 41

What is a PR interval?

Answer 41

Time from atrial depolarization to beginning of ventricular depolarization

Question 42

What is normal time of PR interval?

Answer 42

0.12-0.20 sec

Question 43

What are the 6 steps to assessing the patient?

Answer 43

1) Determine the HR 2) Determine if rhythm is regular 3) Determine if rhythm originate in SA node 4) Determine conduction 5) Eval appearance of rhythm 6) Interpret the rhythm 7) Change from baseline?

Question 44

Step 1: What should always be confirmed?

Answer 44

The heart rate → could be artifact

Question 45

Step 1: Explain the six-second method for calculating HR **Hint: 3**

Answer 45

1) 3 second markers 2) Count ventricular of atrial rate 3) Multiply by 10

Question 46

Step 1: Explain large box method for calculating HR **Hint: 2**

Answer 46

1) Count large boxes between two R waves or P waves 2) Divide number into 300 **Ex. 4 large boxes btwn 2 R waves → 300/ 4 = 75 bpm**

Question 47

Step 1: Explain small box method for calculating HR **Hint: 1**

Answer 47

1) Count # of small boxes between 2 R or P waves & divide # into 1,500 **Ex. 18 boxes counted btwn 2 R waves → 1500/ 18 = 83 bpm**

Question 48

Step 2: How do we determine the rhythm?

Answer 48

1) Measure distance btwn 2 consecutive R & P waves 2) Compare to other RR or PP intervals

Question 48

Step 2: How to interpret rhythm findings on ECG?

Answer 48

Consistent intervals → regular Inconsistent intervals → irregular

Question 49

Step 3: Looking for if the rhythm originated in the SA node **Hint: 4**

Answer 49

1) Look at P wave 2) Assess size & shape → is it upright? 3) Is atrial rate regular? 4) Is there a P wave for every QRS?

Question 50

Step 4: Evaluating conduction

Answer 50

**Measure the intervals** 1) PR interval → 0.12 (3 small boxes) -- 0.20 (5 small boxes) 2) QRS duration → < 0.10 (2.5 small boxes)

Question 51

What does a wide QRS duration (> 0.10 sec) tell us?

Answer 51

Abnormal ventricular conduction

Question 52

Step 5: What do we look for to eval appearance of the rhythm? **Hint: 2**

Answer 52

1) Premature beats 2) Elevated or depressed ST segment

Question 53

Step 6: How can we interpret the rhythm?

Answer 53

Compare your finding to the characteristics of specified arrhythmias

Question 54

Step 7: List 3 things to do if a change from baseline is found & noted

Answer 54

1) Reassess patient 2) 12 lead ECG if needed 3) Report to provider

Question 55

What are the ECG findings of normal sinus rhythm? **Hint: 5 findings**

Answer 55

**SA node → normal conduction path** Rate → 60-100 bpm Rhythm → regular P wave → Round, upright, one P wave for every QRS PR interval → Consistent 0.12-0.20 sec QRS duration → < 0.10 sec

Question 56

What are ECG findings of sinus bradycardia?

Answer 56

Rate → < 60 bpm Rhythm → regular P wave → Present before QRS, consistent size & shape PR interval → normal (0.12-0.20) QRS duration → normal (< 0.10)

Question 57

List 5 reasons we would see sinus bradycardia

Answer 57

1) Lower metabolic needs 2) vagal stimulation 3) Meds → Beta blockers, CCBs, Digoxin 4) Increased ICP 5) Myocardial infarction

Question 58

List 3 nursing interventions for sinus bradycardia

Answer 58

1) Assess pt for Sx 2) Pt may require pacing 3) Meds

Question 59

List 3 medications that can be admin for sinus bradycardia

Answer 59

1) Atropine 2) May also require: → Epinephrine → Dopamine

Question 60

What are ECG findings of sinus tachycardia?

Answer 60

Rate → > 100 bpm Rhythm → regular P wave → Present before each QRS, consistent PR interval → normal (0.12-0.20) QRS duration → normal (< 0.10)

Question 61

List 5 causes of sinus tachycardia

Answer 61

1) Stress → physiologic / psychologic 2) Meds 3) Thyroid disease 4) Anemia 5) Fever

Question 62

List 3 medications that can cause sinus tachycardia

Answer 62

1) Meds that stimulate sympathetic response 2) Stimulants 3) Illicit drugs

Question 63

What happens to diastolic filling time in sinus tachycardia?

Answer 63

It decreases because there is a shorter duration of diastole → meaning the patient loses their "rest" period before refiring

Question 64

List 2 things sinus tachycardia can lead to if it continues

Answer 64

1) Pulmonary edema 2) Cardiac ischemia

Question 65

What is the nursing management for sinus tachycardia?

Answer 65

Treat the cause!!

Question 66

What is sinus arrhythmia? & what is it associated with?

Answer 66

1) Sinus node impulse at an irregular rhythm 2) Associated with resp. cycle