Question

An evaluation is requested for a 53-year-old woman who presents to the clinic reporting a three-week history of progressively worsening shortness of breath and new-onset lower extremity swelling. She reports waking up frequently during the night gasping for air. The patient has a 12-year history of seropositive rheumatoid arthritis that has been stable for the past two years on a regimen of methotrexate and infliximab. She also takes naproxen as needed for joint pain. Her temperature is 37.0°C (98.6°F), blood pressure is 138/85 mmHg, pulse is 96/min, and respiratory rate is 22/min. Pulse oximetry shows 94% on room air. Physical examination reveals jugular venous distention at 9 cm $H_2O$. Lung auscultation demonstrates bibasilar fine crackles. Cardiac examination shows a regular rate and rhythm with a prominent S3 gallop. The abdomen is soft, and there is 2+ pitting edema of the lower extremities bilaterally. Joint examination shows ulnar deviation of the metacarpophalangeal joints but no acute synovitis or effusions. Laboratory studies reveal a hemoglobin of 11.2 g/dL, a normal comprehensive metabolic panel, a thyroid-stimulating hormone (TSH) level of 1.2 $\mu$ U/mL (normal: 0.5-5.0 $\mu$ U/mL), and a slightly decreased total $T_4$ level. Which of the following is the most appropriate next step in the management of this patient?