title: Are left ventricular diastolic function and diastolic asynchrony important determinants of response to cardiac resynchronization therapy?
abstract: Cardiac resynchronization therapy (CRT) has been shown to reduce symptoms and reverse left ventricular (LV) remodeling. It is not known, however, whether diastolic function will improve after CRT and diastolic asynchrony will predict LV reverse remodeling. Seventy-six patients (mean age 65 +/- 12 years, 74% men) who received CRT were studied at baseline and after 3 months. Diastolic function was assessed by transmitral Doppler and tissue Doppler imaging. LV systolic and diastolic asynchrony were assessed by the time to peak myocardial contraction (Ts) and early diastolic relaxation (Te) using the 6 basal, 6 mid-segmental model. There were 42 responders (55%) with LV reverse remodeling (defined as a reduction of LV end-systolic volume >or=15%). Parameters of systolic function were significantly improved only in the responders. For diastolic function, there were reductions of transmitral E velocity in the 2 groups, without any change in atrial velocity or the E/A ratio. Tissue Doppler imaging revealed that myocardial early diastolic velocity was unchanged in responders but was significantly worsened in nonresponders. The systolic asynchrony index (the SD of Ts of 12 LV segments) correlated significantly with LV reverse remodeling (r = -0.64, p <0.001) but not the diastolic asynchrony index (the SD of Te of 12 LV segments) (r = -0.10, p = NS). The systolic asynchrony index was the only independent predictor of reverse remodeling (beta = -0.99, 95% confidence interval -1.41 to -0.58, p <0.001). In conclusion, CRT improves systolic function and systolic asynchrony but has a neutral effect on diastolic function and diastolic asynchrony. LV reverse remodeling response is determined by the severity of prepacing systolic asynchrony but not diastolic asynchrony or the diastolic filling pattern.
authors.affiliation: Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, Institute of Vascular Medicine, The Chinese University of Hong Kong, Hong Kong, People's Republic of China. cmyu@cuhk.edu.hk
authors.forename: Cheuk-Man
authors.initials: CM
authors.lastname: Yu
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: Gabriel Wai-Kwok
authors.initials: GW
authors.lastname: Yip
authors.forename: Yat-Sun
authors.initials: YS
authors.lastname: Chan
authors.forename: Pui-Wai
authors.initials: PW
authors.lastname: Lee
authors.forename: Li-Wen
authors.initials: LW
authors.lastname: Wu
authors.forename: Yat-Yin
authors.initials: YY
authors.lastname: Lam
authors.forename: Leo Chi-Chiu
authors.initials: LC
authors.lastname: Kum
authors.forename: Hamish Chi-Kin
authors.initials: HC
authors.lastname: Chan
authors.forename: Skiva
authors.initials: S
authors.lastname: Chan
authors.forename: Jeffrey Wing-Hong
authors.initials: JW
authors.lastname: Fung
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D002304:Cardiac Pacing, Artificial; D016009:Chi-Square Distribution; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D008297:Male; D012307:Risk Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*