Unusual anomalous single papillary muscle causing symptomatic mid-left ventricular cavity obstruction: octopus papillary muscle.

This report describes a patient with an unusual large anomalous papillary muscle within the left ventricular cavity causing symptomatic midventricular outflow obstruction. The obstructing papillary muscle comprised a large central core that extended multiple circumferential muscular arms to all the walls of the left ventricle, including the septum. The papillary muscle and the arms divided the left ventricle into apical and subaortic chambers. Flow communicated between the two chambers through multiple openings between the arms with a systolic peak Doppler gradient of 50 mm Hg.