A 76-year-old man developed a rare fungal infection on his artificial heart valve caused by Histoplasma capsulatum, a fungus found in soil and bird droppings. After surgery to replace the infected valve, he was treated with isavuconazole, an antifungal medication that proved highly effective and better tolerated than traditional treatments. After nine months of therapy, all signs of infection had resolved and his new valve was working properly.