The vital role of papillary muscles in mitral and ventricular function: echocardiographic insights.

The two left ventricular (LV) papillary muscles are small structures but are vital to mitral valve competence. Partial or complete rupture, complicating acute myocardial infarction, causes severe or even catastrophic mitral regurgitation, potentially correctable by surgery. Papillary muscle dysfunction is a controversial topic in that the role of the papillary muscle itself, in causing mitral regurgitation post infarction, has been seriously questioned; it is less confusing if this syndrome is attributed not only to papillary muscle but also to adjacent LV wall ischemia or infarction. Papillary muscle calcification is easily and frequently detected on echocardiography, but its clinical significance remains uncertain. Papillary muscle hypertrophy accompanies LV hypertrophy of varied etiology and may have a significant role in producing dynamic late-systolic intra-LV obstruction in hypertrophic cardiomyopathy and other hyperdynamic hypertrophied LV chambers. All the above abnormalities can be adequately assessed by 2-D echocardiography and the Doppler modalities. In selected cases, transesophageal echocardiography can provide additional valuable data by improving visualization of papillary muscles and mitral apparatus.