Progressive Shortness Of Breath in Medicine / Internal Medicine — 30yo Woman | Cardiology | SMLE Q#8192

A 30-year-old woman presents 3 days after an uncomplicated vaginal delivery with progressive shortness of breath, paroxysmal nocturnal dyspnea, orthopnea, pleuritic chest pain, and cough. She reports new bilateral leg swelling for 1 week. Exam shows respiratory distress, bilateral pitting edema to the mid-shins, and bibasilar crackles. Cardiac exam reveals a laterally displaced, diffuse apical impulse, an S3 gallop, and a harsh pansystolic murmur at the apex radiating to the axilla. Vitals: BP 90/70 mmHg, HR 120/min, RR 26/min, SpO2 90% on room air. Which of the following is the most appropriate next step in this patient's management?