Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Cardiac Pathologies > EKG (Electrocardiogram) > Flashcards

EKG (Electrocardiogram) Flashcards

1
Q

EKG

The graphic representation of depolarization of the heart → It is a recording of the heart’s electrical activity

A

EKG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Electrical current moving toward the positive electrode causes…

A

positive deflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Electrical current moving away from the positive electrode causes…

A

negative deflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

true or false: EKG measure the function of the heart

A

FALSE

measure only electrical activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

EKG test looks at…

A
  • Rate
  • Rhythm
  • Axis
  • Hypertrophy
  • Infarction (ischemia, injury, and other problems)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Physiologic properties of myocardial cells

A
  • Automaticity
  • Rhythmicity
  • Conductivity
  • Excitability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the RESTING/POLARIZED STATE of myocardium:

A

Negative charge inside of cell membrane (K+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

depolarization of the myocardium occurs as

A

Myocytes (inside of myocardial cells) become positive and contract → moves as a wave through the myocardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

myocardial REPOLARIZATION (relaxation) occurs as

A

Myocardial cells return to resting negative charge inside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

in a positive deflection, the wave of depolarization moves towards the positive electrode. In an ISOELECTRIC DEFLECTION the wave of depolarization moves…

A

perpendicular to (+) electrode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

mediator of the cardiac sympathetic nervous system

A

Norepinephrine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

mediator of the cardiac parasympathetic nervous system

A

Acetylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

action of sympathetic activity in the heart

A
  • Increase rate of SA node
  • Increase rate of AV conduction
  • Increase excitability
  • Increase force of contraction (inotropic)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Cardiac conduction system is composed of:

A
  1. Sino-Atrial node
  2. Atrioventricular node
  3. Bundle of His
  4. Left and Right Bundle Branches
  5. Purkinje Fibers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the sinus rhythm?

A

any cardiac rhythm where depolarisation of the cardiac muscle begins at the sinus node. It is characterised by the presence of correctly oriented P waves on the electrocardiogram (ECG). Sinus rhythm is necessary, but not sufficient, for normal electrical activity within the heart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Depolarization wave emitted by SA node spreads throughout both atria ➔ produces
______ on EKG

A

P wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

the only conduction path between the atria and the ventricles

A

AV node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what does the PR segment represents in the EKG?

A

Depolarization slows within the AV node before depolarization is conducted to ventricles → allows blood to finish passing from atria to ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

After depolarization slows through the AV node → it conducts RAPIDLY through the…

A

Bundle of His to the Right and Left Bundle Branches → Purkinje Fibers have “terminal filaments” which carry depolarization to the myocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the “terminal filaments” in the ventricular conduction system?

A

carry depolarization of the myocytes of the ventricles causing them to contract ➔ represented by the QRS complex on EKG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Q, R, and S waves:

A
  • Q wave = 1st downward wave of the QRS complex May or may not be present
  • R wave = 1st upward wave of the QRS complex
  • S wave = ANY downward wave PRECEDED by an upward wave
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

ST segment represents…

A

initial phase of ventricular repolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Initial plateau after QRS complex

A

ST segment, initial phase of ventricular repolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

in the EKG, ventricular systole spans…

A

depolarization AND repolarization of the ventricles,
– SO it begins with the QRS and continues until the end of the T wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Review of Cardiac Conduction
SA node → internodal pathways (to left atrium via Bachman’s bundle; to AV node via ant/middle/post internodal pathways) → AV node → Bundle of His → Right and Left bundle branch (RBB is thinner; LBB has three divisions or fascicles – anterior, septal and posterior) → Purkinje fibers (located in the ventricular walls) → myocardial cells
26
5 colored wires in telemetry or hardwire:
* White clouds over Green grass * Black smoke over Red fire * Brown: center of chest (ground)
27
PR segment: duration?
* Isoelectric line after P wave * Also known as atrial kick * 0.12 – 0.20 seconds (less than 1 large square)
28
ST interval:
* Full ventricular repolarization *
29
QT interval:
* **duration of ventricular systole** (and repolarization) * Varies with heart rate because depolarization & repolarization occur faster with faster HR * So, QT interval measurements are often corrected for rate and are called QTc values * Normal QT is when it is \< ½ RR interval at normal rates (~0.42 sec)
30
RR interval:
Use to calculate the rate → is it regular?
31
Starts at end of QRS complex and ends at T wave
ST segment
32
If SA node is NOT working then another area in the atria should take over with an inherent rate of
60-80 bpm AV node takes over
33
Junctional Foci AKA
AV node
34
Ventricular foci AKA
Purkinje Fibers
35
What structure may become the pacemaker if SA or AV node aren’t working or are diseased or in emergent situations
Ventricular Foci (Purkinje Fibers)
36
3 things to consider when looking at a rhythm strip or EKG:
1. Is there a P for every QRS? 2. Is the rhythm regular? 3. What is the rate? These 3 things will tell you if you have a “sinus rhythm” and what type by the rate… – Bradycardia – Normal – Tachycardia
37
# EKG 1 small horizontal box (1 mm) =
0.04 sec
38
1 large horizontal box ( 5mm ) =
0.20 sec
39
5 large horizontal boxes =
**1 sec**
40
1 small vertical box =
0.10mV
41
1 large vertical box =
0.50 mV
42
2 large vertical squares =
1 mV
43
duration of the p-wave
0.08 and 0.10 sec | (atrial depolarization)
44
duration of the QRS complex:
* \< 0.12 seconds (less than 3 small squares) * Normally 0.06 - 0.10 seconds * IF QRS COMPLEX DURATION IS PROLONGED → CONDUCTION IS IMPAIRED WITHIN THE VENTRICLES
45
IF QRS COMPLEX DURATION IS PROLONGED →
CONDUCTION IS IMPAIRED WITHIN THE VENTRICLEs
46
Q wave duration
usually not \>0.03 sec or is usually \<25% of the amplitude of the R wave
47
duration of the PR interval
* **Normally 0.12 – 0.20 seconds (less than 1 large square)** * Usually isoelectric * Represents the time for the impulse to travel from the atria to the ventricles – represents the delay at the A-V node
48
ST segment originates at the **J-point** and ends at the beginning of the
T wave
49
Based on it’s elevation or depression, it is the main marker for, ischemia, injury or Infarction
ST segment
50
Represents the final, “rapid” phase of ventricular repolarization
T wave
51
Wave inversion in certain leads (negative T waves) can be a sign of
ischemia and more
52
Represents the total time of ventricular systole and is a good indicator of repolarization
QT interval
53
which leads look at the heart across the transverse plane?
chest leads
54
which leads look at the heart in the frontal plane
limb leads
55
how are the limb leads I, II, IIIpositioned?
often called Einthoven’s Triangle
56
Limb Lead I depicts:
high lateral wall of heart
57
Limb Lead II depicts:
inferior surface of heart
58
Limb lead III depicts
inferior surface of heart
59
Unipolar or **Augmented Limb Leads** look at what?
* Lead **aVR** looks at nothing in the left ventricle * Lead **aVL** looks at high lateral wall of the heart * Lead **aVF** looks at the inferior wall of the heart
60
Formation of a **triaxial system** (Einthoven’s Triangle)
* By bringing the sides of the triangle to the common center, the positives and negatives are now clearly delineated * Triaxial system: By assigning degrees to the triaxial system, the axes are shown to be 60° apart
61
Formation of an **hexaxial** and **semicircle** reference systems
* By pushing all these leads to the center, a hexaxial reference is formed * Central axis point is the AV node * EACH LIMB LEAD RECORDS FROM A DIFFERENT ANGLE → this provides a different view of the same cardiac activity
62
limb leads
63
Precordial Leads location
* Precordial Leads are unipolar and all are **POSITIVE** * V1 through V6 view the **horizontal** plane of the heart * **V1:** 4th ICS R of sternal border * **V2:** 4th ICS @ L sternal border * **V3:** equal distance between V2 and V4 * **V4:** 5th ICS and L midclavicular line * **V5:** 5th ICS and ant axillary line * **V6**: 5th ICS and mid axillary line
64
V1, 2: Right chest leads
* Looks at right ventricle * V2 describes straight line directly from the front to the back of patient
65
V3, 4: Located over interventricular septum
The left/right bundle branches flow through the septum
66
V5, V6: left chest leads looks at
**Looks at left ventricle**
67
The center AXIS of the precordial leads is considered to be the
AV node in the heart
68
When observing precordial leads V1-6, you will see gradual changes in all of the waves as the position of the positive electrode changes
The QRS in V1 will be negative and will progress to positive by V6
69
Cardiac axis refers to the
**direction** **of depolarization** as it passes through the heart * A vector (arrow) is used to demonstrate the direction of depolarization as well as the magnitude of depolarization * Depolarization that moves away from a (+) electrode, will have a (-) deflection * Depolarization that moves towards a (+) electrode, will have a (+) deflection
70
Mean QRS vector =
the sum of all the smaller vectors of ventricular depolarization
71
Origin of mean QRS vector =
AV Node
72
Because depolarization vectors of left ventricle are larger than those of right ventricle...
MEAN QRS VECTOR **points down** and toward the **LEFT** (between 0 - 90°) (Varies in individuals by size and age)
73
when axis moves toward the hypertrophied region
hyperthrophy
74
Axis moves away from infarcted region
INFARCTION
75
Axis occurs in frontal plane → related to ______ leads
* limb * Referred to as AXIS DEVIATION
76
Axis occurs in **horizontal** plane → related to _______ leads
* **precordial** * Referred to as AXIS ROTATION
77
3 things to consider when looking at a rhythm strip or EKG:
* P wave for every QRS * Rhythm * Rate
78
reading EKG steps:
**Regularity:** 1. Check for P wave for every QRS 2. Identify the R wave 3. Mark the distance between the R waves (RR Interval) 4. Assess if the distance is consistent
79
Calculating the Rate by Counting Boxes
* Find a R on athink line * the count **300-150-100-75-60-50** * Between 100 and 150: 50 ➗ 5 = 10 * Bet 100 and 75: 25 ➗ 5 = 5
80
How to measure rate: 6 Second Method
* Count the number of complete complexes found between **two sets of** **3 second** marks (equals 6 seconds) on the ECG strip and multiply by 10 * Useful for: – Slow rates – Irregular rhythms
81
**P - R interval:**
* **Definition:** measured from the beginning of the P wave to the beginning of the QRS complex * **Normal values** = 0.12 – 0.20 sec
82
**QRS complex** represents? Normal duration?
* Definition: represents ventricular depolarization * Normal value: 0.06 - 0.10 sec * **Less than 0.12 (less than 3 small squares**
83
what does the QRS complex represents?
ventricular depolarization
84
What part of the EKG represents the **terminal filaments**?
QRS complex

Cardiac Pathologies (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions