Endocarditis is a rare, but potentially serious, inflammation, of the structures and internal lining of the heart. It can affect the heart valves, or the walls of the chambers of the heart. Endocarditis is not necessarily linked to heart disease, but it is still more common and dangerous in patients with heart disease, including those who have artificial heart valves. The bacteria involved are numerous, but are often streptococci or staphylococci and can penetrate through various entry points, usually a dental or ENT infection. Clinical signs include fever, and a heart murmur heard by the doctor. The diagnosis is made through a blood culture for bacteria or a blood test, but especially a Doppler ultrasound of the heart. Endocarditis is treated with antibiotics, or surgery in severe cases.