Abstract 2473: Prevalence and Predictors of Left Ventricular Mechanical Asynchrony in Patients with Refractory Heart Failure
Background: Left ventricular (LV) systolic asynchrony is predictive of response to cardiac resynchronization therapy (CRT) in drug resistant ischemic (ICM) and non ischemic cardiomyopathy (NICM). We examined predictors of mechanical asynchrony to assist patient (pt) selection for CRT.
Method: 450 consecutive NYHA II–IV pts (68±15 yrs, LVEF 34±11%, 67% M, QRS 137±38 ms) with drug resistant CMP were evaluated for presence of mechanical asynchrony by tissue Doppler imaging (TDI) prior to CRT. Published parameters assessed included QRS duration >120 ms, asynchrony index (SD time to peak(Tp) systolic velocity in 12 LV segments) >33ms, septolateral delay >65 ms, delayed longitudinal contraction (DLC) in 2 of 6 basal segments, septoposterior wall delay (SPWD) >130 ms by M-Mode, peak TDI velocity diff in 6 basal segments >110 ms, apical SPWD by TDI >65 ms, SPWD by mid LV strain >130 ms, interventricular delay >40 ms, SD Tp strain in 12 LV segments >100 ms and diastolic filling time 45%.
Results: Prevalence of mechcanical asynchrony (table 1⇓). 51% women vs 41% men had ≥ 4 aynchrony criteria +ive (p=0.08). 10% pts had both systolic and diastolic asynchrony. Univariate predictors of significant asynchrony included female gender, NICM, QRS >120ms, LV EF, end-diastolic size and volume (EDV) and sinus rhythm. Significant LV asynchrony was present in 45% of pts with preserved LVEF and 62% with LV dysfunction. In both narrow (N=175) and wide (N=250) QRS complex (120ms) subgroups, pts with poor EF had more asynchrony than preserved EF (narrow QRS: 30% vs 49% ms, p=0.05; wide QRS: 54% vs 72%, p=0.04). On linear regression, significant predictors of baseline asynchrony were QRS>120ms(b=1.7, 1.2–2.1, p<0.001) NICM (b=1.1, 0.6–1.5, p<0.001) and baseline EDV (b=0.006, 0.002–0.009, p=0.001).
Conclusions: Significant LV systolic asynchrony is common in pts with ICM/NICM but becomes more severe and prevalent in pts with wide QRS, NICM and dilated LV.