CH3 - Analyzing EKG Rhythm Strips

EKG 5-Step Analysis Method

1. Regularity

   • Are the R-R interval evenly spaced? Is it regulat?

2. Rate

   • What is the HR?

   • Bradycardia: <60bpm

   • Tachycardia: >100bpm

   • Normal: 60-100

3. P Waves

   • Are P waves present?

   • Upright?

   • One for every QRS?

4. PR Internval

   • What is the PR interval

   • Normal: 0.12-0.20s

5. QRS Complex

   • Is it narrow or wide

   • Normal: <0.11s

What to ask yourself for Regularity?

1. Is it regular?

2. Is it irregular?

3. Are there any patterns to the irregularity? 

4. Are there any ectopic beats? If so are they early or late? 

How to check for Regularity?

Check spacing between R-R intervals across the strip → if consistent, the rhythm is regular

Explain Ectopic beat

• When a single beat arises from an ectopic focus (a site outside of the SA node) within the conduction system 

• Common use to suggest that the site became irritable and overrode the sinus node 

How to tell if ectopic beat is caused by irritability or escape?

1. An early or premature beat would be an indication of irritability

2. An escape beat would be preceded by a prolonged R-R cycle

What to ask yourself for Rate?

1. What is the exact rate

2. Is the atrial rate the same as ventricular rate?

How to ACCURATELY measure Heart Rate?

• 6 second method: Count the number of R waves in a 6 second strip x 10

  • Used for regular or irregular rhythms

• Small box method: HR = 1500/ # Small boxes

What to ask yourself for P waves?

1. Are P waves present?

2. Are the P waves regular?

3. Is there one P wave for every QRS?

4. Is the P wave in front of the QRS or behind it?

5. Is the P wve normal and upright in Lead II?

6. Are there more P waves than QRS?

7. Do all the P waves look alike?

8. Are the irregular P eaves associated with ectopic beats?

P waves represent what on an EKG tracing?

Atrial depolarization

What to ask yourself for PRI?

1. Are all the PRIs constant?

2. Is the PRI measurement within normal range?

3. IS the PRI varies is there a pattern to changing measurements?

PRI represent what on an EKG tracing?

Measures time from the start of atrial depolarization to the start of ventricular depolarization 

What is the normal range for PRI?

• 0.12 - 0.20 seconds

• 3-5 small boxes

A Prolonged PRI indicates what?

• 1st Degree AV block → A delay in electrical conduction from the atria to the ventricles usually at the AV node

• Normal = 0.12 - 0.20 seconds

A Shorten PRI indicates what?

• Impulses may be bypassing the AV node 

• Normal = 0.12 - 0.20 seconds

What is the Role of the AV Node?

• Acts as a gatekeeper between atria and ventricles → responsible for “holding” impulses until the ventricles are able to receive them

• Slow conduction allow time for:

  1. Atrial contraction (atrial kick)

  2. Ventricular filling

• Can act as a backup pacemaker if SA node fails

What to ask yourself for QRS Complex?

1. Are all the QRS complexes of equal duration?

2. What is the measument of the QRS complex?

3. Is the QRS measurement within normal limits?

4. Do all the QRS complexes look alike?

5. Are the unusual QRS complexes associated with ectopic beats? 

QRS waves represent what on an EKG tracing?

• Ventricular depolarization

• Normal: <0.11 second

What does a narrow/wide QRS complex mean?

• Narrow

  • A supra-ventricular focus

• Wide

  • A ventricular pacemaker or a supra-ventricular pacemaker that was delayed

Distinguish between Supra-ventricular & Ventricular 

• Supra-ventricular → Originates above the the ventricles (SA node, atria, or AV node)

  • Narrow QRS 

  • Visible waves 

• Ventricular → Originates in the ventricles

  • Wide QRS

  • Often no P wave or P not related to QRS

  • EX: supra-ventricular pacemaker that way delayed with the ventricular conduction system