Non-rheumatic atrial fibrillation and stroke

The risk of systemic embolism and stroke in patients with non-rheumatic atr ial fibrillation (NRAF) should not be underestimated. The annual embolic ra te is approximately 5% and in those with left atrial enlargement and/or lef t ventricular (LV) dysfunction, or who have already had systemic embolism, this rate may be as high as 20%. Decisions on patient management and the pr ophylaxis of stroke must always be individualised The risk of bleeding rela ted to warfarin is almost certainly greater than that encountered in the pr evious randomised trials. Also, clinical and echocardiographic features can further define absolute risk in an individual patient with NRAF. Clinical markers of increased risk of embolism in patients with NRAF include older a ge, previous cerebral embolism, recent congestive heart failure, hypertensi on and diabetes mellitus. Transthoracic echocardiography improves risk stra tification and should be performed in the vast majority of patients. Emboli c risk is greatest in those with increasing left atrial dilation, atrial dy sfunction and LV dysfunction. Transoesophageal echocardiography sharpens th e risk profile in selected patients. Overall randomised trials show greater benefit with warfarin than aspirin. In general, increasing age is associated with a greater incidence of struct ural heart disease and probably implies greater potential benefit with warf arin. Increasing age per se may not increase the risk of warfarin-related b leeding. When the decision is made to warfarinise patients, at the present time data suggest that the target INR should be in the range of 2.0-3.0.