Alessandra W. is a 70-year-old lady referred to you for shortness of breath. She was previously fairly healthy until 2 months ago when she began noticing mild dyspnea with walking one to two blocks, climbing two flights of stairs, and while swimming at her local pool. Her symptoms have progressed since then to the point where she was forced to give up her swimming, which she had been doing regularly for the last several years. She also could no longer climb more than one flight of stairs without stopping. Over the last few days, she has noticed swelling in her ankles. She has become particularly concerned because she has been waking up at night short of breath and for the first time yesterday was forced to sleep sitting in her recliner. She denies any chest pain, fever, or cough.