title: Left ventricular dyssynchrony using three-dimensional speckle-tracking imaging as a determinant of torsional mechanics in patients with idiopathic dilated cardiomyopathy.
abstract: The aim of this study was to use 3-dimensional (3D) speckle-tracking echocardiography to test the hypothesis that left ventricular (LV) dyssynchrony may negatively affect LV torsional mechanics in patients with idiopathic dilated cardiomyopathy (IDC) and that LV torsion may improve after cardiac resynchronization therapy. This study included 65 subjects; 20 with IDC with ejection fractions ≤35% and wide QRS complexes (≥120 ms), 20 with IDC with ejection fractions ≤35% and narrow QRS complexes (<120 ms), and 25 controls. LV dyssynchrony index was determined as the SD of time to peak 3D speckle-tracking radial strain and regional heterogeneity of LV rotation (rotational dispersion index) as the SD of 3D speckle-tracking time to peak rotation. All rotational indexes were significantly impaired in patients with IDC, while LV torsion in patients with IDC with wide QRS complexes was significantly smaller than that in patients with IDC with narrow QRS complexes and controls. Conversely, LV dyssynchrony index (127.3 ± 24.0 ms [p <0.01 vs controls and vs patients with narrow QRS complexes] vs 88.8 ± 22.5 ms [p <0.01 versus controls] vs 30.9 ± 10.0 ms) and rotational dispersion index (115.1 ± 27.5 ms [p <0.01 vs controls and vs patients with narrow QRS complexes] vs 96.0 ± 23.4 ms [p <0.01 versus controls] vs 45.0 ± 13.7 ms) were significantly higher in patients with IDC with wide QRS complexes. Multivariate analysis showed that the LV ejection fraction (β = 0.688, p <0.001) and rotational dispersion index (β = -0.249, p <0.01) were independent determinants of LV torsion. Moreover, LV torsion in patients with IDC with wide QRS complexes improved after cardiac resynchronization therapy (p <0.05), along with reductions in LV dyssynchrony and rotational dispersion indexes. In conclusion, these findings obtained with a novel 3D speckle-tracking system feature a novel aspect of LV torsional mechanics and demonstrate its association with LV dyssynchrony.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Tanaka
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tatsumi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Miyoshi
authors.forename: Mana
authors.initials: M
authors.lastname: Hiraishi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Kaneko
authors.forename: Takayuki
authors.initials: T
authors.lastname: Tsuji
authors.forename: Keiko
authors.initials: K
authors.lastname: Ryo
authors.forename: Yuko
authors.initials: Y
authors.lastname: Fukuda
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yoshida
authors.forename: Hiroya
authors.initials: H
authors.lastname: Kawai
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Hirata
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy; D016022:Case-Control Studies; D015150:Echocardiography, Doppler / Q000379:methods; D019560:Echocardiography, Three-Dimensional / Q000379:methods; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology; D014102:Torsion Abnormality / Q000000981:diagnostic imaging*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy