A 75 year old man presents to his physician for a routine examination. He has a history of hypertension, hypercholesterolemia and osteoarthritis. He takes atenolol, simvastatin and ibuprofen as needed. His pulse is 76/min and irregular. Blood pressure is 130/74. Physical examination and imaging studies are normal except for asymptomatic atrial fibrillation. What is the most appropriate next step in management of this patient? A- Assurance and follow up in 3 months B- Start aspirin C- Start heparin D- Start warfarin E- Start low molecular weight heparin and warfarin Answer