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This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/S10554-020-01888-4, Longitudinal myocardial strain is considered to deteriorate in the early ischemic stage compared to circumferential and radial strains because the subendocardial inner oblique fibers are generally directed along the longitudinal axis. However, it is unclear whether the decrease in longitudinal strain precedes a decrease in circumferential and radial strains during acute coronary flow reduction. The left anterior descending artery was gradually narrowed in 13 open-chest dogs. Whole-wall and subendocardial longitudinal, circumferential, and radial strains were analyzed at baseline and during flow reduction. Peak systolic and end-systolic strains, the postsystolic strain index (PSI), and the early systolic strain index (ESI) were measured in the risk area; the decreasing rate in each parameter and the diagnostic accuracy to detect flow reduction were evaluated. Absolute values of peak systolic and end-systolic strains gradually decreased with flow reduction. The decreasing rate and diagnostic accuracy of longitudinal systolic strain were not significantly different from those in other strains, although the diagnostic accuracy of radial systolic strain tended to be lower. PSI and ESI gradually increased with flow reduction. In these parameters, a lower diagnostic accuracy with respect to radial strain was not demonstrated. During acute coronary flow reduction, the decrease in longitudinal systolic strain did not precede that in circumferential systolic strain; however, the decrease in radial systolic strain may be smaller than that of other systolic strains. In contrast, there appeared to be no differences in the PSI and ESI values among the three strains.

This is a post-peer-review, pre-copyedit version of an article published in Journal of Medical Ultrasonics. The final authenticated version is available online at: https://doi.org/10.1007/s10396-020-01045-3., Purpose: The peak systolic strain decreases due to afterload augmentation. However, its deterioration (i.e., afterload sensitivity) may be different within the left ventricular (LV) segments. We investigated how afterload influences regional strain and whether there is regional heterogeneity of afterload sensitivity. Methods: Afterload was increased by aortic banding in 20 open-chest dogs. Short-axis images were acquired at baseline and during banding. Circumferential strain was analyzed in six segments, and the absolute decrease in the peak systolic strain during banding (Δε) was calculated for each segment. To assess the effect of the compensatory preload recruitment during banding, the endocardial lengths of the septum and free wall were measured at end-diastole, and the rate of increase due to banding was calculated. Results: LV systolic pressure was significantly increased during banding (100 ± 14 vs. 143 ± 18mmHg, P < 0.001). The peak systolic strain in all segments was significantly decreased during banding. Δɛ in the anterior segment, which is a part of the free wall, was significantly lower than that in the inferoseptal segment (2.6 ± 4.7 vs. 6.5 ± 3.5%, P = 0.035). The rate of increase in endocardial length in the free wall was significantly larger than that in the septum (15.6 ± 10.4 vs. 8.1 ± 7.4%, P = 0.014). Conclusion: The decrease in septal strain during afterload augmentation was larger than that in free wall strain, indicating that there was regional heterogeneity of afterload sensitivity in circumferential strain. The larger compensatory preload recruitment in the free wall than in the septum is implicated as a cause of the heterogeneity.

This is a post-peer-review, pre-copyedit version of an article published in Journal of Echocardiography. The final authenticated version is available online at: http://dx.doi.org/10.1007/s12574-019-00449-6., Background: Three-dimensional (3D) speckle tracking echocardiography can simultaneously evaluate circumferential, longitudinal, and radial strain without being affected by through-plane motion. Moreover, the assessment of area change ratio may allow measuring regional myocardial deformation more accurately. We investigated the changes in each deformation parameter during acute coronary flow reduction, and evaluated whether the spatial extent of the abnormal values in each deformation parameter corresponded to that of the perfusion abnormality. Methods: In 10 dogs, myocardial strains of three directions and area change ratio were analyzed at baseline and during three different ischemic conditions. The peak systolic value and the post-systolic index (PSI) were measured in both the ischemic and normal segments. The function abnormality, derived from the deformation parameter, and the perfusion abnormality, derived from Evans blue staining, were evaluated in each segment during complete occlusion and the concordance rate between both abnormalities was calculated. Results: In all deformation parameters, the peak systolic value tended to gradually decrease and the PSI tended to gradually increase with the severity of flow reduction in the ischemic segment. Especially in area change ratio, significant changes were observed in both the peak systolic value and the PSI during occlusion compared to baseline. The concordance rate was the highest in the PSI assessed by area change ratio. Conclusions: Among 3D myocardial deformation parameters, area change ratio demonstrated better detectability of acute coronary flow reduction than conventional strain components. Area change ratio may be a useful parameter for detecting acute ischemia by 3D speckle tracking echocardiography.

Background Persistence of subtle abnormal myocardial deformation such as postsystolic shortening (PSS) after transient ischemia can be used to diagnose a history of myocardial ischemia (myocardial ischemic memory). Furthermore, early systolic lengthening (ESL) has recently attracted attention as another marker of myocardial ischemia. However, it is unclear whether the persistence of such abnormal deformation can be detected by three-dimensional (3D) speckle-tracking echocardiography, which has relatively low spatial and temporal resolution compared with two-dimensional echocardiography. The aim of this study was to evaluate the diagnostic accuracy of myocardial ischemic memory and its spatial extent using 3D speckle-tracking echocardiography. Methods The left circumflex coronary artery was occluded for 2 min, followed by reperfusion, in 33 dogs. Their hemodynamic and 3D echocardiographic data were chronologically acquired. Peak systolic strain, early systolic strain index as a parameter of ESL, postsystolic strain index as a parameter of PSS, and myocardial dysfunction index as a combined parameter of ESL and PSS were analyzed in all left ventricular segments. Results At the center of the risk area, early systolic strain index and postsystolic strain index significantly increased until 20 min after reperfusion compared with baseline, although peak systolic strain recovered by 20 min. Myocardial dysfunction index significantly increased for >20 min after reperfusion and allowed better diagnostic accuracy of ischemic memory than the other parameters. In the 147 risk segments, abnormal values of myocardial dysfunction index remained in 49 segments (33%) at 20 min after reperfusion, whereas abnormal peak systolic strain was observed in only 13 segments (9%). Conclusions ESL and PSS persisted after transient ischemia and could be detected by 3D speckle-tracking echocardiography. Integrated analysis of ESL and PSS provided higher diagnostic accuracy of ischemic memory. This method may be useful for detecting transient ischemic insults in patients after the disappearance of anginal attack.

Left atrial (LA) work can be measured through speckle tracking echocardiography by calculating LA pressure–strain loop area, which includes two distinct phases of active contraction/relaxation (A-work) and passive dilation/emptying (V-work). Echocardiographic and hemodynamic data were acquired at baseline and during occlusions of left anterior descending (LAD: n = 7) and left circumflex (LCx: n = 9) coronary arteries in dogs. Left ventricular (LV) circumferential strain was decreased and mean LA pressure was increased in both occlusions. Doppler-derived stroke volume was maintained during LAD occlusion, but it decreased during LCx occlusion. A-work increased during LAD occlusion, but it did not change during LCx occlusion. V-work decreased during LCx occlusion more than during LAD occlusion. The compensatory mechanism of LA function was limited during LCx occlusion, but this occurred during LAD occlusion. This study provided insight into a role of LA function in variable hemodynamic consequences in acute myocardial infarction.

The diagnosis of coronary artery disease (CAD) with nonstress echocardiography remains challenging. Although the assessment of either early systolic lengthening (ESL) or postsystolic shortening (PSS) allows the sensitive detection of CAD, it is unclear whether the integrated analysis of ESL and PSS in addition to the peak systolic strain can improve the diagnostic accuracy. We investigated the incremental value of ESL and PSS in detecting left anterior descending artery (LAD) stenosis using nonstress speckle-tracking echocardiography. Fifty-nine patients with significant LAD stenosis but without visual wall motion abnormalities on echocardiography at rest (30 single-vessel stenosis, 29 multivessel stenosis) and 43 patients without significant stenosis of any vessel were enrolled. The peak systolic strain, the time to ESL (TESL), and the time to PSS (TPSS) were analyzed in all LAD segments, and the incremental values of the TESL and TPSS in detecting LAD stenosis and the diagnostic accuracy were evaluated. In the apical anterior segment, the peak systolic strain was significantly lower and TESL and TPSS were significantly longer in the single-vessel group than in the no stenosis group. In the single-vessel group, the addition of TESL and TPSS to the peak systolic strain significantly increased the model power in detecting stenosis, and the integrated analysis improved diagnostic accuracy compared with the peak systolic strain alone. In contrast, this incremental value was not demonstrated in the multivessel group. The integrated analysis of the peak systolic strain, ESL, and PSS may allow better screening of single-vessel LAD stenosis using nonstress speckle-tracking echocardiography.

Takeda S., Asanuma T., Masuda K., et al. Novel Estimation of Left Ventricular Filling Pressure Using 3-D Speckle-Tracking Echocardiography: Assessment in a Decompensated Systolic Heart Failure Model. Ultrasound in Medicine and Biology 47, 1536 (2021); https://doi.org/10.1016/j.ultrasmedbio.2021.02.008., E/e′ allows for the non-invasive estimation of left ventricular (LV) filling pressure; however, Doppler malalignment can make the estimation unreliable, especially in dilated systolic failing hearts. The ratio of peak early diastolic filling rate to peak early diastolic global strain rate (FRe/SRe), which is a parameter derived from 3-D speckle-tracking echocardiography to estimate filling pressure, may be better applied in dilated systolic failing hearts because it can be obtained without the Doppler method. We investigated whether FRe/SRe could provide a better estimation of filling pressure than E/e′ in 23 dogs with decompensated systolic heart failure induced by microembolization. FRe/SRe had better correlation coefficients with LV end-diastolic pressure (0.75–0.90) than did E/e′ (0.40). The diagnostic accuracy of FRe/SRe in distinguishing elevated filling pressure was significantly higher than that of E/e′. This study indicates that FRe/SRe may provide a better estimation of LV filling pressure than E/e′ in dilated systolic failing hearts.

Diastolic intraventricular pressure difference (IVPD) reflects left ventricular (LV) diastolic function. The relative pressure imaging (RPI) enables the noninvasive quantification of IVPD based on vector flow mapping (VFM) and visualization of regional pressure distribution. LV dyssynchrony causes deterioration of cardiac performance. However, it remains unclear how IVPD is modulated by LV dyssynchrony. LV dyssynchrony was created in ten open-chest dogs by right ventricular (RV) pacing. The other ten dogs undergoing right atrial (RA) pacing set at the similar heart rate with RV pacing were used as controls. Echocardiographic images were acquired at baseline and during pacing simultaneously with LV pressure measurement by a micromanometer. Pressure difference (ΔP) was computed between the apex and the base of the LV inflow tract during a cardiac cycle by RPI and ΔP during isovolumic relaxation time (ΔPIRT), a parameter of diastolic suction, and that during early filling phase (ΔPE) were measured. During RV pacing, stroke volume (SV) and ΔPIRT decreased significantly, while ΔPE did not change compared to the baseline. During RA pacing, SV, ΔPIRT and ΔPE did not change significantly. ΔPIRT tended to correlate with –dP/dtmin and end-systolic volume, and significantly correlated with ejection fraction. IVPD during isovolumic relaxation time was decreased by LV dyssynchrony, while IVPD during early filling phase was not. A reduction of diastolic suction is observed in LV dyssynchrony and is significantly related to a decrease in SV.

Echocardiography plays a pivotal role as an imaging modality in the modern cardiology practice. Information derived from echocardiography is definitely helpful for a patient care. The Japanese Society of Echocardiography has promoted echocardiography for a routine clinical and research use. One of the missions of the Society is to provide information that is useful for high-quality examinations. To ensure it, we believe equipment in good conditions and a comfortable environment are important for both a patient and an examiner. Thus, the Committee for Guideline Writing, the Japanese Society of Echocardiography published brief guidance for the routine use of echocardiography equipment in 2015. Recently, the importance of international standardization has been emphasized in the medical laboratories. Accordingly, the committee has revised and updated our guidance for the routine use of echocardiography equipment.

Background E/e′ is clinically useful for the noninvasive assessment of left ventricular (LV) filling pressure. However, its use in some conditions is controversial, and angle dependence of the Doppler measurement and preload dependence of mitral e′ in nondilated hearts represent major problems. The ratio of early filling rate derived from the time derivative of LV volume to early diastolic strain rate (FRe/SRe), similar to E/e′, by three-dimensional (3D) speckle-tracking echocardiography has the potential to address such limitations. This study investigated whether FRe/SRe could estimate acute changes in LV filling pressure using the models of volume overload and myocardial ischemia in the nondilated heart. Methods In 25 dogs, hemodynamic conditions were varied by acute volume overload and coronary occlusion. FRe and SRe were obtained from the same beat and automatically analyzed by the 3D speckle-tracking method, and global SRe was measured from longitudinal (L-SRe), circumferential (C-SRe), and area strain rate (A-SRe). E/e′ was measured by two-dimensional echocardiography. LV pressure was derived from a micromanometer catheter and recorded simultaneously with the acquisition of the 3D images. Results Mitral e′ and L-SRe varied by changes in preload, whereas C-SRe and A-SRe did not. C-SRe and A-SRe were more strongly correlated with the time constant of LV relaxation than mitral e′ and L-SRe. FRe/C-SRe and FRe/A-SRe had relatively high correlations with LV preatrial contraction (pre-A) pressure and end-diastolic pressure, but E/e′ and FRe/L-SRe did not. Receiver operating characteristics curve analysis showed that FRe/C-SRe and FRe/A-SRe had larger areas under the curve for the estimation of increased LV filling pressure. Conclusions The novel parameter FRe/SRe has potential as a surrogate marker of LV filling pressure. Especially in nondilated hearts, FRe/C-SRe and FRe/A-SRe may be useful to more accurately predict LV filling pressure than E/e′, although their applicability in dilated hearts requires further investigation.

Imaging technology capable of detecting myocardial ischemic memory is desired because angina is often temporary. Post-systolic shortening (PSS) is myocardial shortening after aortic valve closure, which is easily measured via speckle-tracking echocardiography and is a known sensitive marker of

Background and purpose Peak systolic strain (ε-sys) derived from speckle tracking echocardiography (STE) is a useful parameter for assessing regional contractile dysfunction during acute ischemia. However, low ε-sys does not always indicate myocardial ischemia because of its relatively large variation in segmental normal ranges and intervendor differences. Therefore, comparison of strain before and after an ischemic event and demonstration of a decrease in ε-sys should be necessary to confirm myocardial ischemia, which is not always possible in clinical situations. It is well known that early systolic lengthening (ESL) and post-systolic shortening (PSS) occur during acute ischemia. We hypothesized that ESL and PSS would correlate with the decrease in ε-sys and integrated analysis of ESL and PSS could be useful to diagnose the presence of myocardial ischemia. Methods 2D short-axis or 3D full-volume images were acquired by Artida at baseline, during flow-limiting stenosis (mean 50±20% flow reduction), and during complete occlusion of the left circumflex coronary artery in 22 dogs (2D-STE = 12, 3D-STE = 10).Circumferential strain was analyzed in the center of risk area, and the absolute value of peak systolic strain (ε-sys), post-systolic strain index (PSI) as a parameter of PSS, and early systolic strain index (ESI) as a parameter of ESL were measured. A new parameter, myocardial dysfunction index (MDI), which was calculated as follows: (ESL amplitude + PSS amplitude)/maximal strain amplitude during the cardiac cycle, was also calculated. The difference in ε-sys between at baseline and during ischemia (Δε-sys) was measured and the diagnostic accuracy for estimating Δε-sys < −3% was assessed by the receiver operating characteristics (ROC) curve analysis. Results During ischemia, ε-sys decreased from 19±3 to 12±6% and MDI increased from 2±4 to 27±30%. MDI was significantly correlated with Δε-sys (2D-STE: r=−0.80, 3D-STE: r=−0.83, p Figure 1 Conclusions The novel parameter, MDI was correlated with the decrease in ε-sys during acute ischemia. Integrated analysis of ESL and PSS may be useful for diagnosing the presence of myocardial ischemia.

Aims In aortic regurgitation (AR), energy loss (EL) produced by inefficient turbulent flow may be a burden to the heart predicting decompensation. We attempted to quantify EL in AR induced in an acute dog model and in patients with chronic AR using novel echocardiographic method vector flow mapping (VFM). Methods and results In 11 anaesthetized open-chest dogs, AR was induced by distorting the aortic valve with a pigtail catheter, in totally 20 cases. Regurgitant fraction was determined using pulsed Doppler echocardiography

Echocardiography plays a pivotal role as an imaging modality in modern cardiology practice. Information derived from echocardiography is definitely helpful for patient care. The Japanese Society of Echocardiography has promoted echocardiography in routine clinical and research use. One of the missions of the Society is to provide information that is useful for high-quality examinations. To ensure this, we believe that equipment in good condition and a comfortable environment are important for both patient and examiner. Here, the Guideline Preparation Committee of the Japanese Society of Echocardiography has established brief guidance for the routine use of echocardiography equipment.

This article has been accepted for publication in Heart, 2015 following peer review, and the Version of Record can be accessed online at http://dx.doi.org/10.1136/heartjnl-2013-305403., The assessment of regional wall motion is useful to identify myocardial ischaemia because wall motion abnormalities occur relatively upstream in the ischaemic cascade. Echocardiography is widely used for this, but the subjectivity of visual observation may hamper accurate evaluation. The analysis of myocardial velocity and strain by tissue Doppler and speckle tracking echocardiography has allowed the quantitative assessment of regional wall motion and facilitated the detection of subtle myocardial deformation that is diffi cult to identify by conventional methods, such as post-systolic shortening (PSS). PSS is de fined as myocardial shortening that occurs after end-systole (or aortic valve closure), and it is observed in the myocardium with regional contractile dysfunction. In experimental and clinical studies, it has been reported that the assessment of PSS is superior to that of conventional parameters such as wall thickening or peak systolic strain in detecting acute ischaemia and diagnosing coronary artery disease. Moreover, it has recently been found that PSS remains after recovery from brief ischaemia despite the rapid recovery of peak systolic strain. The assessment of PSS allows after-thefact recognition of myocardial ischaemic insults and is expected to be used for ischaemic memory imaging. In this review, the usefulness of the assessment of PSS for the diagnosis of acute ischaemia and ischaemic memory is demonstrated, and issues that need to be resolved for the widespread use of this assessment in the echocardiographic laboratory are discussed.

Background There have been no reports that show significant direct relationship between echocardiographic parameters and B-type natriuretic peptide (BNP) level. This could be due to the heterogeneous pathophysiology of heart failure and a lack of appropriate echocardiographic parameters. We sought to determine the best echocardiographic parameter that described elevated BNP level in patients with heart failure with and without systolic dysfunction. Methods and Results We studied 111 consecutive heart failure patients. They were divided into patients with heart failure and preserved ejection fraction (HFPEF, n = 61) and that with heart failure and reduced ejection fraction (HFREF, n = 50). Conventional and new echocardiographic parameters including myocardial strains were measured. BNP did not reflect any single echocardiographic parameter in patients with heart failure in total. The ratio of early diastolic transmitral flow velocity and mitral annular velocity had strong positive correlation with BNP level in the HFPEF group but not in the HFREF group. In the group of HFREF, global longitudinal and circumferential strains were positively correlated. Multivariate analysis revealed that predicted factors for BNP value in HFPEF and in HFREF were different. Conclusion High BNP level may indicate high filling pressure when ejection fraction is preserved and may indicate myocardial dysfunction when it is reduced.

Chronic renal failure (CRF) is a risk factor for cardiovascular disease, and recently much interest has focused on the cardiorenal syndrome. However, the relationship between CRF and cardiac function is not fully understood. We investigated the effect of CRF on cardiac function in a rat model. Male Wistar rats (7 weeks old) were randomly divided into the following two groups: (1) control group (n = 5) and (2) CRF group (n = 18). Rats in the CRF group received an adenine suspension orally for 10 days. Measurements of blood pressure and echocardiography were performed at baseline and after 17 weeks (24 weeks old). To investigate the possible effect of hypertension on cardiac function, we analyzed rats in the CRF group with and without hypertension (systolic blood pressure ≥ or

Recently, it has become possible to evaluate left ventricular (LV) torsion by two-dimensional (2D) speckle tracking images. However, LV torsion is a three-dimensional (3D) performance, which per se cannot be assessed by the 2D speckle tracking method. The present study investigated the accuracy of the 2D speckle tracking method and real-time 3D echocardiography in measuring LV rotation, comparing with the MRI tagging method.We assessed LV apical rotation using the 2D speckle tracking method, real-time 3D echocardiography, and MRI tagging method in 26 normal subjects, and compared the results of these three methods. LV apical rotation was measured just before the level in which the posterior papillary muscle was absorbed into the free wall.The degree of LV apical rotation evaluated by the 2D speckle tracking method (Δθ 2D) was significantly smaller than that evaluated by 3D echocardiography (Δθ 3D) and the MRI tagging method (Δθ MRI) (Δθ 2D 7.3 ± 2.8°; Δθ 3D 8.8 ± 3.4°; Δθ MRI 9.0 ± 3.4°; Δθ 2D vs. Δθ 3D, p = 0.0001; Δθ 2D vs. Δθ MRI, p 0.0001). There were good correlations among Δθ 2D, Δθ 3D, and Δθ MRI, but agreement between Δθ 3D and Δθ MRI (mean difference 0.14 ± 1.43°) was better than that between Δθ 2D and Δθ MRI (mean difference 1.68 ± 1.89°).The degree of LV apical rotation was underestimated with the 2D speckle tracking method compared with the MRI tagging method, whereas it could be precisely measured by 3D echocardiography.

This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s12574-010-0051-z., Background: Reports on ultrasound inflammation imaging with non-specific targeted microbubbles in the heart have been scarce. We investigated whether inflammation induced by myocardial ischemia-reperfusion in rats could be evaluated by ultrasound inflammation imaging with non-specific targeted microbubbles. Methods: Six rats subjected to 30 min of occlusion of the left anterior descending artery (LAD) followed by 4 h of reperfusion (ischemia group) and 4 rats subjected to the sham operation (sham group) were used. Ultrasound inflammation imaging was performed 4 h after reperfusion, and non-circulating signal intensity (SI), which reflects the signal derived from microbubbles phagocytosed by neutrophils in inflamed tissue, was calculated by the SI difference between the initial and subsequent imaging both in the LAD and non-LAD areas. The accumulation of neutrophils was confirmed by myeloperoxidase (MPO) staining. Results: Non-circulating SI in the LAD area was significantly greater for the ischemia group than the sham group [5.19 ± 2.19 (ischemia) vs. 0.31 ± 0.13 (sham) dB, p < 0.01]. Non-circulating SI in the LAD area was significantly higher than that in the non-LAD area when compared in the same rat of the ischemia group [5.19 ± 2.19 (LAD) vs. 0.18 ± 0.64 (non-LAD) dB, p < 0.01]. MPO-positive cells were confirmed in the LAD area of the ischemia group. Conclusion: Inflammation induced by myocardial ischemia-reperfusion in rats could be quantitatively assessed by ultrasound inflammation imaging with non-specific targeted microbubbles.

Objective This study was established to examine the efficacy of a high-frequency liner probe for visualizing fine anatomy of coronary microcirculation. Methods The vessel size and its velocity-time integral at the anterior wall in dogs by real-time contrast echocardiography with high-frequency liner probe and pulse Doppler methods, and the coronary flow volume, were measured before and after adenosine triphosphate injection. A 3-dimensional (3D) image was reconstructed by the built-in 3D system using intermittent flash echocardiographic images. Results The increments of flow volume calculated from vessel sizes and velocity-time integral were well correlated with those of coronary flow volume. Using intermittent flash echocardiographic images, fine dots and lines of contrast echocardiographic–expected arterioles were evident, and easily and quickly reconstructed as coronary plexus by 3D system. Conclusion A high-frequency liner probe provides the fine-vessel images to evaluate those morphologic changes; a 3D reconstruction image could provide new information about coronary arterioles.

Background Residual collateral-derived myocardial blood flow (MBF) (A × β) is important to protect against myocardial ischemia after acute coronary occlusion. Methods Recruitment of microcollateral was assessed in 22 dogs with left circumflex coronary artery occlusion by analysis of MBF and regional wall thickening (WT) using real-time myocardial contrast echocardiography. Results Video intensity and WT at the center of risk area were significantly lower than those at the border of risk area. The video intensity, A value, β value, and MBF correlated well with WT after left circumflex coronary artery occlusion. The WT of the area with above 25% of normal MBF was preserved and was higher than that at below 25%. However, the deterioration of WT was not distinguished according to A value. Conclusion Real-time myocardial contrast echocardiography is a useful noninvasive method to evaluate collateral-derived MBF, which can be a reliable index of protection against myocardial ischemia.

背景・目的：心筋血液量は心筋壊死の拡がり程度に応じて減ずる．しかし，心筋梗塞例で冠動脈狭窄がない場合，心筋壊死の程度に影響されることなく，冠微小循環血流速度は一定であるのかどうかはよく分かっていない．この関係を明らかにするために，マイクロスフェアを段階的に冠動脈注入し，均一な虚血巣を作成し，心筋コントラストエコー（MCE）法を用いて，心筋血液量，微小循環血流速度を検討した．方法：麻酔開胸犬8匹を用い，冠血流量をモニターしつつ，マイクロスフェア（平均径100μm）を左回旋枝より段階的に注入し，4段階の斑状心筋虚血モデルを作成した．各段階で安静時とATP負荷時にリアルタイムMCE法を施行した．関心領域を虚血領域と，対側の正常領域に設定し，輝度回復曲線y＝A（1-e-βt）から，心筋血液量（A値）と心筋血流速度（β値）を算出した．結果：虚血領域では冠血流量は第4段階で初めて低下したが（コントロール，第1‐4段階でそれぞれ，20.8，21.8，19.0，13.4，9.2ml/min），ATP負荷時の冠血流量は漸次低下し（47.6，39.0，31.0，20.4，11.6ml/min），冠血流予備能も低下した（2.28，1.83，1.65，1.53，1.23）．A値は漸次低下した（前値111±8.7から104±9.5，90±11.9，74±19.2，56±31.9）．β値は当初は変動せず，実験後半で低下した（前値0.71±0.22から，0.89±0.27，0.65±0.25，0.62±0.33，0.29±0.18）．ATP負荷時のβ値は漸次低下し（前値2.07±1.34から，1.56±0.92，1.18±0.78，0.87±0.47，0.34±0.31），β予備能は漸次低下した．正常領域ではA値，β値とも変動はなかった．結語：斑状の心筋虚血モデルでは，冠動脈狭窄がなくとも，冠血流予備能が低下する．

Background. It is reported that hyperlipidemia may deteriorate the coronary circulation by itself. The aim is to examine the effect of acute hypertriglyceridemia on myocardial perfusion using real-time myocardial contrast echocardiography (MCE).Methods. Hypertriglyceridemia was induced by infusion of fat emulsion (Intralipos) in 7 open-chest dogs. The coronary flow was measured by a flow meter, and its reserve (CFR) was determined by adenosine triphosphate (ATP) injection. MCE was examined using SIEMENS Sequoia-512 during infusion of Definity®. The replenishment curve was obtained to measure the A and β value in the equation of y=A(1-e-βt).Results. The β value did not change by hyperlipidemia, however, its increment by ATP decreased significantly at hyperlipidemia. The β value after ATP decreased concomitantly with the increase of both serum triglyceride level and blood viscosity. However, the A value was not affected by either serum triglyceride or viscosity.Conclusions. Hypertriglyceridemia makes blood viscous followed by high shear stress in the resistant vessels. Although myocardial resistant vessels are dilated for its compensatory response, exaggeration of blood flow speed in the capillaries after ATP is impaired due to high viscosity of hyperlipidemia.

Background: Post-systolic shortening (PSS) is myocardial shortening that occurs after end-systole and is considered as a sensitive marker of myocardial ischemia. Empirically, PSS in patients with multivessel disease is smaller than that in those with single vessel disease. Although this seems to be due to a decrease of difference in contraction between the ischemic and the surrounding myocardium, no study has elucidated it. We investigated the relationship between PSS and the difference of contraction between the ischemic and surrounding myocardium in an animal model which underwent left anterior descending coronary artery (LAD) occlusion (single vessel disease model) followed by left circumflex coronary artery (LCx) occlusion (multivessel disease model). Methods: In 7 open-chest dogs, left ventricular short-axis images (GE Vivid E9) and hemodynamic data were acquired at 3 conditions: (1) at baseline, (2) during LAD occlusion, and (3) during both LAD and LCx occlusion. Circumferential strains were analyzed in 6 segments by speckle tracking software. The amplitude of PSS (ε PSS ) and end-systolic strain (ε ES ) were measured and the difference of ε ES between a segment perfused by the LAD and the average of the other 5 segments was calculated (Δε ES ). Results: In the LAD segment, dyskinetic motion and PSS occurred during LAD occlusion but they were paradoxically attenuated during both LAD and LCx occlusion. ε PSS significantly correlated with Δε ES (r=0.95, pPSS significantly decreased during both occlusion compared to LAD occlusion, ε PSS corrected by Δε ES (ε PSS /Δε ES ) did not decrease (figure). Conclusions: PSS in the ischemic myocardium was attenuated when the surrounding myocardium also became ischemic. The difference of contraction between the ischemic and the surrounding myocardium at end-systole seems to be a determinant of the amplitude of PSS. A parameter ε PSS /Δε ES may be useful for assessing ischemia in patients with multivessel disease.

Background: Early systolic lengthening (ESL) and post-systolic shortening (PSS) is subtle myocardial deformation that occurs in the ischemic myocardium and is easily assessed by spekle tracking echocardiography. Because ESL and PSS in the ischemic region is caused by tension from the surrounding nonischemic region, such deformation may be attenuated in the infarcted myocardium with advanced fibrosis, which is less stretched by tension. We investigated whether the echocardiographic assessment of ESL and PSS can estimate tissue property in the fibrotic infarcted myocardium. Methods: In 20 rats, the left anterior descending coronary artery was occluded and short-axis images were acquired at 1 day (1D, n = 7), 1 week (1W, n = 5), and 4 weeks (4W, n = 8) after the occlusion using GE Vivid 7 (frame rate = 235.4 fps). Circumferential strains were analyzed in the ischemic and nonischemic regions, and amplitudes of ESL (ε ESL ) and PSS (ε PSS ), and the sum of ε ESL and ε PSS (ε ESL+PSS ) were measured. At the end of the protocol, Masson’s trichrome staining was performed on excised hearts to measure the area of fibrous tissue within the infarcted myocardium. Results: The fibrous areas in the 1W and 4W were significantly larger than the 1D (1D vs. 1W vs. 4W: 3.7 ± 5.5% vs. 66.5 ± 12.8% vs. 69.5 ± 17.1%). Although there was no significant difference in the fibrous areas between the 1W and 4W, more dense staining of fibers was observed in all of the 4W. In the ischemic region, ε ESL , ε PSS , and ε ESL+PSS did not significantly change between the 1D and 1W. However, ε PSS and ε ESL+PSS significantly decreased and ε ESL tended to decrease in the 4W compared to the 1W (1W vs. 4W: ε PSS 3.4 ± 1.1% vs. 1.4 ± 1.3%, ε ESL+PSS 5.9 ± 1.8% vs. 2.4 ± 1.9%, p Conclusions: ESL and PSS was attenuated in the infarcted myocardium with advanced fibrosis. The assessment of such subtle deformation by speckle tracking echocardiography may estimate tissue property in the fibrotic infarcted myocardium.

Okuda K, Asanuma T, Hirano T, Masuda K, Otani K, Ishikura F, Beppu S. Impact of the coronary flow reduction at rest on myocardial perfusion and functional indices derived from myocardial contrast and strain echocardiography. J Am Soc Echocardiogr. 2006 Jun;19(6):781-7. doi: 10.1016/j.echo.2005.10.016., Background: The severity of the coronary flow reduction that corresponds to myocardial perfusion and functional abnormalities remains unclear. We estimated the impact of various severities of flow-limiting coronary stenosis at rest on myocardial perfusion and functional indices from myocardial contrast echocardiography and tissue strain imaging and characterized the relationship between both the indices. Methods: Four levels of flow-limiting stenoses (slight, mild, moderate, severe) of the left circumflex coronary artery were examined in 10 open-chest dogs. In the left circumflex coronary artery area, plateau videointensity and time to plateau (TP) of the replenishment curve from myocardial contrast echocardiography were calculated for perfusion analysis, and peak systolic strain and postsystolic strain index (PSI) from tissue strain imaging were measured for functional analysis. Results: Plateau videointensity and peak systolic strain tended to decrease with increased severity of stenosis, although these differences did not reach the level of statistical significance. TP and PSI were significantly increased in the context of moderate (≥30

Background. Myocardial perfusion can be measured by assessing the replenishment of bubbles destroyed by transient high power ultrasound waves (burst) during real-time myocardial contrast echocardiography (MCE). However, the burst procedure may destroy microbubbles in ventricular cavities as well as in the myocardium, which can interfere with the accurate measurement of myocardial perfusion. The goal of the present study was to determine the effect of burst exposure to the ventricular cavities on the replenishment curve parameters during real-time MCE.Methods. The myocardial opacification of the left ventricular (LV) short-axis view was observed using SIEMENS Sequoia-512 (mechanical index = 0.1) during infusion of Optison in 11 open-chest dogs. A 1-second or 6-second ultrasound burst was applied to the right ventricle (RV-burst), lateral wall (Myo-burst), or in the usual fashion (General-burst). The LV cavity was insonified by the General-burst but not by the RV-burst or Myo-burst. The time course of myocardial opacification of the lateral wall after burst was fitted to an exponential function: y=a(1-e-βt)+c.Results. Although the opacification inside the RV cavity recovered soon after RV-burst regardless of burst duration (1-second burst, 0.88±0.42 sec; 6-second burst, 0.82±0.37 sec), the recovery time of opacification inside the LV cavity was significantly prolonged after the 6-second RV-burst (1-second burst, 0.49±0.39 sec; 6-second burst, 4.30±1.14 sec). Further, in the General-burst, the β-value was significantly lower with the 6-second burst than with the 1-second burst (1-second burst, 0.29±0.10 vs. 6-second burst, 0.11±0.05). However, with the Myo-burst, the β-value was similar when comparing the two burst durations (1-second burst, 0.38±0.13 vs. 6-second burst, 0.35±0.09)Conclusions. In real-time MCE, the replenishment curve was significantly influenced by the burst procedure area, possibly due to bubble destruction in the ventricular cavities. However, this effect was minimized by the use of a short burst duration.

Hirano T, Asanuma T, Azakami R, Okuda K, Ishikura F, Beppu S. Noninvasive quantification of regional ventricular function in rats: assessment of serial change and spatial distribution using ultrasound strain analysis. J Am Soc Echocardiogr. 2005 Sep;18(9):907-12. doi: 10.1016/j.echo.2005.01.009., Background: The optimal method for quantitative assessment of regional ventricular function in rats remains unclear. The goal of this study was to investigate the use of ultrasonic strain rate (SR) and strain analysis in evaluating the serial change and spatial distribution of regional contractile function in rats. Methods: In all, 22 anesthetized rats underwent incremental dobutamine infusion (protocol 1) for assessment of serial change or underwent coronary ligation (protocol 2) for assessment of spatial distribution. For protocol 1, the serial change of systolic SR and strain during dobutamine was measured in the posterior myocardium on the short-axis view, and the systolic strain was compared with the percent change in wall thickening. For protocol 2, the spatial distribution of strain profile was analyzed in normal, peripheral ischemic, and central ischemic regions that were identified by myocardial contrast echocardiography. Results: In protocol 1, the incremental dobutamine infusion resulted in a gradual increase in peak systolic SR. In contrast, peak systolic strain increased with low-dose dobutamine but tended to decrease for higher doses of dobutamine. Further, the serial change of peak systolic strain corresponded to changes in percent change in wall thickening, but the strain values were always lower than percent change in wall thickening. In protocol 2, the strain profile indicated postsystolic thickening in the peripheral ischemic region and indicated systolic wall thinning in the central ischemic region. Conclusions: Ultrasonic determination of SR and strain is an accurate and noninvasive method of quantitation of the serial change and spatial distribution of regional contractile function in rats. Copyright 2005 by the American Society of Echocardiography.

Background. Myocardial perfusion can be quantified using the replenishment curve of the myocardial opacification derived after transient high power ultrasound exposure (burst) in real-time myocardial contrast echocardiography (MCE). However, the effect of acoustic power of burst for bubble destruction may confound results. Thus, the goal of the present study was to examine the effect of burst intensity on the parameters of the replenishment curve. Methods. Myocardial opacification of the left ventricular short-axis view was observed using SIEMENS Sequoia 512 (mechanical index = 0.1) during infusion of Definity in eight open-chest dogs. The mechanical index (MI) of burst was set as high and low (0 and -11dB), and the regions of interest were placed on the anterior and lateral walls of the left ventricle. The temporal changes in video intensity of the end-diastolic phase after the burst procedure were fitted to an exponential function: y=a(1-e-βt)+c. The plateau video intensity was defined as the A-value which was calculated as the sum of the a and c values.Results. The A-value remained constant with changes in the burst MI. Although the video intensity after the high intensity (0dB) burst was similar to that of the baseline, the video intensity after the low intensity (-11dB) burst was significantly higher than that of the baseline (anterior: 5.5±2.2 dB at baseline vs. 7.4±2.4 dB at -11dB burst; lateral: 5.9±2.5 dB at baseline vs. 9.3±3.2 dB at -11dB burst), which suggests that low MI burst results in incomplete bubble destruction. Furthermore, the β-value increased as the burst MI decreased (anterior: 0.39±0.07 and 0.54±0.15; lateral: 0.27±0.05 and 0.39±0.12 in response to a burst MI of 0 and -11dB, respectively).Conclusions. The myocardial microbubble velocity (β-value) derived from the replenishment curve by using bubble destruction technique in real-time MCE is overestimated when bubble destruction is incomplete.

Background. Although second harmonic (2H) imaging is utilized to minimize the tissue signals in myocardial contrast echocardiography (MCE), the native tissue harmonic signal is sufficiently high enough to cause a misreading of myocardial opacification when high mechanical index (MI) is used.Purpose. The backscattered signal from microbubbles at high MI is broadband, while it is narrowband at low MI. Therefore, the bubble/tissue signal ratio is expected to be high between the fundamental signal and 2H frequencies at high MI. Our aim was to elucidate the efficacy of a new imaging method using an in-between frequency, denoted as 1.5 harmonic (1.5H) imaging.Methods. Six open-chest dogs were examined using Toshiba APLIO with 1.5H and conventional 2H system. The transmitting/receiving frequencies were 2.3/3.3 MHz for 1.5H and 1.4/2.8MHz for 2H imaging, respectively. Intermittent MCE was performed at a MI of 1.6 after injection of Levovist®, and baseline intensity and peak intensity of opacification of the ventricular septum were measured.Results. While baseline intensity of the septum was significantly lower using 1.5H than 2H (26±4 vs. 43±14 gray level, pConclusion. The 1.5H imaging system provides superb contrast opacification when using high MI.

Asanuma T, Fujihara T, Otani K, Miki A, Ishikura F, Beppu S. Noninvasive vessel-selective perfusion imaging with intravenous myocardial contrast echocardiography. J Am Soc Echocardiogr. 2004 Jun;17(6):654-8. doi: 10.1016/j.echo.2004.03.011., Background Intravenous myocardial contrast echocardiography (MCE) cannot identify each perfusion area of coronary vessels separately. However, by destroying microbubbles passing through a specific vessel using high-power ultrasound during intravenous MCE, vessel-selective perfusion imaging (VSPI) may be feasible. Methods In 10 open-chest dogs, intermittent short-axis images were obtained during contrast agent infusion using an ultrasound system. For VSPI, a probe coupled to another ultrasound machine was placed on the proximal left circumflex coronary artery (LCx). High-power ultrasound pulses were transmitted to destroy bubbles passing through the LCx. A negative contrast area on VSPI was considered to represent the perfusion area of the LCx (LCx-VSPI). A negative contrast area on conventional MCE during LCx occlusion and a region without staining by Evans blue dye were used as gold standards for defining the LCx perfusion area. LCx-VSPI was compared with a negative contrast area on conventional MCE during LCx occlusion and a region without staining by Evans blue dye. Results Despite lack of LCx occlusion, high-power destructive pulses produced a definite area of negative contrast on the LCx region. Decreased power of ultrasound pulses resulted in disappearance of the negative contrast area. An excellent relationship was demonstrated between both LCx-VSPI and a negative contrast area on conventional MCE during LCx occlusion (r = 0.93, P < .0001), and LCx-VSPI and a region without staining by Evans blue dye (r = 0.92, P = .0002). Conclusion: VSPI during intravenous MCE may be feasible for noninvasive assessment of perfusion areas associated with specific vessels.

Background. Although collateral circulation is important for myocardial salvage in acute coronary syndrome, effects of collaterals are significantly reduced by systemic hypotension. The objective of this study is to evaluate the effects of nitroglycerin and nicorandil on micro-collateral circulation during systemic hypotension.Methods. Real-time myocardial contrast echocardiography (MCE) was performed in 15 open-chest dogs during occlusion of the left circumflex artery using a snare. Ischemic area was identified using high ultrasound power exposure (burst) just after coronary occlusion. Micro-collateral vessels were recognized by re-opacification during 30 seconds of occlusion. Final subjects for this study were 8 of the 15 dogs that displayed micro-collateral vessels. Flow volume of the donor artery, i.e., the left anterior descending coronary artery (LAD), was measured. Video intensity (VI) were measured and percent wall thickening (%WT) was calculated. Replenishment curves of VI for the ischemic area after burst were obtained and used in the exponential function y=A (1-e-βt), for estimation of myocardial blood flow volume (A×β). These indices were compared at control and during hypotension after nitroglycerin (0.01-0.02 mg/kg) or nicorandil (0.1-0.2 mg/kg) administration.Results. Equivalent hypotension was induced by each drug. VI, %WT and A×β at the ischemic area were significantly decreased after nitroglycerin (p

The effect of ultrasound signal attenuation on myocardial blood flow parameters derived from contrast replenishment was evaluated using harmonic gray-scale (HGS) and harmonic power Doppler (HPD) imaging. In vitro experiments were performed in a flow model, whereas in vivo experiments were performed in 5 open-chest dogs. In each study, intermittent HGS and HPD images were acquired at various pulsing intervals during contrast infusion. A silicone pad was interposed between the transducer and target region to simulate attenuation conditions. Baseline-subtracted HGS and HPD signal intensities were measured with and without silicone pad, and myocardial blood flow parameters A and beta were calculated using contrast replenishment. Attenuation with HGS images could be offset by baseline subtraction, as baseline images provided the reference for attenuation. However, attenuation with HPD images could not be compensated for, as baseline signal intensity was theoretically 0. In HGS mode, silicone attenuation produced no significant decreases in A and beta. In HPD mode, however, A and beta were significantly decreased by silicone attenuation (A, P.001; beta, P.05). Compared with nonattenuated regions, myocardial blood flow parameters in attenuated regions are underestimated when HPD imaging is used. Baseline-subtracted HGS imaging may be useful to compensate for thoracic wall attenuation.

Objective: To examine the efficacy of the intravenous myocardial contrast echocardiography (MCE) for detection of the territory of the coronary bypass graft.Methods: The subjects were 5 beagles having a bypass tube between the left circumflex and carotid artery. MCE was performed with bolus injection of Optison during short axis view recording using harmonic and ECG-triggered modes of every two cardiac cycles. Time video-intensity curve was obtained at the lateral (perfused by the bypass) and the septal wall (perfused by the native coronary artery). Their peak intensities and time interval between these two peaks were measured. Selective MCE into the bypass tube was performed to confirm the territory of the bypass. Flow volume of the bypass was also measured.Results: The bypass area was clearly recognized by delayed opacification in comparison with the native coronary artery's area. Time lag of opacification between the two areas showed a good hyperbolic correlation with bypass flow, and was almost identical to the theoretically calculated time lag (r=0.889, p

Our objective was to compare harmonic-to-fundamental frequency ratio peak (HFRp) analysis with conventional harmonic gray-scale densitometric analysis on the basis of ability to eliminate heterogeneity in ultrasound signals. Broadband radio frequency and harmonic data were obtained by using intermittent short-axis scans in 10 open-chest pigs before and during infusion of contrast microbubbles. HFRp and gray-scale intensity values were measured in 6 segments of left ventricular myocardium. In baseline images, the influence of anisotropy on HFRp values was significantly less than that in gray-scale intensities. In perfusion assessment with subtraction, contrast heterogeneity in HFRp values was significantly smaller than that in gray-scale intensities. The increase in HFRp values after subtraction was significantly greater than that in gray-scale intensities in lateral (P.001), posterior (P.0001), and inferior (P.01) myocardium. HFRp analysis can compensate for baseline myocardial anisotropy and regional contrast heterogeneity. With background subtraction, HFRp analysis allows better quantification of myocardial perfusion.

Three-dimensional (3-D) speckle tracking echocardiography allows us to track a change in regional endocardial surface area. The change of regional area during a cardiac cycle should be useful for assessing left ventricular regional work. We investigated the feasibility of assessing regional work, calculated as the area within the wall tension-regional area (T-A) loop using 3-D echocardiography. Three-dimensional full-volume images were acquired using 3-D echocardiography (Artida, Toshiba) at baseline and during brief occlusion of the left circumflex coronary artery in eight dogs. Wall tension was calculated according to Laplace's law for a spherical model. Area change ratio (in %) determined by area tracking was transformed into a change of regional area (in cm2) by a custom software. We calculated the area within the T-A loop (TAA) in the area under transient ischemia (risk area) and the remote area as regional work and validated the T-A loop method by comparing the global integral of TAA with the total work assessed by the pressure-volume loop. During coronary occlusion, regional work for the risk area significantly decreased (baseline vs. occlusion, 26.8 ± 10.7 vs. 18.4 ± 7.8 mmHg·cm3; P < 0.05), whereas that for the remote area did not change. The global integral of TAA closely correlated with the total work assessed by the pressure-volume loop ( r = 0.91, P < 0.0001). The wall T-A loop reflected regional dysfunction caused by myocardial ischemia. This analysis using 3-D speckle tracking echocardiography might be useful to quantify left ventricular regional work.

Background: Vortex flow in the left ventricle (LV) has three-dimensional structure and plays an important role in avoiding excessive dissipation of energy. However, quantitative characteristics of long and short axis (LAX and SAX) vortex flow have not been elucidated. Echocardiographic particle image velocimetry (Echo-PIV) is an emerging technique to evaluate instantaneous vortical flow inside the LV. However, it has a limitation of underestimation of high velocities due to limited frame rate. Moreover, previous investigations have mainly focused on vortex from LAX view. Therefore, we used high frame rate Echo-PIV to quantitate vortex flow in SAX as well as in LAX views to understand characteristics of vortex three-dimensionally. Methods: Echocardiographic contrast images of the LV SAX and LAX were acquired from 8 open-chest healthy dogs. The acquisition frame rate was 135 frames per second and the contrast bubbles density was optimized for blood flow analysis. Echo-PIV analysis was performed off-line by using commercially available software and vorticity data were calculated in the region of interest (ROI) throughout the cardiac cycle. ROI was manually placed on the vortex. Vortex strength was defined as the averaged vorticity within the ROI. Results: In SAX, counterclockwise vortex was seen near the anterior wall, and in LAX clockwise vortex was seen in the anterior mid-ventricle. Both in SAX and LAX views, vortex strength showed significant phasic variations being largest in isovolumic contraction (vortex strength, SAX 9.2±2.3/s, p Conclusion: High frame rate Echo-PIV successfully demonstrated a complicated pattern of intracardiac vortex with phasic variation of its strength throughout a cardiac cycle in both SAX and LAX. This method may be a useful tool to assess physiological role of vortex in the flow dynamics.

Introduction: Afterload mismatch is considered as a cause of acute decompensation in patients with heart failure with preserved ejection fraction (HFPEF). However, behaviors of left atrium (LA) and ventricle (LV) to afterload increase have not been fully elucidated. We investigated how LA and LV acted to acute increase in afterload using speckle tracking echocardiography. Methods: Serial echocardiographic and hemodynamic data were acquired in 10 dogs during banding of the descending aorta (AoB). LA pressure was measured by a micromanometer via left pulmonary vein. As shown in Figure, peak negative strain during LA contraction and strain change during LA relaxation (early reservoir strain) and that during systole (late reservoir strain) were generated by simultaneous acquisition of LA longitudinal strain and volume. Pressure-strain curve showed 2 loops (A-loop, V-loop) and areas in A-loop and V-loop were computed as the work during active contraction and relaxation (A-work) and that during passive filling and emptying (V-work), respectively. Results: AoB increased LV systolic pressure by about 60 mmHg, mean LA pressure (3.8±1.3 vs. 7.1±2.0 mmHg) and LV end-diastolic pressure (4.5±1.7 vs. 10.7±4.0 mmHg, all p < 0.01). LV global circumferential strain decreased (-18.8±3.5 vs. -13.2±3.5%, p < 0.01) but LV stroke volume was maintained (8.4±2.3 vs. 9.6±3.6 ml). LA peak negative strain (-2.9±2.3 vs. -9.8±4.0%, p < 0.01) and early reservoir strain (3.4±1.1 vs. 7.8±2.6%, p < 0.01) increased substantially by AoB, but late reservoir function did not change (9.3±3.5 vs. 6.1±2.0%). A-work significantly increased (3.2±2.0 to 19.2±15.1 mmHg %, p < 0.01), while V-work did not change (13.3±7.1 vs. 13.6±8.0 mmHg %). Conclusions: During aortic banding, LA contraction, early reservoir function and thereby external work during the phase increased as a compensation to LV dysfunction. The failure of this mechanism may lead to decompensation in HFPEF.

Background: Post-systolic shortening (PSS) and early systolic lengthening (ESL) are sensitive markers of acute myocardial ischemia and the magnitude of these deformation is considered proportional to the severity of ischemia. Theoretical and mathematical models have suggested these deformation is caused by the difference of contractility between the ischemic and its adjacent normal segments. However, it has not been fully confirmed in an in vivo model yet. The aim of the study was to investigate whether PSS and ESL are affected by the contractility of its adjacent segment in an animal model which underwent left anterior descending coronary artery (LAD) occlusion (ischemic segment) followed by left circumflex coronary artery (LCx) occlusion (adjacent segment). Methods: In 6 open-chest dogs, left ventricular short-axis images with frame rate of over 90 fps (GE Vivid E9) and hemodynamics data were acquired at 3 conditions: (1) at baseline, (2) during LAD occlusion, and (3) during both LAD and LCx occlusion. Circumferential strain was analyzed in the LAD and LCx segments by speckle tracking software. End-systolic strain (ε ES ) and the amplitude of PSS and ESL (ε PSS and ε ESL ) were measured. Results: During LAD occlusion, ε PSS and ε ESL in the LAD segment significantly increased compared with baseline (ε PSS , 1.2 ± 1.1% vs. 9.5 ± 2.7%, pESL , 1.3 ± 1.0% vs. 8.5 ± 4.2%, pES in the LCx segment decreased, and both ε PSS and ε ESL in the LAD segment significantly decreased compared with during LAD occlusion (ε PSS , 9.5 ± 2.7% vs. 2.8 ± 1.3%, pESL , 8.5 ± 4.2% vs. 2.3 ± 1.9%, p Conclusions: PSS and ESL diminished with the decrease of contractility in its adjacent segment. This suggests PSS and ESL occur based on the interplay of contraction between ischemic and adjacent segments and do not always reflect the severity of ischemia.

Afterload mismatch can cause acute decompensation leading to an occurrence of acute heart failure. We investigated how the left atrium (LA) and left ventricle (LV) react to acute increases in afterload using speckle tracking echocardiography (STE). LA strain and volume were obtained by STE in 10 dogs during banding of descending aorta (AoB). Simultaneously, LA pressure was measured by a micromanometer-tipped catheter. LA peak negative strain during LA contraction, strain change during LA relaxation (early reservoir strain), and that during LA dilatation (late reservoir strain) were obtained from LA longitudinal strain-volume curves. From pressure-strain curves, the areas of A-loop and V-loops were computed as the work during active contraction and relaxation (A-work) and that during passive filling and emptying (V-work). AoB increased LV systolic pressure (105 ± 15 vs. 163 ± 12 mmHg, P < 0.01) and mean LA pressure (3.8 ± 1.2 vs. 7.1 ± 2.0 mmHg, P < 0.01). LV global circumferential strain decreased (−18.8 ± 3.5 vs. −13.2 ± 3.5%, P < 0.01), but LV stroke volume was maintained (8.4 ± 2.3 vs. 9.6 ± 3.6 ml). LA peak negative strain (−2.9 ± 2.3 vs. −9.8 ± 4.0%, P < 0.01) and early reservoir strain (4.5 ± 2.1 vs. 7.7 ± 2.4%, P < 0.05) increased by AoB, but late reservoir strain did not change (8.9 ± 3.4 vs. 6.1 ± 3.4%). A-work significantly increased (3.2 ± 2.0 vs. 19.2 ± 15.1 mmHg %, P < 0.01), whereas V-work did not change (13.3 ± 7.1 vs. 13.1 ± 7.7 mmHg %). In conclusion, LA external work during active contraction and relaxation increased as compensation for LV dysfunction during aortic banding. Atrial dysfunction may lead failure of this mechanism and hemodynamic decompensation.