Cardioembolic Stroke as tche Initial Manifestation of Previously Undiagnosed Moderate Mitral Stenosis with Atrial Fibrillation: A Case Report

Abstract

Cardioembolic stroke remains one of the most severe complications of atrial fibrillation (AF), particularly in patients with structural heart disease such as mitral stenosis (MS). Moderate-to-severe MS contributes to left atrial enlargement and blood stasis, thereby increasing the risk of thromboembolism even in the absence of visible intracardiac thrombus on imaging.1,2 Early identification of underlying valvular abnormalities in patients presenting with ischemic stroke is essential for optimizing secondary prevention.3 A 40-year-old woman was referred to a tertiary healthcare facility for echocardiographic evaluation following hospitalization for suspected nonhemorrhagic stroke associated with atrial fibrillation and a urinary tract infection. She initially presented with dysarthria, aphasia, and dysphagia. Physical examination revealed stable hemodynamics with central cranial nerve VII and XI paresis. Electrocardiography demonstrated atrial fibrillation with a controlled ventricular response. Brain computed tomography showed infarction in the left frontal lobe and left corona radiata, with additional lacunar infarcts in the midbrain and pons. Transthoracic echocardiography revealed moderate mitral stenosis with a mitral valve area of 1.44 cm², mild mitral regurgitation, left atrial dilation, mildly reduced left ventricular systolic function, reduced right ventricular systolic function, and minimal pericardial effusion, without evidence of intracardiac thrombus or vegetation. The patient received multidisciplinary management involving neurologists and cardiologists, including antiplatelet therapy, a beta-blocker, a statin, diuretics, and supportive care, resulting in gradual neurological improvement. This case highlights ischemic stroke as the first clinical manifestation of previously undiagnosed moderate mitral stenosis accompanied by atrial fibrillation. The coexistence of AF and left atrial enlargement likely contributed to the cardioembolic risk despite the absence of a demonstrable intracardiac thrombus.