Basic rhythm analysis

Order of Standard ECG Analysis:

1. Calculate the Rate 

2. Assess the Rhythm

3. Conduction
- Any Heart Blocks present
- Any Atrial Fibrillation preset
- Either RBBB or LBBB present

4. Axis 
- Right Axis Deviation
- Left Axis Deviation

5. P-R interval
- Heart blocks

- P Wave
- Right or left Atrial Enlargement

6. QRS 
- Narrow - sinus, atrial or junctional origin
-Broad - ventricular origin, or supraventricular with aberrant conduction

7. S-T Segment
- Depression
- Elevation

8. T waves
- Tall Tented - Hyperkalaemia 
- Small - Hypokalaemia

Rate

For regular rhythms:  Rate = 300 / number of large squares in between each consecutive R wave

For very fast rhythms:  Rate = 1500 / number of small squares in between each consecutive R wave

For slow or irregular rhythms:  Rate = number of complexes on the rhythm strip x 6
(this gives the average rate over a ten-second period)

Conversion Values:
ECG paper speed   =  25 mm/sec
Voltage calibration 1 mV   =   1 cm
ECG paper - standard calibrations:
each small square   =   1 mm
each large square   =   5 mm
Timings: 1 small square   =   0.04 sec
1 large square   =   0.2 sec
25 small squares   =   1 sec
5 large squares   =   1 sec

This heartbeat is 300/4.5 = Rate of 67 BPM

Irregular Narrow-Complex Tachycardia at ~ 6*13 = 78 bpm

Rhythm

Look to the Rhythm strip to accurately observe this:

Usually divided into:

Regular

Irregularly Regular

Examples:

Second Degree Heart Block

Irregularly Irregular

Examples:

Atrial or ventricular ectopics

Atrial fibrillation