Case 204

Female patient, 72 years old, previously healthy, seeks hospital care after ischemic stroke of sudden onset confirmed by computed tomography and magnetic resonance imaging of the skull. Laboratory tests and Doppler of the vertebral and carotid arteries were requested, which did not reveal the cause of the stroke. The investigation followed with transesophageal and transthoracic echocardiograms. On physical examination: oriented, afebrile, blood pressure of 120 / 70mmHg, cardiac frequency of 74bpm, regular rhythm, respiratory rate of 14bpm.

Image 1: Transthoracic echocardiography in apical 4-chamber window.

Image 2: Transthoracic echocardiography on the long axis of the left ventricle, parasternal window, with the mitral valve open.

Image 3: Transthoracic echocardiography on the long axis of the left ventricle, parasternal window, with the mitral valve closed.

Question:

Based on the information and the images presented, what is the most likely cause of the stroke?