With prompt diagnosis and proper medical treatment, over 90% of patients with bacterial endocarditis recover. Those whose endocarditis affects the right side of the heart usually have a better outlook than those with left-side involvement. In cases in which endocarditis is caused by fungi, the prognosis is usually worse than for bacterial endocarditis.
Some possible complications of endocarditis include:
Congestive heart failure
Floating blood clots, called emboli, in the bloodstream that lodge in the brain, lungs or coronary arteries
If acute endocarditis remains untreated, it can be fatal in less than six weeks. Untreated subacute endocarditis can cause death within six weeks to one year.