Biomedical subjects

Takahiro Shiota

Publications and source records attributed to Takahiro Shiota.

At least 19 recordsLinked to original sources

PubMed2006

3D geometry of a normal tricuspid annulus during systole: a comparison study with the mitral annulus using real-time 3D echocardiography.

AIM: This study was done to explore the 3D geometry of the normal tricuspid annulus and compare it with the mitral annulus (MA), using real-time 3D echocardiography (RT3DE) and newly developed 3D computer software. METHODS: Thirteen left ventricular (LV) and 13 right ventricular (RV) volumetric images were obtained using RT3DE from normal subjects. LV and RV volumetric data were segmented into 16 rotational apical planes (angle increment=11.25 degrees ) around the rotational axis from the apex through the center of two annuli, using newly developed 3D software (TomTec, Co., Munich, Germany). Two hinge points of the MA and the TA were traced in each plane during early and late systole. The MA and the TA were then automatically reconstructed with those 32 traced points. 3D surface (3DMAA, 3DTAA) and 2D projected areas (2DMAA, 2DTAA) of the annuli were calculated automatically as well, from those fitted data. For a comparison between the two annuli, the 3D and 2D area measurements of both annuli were corrected (c) according to the height of each patient (c2DMAA, c2DTAA, c3DMAA, and c3DTAA). Non-planarity of the annuli was estimated by their non-planar angles (MA: the angle between the anterior and posterior parts of the annulus; TA: the angle between the septal and free wall parts of the annulus). RESULTS: The TA revealed a less non-planar saddle shape than did the MA, which had a significantly wider non-planar angle (167.7+/-3.2 vs 145.5+/-6.1 degrees , p<0.01) and a round or oval appearance on the projected view. The c2DTAA was significantly larger than the c2DMAA during early systole (p<0.01). However, there was no significant difference between the c3DTAA and c3DMAA during early and late systole (p>0.01). CONCLUSION: We assessed the 3D geometry of the MA and the TA by 3D reconstruction using RT3DE and newly developed computer software. The TA had a less non-planar shape compared with the MA, with either a round or oval appearance on the projected view.

Adult↗

PubMed2006

Value of mitral valve tenting volume determined by real-time three-dimensional echocardiography in patients with functional mitral regurgitation.

This study sought to evaluate mitral valve tenting volume (TnV) as a clinical parameter using real-time 3-dimensional echocardiography in patients with functional mitral regurgitation (MR). In 27 patients with functional MR and 4 controls without mitral disease, real-time 3-dimensional echocardiographic images were obtained to measure TnV frame by frame from presystole to end-systole. The maximal and minimal TnVs during systole were identified in each patient, and mitral annular areas and tenting heights were also measured. Using 2-dimensional echocardiography, tenting area (TnA) was measured from the apical long-axis, apical 4-chamber, and apical 2-chamber views. The regurgitant orifice area was measured by the proximal isovelocity surface area method. Maximal and minimal TnVs occurred at the time of 2 +/- 6% and 78 +/- 6% of whole systolic duration, respectively, and the systolic percentage change of TnV was related to that of tenting height but not to that of mitral annular area. TnA on the long-axis images was significantly larger than that on the 4- and 2-chamber images (2.5 +/- 1.4 vs 1.7 +/- 1.3 and 1.9 +/- 1.4 cm(2), respectively, p <0.001). Regurgitant orifice area was significantly correlated with maximal TnV (r = 0.90), minimal TnV (r = 0.86), and TnA on the long-axis (r = 0.79), 4-chamber (r = 0.75), and 2-chamber (r = 0.73) images. Among minimal TnV and 3 TnAs, minimal TnV was the only independent determinant of regurgitant orifice area (p <0.001). Minimal TnV >or=3.90 ml identified significant functional MR with a sensitivity of 86% and a specificity of 100%. In conclusion, TnV derived from real-time 3-dimensional echocardiography is a preferable novel single index for assessing mitral valve tethering in functional MR to TnA that is dependent on the location of 2-dimensional planes.

Blood Flow Velocity↗

PubMed2006

Three-dimensional geometry of the tricuspid annulus in healthy subjects and in patients with functional tricuspid regurgitation: a real-time, 3-dimensional echocardiographic study.

BACKGROUND: Most rings currently used for tricuspid valve annuloplasty are formed in a single plane, whereas the actual tricuspid annulus (TA) may have a nonplanar or 3-dimensional (3D) structure. The purpose of this study was therefore to investigate the 3D geometry of the TA in healthy subjects and in patients with functional tricuspid regurgitation (TR). METHODS AND RESULTS: This study consisted of 15 healthy subjects and 16 patients with functional TR who had real-time 3D echocardiography. With our customized software, 8 points along the TA were determined with the rotated plane around the axis at 45 degrees intervals. The TA was traced during a cardiac cycle. The distance between diagonals connecting 2 points was measured. The height was defined as the distance from the plane determined by least-squares regression analysis at all 8 points. Both the maximum (7.5+/-2.1 versus 5.6+/-1.0 cm2/m2) and minimum (5.7+/-1.3 versus 3.9+/-0.8 cm2/m2) TA areas in patients with TR were larger than those in healthy subjects (both P<0.01). Healthy subjects had a nonplanar-shaped TA with homogeneous contraction. The posteroseptal portion was the lowest toward the apex from the right atrium, and the anteroseptal portion was the highest. In patients with functional TR, the TA was dilated in the septal to lateral direction, resulting in a more circular shape than in healthy subjects. A similar 3D pattern was observed in patients with TR, but it was more planar than that in healthy subjects. CONCLUSIONS: Real-time 3D echocardiography showed a complicated 3D structure of the TA, which appeared to be different from the "saddle-shaped" mitral annulus, suggesting an annuloplasty for TR different from that for mitral regurgitation.

Adult↗

PubMed2006

Determinants of recurrent or residual functional tricuspid regurgitation after tricuspid annuloplasty.

BACKGROUND: The durability of tricuspid valve (TV) repair by annuloplasty is limited. Identification of mechanisms of recurrent or residual tricuspid regurgitation (TR) after annuloplasty is necessary to improve results of TV repair. The purpose of this study was to investigate echocardiographic determinants of mid-term outcome after TV annuloplasty. METHODS AND RESULTS: This study consisted of 39 patients with functional TR who had echocardiography preoperatively, early postoperatively (5+/-2 days), and >1 year (20+/-6 months) after TV annuloplasty. Detailed echocardiographic measurements were performed, including TR severity, TV annular dimension, TV leaflet displacement, left ventricular (LV) function, and right ventricular (RV) function and pressures. Preoperative leaflet tethering height and area predicted early and mid-term outcome of annuloplasty. Early postoperative LV ejection fraction and TR severity influenced degree of TR >1 year after surgery. In addition, increased RV pressure was related to worse TR during late follow-up. CONCLUSIONS: Although TV tethering is an important determinant of recurrent or residual TR, LV and RV function and pressures impact repair durability. These factors identify patients at risk for repair failure; such individuals require development of additional surgical strategies to improve results of tricuspid valve repair and close surveillance after surgery.

Aged↗

PubMed2006

Mitral valve repair with Carpentier-McCarthy-Adams IMR ETlogix annuloplasty ring for ischemic mitral regurgitation: early echocardiographic results from a multi-center study.

BACKGROUND: Ischemic mitral regurgitation (IMR) is associated with asymmetric changes in annular and ventricular geometry. Surgical repair with standard symmetric annuloplasty rings results in a high incidence of residual or recurrent mitral regurgitation (MR). The Carpentier-McCarthy-Adams (CMA) IMR ETlogix annuloplasty ring is the first remodeling ring specifically designed to treat asymmetric leaflet tethering and annular dilatation. We used quantitative 2-dimensional echo to examine early results of mitral valve (MV) repair with the CMA IMR ETlogix annuloplasty ring in patients with IMR. METHODS AND RESULTS: Fifty-nine patients (aged 68+/-12 years) with grade > or = 2+ IMR (graded on a scale of 0 to 4+) underwent MV repair with the CMA IMR ETlogix annuloplasty ring. We assessed the mitral annular diameter (MAD), tethering area (TA), and tenting height (TH) of the MV in 4-chamber, 2-chamber, and long axis views at mid-systole before and 3 to 10 days after surgery. After surgery, 57 of 59 (97%) patients had grade 0 or 1+ MR, whereas 2 patients had 2+ MR. MV repair with the CMA IMR ETlogix ring significantly reduced MAD, TA, and TH (P<0.001, for all 3 echo views), particularly in the long axis and 4-chamber views. CONCLUSIONS: Surgical repair of IMR with the novel asymmetric CMA IMR ETlogix annuloplasty ring provided excellent early results with effective reduction of MR, MAD, and leaflet tethering. This novel etiology-specific strategy may result in improved outcomes in IMR patients.

Aged↗

PubMed2006

Echocardiographic predictors of successful versus unsuccessful mitral valve repair in ischemic mitral regurgitation.

Mitral valve (MV) annuloplasty is the standard surgical technique for the management of ischemic mitral regurgitation (MR). However, < or = 1/3 of patients develop recurrent MR after annuloplasty. Therefore, we sought to identify the preoperative echocardiographic parameters that predict annuloplasty failure in patients with ischemic MR. Intraoperative transesophageal echocardiograms from 365 patients who underwent MV repair for ischemic MR were reviewed. Of the 365 patients, 297 (81%) had satisfactory outcomes with < 2+ MR, and 68 (19%) had recurrent MR (> or = 2+) during a mean follow-up of 269 days. The mitral annular parameters, including mitral annular diameter, tethering height, and tethering area of the mitral leaflets, were determined in 3 different echocardiographic views. On multiple logistic stepwise regression analysis, a higher mitral annular diameter, higher tethering area, and higher MR severity were identified as independent predictors for failure of MV repair (p < 0.0001). In conclusion, these results demonstrated that preoperative echocardiographic findings can be used to identify patients with ischemic MR at increased risk of repair failure. These echocardiographic measurements should be used to guide the cardiologist and cardiac surgeon in the choice of MV repair versus replacement in patients with ischemic MR.

Adult↗

PubMed2006

Maturational and adaptive modulation of left ventricular torsional biomechanics: Doppler tissue imaging observation from infancy to adulthood.

BACKGROUND: Left ventricular (LV) torsional deformation, based in part on the helical myocardial fiber architecture, is an important component of LV systolic and diastolic performance. However, there is no comprehensive study describing its normal development during childhood and adult life. METHODS AND RESULTS: Forty-five normal subjects (25 children and 20 adults; aged 9 days to 49 years; divided into 5 groups: infants, children, adolescents, and young and middle-age adults) underwent assessment of LV torsion and untwisting rate by Doppler tissue imaging. LV torsion increased with age, primarily owing to augmentation in basal clockwise rotation during childhood and apical counterclockwise rotation during adulthood. Although LV torsion and untwisting overall showed age-related increases, when normalized by LV length, they showed higher values in infancy and middle age. The proportion of untwisting during isovolumic relaxation was lowest in infancy, increased during childhood, and leveled off thereafter, whereas peak untwisting performance (peak untwisting velocity normalized by peak LV torsion) showed a decrease during adulthood. CONCLUSIONS: We have shown the maturational process of LV torsion in normal subjects. Net LV torsion increases gradually from infancy to adulthood, but the determinants of this were different in the 2 age groups. The smaller LV isovolumic untwisting recoil during infancy and its decline in adulthood may suggest mechanisms for alterations in diastolic function.

Adaptation, Physiological↗

PubMed2006

Enhanced ventricular untwisting during exercise: a mechanistic manifestation of elastic recoil described by Doppler tissue imaging.

BACKGROUND: The cascade of events by which early diastolic left ventricular (LV) filling increases with exercise is not fully elucidated. Doppler tissue imaging (DTI) can detect myocardial motion, including torsion, whereas color M-mode Doppler (CMM) can quantify LV intraventricular pressure gradients (IVPGs). METHODS AND RESULTS: Twenty healthy volunteers underwent echocardiographic examination with DTI at rest and during submaximal supine bicycle exercise. We assessed LV long-/short-axis function, torsion, volume, inflow dynamics, and early diastolic IVPG derived from CMM data. LV torsion and untwisting velocity increased with exercise (torsion, 11+/-4 degrees to 24+/-8 degrees ; untwisting velocity, -2.0+/-0.7 to -5.6+/-2.3 rad/s) that was associated with an increase in IVPG (1.4+/-0.5 to 3.7+/-1.2 mm Hg). Untwisting in normal subjects occurred during isovolumic relaxation and early filling, significantly before long-axis lengthening or radial expansion. The clinical feasibility of this method was tested in 7 patients with hypertrophic cardiomyopathy (HCM); torsion was higher at rest but did not increase with exercise (16+/-4 degrees to 14+/-6 degrees), whereas untwisting was delayed and unenhanced (-1.6+/-0.8 to -2.3+/-1.2 rad/s). In concert, IVPG was similar at rest (1.2+/-0.3 mm Hg), but the exercise response was blunted (1.6+/-0.8 mm Hg). In normal subjects and HCM patients, there was a similar linear relation between IVPG and untwisting rate, with an overall correlation coefficient of r=0.75 (P<0.0001). CONCLUSIONS: LV untwisting appears to be linked temporally with early diastolic base-to-apex pressure gradients, enhanced by exercise, which may assist efficient LV filling, an effect that appears blunted in HCM. Thus, LV torsion and subsequent rapid untwisting appear to be manifestations of elastic recoil, critically linking systolic contraction to diastolic filling.

Adult↗

PubMed2006

Geometric predictor of significant mitral regurgitation in patients with severe ischemic cardiomyopathy, undergoing Dor procedure: a real-time 3D echocardiographic study.

BACKGROUND AND PURPOSE: Significant mitral regurgitation (MR) is frequently associated with coronary artery disease. The precise geometric predictors of significant MR in ischemic cardiomyopathy are not clearly defined. We performed real-time 3D echocardiography (RT3DE) in 48 patients scheduled for infarct exclusion surgery or Dor procedure, 22 of whom had moderate or severe MR (DorMR) and 26 with no or trivial MR (DorNoMR). METHODS: Two orthogonal apical volumetric planes of LV, commissure-commissure (CC) and antero-posterior (AP) planes, were generated during mid-systole. Mitral valve tenting height (MVTht) and area (MVTa) were measured. The degree of leaflet tethering was estimated by the angles between the annular plane and each leaflet (anterior leaflet: Aalpha, posterior leaflet: Palpha). RESULTS: MVTht (1.11+/-0.14 vs 0.78+/-0.20 cm, P<0.01) and MVTa (1.30+/-0.34 vs 0.87+/-0.27 cm(2), P<0.01) were significantly larger in DorMR compared with DorNoMR. In DorMR, both Aalpha (38+/-6 vs 31+/-7 degrees , P<0.01) and Palpha (60+/-7 vs 41+/-8 degrees , P<0.01) significantly increased more than those in DorNoMR. Multiple logistic regression analysis found Palpha to be the most important geometric predictor of significant MR. MV tenting area was found to be the strongest determinant of MR severity in ischemic cardiomyopathy patients with significant MR by multivariate linear regression analysis. CONCLUSIONS: Detecting significant posterior leaflet tethering, the most important predictor of significant MR, and measuring MV tenting area, the strongest determinant of MR severity, using RT3DE may be helpful in decision making of additive surgical intervention for MR in patients with severe ischemic cardiomyopathy.

Cardiomyopathies↗

PubMed2006

Echocardiographic insights into atrial and ventricular mechanisms of functional tricuspid regurgitation.

BACKGROUND: The etiology of functional tricuspid regurgitation (TR) is thought to be annular dilatation and tethering of tricuspid valve (TV) leaflets. However, mechanisms of leaflet tethering are incompletely understood. The purpose of this study was therefore to investigate the relationships between TV annular dilatation and leaflet tethering with the severity of functional TR and to investigate factors that influence these TV deformations. METHODS: Two hundred forty-five patients with functional TR had 2-dimensional echocardiography. Echocardiographic investigations focused on the ventricles and on the TV. Ventricular measurements included left ventricular (LV) volume, right ventricular (RV) area, and RV spherical index. Valvular measurements included systolic TV annular dimension and apical displacement (tethering height), as well as severity of TR (vena contracta width). RESULTS: Tethering height (r2 = 0.25) was related to the severity of TR (P < .001). The RV and right atrium areas influenced both annular dimension and tethering height. However, LV ejection fraction and RV spherical index affected tethering height but not annular dimension. CONCLUSIONS: Tethering of TV leaflets, a determinant of functional TR, is associated with changes in right-sided cavity size as well as RV sphericity and LV function, emphasizing the impact of changes in ventricular geometry and function on the severity of functional TR.

Adult↗

PubMed2006

Relationship between left atrial and left ventricular function in hypertrophic cardiomyopathy: a real-time 3-dimensional echocardiographic study.

BACKGROUND: Left atrium (LA) in patients with hypertrophic cardiomyopathy (HC) has been known to have an increased size and decreased contractile function. The purpose of this study was to investigate LA and left ventricular (LV) volume change and function with real-time 3-dimensional (3D) echocardiography and to investigate association between LA and LV function in HC. METHODS: We performed real-time 3D echocardiography on 26 patients with HC and on 15 control subjects. LA and LV time-volume curves were obtained from real-time 3D echocardiography and the maximal slope of the time-volume curve was expressed as dV/dt. LA active emptying fraction was calculated as: [(precontraction LA volume - minimal LA volume)/precontraction LA volume] x 100. RESULTS: The maximal LA volume index was larger, and LA active emptying fraction was lower, in those with HC than control subjects (50.1 +/- 15.9 vs 30.1 +/- 6.8 mL/m(2) and 33.3 +/- 13.7 vs 40.4 +/- 8.6%, both P< .05). LA active emptying fraction showed a negative correlation with precontraction LA volume (r = -0.64, P < .01) in HC. Patients with HC showed decreased LV early diastolic dV/dt compared with control subjects (0.10 +/- 0.05 vs 0.14 +/- 0.04 mL/ms, P < .05). LA passive and active emptying dV/dt were correlated with LV early and late diastolic dV/dt, respectively (r = 0.47 and r = 0.48, both P < .05). CONCLUSION: Our 3D echocardiographic study showed that increased LA volume was related to decreased LA contraction in HC. LA passive emptying was related to LV relaxation whereas LA active contraction was related to LV stiffness.

Adult↗

PubMed2006

Intraventricular pressure gradients in left ventricular aneurysms determined by color M-mode Doppler method: an animal study.

BACKGROUND: Left ventricular aneurysm (LVA) may affect diastolic intraventricular blood flow. Color M-mode (CMM) Doppler flow propagation patterns are abnormal in the presence of apical aneurysms. The aim of this study was to validate the accuracy of CMM echocardiography for assessing the existence and size of LVA and to determine the intraventricular pressure gradient in LVA. METHODS: CMM of the transmitral inflow in early diastole was obtained from the apical 4-chamber view in 19 sheep. The presence of the break point where the velocity decreased abruptly in the mitral inflow (point D) was determined and the distance between the apex and point D was measured. The intraventricular pressure difference between the base and the apex was measured by a catheter while it was calculated using CMM with the Euler equation. RESULTS: The presence of the break point D showed 84% sensitivity and 100% specificity for determining the existence of an LVA. Distance between the apex and point D correlated well with scar size. Catheter- and CMM-derived intraventricular pressure difference correlated and agreed well (y = 1.0 x -0.2, r = 0.94). CONCLUSIONS: The point of abrupt decrease in propagation velocity of the CMM recording indicated the presence and size of LVA. Intraventricular pressure gradients were determined noninvasively by CMM echocardiography with reasonable accuracy.

Animals↗

PubMed2006

Asymmetry of systolic anterior motion of the mitral valve in patients with hypertrophic obstructive cardiomyopathy: a real-time three-dimensional echocardiographic study.

By geometric analysis of real-time 3-dimensional echocardiography performed in 39 patients with hypertrophic obstructive cardiomyopathy and definite systolic anterior motion of the mitral valve, we found that the angle between the mitral annular plane and basal portion of the anterior mitral valve leaflet, and the angle between the basal portion of the anterior leaflet and its tip portion measured in the medial and central anteroposterior planes, were significantly smaller than those in the lateral plane. The distance between the interventricular septum and the anterior mitral valve tip in the medial and central plane was also significantly smaller than that in the lateral plane. The lateral distance between the interventricular septum and the anterior mitral valve tip was the only independent determinant of left ventricular outflow tract pressure gradient by multiple stepwise regression analysis. In conclusion, systolic anterior motion of the mitral valve develops predominantly in the medial side, resulting in laterally located narrow left ventricular outflow tract opening in patients with hypertrophic obstructive cardiomyopathy.

Adult↗

PubMed2006

Determinants of ischemic mitral regurgitation in patients with chronic anterior wall myocardial infarction: a real time three-dimensional echocardiography study.

OBJECTIVE: We sought to elucidate the geometric determinants of ischemic mitral regurgitation (IMR) in patients with chronic anterior myocardial infarction (MI). MATERIALS AND METHODS: In 16 patients with anterior MI only (Group A) and 18 patients with both anterior and inferoposterior MI (Group B), three parallel equidistant anteroposterior (AP) planes (medial, central, lateral) perpendicular to the mitral valvular commissure-commissure plane were generated. The systolic tenting area of the mitral valve (MVTa) and the angles between the annular plane and leaflets (anterior, Aalpha; posterior, Palpha) on the AP planes were measured. The left ventricular end-systolic and end-diastolic volumes, and end-diastolic and end-systolic mitral annular area (MAAs) were obtained. RESULT: The regurgitant orifice area (ROA) was significantly smaller in Group A than Group B (0.08 +/- 0.09 vs 0.20 +/- 0.18 cm(2), P < 0.05). In the total of 34 patients, the medial MVTa (P < 0.001), MAAs (P < 0.05) and the spherical index (P < 0.05) were three independent determinants of ROA while the left ventricular volumes were not. MAAs was the only independent determinant of ROA in Group A, while the medial MVTa was in Group B. Palpha (P < 0.05) and MVTa (P = 0.06) tended to be larger in the medial than the lateral side in Group B, while no differences were found in Group A. CONCLUSION: The geometry of the mitral valve apparatus was more important than the left ventricular volumes in determining the severity of IMR in patients with anterior MI. The posteromedial side tenting could play a critical role in causing significant IMR when the inferoposterior MI coexists with anterior MI.

Aged↗

PubMed2006

Acute geometric changes of the mitral annulus after coronary occlusion: a real-time 3D echocardiographic study.

We performed real-time 3D echocardiography in sixteen sheep to compare acute geometric changes in the mitral annulus after left anterior descending coronary artery (LAD, n=8) ligation and those after left circumflex coronary artery (LCX, n=8) ligation. The mitral regurgitation (MR) was quantified by regurgitant volume (RV) using the proximal isovelocity surface area method. The mitral annulus was reconstructed through the hinge points of the annulus traced on 9 rotational apical planes (angle increment=20 degrees). Mitral annular area (MAA) and the ratio of antero-posterior (AP) to commissure-commissure (CC) dimension of the annulus were calculated. Non-planar angle (NPA) representing non-planarity of the annulus was measured. After LCX occlusion, there were significant increases of the MAA during both early and late systole (p<0.01) with significant MR (RV: 30+/-14 mL), while there was neither a significant increase of MAA, nor a significant MR (RV: 4+/-5 mL) after LAD occlusion. AP/CC ratio (p<0.01) and NPA (p<0.01) also significantly increased after LCX occlusion during both early and late systole. The mitral annulus was significantly enlarged in the antero-posterior direction with significant decrease of non-planarity compared to LAD occlusion immediately after LCX occlusion.

Animals↗

PubMed2005

Electrical conduction disturbance effects on dynamic changes of functional mitral regurgitation.

OBJECTIVES: The aim of this study was to investigate the relationship between dynamics of functional mitral regurgitation (MR) and the degree of electrical conduction disturbance, and to evaluate the impact of cardiac resynchronization therapy (CRT) on MR severity and its phasic pattern. BACKGROUND: Mechanisms of phasic changes of functional MR, which may be determined by annulus dilation and tethering of the leaflet, remain unclear. METHODS: Transthoracic two-dimensional echocardiography was performed in 60 patients with functional MR. A biventricular pacemaker was implanted in 19 patients. The mitral annulus area (MAA) and the tenting area (TA) were measured from apical views. The MR volume and fraction were assessed by the quantitative pulsed Doppler method. Instantaneous regurgitation flow rate was measured by proximal flow convergence method. A dynamic change in MR flow rate was evaluated by frame-by-frame analysis throughout systole. RESULTS: A phasic pattern with two peaks at early- and late-systole and decrease in mid-systole was noticed in 57 patients. The early-systolic peak of MR was larger than the late-systolic peak (128.4 +/- 64.3 ml/s vs. 73.9 +/- 55.1 ml/s, p < 0.001). The ratio of flow rate at these two peaks correlated with QRS duration (r = 0.55, p < 0.001). Early-systolic flow rate reduced after CRT (143.9 +/- 60.8 ml/s to 90.7 +/- 54.1 ml/s, p < 0.05), but late-systolic flow rate did not (61.5 +/- 55.0 ml/s to 51.2 +/- 40.9 ml/s, p = NS). A similar pattern was observed for TA, whereas MAA did not change after CRT. CONCLUSIONS: Biphasic pattern was found in functional MR, and the ratio of flow rate at two peaks correlated with QRS duration. The CRT decreased regurgitation flow volume by reducing early-systolic MR but not late-systolic MR, resulting in the change in phasic pattern of functional MR.

Aged↗

PubMed2005

Measurement of ventricular torsion by two-dimensional ultrasound speckle tracking imaging.

OBJECTIVES: We sought to examine the accuracy/consistency of a novel ultrasound speckle tracking imaging (STI) method for left ventricular torsion (LVtor) measurement in comparison with tagged magnetic resonance imaging (MRI) (a time-domain method similar to STI) and Doppler tissue imaging (DTI) (a velocity-based approach). BACKGROUND: Left ventricular torsion from helically oriented myofibers is a key parameter of cardiac performance but is difficult to measure. Ultrasound STI is potentially suitable for measurement of angular motion because of its angle-independence. METHODS: We acquired basal and apical short-axis left ventricular (LV) images in 15 patients to estimate LVtor by STI and compare it with tagged MRI and DTI. Left ventricular torsion was defined as the net difference of LV rotation at the basal and apical planes. For the STI analysis, we used high-frame (104 +/- 12 frames/s) second harmonic two-dimensional images. RESULTS: Data on 13 of 15 patients were usable for STI analysis, and LVtor profile estimated by STI strongly correlated with those by tagged MRI (y = 0.95x + 0.19, r = 0.93, p < 0.0001, analyzed by repeated-measures regression models). The STI torsional velocity profile also correlated well with that by the DTI method (y = 0.79x + 2.4, r = 0.76, p < 0.0001, by repeated-measures regression models) with acceptable bias. CONCLUSIONS: The STI estimation of LVtor is concordant with those analyzed by tagged MRI (data derived from tissue displacement) and also showed good agreement with those by DTI (data derived from tissue velocity). Ultrasound STI is a promising new method to assess LV torsional deformation and may make the assessment more available in clinical and research cardiology.

Echocardiography↗

PubMed2005

Percutaneous mitral valve repair for chronic ischemic mitral regurgitation: a real-time three-dimensional echocardiographic study in an ovine model.

BACKGROUND: Although surgical annuloplasty is the standard repair for ischemic mitral regurgitation (IMR), its application is limited by high morbidity and mortality. Using 2D and real-time 3D echocardiography in an ovine model of chronic IMR, we evaluated the geometric impact and short-term efficacy of a percutaneous transvenous catheter-based approach for mitral valve (MV) repair using a novel annuloplasty device placed in the coronary sinus. METHODS AND RESULTS: Six sheep developed IMR 8 weeks after induced posterior myocardial infarction. An annuloplasty device optimized to reduce anterior-posterior (A-P) mitral annular dimension and MR was placed percutaneously in the coronary sinus. Mitral annular A-P and commissure-commissure dimensions and MV tenting area (MVTa) in 3 parallel A-P planes (medial, central, and lateral) were assessed by real-time 3D echocardiography with 3D software. The annuloplasty device reduced MR jet area from 5.4+/-2.6 to 1.3+/-0.9 cm2 (P<0.01), mitral annular A-P dimension in both systole and diastole (24.3+/-2.5 to 19.7+/-2.4 mm; P<0.03; 31.0+/-3.9 to 24.7+/-2.1 mm; P<0.001), and MVTa at mid systole in all 3 planes (153+/-46 to 93+/-24 mm2, P<0.01; 140+/-47 to 88+/-23 mm2, P<0.03; and 103+/-23 to 87+/-26 mm2, P<0.03). CONCLUSIONS: Percutaneous coronary sinus-based mitral annuloplasty reduces chronic IMR by reducing mitral annular A-P diameter and MVTa. This suggests the potential clinical application of a new nonsurgical therapeutic approach in patients with IMR.

Animals↗