EKG Interpretation Flashcards

1
Q

Lead Location and View of Heart

A
  • V1: 4th intercostal on right - septum view (anterior wall)
  • V2: 4th intercostal on left - septum view (anterior wall)
  • V3: directly between V2 and V4 - anterior view
  • V4: 5th intercostal midclavicular - anterior view
  • V5: level with V4 anterior axillary - lateral view
  • V6: level with V5 midaxillary - lateral view
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Direction of EKG Spikes

A
  • upward/positive deflection - neg. to pos. direction
  • downward/negative defletion - pos. to neg. direction
  • equiphasic deflection/pos. AND neg. - between neg. and pos.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

EKG Paper Wave Description

A
  • small box:
    • 1mm tall x 0.04sec wide
  • large box:
    • 5mm tall x 0.2sec wide
  • paper speed: 25mm/sec
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Order and Meaning of Waves

A
  • P (upward)- atrial depolarization
  • QRS complex- ventricular depolarization and contraction
    • Q (downward)- depolarization of interventricular septum
    • R (larger upward)
    • S (downward)
  • T (modest upward)- ventricular repolarization
  • U (small/nonobserved upward)- recovery of Perkinje fibers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Intervals vs. Segments

A

invertval - contains a wave

segment - section with no wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Pathologic Q Wave

A

>.04sec (1 small block) wide

>25% of height of R wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

J point

A

level of ST segment compared to PQ segment

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

EKG Reading Scheme

(what you need to read)

A
  • Rate:
    • 300, 150, 100, 75, 60, 50…
    • strip is 10sec - count # beats x 6
  • Rhythm:
    • P-QRS coupling present and constant
    • QRS complexes occurring regularly
  • Waves: present and normal
  • Axis
  • Intervals:
    • PR interval
    • QRS interval
    • QT interval
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the QRS Axis

A

summation vector of where the heart’s electrical current

is spending most of its time (avg direction of electrical activity)

normal = -30 to +90

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

On what is the axis charted

A

Einthoven’s Triangle / Hexaxial System

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

Causes of Axis Deviation

A
  • left axis deviation (-30 to -90)- left ventricular hypertrophy
  • right axis deviation (+90 to 180)- MI (tissue death) in left ventricle
  • extreme right axis deviation (-90 to 180)- “no mans land”
    • could be extreme right or left
    • typically a congenital anomaly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

2 Steps to Determining Axis

A
  1. QRS complex in I and aVF:
    • +/+ = normal
    • +/- = POSSIBLE left axis (0 to -30 is normal)
      • Look at Lead II:
        • (+) = normal
        • (-) = left axis
    • -/+ = right axis
    • -/- = extreme right axis
  2. Look for equiphasic lead in 1st 6 leads
    • axis will be at right angle to equiphasic lead
    • will point to quadrant determined by step 1
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why a bundle branch block (BBB) occurs

A

block in propogation of AV signal

ventricles normally contract simultaneously, but this interrupted

see split in QRS complex as a result

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Right BBB

A
  • “rabbit ears” (RSR’) in V1 and V2
  • prominent S wave in 1 and aVL

d/t lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Left BBB

A
  • “rabbit ears” (RR’) in V5 and V6
  • broad R waves in 1, aVL, V6

d/t ischemic heart failure, HTN

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

Role of T-wave in BBB

A

  • want T wave to be inverted with BBB (downward)
  • elevated T wave may be an infarction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Hemiblocks (Fascicular Block)

A
  • Anterior hemiblock
    • left axis deviation > -45’ with no explanation
    • small q in 1, aVL
    • small r in II, III, aVF
  • Posterior hemiblock
    • right axis deviation > +120’ with no explanation
    • small r in 1, aVL
    • small q in II, III, aVF
18
Q

Bifascicular Blocks

A
  • RBBB + anterior fascicular block
  • RBBB + posterior fascicular block
19
Q

Complete Heart Block (3rd degree)

A

All 3 Fascicles blocked - no coupling

(atria no longer talking to ventricles - irregular rhythms)

look for P without QRS periodically

20
Q

Chamber Enlargement - Right Atrium

A

P-wave large (>3mm) and pointed particularly in inferior leads

21
Q

Chamber Enlargement - Left Atrium

A

Wide, notched P wave (>.12sec) particularly in inferior leads

22
Q

Chamber Enlargement - Right Ventricle

A
  • axis moves to right (spending more time here)
  • J point lowered (ST depression)
  • inverted T-wave
23
Q

Chamber Enlargement - Left Ventricle

A
  • amplified S and R waves
  • (S-wave in V1) + (greater of R-wave in V5 or V6) > 35mm
    • then check lead II to see if it’s negative
24
Q

First Degree Block

A

prolonged PR interval

(0.1 - 0.2sec)

25
Second Degree: Mobitz Type 1 (Wenckebach)
short PR -\> longer PR -\> even longer PR -\> **dropped QRS**
26
Second Degree Block: Mobitz Type II
P-wave then **dropped QRS** (no P-wave lengthening) DANGEROUS!
27
Third Degree (Complete) Block
No P to QRS Coupling | (often requires pacemaker)
28
Potassium
Potassium (K+) "lives under the T-wave" * Increased potassium - elevated T-wave * Decreased potassium - lowered T-wave and U-wave created
29
Calcium
Ca++ determines time of repolarization * Low Ca++ = prolonged QT interval (longer to repolarize) * High Ca++ = shortened QT interval
30
EKG Changes d/t MI
* ischemia- ST depression with or without T-wave inversion * injury- ST elevation with or without loss of R wave * infarction- DEEP Q waves
31
Timing of EKG Changes with Acute Occlusion
* pathologic Q waves: hours to days * ST segments: minutes to hours * T-waves: * Hyperacute T-waves in minutes * T-wave inversion in hours
32
Location of Ischemia per EKG
* inferior: * 2, 3, aVF * right coronary and circumflex * lateral * 1, aVL, V5, V6 * left circumflex * septal * V1, V2 * LAD * anterior * V3, V4 * LAD
33
"Fooler" EKG
"Humped" ST elevation (possible ventricular aneurism)
34
Digoxin Effect
inverted T-wave in lateral leads "moustache affect"
35
"knife-like" chest pain eased with bending over ST elevation in I and II and "all over"
Pericarditis
36
"Slurring" of QRS - Delta wave followed by tachycardia in later EKG
Wolff-Parkinson-White Syndrome IMPORTANT!
37
Wolff-Parkinson-White Orthodromic
impulse flows up accessory path to atria - atria overstimulated tachycardia
38
Wolff-Parkinson-White Antidromic
impulse flows down accessory path
39
Accessory Path through AV Node
Lown-Ganong-Levine (LGL) Syndrome * short PR segment * no delta wave d/t accessory path
40
Posterior Wall MI
1. ST depression in V1 - V4 (septal and anterior) 2. R/S wave ratio greater than 1 in V1 or V2
41
Right Ventricular MI
1. ST elevation in V1 (only lead that looks directly at right ventricle) 2. ST elevation in III \> II (b/c III is more rightward facing than II)