Arrhythmias

Arrhythmias are abnormal heart rhythms resulting from a disruption to the normal electrical signals that coordinate myocardial contraction. It's causes can be classified by whether it's cardiac or non-cardiac:

• Cardiac - IHD, Cardiomyopathy, Pericarditis, Myocarditis, Disrupted conduction pathways e.g. post-MI

• Non-cardiac - Caffeine, Smoking, Alcohol, Drugs, Electrolyte imbalance (e.g. potassium)

Investigated with a 24 hr ECG monitor.

Cardiac Arrest

Defined as the cessation of cardiac activity.

Shockable rhythms - Includes Pulseless Ventricular Tachycardia and Ventricular Fibrillation. Managed with CPR 30:2 + Unsynchronised shock.

• If the rhythm is still persistent after 3 shocks, give Amiodarone 300mg IV + Adrenaline 1mg IV (1:10,000) at the same time. Adrenaline can then be repeated after every other cycle following a shock (i.e. cycles 3, 5, 7 etc.).

Non-shockable rhythms - Includes Pulseless electrical activity (normal ECG w/o a pulse) and Asystole (no QRS complexes). Managed with CPR 30:2 + IV Adrenaline 1mg.

N.B. Unsynchronised shock is the same as a Defibrillation.