Determinants of Left Ventricular Untwisting Behavior in Patients with Dilated Cardiomyopathy: Analysis by Two-dimensional Speckle Tracking

Makoto Saito ¹, Hideki Okayama ^1*, Kazuhisa Nishimura ¹, Akiyoshi Ogimoto ¹, Tomoaki Ohtsuka ¹, Katsuji Inoue ², Go Hiasa ², Takumi Sumimoto ², Junichi Funada ³, Yuji Shigematsu ¹ and Jitsuo Higaki ¹

¹ Ehime University Graduate School of Medicine, Japan
² Kitaishikai Hospital, Japan
³ Ehime National Hospital, Japan

^* To whom correspondence should be addressed. E-mail: hiokayam{at}m.ehime-u.ac.jp.

Accepted 26 August 2008

Abstract

Objective: Left ventricular (LV) untwisting velocity has emerged as a novel index of LV diastolic function since it is thought to be related to LV diastolic suction. However, the pathophysiology of LV untwisting behavior has not been fully investigated. The aim of this study was to investigate the determinants of LV peak untwisting velocity in patients with dilated cardiomyopathy (DCM).

Patients and methods: One-hundred-one patients with DCM (mean age 60 ± 13 years) and 50 control subjects were evaluated. After a standard echocardiographic examination, peak torsion and peak untwisting velocity were measured using two-dimensional speckle tracking imaging. Radial dyssynchrony was assessed by speckle-tracking radial strain analysis. Tissue Doppler derived systolic (Ts-SD) and diastolic (Te-SD) dyssynchrony indices were also assessed.

Results: The patients with DCM had significantly smaller peak torsion (P < 0.001) and peak untwisting velocity (P < 0.001) and greater radial dyssynchrony (P < 0.001) and Ts-SD (P<0.001) and Te-SD (P=0.001) compared with the control subjects. The peak untwisting velocity was correlated with end-systolic volume index (r = 0.524, P < 0.001), E/e' (r = 0.365, P < 0.001), radial dyssynchrony (r = 0.578, P < 0.001), Ts-SD (P<0.001), Te-SD (P<0.001) and peak torsion (r = -0.635, P < 0.001) in patients with DCM. Multivariate analysis revealed that peak torsion, radial dyssynchrony and E/e' were independent predictors of peak untwisting velocity in patients with DCM (standard coefficient = -0.483, P < 0.001, 0.330, P < 0.001, and 0.241, P = 0.001, respectively).

Conclusion: These results suggest that strain based LV radial dyssynchrony and E/e' as well as LV torsion are related to diastolic untwisting behavior in patients with DCM.