Abstract 12641: Improvements in Mitral Regurgitation are Associated with Reductions in Mechanical Dyssynchrony in Patients Supported by a Continuous Flow Left Ventricular Assist Device
Background: The reduction of mechanical dyssynchrony is a major contributing factor to improvement of mitral regurgitation (MR) after cardiac resynchronization therapy. However, the impact of mechanical dyssynchrony on MR in patients supported by a continuous flow left ventricular (LV) assist device (c-LVAD) are unknown.
Objective: To test the hypothesis that reductions in LV dyssynchrony are associated with MR improvement in heart failure patients on c-LVAD.
Methods: We studied 46 c-LVAD patients before and after mechanical support. MR was graded from 0 to 3 (0=none, 1=mild, 2= moderate, 3=severe). Patients were divided into 2 groups by MR grade at follow-up (mean 195 ± 103 days): 34 with none-mild and 12 with moderate-severe. Speckle tracking echo defined dyssynchrony as the time from mid-LV anteroseptal to posterior wall peak radial strain ≥130 ms. In addition, LV geometry was assessed by the sphericity index, calculated as maximal LV diameter by maximal length. Larger numbers represent more spherical.
Results: Speckle tracking echo was feasible in 33 patients (72%) on c-LVAD. Baseline characteristics were comparable between MR groups except for degree of tricuspid regurgitation grade which was greater in the moderate-severe MR group (p = 0.01). Similar significant dyssynchrony was observed before c-LVAD in both groups (154 ± 119 and 195 ± 118 ms, p=NS). A greater reduction in dyssynchrony after c-LVAD was observed in patients with none-mild MR on c-LVAD than those with moderate-severe MR (-50 ± 123 ms vs. 63 ± 121 ms, p= 0.018). In addition, LV sphericity was significantly greater in patients on c-LVAD with moderate-severe MR than those with none-mild MR (0.74 ± 0.07 vs. 0.66 ± 0.12; p = 0.01).
Conclusion: Improvements in mechanical dyssynchrony and LV geometry are associated with reduction of MR in patients on c-LVAD. These observations appear to be of mechanistic and clinical importance.
- © 2012 by American Heart Association, Inc.