This case presentation summarizes a 76-year-old male patient admitted to the hospital for atrial fibrillation and hypothyroidism. The patient presented with frothing from the mouth, loose stools, and breathlessness. Diagnostic tests showed abnormal thyroid and cardiac function. The patient was diagnosed with atrial fibrillation and hypothyroidism based on physical exam findings, lab results, echocardiogram, and information from the referring physician. He was prescribed various medications to treat his conditions and symptoms, including drugs to maintain normal heart rhythm and thyroid hormone replacement. His hospital course and treatment plan are outlined over several days.