Rheumatic heart disease often results from repeated instances of rheumatic fever leading to issues such as heart valve malformations, rheumatic inflammation of the heart, or pericarditis. Common symptoms include accelerated heartbeat, tightness in the chest, and difficulty breathing. In cases of severe mitral stenosis combined with significant enlargement of the left atrium, atrial fibrillation can occur, which is likely to lead to the formation of atrial thrombi in patients with mitral valve issues. Hence, this type of disease can cause considerable complications, primarily leading to further deterioration of heart function. Secondly, the formation of cardiac thrombi due to atrial fibrillation might lead to the thrombus dislodging, potentially resulting in sudden symptoms like paralysis, aphasia, or even sudden death. Therefore, patients with rheumatic heart disease concurrent with atrial fibrillation should seek treatment promptly. Alleviating the narrowing would be ideal. If that is not possible, consistent anticoagulation therapy should be maintained to prevent the formation of thrombi.