My husband was just prescribed Topral XL and Coumadin for an irregular heart beat - told that with his problem the blood could pool and clot. His blood pressure is low. Wont the 25 mg of Topral XL be harmful to his already low bp? He said his cardiologist told him his heart beats too fast. After being on these meds a while, he is having some other tests done at the hospital - that may take as long as 4-5 hours.