47. CARDIAC ARRHYTHMIAS

Anaesthetists will often see patients with perioperative arrhythmias. There are thee basic questions that the anaesthetist must quickly answer:

What is the rhythm?

What is the cause?

What is the urgency?

What is the Rhythm?

There are two basic rhythms: bradycardia and tachycardia. The anaesthetist should obtain an ECG. The anaesthetist should check if there are P waves and if so, what their relationship to the QRS complex. Is the QRS complex normal? Is the rhythm regular?

What is the Cause?

Perioperative arrhythmias usually occur in patients with some structural heart disease and a precipitating event. The precipitating event that initiates the arrhythmia may be: ischaemia, sympathetic stimulation, drugs, electrolyte disturbance, hypoxia or hypercarbia. The anaesthetist must always ensure that the patient is adequately oxygenated and ventilating.

What is the Urgency?

The anaesthetist must assess the urgency of the situation. All arrhythmias are significant but if the patient is well oxygenated, ventilating and has a stable blood pressure then the anaesthetist has time to look for a cause and treat the cause. Some arrhythmias are life theatening and need immediate treatment.

A life theatening bradycardia needs immediate treatment with drugs and/or pacing.

A life theatening tachycardia needs immediate treatment with electrical cardioversion/defibrillation.

An unstable bradycardia needs the cause identified and treatment with drugs.

An unstable tachycardia needs the cause identified and treatment with drugs.