The reported annual risk of stroke in controlled heart failure studies is between 1 and 2% and the risk of myocardial infarction from 2 to 5.4%, respectively. The annual risk of stroke in Stroke Prevention in Atrial Fibrillation study was 10.3% in atrial fibrillation patients with definite heart failure and 17.7% with recent congestive heart failure . Yet, the corresponding risk of stroke analysed from pooled data from 5 randomized controlled atrial fibrillation trials was less than in the SPAF I analysis; 6.8% in the placebo group and 1.6% in the warfarin group .