A 28-year-old male patient presented with fever, night sweats, fatigue, and severe shortness of breath. He has a history of congenital valvular heart disease. O/E there is a new holosystolic murmur best heard at the apex. Skin examination reveals multiple 1- to 2-mm red-purple spots on both legs. If the patient is not treated, which of the following complications is most likely to occur in the next month?