Symptoms. Endocarditis may develop slowly or suddenly — depending on what's causing the infection and whether you have any underlying heart problems. Endocarditis signs and symptoms vary, but may include: 1  Fever and chills.2  A new or changed heart murmur — heart sounds made by blood rushing through your heart.3  Fatigue.f you develop signs or symptoms of endocarditis, see your doctor right away — especially if you have risk factors for this serious infection, such as a heart defect or a previous case of endocarditis. Although less serious conditions can cause similar signs and symptoms, you won't know for sure until you're evaluated.