Rajneesh Calton, MD, FACC, Division of Cardiac Electrophysiology, University Health Network, Toronto General Hospital, Toronto, ON.
Vijay Chauhan, MD, FRCPC, Division of Cardiac Electrophysiology, University Health Network, Toronto General Hospital, Toronto, ON.
Kumaraswamy Nanthakumar, MD, FRCPC, Division of Cardiac Electrophysiology, University Health Network, Toronto General Hospital, Toronto, ON.

Atrial fibrillation (AF) is the most common clinically significant cardiac arrhythmia worldwide, with an estimated prevalence of 0.4% in the general population. Despite recent advances in our understanding of the mechanism and consequences of AF, effective therapy for patients with AF remains difficult in many patients. Antiarrhythmic drug therapy includes control of ventricular rate as well as restoration and maintenance of sinus rhythm. The risks and benefits of each treatment modality must be assessed according to each individual patient’s circumstances. Anticoagulation for stroke prevention is a critical component of AF management that is currently underprescribed. Anticoagulation with vitamin K antagonists, such as warfarin, remains the treatment of choice for preventing stroke and cardio embolism. The oral direct thrombin inhibitor ximelagatran has the potential to favourably influence the management of patients with AF by maximizing the potential of anticoagulation for stroke prevention.
Key words: atrial fibrillation, anticoagulation, rate control, warfarin, ximelagatran, antiarrhythmic.

Robert S. Sheldon, MD, PhD, FRCP(C) and Satish R. Raj, MD, FRCP(C), Cardiovascular Research Group, University of Calgary, Calgary, AB.

Implantable cardioverter-defibrillators are pacemaker-like devices that sense and treat ventricular tachycardia and ventricular fibrillation, and are generally used in an aging population. They have been proven in large randomized clinical trials to prevent death in patients who have already survived a life-threatening episode of ventricular arrhythmias. Recent studies have expanded their indications to the prevention of arrhythmic death in patients who have risk factors for this disorder. How widely they will be used, and at what cost, is unknown.
Key words: implanted defibrillator, arrhythmia, sudden death, anti-arrhythmic therapy, heart disease.