Tissue Doppler velocity is superior to strain imaging in predicting long-term cardiovascular events after cardiac resynchronisation therapy

摘要

Objective: To examine the predictive value of systolic dyssynchrony measured by tissue Doppler velocity versus tissue Doppler strain imaging on long-term outcome after cardiac resynchronisation therapy (CRT). Design: Cohort study. Setting: Two university hospitals. Patients: Two hundred and thirty-nine patients (65 (SD 12) years, 76% males) who underwent CRT. Interventions: Baseline echocardiography with tissue Doppler imaging (TDI) and clinical follow-up for 37 (20) months. Main outcome measures: The time to peak systolic velocity during ejection phase (T_s) and the time to peak systolic strain (T_ε) were assessed for dyssynchrony, that is the maximal delay in Ts and the maximal delay in T_ε among the four left ventricular basal segments. Occurrence of cardiovascular endpoints between patients with and without dyssynchrony was compared by Kaplan-Meier curves, followed by Cox regression analysis for potential predictor(s). Results: There were 78 (33%) deaths, with cardiovascular causes in 64 (27%) patients, while 136 (57%) patients were hospitalised for cardiovascular events, including decompensated heart failure in 87 (36%) patients. Patients with the maximal delay in T_s of ≥ 65 ms showed a lower event rate for cardiovascular mortality (19% vs 38%, logrank χ~2 = 7.803, p = 0.005) and other prognostic endpoints. In Cox regression analysis, the maximal delay in T_s (hazard ratio (HR) 0.463, 95% Cl 0.270 to 0.792, p = 0.005) and ischaemic aetiology (HR 2.716, 95% Cl 1.505 to 4.901, p = 0.001) were independent predictors of cardiovascular mortality. In contrast, the maximal delay in T_ε of ≥ 80 ms failed to predict any cardiovascular event. Conclusions: Echocardiographic evidence of prepacing systolic dyssynchrony measured by TDI velocity, but not TDI strain, predicted lower long-term cardiovascular events after CRT.