Review Question - QID 214275

A 42-year-old man presents to his primary care physician for an annual physical exam. His past medical history is significant for alcohol use disorder complicated by periods of homelessness. Otherwise, he has been well with no major complaints during this visit. On physical exam, a new cardiac murmur is heard between the S1 and S2 heart sounds. The murmur does not appear to vary much in intensity, and it is best heard along the left sternal border in the 4th intercostal space. Physical exam also reveals 1+ edema of the lower extremities bilaterally as well as increased jugular venous pressure. Which of the following is most likely associated with the cause of this patient's murmur?