Hatim Al Lawati, MD, FRCPC, Cardiology Resident, Division of Cardiology, Faculty of Medicine, University of Toronto, Toronto, ON.
Fatemeh Akbarian, MD, Dermatologist, Research Fellow, University of Toronto, Toronto, ON.
Mohammad Ali Shafiee, MD, FRCPC, General Internist, Nephrologist, Department of Medicine, Toronto General Hospital, University Health Network; Clinician Teacher, University of Toronto, Toronto, ON.

Atrial fibrillation (AF) is by the far the most common cardiac rhythm disturbance encountered in clinical practice. It is associated with significant morbidity and mortality and has potentially lifelong implications in terms of therapy and complications. This disease is more commonly seen now given the increased life expectancy and the remarkable advances made in health care. The already at-risk older adult population is particularly vulnerable to complications from AF, especially embolic cerebrovascular events. This article reviews the evidence-based management of AF with a particular focus on the older adult population.
Key words: atrial fibrillation, older adults, stroke, rate control, rhythm control, stroke prophylaxis, anticoagulation.

Jagdish Butany, MBBS, MSc, FRCPC, Department of Pathology, Toronto General Hospital, University Health Network; Departments of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON.
Nasir A. Khan, BSc, Department of Pathology, Toronto General Hospital, University Health Network, Toronto, ON.
Sarah A. Erlich, BSc, Department of Pathology, Toronto General Hospital, University Health Network, Toronto, ON.
Anusha Jegatheeswaran, MD, Department of Cardiac Surgery, Toronto General Hospital, University Health Network, Toronto, ON.
Frances Budden, MD, FRCPC, Department of Geriatric Medicine, St. Joseph’s Health Centre, Toronto, ON.
Vivek Rao, MD, PhD, Department of Cardiac Surgery, Toronto General Hospital, University Health Network, Toronto; Department of Surgery, University of Toronto, Toronto, ON.

The incidence of valvular heart disease continues to increase, and the majority of individuals undergoing heart valve replacement today are older adults. Good postoperative management of these patients is critical and should include a complete history and thorough physical examination along with regular testing (typically including chest x-ray, echocardiogram, and blood tests) to carefully monitor heart function. Older adults are particularly at risk of bleeding and thromboembolic complications and, as such, compliance with anticoagulation and other medication should be closely monitored. Judicious attention to these issues will help minimize potential complications and improve survival in this patient population. This review discusses the postoperative management of older adults with a mechanical or a biological prosthetic heart valve.
Key words: heart valve replacement, prosthetic heart valves, older adults, anticoagulation, prosthetic valve endocarditis.

Sarah E. Wilson, MSc, MD, PGY1, Internal Medicine, University of Toronto, Toronto, ON.
Mark A. Crowther, MD, MSc, Associate Professor of Medicine, Department of Medicine, McMaster University, Hamilton, ON.

Warfarin reduces the risk of thrombotic complications in a wide range of patients and appears to be particularly effective in older adults. Warfarin initiation should be undertaken with care in the older adults because they are likely to require smaller maintenance doses to achieve the same target international normalized ratio (INR). Inappropriate prescribing of medications among older adults increases the risk of drug interactions that may alter warfarin anticoagulation. Such interactions should be anticipated and monitored to ensure that over- or under-anticoagulation do not persist. A range of strategies are available to follow warfarin therapy in the outpatient setting to ensure safe and effective anticoagulation.
Key words: warfarin, anticoagulation, vitamin K, atrial fibrillation.

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.

Lilia Malkin, BSc

According to a study conducted by Dr. Elaine Hyle and associates at the Massachusetts General Hospital and Harvard Medical School in Boston and reported in the March 4, 1998 issue of the Journal of the American Medical Association (JAMA), acetaminophen significantly increases the level of anticoagulation, measured and commonly reported as the international normalized ratio (INR). Other important risk factors for increased anticoagulation identified in the study included decreased food intake, diarrhea, and increased warfarin dosage, as well as a recently initiated course of antibiotics or other medications previously known to augment the response to warfarin. Hylek and associates also identified factors that inversely affected the INR, such as alcohol and increased dietary intake of Vitamin K.