Abstract 2718: Does the Lack of Ventricular Dyssynchrony Prior to Cardiac Resynchronization Therapy Affect Ventricular Remodeling and Long-Term Clinical Outcomes?
Introduction: Left ventricular (LV) dyssynchrony, determined by tissue Doppler imaging (TDI), has been proposed as a method to select patients with heart failure (HF) with prolonged QRS intervals that are likely to respond to cardiac resynchronization therapy (CRT). It has been reported that the lack of LV dyssynchrony prior to CRT can be associated with less LV reverse remodeling and less clinical improvement after CRT.
Methods: 80 patients were evaluated by 2D/pulsed-wave Doppler (PWD) echocardiography and TDI prior to and 4 ± 1 months after CRT. Measurements included LV end-diastolic (EDV), end-systolic (ESV) volume and ejection fraction (LVEF). TDI-derived time intervals of Q to peak systolic (Sm) velocity were measured at 4 mitral annular sites (i.e., lateral, septal, anterior, inferior); maximal difference between sites was defined as presence of LV dyssynchrony. Functional measurements included NYHA class, HF score, and 6 minute walk distance. Clinical events, defined as HF re-hospitalization or cardiac-related death/transplant, were evaluated at median follow-up of 30 months (range 3– 68). Patients were grouped by pre-CRT TDI-derived Q-Sm difference of ≤ or > 65 ms ( Bax et al JACC 2004;44:1834–40).
Results: Age, gender, HF etiology, QRS duration, and LV lead position were similar between groups. LV volumes decreased and LVEF increased significantly in both groups after CRT (see table⇓). TDI-determined Q-Sm difference decreased significantly only in the ≤ 65 ms group. Functional measurements improved in both groups. Clinical events at long-term follow-up were similar in the group with Q-Sm ≤ 65 ms. vs. Q-Sm > 65 ms. [n = 13 (33%) vs. n = 11 (28%), respectively].
Conclusions: Despite a lack of significant LV dyssynchrony by TDI measurements prior to CRT, LV volumes decreased, LVEF increased, and functional measurements improved significantly at 4-month follow-up. Furthermore, the lack of LV dyssynchrony did not influence long-term clinical outcomes.