Isolated papillary muscle rupture with nonobstructive coronary artery disease, minimal myocardial infarction, and normal wall motion.

Papillary muscle (PM) rupture can usually complicate inferior or posterior myocardial infarctions, but selective PM infarction is extremely rare, and the exact underlying pathophysiological mechanism is not entirely clear. We present a case of PM rupture due to isolated PM infarction in a patient with unobstructed coronary arteries, which could be misdiagnosed as a vegetation or other mass given the absence of regional wall motion abnormalities (RWMAs) on transthoracic echocardiogram. Our case highlights that in patients with severe mitral regurgitation and associated mitral valve mass, the absence of RWMAs should not exclude ischemic PM rupture from differential diagnosis.