EKG Practice

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What is the normal duration of the PR Interval

0.12 to 0.20 seconds (3-5 small boxes wide)

What is the normal duration of the QRS Complex

≤ 0.10 seconds

What do QRS Complexes look like limb leads

Tall and Positive in all limb leads except aVR

What is seen in the V1-V6 leads for the QRS complex

What is considered ST Segment Depression

0.5 mm or more

What is considered ST elevation

1 mm or more in all leads except V2-V3 suggests MI

• V3/V4 STE is significant if 2+ mm in men or 1.5+ mm in women

What can cause Peaked T waves

Hyperkalemia

What can cause T wave inversion/flattening

Ischemia

What are 3 ways to determine rate?

a. (Count PP/RR) waves on 6 second strip and multiply by 10 to get BPM

b. Large (# of large boxes/300) Box method

c. Small (# of small box/1500) Box method

Normal Sinus Rhythm

• 60-100 BPM

  • Normal P, PR, QRS, T

Sinus Tachycardia

• Sinus Rhythm but HR > 100 BPM

Sinus Bradycardia

• Sinus but HR < 60 BPM

Sinus Arrhythmia

• HR increases with inspiration and decreases with expiration

  • No treatment require

Sinus Exit Block

• SA Node sends impulse but isn’t able to exit the node

• each pause is equal to a multiple of previous P-P intervals.

Sinus Arrest

• SA node fails to generate an impulse → for 1+ beats resulting in absent PQRST complex → decreased CO

Premature Atrial Contraction (PAC)

• Single ectopic beat that arising from atrial tissue NOT SA node → causes atria to discharge before the next SA node impulse is due

  • Increase in PACs may occur before afib/flutter

Multifocal Atrial Tachycardia (MAT)

• Common in COPD/Pulm Hypertension patients → fix pulm problems

  • 150-250 bpm

Atrial Flutter

• P wave = Sawtooth appearance

  • Rapid ventricular response (RVR) >100

  • Flutter waves are usually regular; QRS are not

  • 240-320 BPM

Atrial Fibrillation

• loss of atrial kick

  • High risk for pulmonary/systemic emboli

1. Junctional Escape Rhythm

2. Junctional Escape Beat

AV Node takes over → 40-60 bpm

• P waves inverted in Lead II, occur immediately before, after, or within the QRS