The 11-STEP Method

-

THE 11 STEP METHOD

1. Other

2. Evaluate the P wave

3. Determine the rhythm

4. Determine the rate

5. Calculate the duration of the PR interval

6. Calculate the duration of the QRS complex

7. Evaluate the T wave

8. Calculate the duration of the QT interval

9.  Assess the ST segment

10. Interpretation

11. Treatment

  

THE 11 STEPS

1. Other

Identify anything you consider unusual or obvious about the rhythm, e.g., extra P waves, inverted T waves.

2. Evaluate the P Wave

  •          Are P waves present?
  •          Do the P waves have a normal configuration?
  •          Do all the P waves have a similar size and shape?
  •          Is the P wave consistently followed by a QRS complex?
  •         Is there a QRS after every P wave?

3. Determine the Rhythm

You can use the pencil and paper method or the calipers method to assess whether the rhythm is regular. For atrial rhythm assessment, measure the intervals between consecutive P waves.

Place a piece of paper over the rhythm and place a mark on a P wave and again on the next P wave. Move the markers across the rhythm from P wave to P wave to check that the rhythm is regular.

These intervals, known as P-P intervals, should occur regularly with only very small differences associated with respiration.

For determining ventricular rhythm, measure intervals between consecutive R waves.

After completing your measurement ask if the rhythm is regular or irregular? If the rhythm is irregular, is it regularly irregular, or completely irregular

4.     Determine the Rate

Heart rate is the number of heartbeats occurring in 1 minute. On an ECG, the heart rate is measured from P wave to P wave to determine the atrial rate and from R wave to R wave to determine the ventricular rate.

Heart rate is dependent on age:

Newborn 100 – 150,                        <100 bradycardia,          >150 tachycardia

2 years 85 – 125,                              < 85 bradycardia,          >125 tachycardia

4 years 75 – 115,                              < 75 bradycardia,          >115 tachycardia

6 years 65 – 100,                              < 65 bradycardia,          >100 tachycardia

Adult 60 – 100,                                < 60 bradycardia,           >100 tachycardia

To determine the heart rate:

  •         Obtain a six-second rhythm strip (a piece of ECG paper showing 30 large squares because 1 large square of 0.20 secs x 30 = 6 secs).
  •         Count the number of P waves and multiply by 10 for atrial rate (i.e. a 6 second strip x 10 = 1 minute).
  •         Count the number of QRS complexes and multiply by 10 for the ventricular rate.

 

17 QRS complexes are in the 6 second strip (30 large boxes)

17     10 = 170 beats / minute

5.     Calculate the Duration of the PR Interval

  •        Count the number of small squares between the start of the P wave and the start of the QRS complex.
  •         Multiply the number of squares by 0.04 seconds.
  •         Normal PR interval is:

·         according to the table for pediatrics.

·         between 0.12 and 0.20 seconds (3-5 small squares) for adults.

 

6.     Calculate the Duration of the QRS Complex

  •     Count the number of small squares from the start of the Q wave to the end of the S wave
  •     Multiply the number of squares by 0.04 seconds
  •     The normal QRS complex is;

o   according to the table for pediatrics

o   between 0.06 and 0.10 seconds (1.5 – 2.5 small squares) for adults.

 

7. Evaluate the T Wave

  •         Are T waves present?
  •         Do they have a normal shape (upright and rounded)?
  •          Are there any bumps in the T wave (possibly extra P waves)?
  •          Do the T waves have normal amplitude?

8. Calculate the Duration of the QT Interval

  •          Count the number of small squares from the beginning of the Q wave to the end of the T wave.
  •          Then multiply the number of squares by 0.04 seconds.
  •          Normal QT interval is dependent on rate – see the table below. For an adult the normal range is between 0.36 and 0.44 seconds (9 – 11 small squares).

9. Evaluate Any Other Components

  •          Check the ST segment for any abnormalities. Is it isoelectric, depressed or elevated?
  •          Look for a U wave.
  •         Observe for other components including ectopic or aberrantly conducted beats.
  •          Note any findings.

10. Interpretation

Based on your assessment of the strip, and by knowing the rules associated with each rhythm, what is your interpretation?

11. Treatment

Appropriate treatment will be based on the interpretation of the rhythm.


Comments

Post a Comment

Popular posts from this blog

Conduction System

-
Image
Learning Objectives 1) Describe the conduction system 2) Describe the basic function of the 3 pacemakers 3) Relate the pacemakers to the tracing on an ECG Overview The cardiac conduction system is a group of specialized cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract. The main components of the cardiac conduction system are the SA node, AV node, bundle of His, bundle branches, and Purkinje fibers. The SA node (anatomical pacemaker) starts the sequence by causing the atrial muscles to contract. From there, the signal travels to the AV node, through the bundle of His, down the bundle branches, and through the Purkinje fibers, causing the ventricles to contract. This signal creates an electrical current that can be seen on a graph called an Electrocardiogram (EKG or ECG). Doctors use an EKG to monitor the cardiac conduction system's electrical activity in the heart. The Sino-Atrial Node Figure 1 (SA) (Figure 1) is an oval sha...
Read more

Calculating the Heart Rate

-
Image
Learning Objectives:   1. Calculate the heart rate using the Box Method and Division Method   Calculating the rate in an ECG is an important as identifying the rhythm itself as it bears implication to the treatment. Although various methods are available, for simplicity and practicality only 2 methods will be introduced here.   The Box Method 1. Find a R wave that lands on a heavy line 2. Place the following value on succeeding heavy line as done in the diagram below 3. If the next R wave falls on a heavy line assigned the appropriate rate value to it. 4. If however the next R wave falls between 2 heavy lines, take the difference between the 2 value and divide by 5. Each of the small square is then worth that quotient.   The Division Method 1) Count the number of large boxes between 2 R waves 2) Divide that number by 300, and assign that as the approximate rate.
Read more