Atrial fibrillation may prove quite symptomatic and an individual may feel palpitations, activity intolerance, shortness-of-breath, or lightheadedness. Or atrial fibrillation in a given individual may take the form of no symptoms whatsoever. The absence of symptoms does not mean that an individual does not have an increased risk of potential problems from atrial fibrillation. Faster heart rates sustained for days or weeks on end can weaken the heart muscle. Atrial fibrillation itself is a small risk for the development of blood clots or strokes. With atrial fibrillation an individual does need treatment to make sure that the heart rate does not race, and that the risk of stroke is made as low as possible.