Table 4.2 Interpretation of an ECG
- Assess the quality of ECG. Check the calibration of the amplitude of deflection, the paper speed and whether the filter was on or off. Look for artefacts.
- Calculate the heart rate. Establish whether it is fast, slow or normal, and whether it is variable.
- Assess the overall rhythm. Establish whether changes in rhythm are intermittent or persistent and whether they are induced or terminated by excitement or any procedures such as a vagal manoeuvre (e.g. ocular pressure or carotid sinus massage).
- Assess each wave/complex in turn. Measure the duration and amplitude of the P wave and QRS complex and the duration of the intervals. Establish whether all the complexes are similar or not.
- Examine the relationship between the complexes. Check whether each P wave is followed by a QRS complex, and whether there is a P wave before each QRS complex.
- Define the heart rhythm and a plan for further diagnostic investigations and treatment if necessary.