Heart Vessels DOI 10.1007/s00380-014-0586-4
ORIGINAL ARTICLE
The association between left ventricular twisting motion and mechanical dyssynchrony: a three‑dimensional speckle tracking study Shohei Fujiwara · Kazuo Komamura · Ayumi Nakabo · Mitsuru Masaki · Miho Fukui · Masataka Sugahara · Kanako Itohara · Yuko Soyama · Akiko Goda · Shinichi Hirotani · Toshiaki Mano · Tohru Masuyama
Received: 26 May 2014 / Accepted: 19 September 2014 © Springer Japan 2014
Abstract Left ventricular (LV) dyssynchrony is a causal factor in LV dysfunction and thought to be associated with LV twisting motion. We tested whether three-dimensional speckle tracking (3DT) can be used to evaluate the relationship between LV twisting motion and dyssynchrony. We examined 25 patients with sick sinus syndrome who had received dual chamber pacemakers. The acute effects of ventricular pacing on LV wall motion after the switch from atrial to ventricular pacing were assessed. LV twisting motion and dyssynchrony during each pacing mode were measured using 3DT. LV dyssynchrony was calculated from the time to the minimum peak systolic area strain of 16 LV imaging segments. Ventricular pacing increased LV dyssynchrony and decreased twist and torsion. A significant correlation was observed between changes in LV dyssynchrony and changes in torsion (r = −0.65, p 3 s or sinus bradycardia 60 %). Exclusion criteria included the presence of ischemic heart disease, atrioventricular (AV) block, valvular heart disease, ventricular dysfunction, LV hypertrophy, and congestive heart failure, and history of recent open heart surgery. The control group comprised 9 healthy individuals without pacemakers (4 males and 5 females; mean age: 70 ± 8 years). Written informed consent was obtained from all subjects after explanation of the purpose and detailed protocol of the study, which was approved by the Ethics Committee of the Hyogo College of Medicine. Protocol To simulate LV mechanical dyssynchrony, we performed right ventricular pacing using a pacing lead placed in the right ventricular apex. Serial echocardiograms using 3DT during atrial and ventricular pacing in the same patient were recorded at the end of each 5-min pacing. To eliminate the effects of cardiac memory by ventricular pacing, echocardiograms were evaluated during atrial pacing prior to ventricular pacing [14]. The pacing rate was fixed at 70 beats per minute both for atrial and ventricular pacing. Atrial pacing was made to be intrinsic ventricular conduction, whereas the shortening of AV delay to 100 ms made ensure ventricular pacing. LV mechanical dyssynchrony during atrial and ventricular pacing was measured using 3DT. The correlation between LV twisting motion and dyssynchrony was determined. 3DT echocardiography 3DT echocardiography was performed using Artida™ ultrasound diagnostic equipment (Toshiba Medical Systems Fig. 1 Definition of twist and torsion: a Twist was defined as the difference between apical and basal rotations and b torsion was defined as the difference between apical and basal rotations per left ventricular (LV) length. Torsion can be used to evaluate LV twisting motion in the entire heart
13
Heart Vessels
Co., Tochigi, Japan) with PST-25SX probes. The frame rate was 26 volumes/s. Three-dimensional data sets were stored in raw data format for off-line analysis and exported to the UltraExtend workstation (Toshiba Medical Systems) using a semi-automated contour-tracing algorithm [15] and were analyzed using the 3D wall motion tracking software (Toshiba Medical Systems). Full-volume images from the LV apex were recorded for 6 consecutive electrocardiogram (ECG)-gated heartbeats in the same patient during atrial and ventricular pacing. Basal short-axis planes were obtained at the mitral valve level, and apical short-axis planes were obtained at the level detecting LV cavity alone with no visible papillary muscles [16]. The peak of the radial strain (RS), longitudinal strain (LS), circumferential strain (CS), LV endocardial area strain (AS), and peak strain rate during the isovolumic relaxation phase in AS (ASsr) as a diastolic index [17] were measured. Twist was calculated as the difference between LV apical and basal rotations (Fig. 1a), while torsion was calculated as the difference between apical and basal rotations per LV length (Fig. 1b) [18]. Twist and torsion were used as indices for LV twisting motion. LV mechanical dyssynchrony was calculated as the standard deviation of time to the minimum peak systolic area strains of 16 LV segments pertaining to the heart cycle (Fig. 2) [15, 19– 21]. We can appreciate the quality of the images. When ≥3 segments in 16 LV segments were not adequately observed, we excluded the echocardiographic images from the subjects [15]. Statistical analysis Continuous variables are expressed as means ± standard deviations. Continuous variables were compared using Student’s t test or the Mann–Whitney U test. The relationship between LV mechanical dyssynchrony derived from 3DT measurements and other echocardiographic parameters
Heart Vessels
Fig. 2 Area strain as per three-dimensional speckle tracking (3DT). a A color coded bull’s-eye plot image is shown with the 16 standard myocardial segments, as defined by the American Society of Echocardiography. b Left ventricular (LV) dyssynchrony was determined by the standard deviation of time to the minimum peak systolic area
strains of 16 LV segments relating to the heart cycle. X-axis time (ms), Y-axis area strains in each of the 16 LV segments (%). ant anterior segment of LV, ant-sept anteroseptal segment of LV, sept septal segment of LV, lat lateral segment of LV, post posterior segment of LV, inf inferior segment of LV
was examined using linear regression analysis. A p value of
ORIGINAL ARTICLE
The association between left ventricular twisting motion and mechanical dyssynchrony: a three‑dimensional speckle tracking study Shohei Fujiwara · Kazuo Komamura · Ayumi Nakabo · Mitsuru Masaki · Miho Fukui · Masataka Sugahara · Kanako Itohara · Yuko Soyama · Akiko Goda · Shinichi Hirotani · Toshiaki Mano · Tohru Masuyama
Received: 26 May 2014 / Accepted: 19 September 2014 © Springer Japan 2014
Abstract Left ventricular (LV) dyssynchrony is a causal factor in LV dysfunction and thought to be associated with LV twisting motion. We tested whether three-dimensional speckle tracking (3DT) can be used to evaluate the relationship between LV twisting motion and dyssynchrony. We examined 25 patients with sick sinus syndrome who had received dual chamber pacemakers. The acute effects of ventricular pacing on LV wall motion after the switch from atrial to ventricular pacing were assessed. LV twisting motion and dyssynchrony during each pacing mode were measured using 3DT. LV dyssynchrony was calculated from the time to the minimum peak systolic area strain of 16 LV imaging segments. Ventricular pacing increased LV dyssynchrony and decreased twist and torsion. A significant correlation was observed between changes in LV dyssynchrony and changes in torsion (r = −0.65, p 3 s or sinus bradycardia 60 %). Exclusion criteria included the presence of ischemic heart disease, atrioventricular (AV) block, valvular heart disease, ventricular dysfunction, LV hypertrophy, and congestive heart failure, and history of recent open heart surgery. The control group comprised 9 healthy individuals without pacemakers (4 males and 5 females; mean age: 70 ± 8 years). Written informed consent was obtained from all subjects after explanation of the purpose and detailed protocol of the study, which was approved by the Ethics Committee of the Hyogo College of Medicine. Protocol To simulate LV mechanical dyssynchrony, we performed right ventricular pacing using a pacing lead placed in the right ventricular apex. Serial echocardiograms using 3DT during atrial and ventricular pacing in the same patient were recorded at the end of each 5-min pacing. To eliminate the effects of cardiac memory by ventricular pacing, echocardiograms were evaluated during atrial pacing prior to ventricular pacing [14]. The pacing rate was fixed at 70 beats per minute both for atrial and ventricular pacing. Atrial pacing was made to be intrinsic ventricular conduction, whereas the shortening of AV delay to 100 ms made ensure ventricular pacing. LV mechanical dyssynchrony during atrial and ventricular pacing was measured using 3DT. The correlation between LV twisting motion and dyssynchrony was determined. 3DT echocardiography 3DT echocardiography was performed using Artida™ ultrasound diagnostic equipment (Toshiba Medical Systems Fig. 1 Definition of twist and torsion: a Twist was defined as the difference between apical and basal rotations and b torsion was defined as the difference between apical and basal rotations per left ventricular (LV) length. Torsion can be used to evaluate LV twisting motion in the entire heart
13
Heart Vessels
Co., Tochigi, Japan) with PST-25SX probes. The frame rate was 26 volumes/s. Three-dimensional data sets were stored in raw data format for off-line analysis and exported to the UltraExtend workstation (Toshiba Medical Systems) using a semi-automated contour-tracing algorithm [15] and were analyzed using the 3D wall motion tracking software (Toshiba Medical Systems). Full-volume images from the LV apex were recorded for 6 consecutive electrocardiogram (ECG)-gated heartbeats in the same patient during atrial and ventricular pacing. Basal short-axis planes were obtained at the mitral valve level, and apical short-axis planes were obtained at the level detecting LV cavity alone with no visible papillary muscles [16]. The peak of the radial strain (RS), longitudinal strain (LS), circumferential strain (CS), LV endocardial area strain (AS), and peak strain rate during the isovolumic relaxation phase in AS (ASsr) as a diastolic index [17] were measured. Twist was calculated as the difference between LV apical and basal rotations (Fig. 1a), while torsion was calculated as the difference between apical and basal rotations per LV length (Fig. 1b) [18]. Twist and torsion were used as indices for LV twisting motion. LV mechanical dyssynchrony was calculated as the standard deviation of time to the minimum peak systolic area strains of 16 LV segments pertaining to the heart cycle (Fig. 2) [15, 19– 21]. We can appreciate the quality of the images. When ≥3 segments in 16 LV segments were not adequately observed, we excluded the echocardiographic images from the subjects [15]. Statistical analysis Continuous variables are expressed as means ± standard deviations. Continuous variables were compared using Student’s t test or the Mann–Whitney U test. The relationship between LV mechanical dyssynchrony derived from 3DT measurements and other echocardiographic parameters
Heart Vessels
Fig. 2 Area strain as per three-dimensional speckle tracking (3DT). a A color coded bull’s-eye plot image is shown with the 16 standard myocardial segments, as defined by the American Society of Echocardiography. b Left ventricular (LV) dyssynchrony was determined by the standard deviation of time to the minimum peak systolic area
strains of 16 LV segments relating to the heart cycle. X-axis time (ms), Y-axis area strains in each of the 16 LV segments (%). ant anterior segment of LV, ant-sept anteroseptal segment of LV, sept septal segment of LV, lat lateral segment of LV, post posterior segment of LV, inf inferior segment of LV
was examined using linear regression analysis. A p value of
