Rheumatic heart disease (RHD) often follows a recent streptococcal infection. To confirm the presence of a streptococcal infection, a throat culture or a blood test may be performed. During a physical examination, a heart murmur or a friction rub might be detected. A heart murmur indicates altered blood flow through damaged heart valves, while a friction rub suggests inflammation and movement of cardiac tissues against each other.

Following a thorough physical examination, several diagnostic tests may be utilized to confirm a diagnosis of rheumatic heart disease:

* Blood Test: This test checks for antibodies, indicating a recent Group A streptococcal infection.
* Echocardiogram (Echo): Considered the most suitable test for diagnosing heart valve problems, an echocardiogram provides detailed images of the heart's chambers and valves. It can reveal issues such as blood backflow through a damaged valve, fluid accumulation around the heart, or an enlarged heart.
* Electrocardiogram (ECG): An ECG identifies abnormal heart rhythms (arrhythmias) and can sometimes detect damage to the heart muscle.
* Cardiac MRI: In specific cases, a cardiac MRI may be used for a more detailed assessment of the heart valves and muscle.