Review Question - QID 109960

A 72-year-old woman presents to her primary care physician because she is coughing pink sputum and has difficulty breathing. She says that she was feeling pretty good until she traveled to her grandson's wedding last week. Since then she has had increasing difficulty sleeping and walking due to her shortness of breath. Physical exam reveals swollen ankles, basilar crackles bilaterally, and a murmur best heard in the left lateral decubitus position. She is already taking several medications for this condition; however, given the recent worsening of symptoms she is started on an additional medication. Which of the following is the most likely mechanism of action for the medication that was started in this patient?