Akiko Atsumi

Transmural Compensation of Myocardial Deformation to Preserve Left Ventricular Ejection Performance in Chronic Aortic Regurgitation

BACKGROUND In patients with chronic aortic regurgitation (AR), systolic wall stress and volume overload affects left ventricular (LV) systolic function and remodeling. The aim of this study was to assess transmural rearrangements of myocardial deformation to preserve LV ejection performances using speckle-tracking echocardiography in patients with chronic AR. METHODS Ninety patients with AR were enrolled. On LV short-axis images, total, inner, and outer radial strain and circumferential strain at the inner, mid, and outer layers were calculated. On apical four-chamber images, endocardial longitudinal strain was calculated. End-systolic wall stresses were calculated using previous methods. RESULTS AR severities were classified as moderate in 31 patients, severe and preserved LV ejection fraction (LVEF) (≥50%) in 42 patients, and severe and reduced LVEF (<50%) in 17 patients. Longitudinal strain was decreased even in the moderate AR group, despite normal end-systolic wall stress. Inner radial strain progressively decreased with increasing end-systolic wall stress, whereas outer radial strain in the moderate and severe AR and preserved LVEF groups was higher than in the control group. Consequently, total radial strain was preserved even in the severe AR and preserved LVEF groups with increased end-systolic wall stress. Similarly, despite reduced inner circumferential strain, outer circumferential strain was higher in the severe AR and preserved LVEF group than in the control group. All strain parameters were lower in the severe AR and reduced LVEF group with dramatically increased end-systolic wall stress than in other groups. CONCLUSIONS Transmural strain analysis revealed that subendocardial dysfunction accompanied by increased wall thickening at the subepicardium may be a compensatory mechanism of wall thickening to preserve LVEF in patients with chronic AR.

Feasibility of left ventricular volume measurements by three-dimensional speckle tracking echocardiography depends on image quality and degree of left ventricular enlargement: Validation study with cardiac magnetic resonance imaging

BACKGROUND Novel 3-dimensional echocardiography with speckle tracking imaging (3D-STE) may have advantages in assessing left ventricular (LV) volume through a cardiac cycle. The feasibility of 3D-STE may be affected by image quality and LV morphology. METHODS AND RESULTS We studied 64 patients (38 men, age 55±12 years) who underwent cardiac magnetic resonance imaging (CMRI) and 3D-STE on the same day. LV end-diastolic volume (EDV) and end-systolic volume (ESV) were measured by both modalities. Imaging qualities were quantified in each of 6 LV segments by an imaging quality score (IQS) of 1-3, and scores were averaged (mean IQS) at end-diastole and end-systole. Compared to CMRI, 3D-STE showed a tendency to underestimate LV volume measurements, but not significantly (EDV: bias=-18±37ml; ESV: bias=-10±34ml), and measurements correlated well with those by CMRI (EDV: R=0.80, ESV: R=0.86, ejection fraction: R=0.75, p<0.001). The absolute differences of LVEDV and ESV between 3D-STE and CMRI correlated significantly with mean IQS (LVEDV, R=-0.35, p=0.005; LVESV, R=-0.30, p=0.02). Based on the medium value of LVEDV by CMRI (127ml), subjects were classified into the small (<127ml) and large LVEDV (≧127ml) groups. In the large LVEDV group, mean IQS significantly correlated with the absolute differences of LVEDV (mean IQS, r=-0.45, p=0.01), despite no significant correlation in the small LVEDV group. CONCLUSION 3D-STE could measure LV volume as well as CMRI, however, its accuracy depends on the quality of the acquired image and particularly on enlargement of the left ventricle.

Novel dyssynchrony evaluation by M-mode imaging in left bundle branch block and the application to predict responses for cardiac resynchronization therapy

BACKGROUND To determine an appropriate M-mode method in assessing left ventricular (LV) dyssynchrony in left bundle branch block (LBBB), and to assess feasibility of the method to predict cardiac resynchronization therapy (CRT) responses. METHODS AND RESULTS Fifty-one patients with LBBB were enrolled. Among them 31 patients underwent CRT. In addition to original septal to posterior wall motion delay (SPWMD), first peak-SPWMD was proposed as time of difference between the first septal displacement and the maximum displacement of the posterior. If an early septal point was not present, anatomical M-mode was used to visualize an early septal displacement spreading scan-area until inferoseptal wall. CRT responders were defined as LV end-systolic volume reduction (>15%) at 6 months after CRT. Twenty patients (65%) were identified as CRT responders. First peak-SPWMD in responders was significantly higher than those in nonresponders, although SPWMD did not differ between groups. Strong predicting ability of first peak-SPWMD was revealed (first peak-SPWMD: 80/90/83%; SPWMD: 35/100/58%), and area under the curve in receiver operating characteristic analysis of first peak-SPWMD (0.88) was significantly higher than that of SPWMD (0.61) (p<0.05). CONCLUSION In patients with LBBB, time differences between early septal and delayed displacement of posterolateral wall on M-mode images were the appropriate dyssynchrony parameter, and could improve the predictive ability for CRT responses.

Global and Regional Right Ventricular Function Assessed by Novel Three-Dimensional Speckle-Tracking Echocardiography

Background: Accurate assessment of global and regional right ventricular (RV) systolic function is challenging. The aims of this study were to confirm the reliability and feasibility of a three‐dimensional (3D) speckle‐tracking echocardiography (STE) system, using comparison with cardiac magnetic resonance imaging (CMR), and to assess the contribution of regional RV function to global function. Methods: In a retrospective, cross‐sectional study setting, RV volumetric data were studied in 106 patients who were referred for both CMR and 3D echocardiography within 1 month. Three‐dimensional STE‐derived area strain, longitudinal strain, and circumferential strain were assessed as global, inlet, outflow, apical, and septal segments. Results: Seventy‐five patients (70%) had adequate 3D echocardiographic data. RV measurements derived from 3D STE and CMR were closely related (RV end‐diastolic volume, R2 = 0.84; RV end‐systolic volume, R2 = 0.83; RV ejection fraction [RVEF], R2 = 0.70; P < .001 for all). RVEF and RV end‐diastolic volume from 3D STE were slightly but significantly smaller than CMR values (mean differences, −2% and −10 mL for RVEF and RV end‐diastolic volume, respectively). Among conventional echocardiographic parameters for RV function (tricuspid annular plane systolic excursion, fractional area change, S′ of the tricuspid annulus, RV free wall two‐dimensional longitudinal strain), only fractional area change was significantly related to RVEF (r = 0.34, P = .003). Among segmental 3D strain variables, inlet area strain (r = −0.56, P < .001) and outflow circumferential strain (r = −0.42, P < .001) were independent factors associated with CMR‐derived RVEF. Conclusions: RV volume and RVEF determined by 3D STE were comparable with CMR measurements. Regional RV wall motion showed that heterogeneous segmental deformations affect global RV function differently; specifically, inlet area strain and outflow circumferential strain were significant factors associated with RVEF in patients with underlying heart diseases. HighlightsWe present a novel 3D speckle‐tracking echocardiographic measurement system for the assessment of right ventricular systolic function.This system provides a reliable measurement of right ventricular systolic function using an echocardiographic methodology.The right ventricular regional strain derived by this system was revealed to contribute differently to the right ventricular ejection fraction. Abbreviations: 2D = Two‐dimensional; 3D = Three‐dimensional; BNP = Brain natriuretic peptide; CMR = Cardiac magnetic resonance imaging; RV = Right ventricular; RVEDV = Right ventricular end‐diastolic volume; RVEF = Right ventricular ejection fraction; RVESV = Right ventricular end‐systolic volume; RVOT = Right ventricular outflow tract; STE = Speckle‐tracking echocardiography; TAPSE = Tricuspid annular plane systolic excursion; TOF = Tetralogy of Fallot.

Diastolic suction in heart failure: Impact of left ventricular geometry, untwist, and flow mechanics

AIMS Vector flow mapping (VFM) can be used to assess intraventricular hemodynamics quantitatively. This study assessed the magnitude of the suction flow kinetic energy with VFM and investigated the relation between left ventricular (LV) function and geometry in patients with an estimated elevated LV filling pressure. MATERIALS AND METHODS We studied 24 subjects with an elevated LV filling pressure (EFP group) and 36 normal subjects (normal group). Suction was defined as flow directed toward the apex during the period from soon after systolic ejection to before mitral inflow. The flow kinetic energy index was quantified as the sum of the product of the blood mass and velocity vector and its magnitude to the peak value was measured. KEY FINDINGS Suction flow was observed in 12 (50%) EFP-group patients and 36 (100%) normal-group subjects. The magnitude of the suction kinetic energy index was significantly smaller in EFP versus normal group (2.7 ± 3.8 vs. 5.7 ± 4.4 g/s/cm(2), P<0.01). The EFP-group patients with suction had a smaller LV end-systolic volume (ESV) (P<0.01), greater ellipsoidal geometry (P<0.05) and untwisting rate (P<0.01) than the EFP-group patients without suction. A regression analysis indicated a significant linear relation between the suction kinetic energy index and LVEF (r=0.43, P=0.04), ESV (r=-0.40, P=0.05), eccentricity index (r=0.44, P=0.04), and untwisting rate (r=0.51, P=0.04). SIGNIFICANCE The magnitude of the suction flow kinetic energy index derived from VFM may allow the quantitative assessment of the suction flow, which correlates with LV systolic function, geometry, and untwisting mechanics.

Three-dimensional echocardiography in the diagnosis of pacemaker lead perforation

Recently, due to increases in the number of cardiac device implantations, especially implantable cardioverter-defibrillators and cardiac resynchronization therapy, device complications have been experienced more frequently. Myocardial perforation of an implanted lead is one of the most severe complications. We report a case of ventricular lead perforation clearly visualized by 3-dimensional echocardiography, which was not identified by 2-dimensional echocardiography.