Abstract 13618: Improvement of Left Ventricular Mechanics and its Relationship with Reverse Remodeling in Patients Treated by Cardiac Contractility Modulation
Introduction: Cardiac contractility modulation (CCM) is a new device-based therapy which has recently been suggested to improve clinical status and induce left ventricular (LV) reverse remodeling in patients with advanced heart failure. However, it remains unclear that the changes in LV mechanics after CCM and its relationship with reverse remodeling.
Methods: 30 patients (61±11 years, 82% male) with ejection fraction (EF) <35% and QRS <120ms who had symptomatic NYHA class III heart failure despite optimal medical therapy were enrolled to receive CCM. Two-dimensional speckle tracking imaging was adopted to measure LV mechanics before and 3 months after device therapy, including global myocardial longitudinal, circumferential, radial strains and torsion.
Results: At 3 month, there was obvious improvement in every component of LV mechanics, i.e. longitudinal (8.8±2.5 vs. 9.5±3.3%, p<0.05), circumferential (9.6±3.0 vs. 11.1±3.3%, p<0.01) and radial (13.5±7.5 vs. 18.3±7.5%, p<0.001) strain as well as torsion (8.0±4.5 vs. 10.3±5.5deg, p<0.05). At the same time, significant LV reverse remodeling was observed as reflected by reduction in LV end-systolic volume (LVESV) (117±36 vs. 104±38ml) and increase in LVEF (28.0±6.3 vs. 32.7±6.5%) (both p<0.001). The improvement of longitudinal strain was associated with the change of LVEF after CCM (r=0.541, p<0.005). Furthermore, patients with improvement in all the 3 myocardial strain (Group 1, n=12) were compared to those with partial or no improvement (Group 2, n=18). Despite identical baseline characteristics, Group 1 showed greater decrease of LVESV (-17.4±11.4 vs. -7.1±11.2%, p<0.005) and augmentation of LVEF (7.3±3.4 vs. 2.9±3.4%, p<0.05) than Group 2. However, there was no difference in the degree of clinical improvement measured by NYHA class and quality of life score.
Conclusion: CCM induces favorable changes in multiple components of LV mechanics in patients with advanced congestive heart failure, which could be translated into LV reverse remodeling response.
Acknowledgement: This project was supported by a research grant from the Hong Kong Research Grant Council (RGC grant No. 479709).
- © 2012 by American Heart Association, Inc.