EKG Basics Flashcards
1
Q
12 Leads
A
- Bipolar Limb Leads
- I - R arm (-) to L arm (+)
- II - R arm (-) to L leg (+)
- III- L arm (-) to L leg (+)
- Augmented limb leads
- aVR - all other leads (-) to R arm (+)
- aVL - all other leads (-) to L arm (+)
- aVF - all other leads (-) to L foot (+)
- Precordial (unipolar) Leads
- V1/V2 in 4th intercostal space; R and L sternal border respectively
- V3
- V4- 5th intercostal space mid sternal
- V5
- V6- mid axillary
2
Q
7 Steps of Interpretation
A
- 1- Calibration/connections
- 2- Measurable Values - rate, axis, intervals
- 3- Rhythm
- 4- Conduction
- 5- Hypertrophy
- 6- Ischemia, Injury or Infarct
- 7- Other ST and T Wave Abnormalities
3
Q
Calibration/Connections
A
- Calibration rectangle is 10 mm high/5 mm wide
- Check if Lead II = Lead I + Lead III
- Check if R amp inc as you go from V1 —> V6 (makes sense b/c getting closer to apex)
- Check if Lead I similar in size to V6
4
Q
How to measure rate (2 methods)
A
- Count # large boxes b/n QRS complexes
- 1 box - 300 bp
- 2 boxes - 150 bpm
- 3 boxes - 100 bpm
- 4 boxes - 75 bpm
- # complexes in 6 second strip (b/n 2 bold vertical lines) x 10 (beats/60 sec or beats/min)
5
Q
How to determine frontal axis/ what are normal values?
A
- Orthogonal Approach - height of QRS above baseline in Lead I is horizontal in direction of +; then height of QRS in aVF drawn down from tip of lead I vector; then complete vector and this 3rd vector is frontal plane axis (-30 to +110 is normal)
- -30 to -90 is L deviation
- +110 to +180 is R deviation
6
Q
3 Intervals to Measure (+normal values)
A
- PR interval - represents AV delay (normal = 120-200 ms)
- QRS duration - timed required to depolarize ventricles (normal = or < 100 ms)
- QT interval - time required for ventricles to repolarize; differs by HR so must correct
- QTc = QT / square root of RR interval
7
Q
3 Major Types of Rhythm
A
- If driven by atrium… normal sinus rhythm OR atrial fibrillation (irregularly irregular QRS- no clear P)
- If driven by junction (AV node not SA node) … narrow QRS; p wave not seen or abnormal
- If driven by ventricle… slow (accelerated idioventricular rhythm) OR fast (ventricular tachycardia); both show wide/odd QRS
8
Q
Types of AV Block
A
- 1st degree - all signals make it to ventricle but SLOWER; PR >200 ms
- 2nd degree - most signals get to ventricles
- Type 1 Mobitz - prolonged PRs then dropped QRS
- Type 2 Mobitz - no prolongation; just dropped QRS
- 3rd degree- many or all signals do not make it to ventricle; no connection b/n p wave rate and QRS rate
9
Q
Types of Distal Block
A
once thru bundle of His - worse b/c no intrinsic pacemaker activity at this point
- Right Bundle Block - V1/V2 - bunny ears R wave; QRS > 120 ms
- Left Bundle Block - I/V5/V6 - wide R w/ poss notch; QRS > 120 ms
- Anterior Fasicle L Bundle - I/aVL - R axis deviation and qR
- Posterior Fasicle L Bundle - I/aVL - L axis deviation and rS
10
Q
R atrial hypertrophy
A
- tall p wave in inferior leads (II) or V1; P pulmonale
11
Q
L atrial hypertrophy
A
- longer duration p wave in inferior leads (II) or V1; P mitral
12
Q
R ventricle hypertrophy
A
consider if large R wave in V1 or V2
13
Q
L ventricle hypertrophy
A
consider if large R waves in I II III, aVL, aVF or V5/V6
14
Q
Ischemic
Injury
Infarction
+How to tell location
A
- Ischemia - T wave inversion
- Injury (acute infarction) - ST elevated
- Infarction - denoted by Q waves
- Lateral - I aVL
- Septal - V1/V2
- Anterior - V2 to V4 (L anterior descending artery)
- Inferior - II/III/aVF (R coronary)
15
Q
Evidence of Digoxin Use on EKG
A
ST depression; “scooped out T wave”
