Introduction

Arrhythmias are a common problem in the cardiothoracic critical care unit. Although a broad spectrum of arrhythmia types and mechanisms are possible, atrial fibrillation (AF) and ventricular tachycardia (VT) are the commonest tachycardias encountered. Bradycardias, such as atrioventricular block (AV block) or sinoatrial disease, can also be problematic. These rhythm disturbances often require prompt recognition and treatment. Failure to do so may result in life-threatening cardiac events.

Atrial arrhythmias

Atrial fibrillation

The most common postoperative arrhythmia, AF usually happens within the first 4 to 5 days after cardiac surgery. It occurs in approximately 30% of all postcardiac surgical patients, although up to 60% of those undergoing valve repair or replacement may be affected. The risk of developing postoperative AF depends on a number of preexisting and perioperative factors.

The mechanism of postoperative AF is unknown. However, inflammation has been shown to play a role. Patients with higher C-reactive protein levels after cardiac surgery have a greater chance of developing AF. There is some evidence that offpump surgery reduces inflammation and postoperative AF, although this has not been confirmed in randomized controlled trials. The development of AF in the early postoperative period has an adverse effect on prognosis, with a threefold increase in risk of stroke, plus an increased incidence of myocardial infarction, ventricular arrhythmias, cardiac failure and the need for mechanical circulatory support. Postoperative AF increases the overall hospital stay by an average of 3 days, and recurrent AF is the commonest cause of hospital readmission after discharge after cardiac surgery.