7.2 Identification of arrhythmias
When an arrhythmia is suspected from clinical examination or historical findings, it is helpful to document the rhythm disturbance using an ECG. In certain situations it may be important to record the ECG over a prolonged period with a Holter monitor, or to examine the effect of exercise on rhythm using radio-telemetry. These techniques of recording ECGs and the principles of interof the ECG were described in section 4.1.
In order to assess the significance of an arrhythmia, a specific diagnosis must be made. The important steps when an abnormal rhythm is detected are to:
- Classify the arrhythmia. This requires a good knowledge of the normal anatomy and electrophysiology of the heart (see section 1.5), a clear ECG recording and a logical approach to the interpretation of the ECG (see section 4.1.4).
- Identify underlying cardiac or systemic disease.
- Direct management and treatment of the horse, if it is appropriate.
The clinical approach to horses with arrhythmia is shown in Table 7.1, and a summary of the main features of each arrhythmia is shown in Table 7.2.