Abstract 2920: Left Ventricular Remodeling Reduces Papillary Muscle Contractility in Patients with Dilated Cardiomyopathy: Quantitative analysis by 2-Dimensional Tissue Tracking Technique
Background: Quantification of papillary muscle (PM) function has become feasible with newly developed two-dimensional echocardiographic tissue tracking system (2DTT), which enables us to track selected points automatically during the whole cardiac cycle using digital image files. Although left ventricular (LV) remodeling causes outward displacement of the PM in patients with dilated cardiomyopathy (DCM), the PM function in DCM remains uncertain.
Objective: To evaluate the relationship between PM function and LV geometry in patients with DCM.
Methods: The LV apical two-chamber image was digitally acquired in 15 patients with DCM (LVEF: 27.7 ± 8.0%) and 12 normal subjects (62.1 ± 6.8%). Two points were manually placed on both tip and base of posteromedial PM, and the movement of these points during one cardiac cycle was tracked by 2DTT (EUB-8500, HITACHI, Japan). The PM length in each frame were measured automatically, and % systolic PM shortening (%SS: (diastolic length - systolic length) /diastolic length) was calculated in its long axis direction. The LV shape was assessed using the LV short-to-long axis dimension ratio as spherical index (SI) in mid-systolic apical two-chamber view.
Results: Compared to normal subjects, patients with DCM had a significantly larger SI (0.70 ± 0.09 vs 0.50 ± 0.04, P < 0.01), and a greater reduction in %SS (4.1 ± 4.1 vs 22.1 ± 4.0%, P < 0.01). Furthermore in DCM, %SS showed significant negative correlation with SI (figure⇓), although there was no correlation between %SS and LVEF.
Conclusion: These results suggest that left ventricular remodeling may attribute to papillary muscle dysfunction regardless of LVEF in patients with dilated cardiomyopathy.