Cardiac arrhythmias are common in the critically ill. This chapter will give an overview of the prevalence, aetiology, therapy and impact of cardiac arrhythmias in the intensive care unit (ICU).

Amiodarone is a drug increasingly being used to treat arrhythmias within the ICU, but it is not without hazard. Amiodarone will be discussed but there is no scope in this chapter for in-depth discussion of the other anti-arrhythmic agents.

Prevalence of arrhythmias in ICU

Some of the early work on the prevalence of arrhythmias in ICU came from South America [1]. Artucio and co-workers looked at over 2800 patients admitted to their ICU over a 12-year period between 1971 and 1983. They found:

• An overall prevalence of cardiac arrhythmia of 78%.

• Atrial tachyarrhythmias were the commonest arrhythmia (28%) followed by ventricular tachyarrhythmias (22%).

• Atrial fibrillation (AF) and atrial flutter accounted for 52% and 27% of the atrial tachyarrhythmias, respectively.

• Ventricular tachycardia accounted for 43% of the ventricular tachyarrhythmia which was only exceeded by ventricular premature beats (VPB) (56%).

The surprisingly high prevalence of arrhythmias in this study can be explained by the patient population and study design. The data was collected from medical ICU (that included post-cardiac surgery patients); a very high proportion of patients had been admitted with cardiac (63%) and respiratory (12%) disease.