Unilateral cardiogenic pulmonary edema (CPE) accounts for ~2% of pulmonary edema cases and is classically caused by posterior papillary muscle rupture, resulting in acute, severe, eccentric mitral regurgitation. Flow is directed specifically to the right-sided pulmonary veins. This, in turn, overwhelms the lymphatic capacity of the right lung and results in lateralized pulmonary edema as seen in this chest x-ray.
