The initial symptoms of endocarditis are similar to flu and include:
Without treatment, the infection damages the heart valves and disrupts the normal flow of blood through the heart.
This triggers a range of life-threatening complications, such as:
Endocarditis is treated with a course of antibiotics given via a drip. You'll need to be admitted to hospital for this.
Some people also need surgery to repair or replace a damaged heart valve or drain away any abscesses that develop.
Endocarditis is a serious illness, especially if complications develop. Early diagnosis and treatment is vital to improve the outlook for the condition.
Endocarditis is a rare condition in England, even in those with a higher risk.
It's more common in older people, with half of all cases developing in people aged over 50.
But cases of endocarditis have been recorded in children, particularly those born with congenital heart disease.
Twice as many men are affected as women.
Although it may sound strange, rates of endocarditis are increasing because of advances in medical care.
This is because there's an increasing number of people being treated with valve replacement surgery or surgery to repair congenital heart disease.