A woman in her 50s with a history of rheumatic heart disease with mechanical mitral and tricuspid valve replacements, paroxysmal atrial fibrillation, antiphospholipid syndrome, recurrent embolic strokes, and prior spontaneous subdural hematomas while taking warfarin therapy presented to the hospital with 1 week of shortness of breath and fatigue. She reported gradual weight gain over the previous month despite diuretic and diet compliance, and outpatient laboratory testing demonstrated well-controlled international normalized ratios in the range of 3.0 to 3.5.