Left ventricular papillary muscle mass: Relationship to left ventricular mass and volumes by magnetic resonance imaging

Objective: To evaluate the effect of papillary muscle mass on the calculation of left ventricular (LV) function and mass and to determine the relationship between papillary muscle mass with body size and sex. Methods: Cardiac magnetic resonance imaging examinations from 50 men and 50 women were randomly selected from the Multi-Ethnic Study of Atherosclerosis database. The contours of the papillary muscles were traced manually, and the LV wall contours were outlined semiautomatically based on short-axis images. Papillary muscle mass, LV mass, and volumes were calculated. Results: Inclusion of the papillary muscles results in significantly higher total LV mass values (P < 0.001) and lower end-diastolic volume values (P < 0.001) compared with measurements excluding papillary muscles from the LV mass. Papillary muscle mass accounts for 8.9% of the total LV mass and is correlated with LV wall mass (r = 0.81, P < 0.001). Conclusion: Papillary muscle mass significantly affects LV volumes and mass determined by cine magnetic resonance imaging.