Abstract 2816: Differential Impacts of Left Ventricle Filling Index versus Ejection Fraction on Global and Regional Electromechanical Coupling Before and After Exercise Stress in Patients with Systolic Heart Failure
Background. Little is known about the relative contribution of two most common indices of heart failure (HF), i.e. left ventricle (LV) ejection fraction (EF) and diastolic filling Index (FI), to post-exercise LV contractile decompensation-related clinical HF manifestation.
Methods. We investigated a total of 70 pts (56 male, 14 female, mean age 58 ± 15 years) with compensated SHF (LVEF<50%) from NYHA class II to III for at least 3 months. Conventional and tissue-Doppler (TDI) echocardiography was performed before and immediately after a 6-minutes treadmill exercise test by modified Bruce protocol. Diastolic FI was measured by Mitral E/Ea (annular early diastolic velocity). Global and regional LV contractile parameters were evaluated by mean and standard deviation (SD) of peak systolic myocardial velocity (Sm) and electromechanical delay (Ts) from the QRS onset to peak Sm taken from 12 LV segments in TDI.
Results. As in Table⇓, both decline of LVEF and elevation of FI were corresponding with progressive depression of mean Sm and prolongation of mean Ts, but not regional heterogeneity (SD-Sm, SD-Ts). After exercise, less increase of regional Sm but more time delay over the free wall in pts with higher FI resulted in significantly blunted heterogeneity of LV segmental myocardial velocity (SD-Sm) and aggravated ventricular dyssynchrony (SD-Ts). Nevertheless, both higher LVFI and lower EF were still accompanied with more global contractile dysfunction after exercise. Multivariate analysis showed resting mitral E/Ea > 10 as an independent predictor of post-exercise ventricular dyssynchrony (SD-Ts > 35 ms) (OR = 8.4; p < 0.002, 95 % C.I. = 2.2–32).
Conclusion. LVEF and diastolic FI appropriately reflected progressively compromised global LV contractile function. However, only elevated resting mitral E/Ea, prior demonstrated as a better correlate of filling pressure and exercise capacity, could predict post-exercise LV regional myocardial contractile decompensation.