Yes, there is still a 1%/year risk of a stroke if you are in continuous afib (& are rate controlled) and take warfarin/coumadin and you had a prior history of high blood pressure. So the odds of a stroke over the next 30 years is about 25- 30%. On the other hand, this is about the average (1%/yr) for the general population (who are not in afib). So you are not at greater risk than the average person--- but the risk is still there.
Here's a website that briefly discusses the probabilities (based on the CHADS model)
The odds of a stroke increase if valve problems are contributing to your afib, or if you have a history of diabetes, heart failure, prior stroke and if you are over 75 years of age.
I assumed that you had a CHADS score of 1 (for prior high bp) = 2.8% risk a year without anticoagulation and less than 1% with warfarin/coumadin.
I also have a CHAD score of 1 and am curently in afib that is rate controlled (resting HR varying between 55-80) and take coumadin.