This 78 year old female with right hip pain due to degenerative joint disease is admitted for a total hip arthroplasty. Her pain started eight years ago. Her activities of daily living are now severely limited, as she has a limited ROM. In addition to the hip problem, she has glaucoma with decreased visual acuity. For this problem, she has taken Timoptic 0.25% for two years. X-ray showed degeneration of the hip. Her CBC was normal. Her EKG showed atrial fibrillation. A cardiologist was consulted and he recommended that the surgery be canceled until the atrial fibrillation could be controlled. The patient was discharged with the instructions to see the cardiologist in one week. What is the patient’s principal diagnosis?