Clinical Reasoning: Cardioembolic stroke in a 23-year-old man with elbow contracture.

Section 1 A 23-year-old right-handed man with a diagnosis of spinal muscular atrophy (SMA) type 3 presented with right facial droop, hemiparesis, and expressive aphasia. CT angiography revealed a thrombus in the distal left middle cerebral artery. IV tissue plasminogen activator was administered and he recovered without any residual deficit. His cardiac monitoring revealed episodes of atrial fibrillation (figure, C) and episodes of narrow junctional escape rhythm in 20–30 s. ECG showed normal left ventricular ejection fraction (>55%). Cardiac MRI showed moderate dilation of right atrium, moderate left atrial elongation, and severely increased left ventricular cavity size with normal systolic function.