Backgrounds:
The mechanical dyssynchrony has been commonly observed in idiopathic dilated cardiomyopathy (DCM) patients, and several cardiac magnetic resonance (CMR) imaging techniques were used to evaluate the mechanical dyssynchrony. Standard deviation of time-to-peak (T2Psd) and uniformity ratio estimate (URE) indices are two widely used parameters to reflect the incoordinate movement of the left ventricle. However, the prognostic value of mechanical dyssynchrony in DCM patients is not clear.
Methods and Results:
We prospectively enrolled 402 DCM patients undergoing CMR imaging between Jun 2012 to Sep 2018. Mechanical dyssynchrony was measured as T2Psd and URE indices by CMR deformable registration algorithm (DRA) analysis. The primary endpoint was defined as all-cause mortality and heart transplantation, and the secondary endpoint was a combination of primary endpoint, aborted sudden cardiac death, and heart failure readmission. Univariate and multivariate Cox regression analyses were performed to identify the association between variables and outcome. Survival curves were obtained by Kaplan-Meier survival analysis and compared by log-rank test. During a median follow-up of 25.1 months (IQR: 16.2-41.6), there were 57 patients reached primary endpoints, and secondary endpoints occurred in 132 patients. Circumferential uniformity ratio estimate (CURE) at basal, mid and apical level, radial uniformity ratio estimate (RURE)at mid and apical level and longitudinal uniformity ratio estimate (LURE) were significantly worse in patients with primary endpoint compared to patients without primary endpoint. While no significant differences were observed regarding the T2Psd value between patients with and without primary endpoints. In multivariate analysis, CURE at apical level was independently associated with primary endpoints (HR 0.214, P=0.005) and secondary endpoints (HR 0.402, P=0.018). Furthermore, among patients with LVEF <35% or presence of LGE, those with decreased CURE at apical level (<0.917) showed a significantly higher rate of adverse outcome.
Conclusion:
The CURE at apical level is an independent predictor of adverse cardiac events in DCM patients. Compared with T2Psd, URE index is a better predictor of adverse events.
Mechanical Dyssynchrony Precedes QRS Widening in ATP‐Sensitive K
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Channel–Deficient Dilated Cardiomyopathy
