Regional Myocardial Dysfunction Research Articles

Regional Left Ventricular Myocardial Dysfunction as a Predictor of Incident Cardiovascular Events: MESA (Multi-Ethnic Study of Atherosclerosis)

We sought to examine the prognostic value of subclinical left ventricular (LV) regional myocardial dysfunction (RMD) measured by magnetic resonance imaging (MRI) among asymptomatic individuals. LV RMD, defined as segmental impairment in systolic wall thickening, predicts adverse events in patients with established cardiovascular disease. MRI is highly accurate for detecting subtle RMD, of which the prognostic significance in a large multiethnic asymptomatic population is not known. We used MRI to evaluate baseline regional LV myocardial function and prospectively followed a multiethnic (African American, Caucasian, Chinese, and Hispanic) population-based sample of 4,510 men and women without cardiovascular disease for a mean of 4.6 years. Regional myocardial dysfunction was defined as the presence of impaired systolic wall thickening (<10th percentile of segment-specific population distribution) in ≥2 contiguous LV segments within any given coronary artery territory. Baseline prevalence of RMD was 25.6%. Heart failure developed in 34 (1.0%) and 30 (2.6%) participants without and with RMD, respectively (p < 0.001). After adjustment for demographics and traditional risk factors, RMD remained independently associated with incident heart failure (hazard ratio [HR]: 2.62; 95% confidence interval [CI]: 1.56 to 4.39; p < 0.001). The relationship persisted after further adjustment for biomarkers of reported association with cardiovascular disease and indexes of global LV systolic dysfunction and hypertrophy (HR: 1.80; 95% CI: 1.02 to 3.20; p = 0.044). Similarly, RMD independently conferred an increased risk for hard coronary events (myocardial infarction or death from coronary heart disease; HR: 1.75; 95% CI: 1.06 to 2.89; p = 0.029), the composite of hard coronary events and stroke (HR: 1.72; 95% CI: 1.16 to 2.56; p = 0.005), and all atherosclerotic cardiovascular events (HR: 1.50; 95% CI: 1.09 to 2.07; p = 0.012). Among an asymptomatic multiethnic American cohort, RMD is an independent predictor beyond traditional risk factors and global LV assessment for incident heart failure and atherosclerotic cardiovascular events. The clinical utility of early recognition of this subclinical phenotype deserves further investigation. (Multi-Ethnic Study of Atherosclerosis [MESA]; NCT00005487).

Strain and Strain Rate Echocardiography and Coronary Artery Disease

The echocardiographic assessment of regional myocardial function plays a critical role in the diagnosis and management of ischemic heart disease and in most laboratories relies on the visual detection of endocardial wall motion abnormalities and assessment of left ventricular (LV) ejection fraction. However, this approach is subjective and operator dependent, demands complete visualization of the endocardium, and is subject to the vicissitudes of cardiac loading and heart rate. Although estimation of myocardial shortening and thickening reflect the radial mechanics of the heart, the contribution of longitudinal (and to a lesser extent circumferential) myocardial deformation is largely neglected. Thus, there is a need for an objective, comprehensive, noninvasive measurement of myocardial performance and contractility with acceptable interpretative variability. Doppler tissue imaging, which measures the velocity of myocardium (in the longitudinal direction from apical windows and in the radial direction from short-axis scans) during systole and diastole is used to quantify ventricular function and is more sensitive to subtle changes in contractility than ejection fraction.1 However, tissue velocities are affected by translational movement and tethering, making it difficult to discriminate akinetic segments that are pulled (or tethered) from actively contracting segments.2 In addition, velocities are not uniformly distributed across the myocardium, decreasing from base to apex, making difficult the establishment of reference values. Measurements of myocardial strain and strain rate (SR) are newer indices that have the potential to overcome these limitations. Strain and SRs represent the magnitude and rate, respectively, of myocardial deformation, which is an energy-requiring process that occurs in both systole and diastole. Abnormalities of myocardial deformation are seen early in the development of many pathophysiologic states, including ischemia, and thus provide a sensitive means for detecting regional myocardial dysfunction. The objective of this report is to review the use of strain and SR echocardiography in patients …

Detection of prolonged regional myocardial systolic dysfunction after exercise-induced myocardial ischemia by strain echocardiography with high frame rate tissue Doppler echocardiography.

Strain echocardiography has enabled quantification of regional myocardial systolic function objectively and is less influenced by tethering effects and cardiac translational artifact than Doppler tissue imaging. Although strain echocardiography has been applied for the detection of inducible ischemia during dobutamine stress, it has not been fully applied to exercise stress echocardiography (ESE) because of technical difficulties. Prolonged myocardial systolic dysfunction after exercise-induced ischemia has been shown previously. Thus, we designed this study to evaluate whether the myocardial strain analysis can detect myocardial ischemia by the assessment of prolonged regional left ventricular (LV) dysfunction in ESE. We performed ESE with myocardial strain imaging system in 20 consecutive patients who had exercise Tl-201 single photon emission computed tomography (SPECT). Myocardial strain curves were obtained at six segments in mid LV walls from the apical approach before and 5min after ESE. We measured the duration from the R wave in the electrocardiogram to the timing of peak systolic strain corrected by the square root of the RR interval (TPSc). We finally calculated the differences of TPSc (ΔTPSc) before ESE and 5min after ESE. The results were compared with SPECT as a reference standard. A receiver operating characteristic curve demonstrated that a ΔTPSc cutoff value of 70ms had a sensitivity of 80% and a specificity of 84% for the detection of myocardial ischemia. Prolonged regional LV systolic dysfunction assessed by ESE with strain analysis was useful for the detection of myocardial ischemia.

Experimental study of relationship on myocardial perfusion, regional contractile function and cell apoptosis in stunned myocardium by myocardial contrast echocardiography with computer-aided technique

Objective To evaluate a new computer-aided technique applicable for myocardial contrast echocardiography(MCE) to quantitate automatically calibrated myocardial contrast intensity(CD and to test the feasibility of calibrated CI in assessing myocardial perfusion. To analyze the relationship on myocardial perfusion,regional contractile function and cell apoptosis in stunned myocardium. Methods According to coronary occlusion and reperfusion at different times, rabbits were divided into three groups: 15 min occlusion/30min reperfusion (group Ⅰ ),30 min occlusion / 60min reperfusion (group Ⅱ ) and 120 min occlusion / 60min reperfusion (group Ⅲ ). MCE was performed on all rabbits at baseline,occlusion and after reperfusion,and its images were analyzed by a new computer-aided technique. Myocardial calibrated CI of each segment was measured automatically by software. Percentage wall thickening (WT) of each risk segment at each stage were also measured by echocardiography. The apoptotic index(AI) in regional left myocardial dysfunction was calculated by terminal deoxynucleotidyl transferease-mediated biotinylated deoxyuridine triphosphate nick end labeling(TUNEL ). Results (1) During occlusion, WT in the areas at risk decreased to zero or negative and the calibrated CI values were significantly lower than those at baseline ( P ＜0.01 ). After reperfusion, WT in all risk segment remained depressed, but calibrated CI significantly improved in group Ⅰ and Ⅱ while those remained unchanged in group Ⅲ. (2)AI in risk myocytes were (13. 70 ± 5.48 ) %, (36.25 ± 5.55 ) % and ( 62.06 ± 6. 70 ) %, respectively, both statistically significant difference between the two groups ( P ＜0.05 or P ＜ 0.01 ). AI were negatively correlated to WT and calibrated CI ( r = - 0. 87 and r = - 0. 77, P ＜0.05). Conclusions MCE with computer-aided technique can assess quantitatively myocardial perfusion and regional contractile function. Short-term ischemiareperfusion does not cause myocardial necrosis, but it will lead to myocardial cell apoptosis and the phenomenon of myocardial stunning. Prolonged ischemia, even if given sufficient reperfusion, can lead to apoptosis and necrosis simultaneously. Key words: Echocardiography; Microbubbles; Image processing,computer-aided; Myocardial reperfusion; Apoptosis

Contrast Enhanced Cardiac CT May Be Used to Accurately Measure the Coronary Calcium Score

Introduction: Coronary artery calcium score (CACS) measurement is a well validated and commonly used prognostic tool that currently requires a second noncontrast scan in additional to contrast enhanced CT coronary angiography. We present the final results of a prospectively registered validation study of a new technique tomeasure the coronary calcium score froma single contrast-enhanced cardiac CT. Methods: Paired contrast enhanced and calcium score scans from 120 sequential patients were prospectively analysed. All scans were performed using a wide-volume 320-detector row CT scanner. Eleven contrast scans were excluded due to pre-specified exclusion criteria of complete coronary occlusion or excessive image noise. The volume of intramural coronary calcium above 320 regional myocardial dysfunction. Cardiac MRI (CMR) accurately evaluates LV morphology and can assess myocardial injury using late gadolinium enhancement (LGE). Although studies during the acute phase of ABS havedocumentedLGE, data is lacking regarding longterm sequelae. Methods: We retrospectively reviewed a cohort of ABS patients who had undergone convalescent CMR (>10 days since admission). Results: Thirty-two patients (mean age 64± 10 yrs) underwent convalescent CMR, and 94% were female. The average peak troponin I = 5.14± 6.39, and mean time to CMR=122± 206 days. LV volumetric analysis was normal with ejection fraction 63± 6%, EDV=127± 27mL andESV 48± 14mL. LGE was noted in four cases (12.5%), and all had a pattern which was non-coronary in distribution. In three cases the LGE was limited to the apical segments of which two notably involved all four apical segments with diffuse transmyocardial enhancement not typical of either ischaemic injury or myocarditis (figure). The apical location correlates to the acute wall motion abnormality – although convalescent wall motion was normal in all. One case had basal septal LGE, also with normal wall motion. Patients with LGE were similar to those without with respect to age, sex, peak troponin and LV volumes.

Detection of subclinical regional myocardial dysfunction around left ventricular cardiac tumor using a two-dimensional speckle tracking imaging: a case report

症例は74歳，男性．当院糖尿病内科に通院中，発作性心房細動を認めたため，2008年12月心エコー検査を施行したところ，左室後壁に2×5 cmの腫瘤を指摘された．手術歴や外傷歴はなく，3ヵ月後の心エコー検査でも腫瘤径は変化せず，全身のCT検査で悪性腫瘍を示唆する所見を認めないことから，良性心臓腫瘍と判断し，経過観察を行っていた．冠動脈CT検査で前下行枝に狭窄病変の存在が疑われたため，2009年12月に腫瘍精査も兼ねて入院となった．臨床所見及び，その形態やエコー輝度，CT所見から鑑別した結果，線維腫である可能性が最も考えられた．入院時の心エコー検査で，2次元（2D）スペックルトラッキング法を用いて長軸，短軸及び円周方向のstrain解析を行ったところ，腫瘍部位に一致する後壁基部に限局した局所心機能異常が認められた．冠動脈造影では，後壁を灌流する右冠動脈及び左回旋枝に狭窄病変を認めなかったことから，腫瘍の存在そのものが，局所心機能異常の原因の一つとなる可能性が考えられた．2Dスペックルトラッキング法は，左室腫瘍周囲の潜在的心機能異常の検出に有用である可能性が示唆された．

Dobutamine-Induced Improvement in Inferior Myocardial Contractile Function Predicts Reduction in Functional Mitral Regurgitation

Background— Left ventricular (LV) remodeling can increase tethering force to mitral valve and functional mitral regurgitation (FMR). Because the relationship between FMR and regional myocardial function has not been quantitatively evaluated, we conducted a quantitative investigation of this association. Methods and Results— The effective regurgitant orifice (ERO) of FMR in 51 patients with depressed LV ejection fraction (32±9%) secondary to ischemic or nonischemic cardiomyopathy was compared with mitral deformation (valve and annulus), global LV remodeling (volume indices, function, and sphericity), and regional myocardial contractile function, as assessed by longitudinal peak systolic strain rate (Ssr) in LV anterior, anteroseptal, inferoseptal, inferior, inferolateral, and anterolateral segments at rest. Low-dose dobutamine (10 μg/kg per minute)-induced changes in ERO were compared with changes in the variables. Multivariable analysis identified the predictors of ERO at rest as mitral valvular tenting (β=0.062; P &lt;0.001), Ssr in the inferior segment (inferior Ssr) (β=−0.178; P &lt;0.001), and LV sphericity (β=0.414; P =0.001) and the predictors of valvular tenting at rest as inferior Ssr (β=−1.680; P &lt;0.001), LV end-systolic volume index (β=0.022; P =0.001), and LV sphericity (β=3.886; P =0.012). Furthermore, dobutamine-induced reduction in ERO was predicted by reduction in valvular tenting (β=0.087; P &lt;0.001) and increase in inferior Ssr (β=−0.082; P &lt;0.001), and dobutamine-induced reduction in valvular tenting was predicted by increase in inferior Ssr (β=−0.860; P &lt;0.001). Conclusions— Inferior regional myocardial dysfunction was quantitatively associated with mitral valvular tenting and FMR. Moreover, improvement with dobutamine of inferior myocardial contractile function attenuated valvular tenting and FMR. Inferior myocardial contractile function can affect the configuration of the mitral apparatus and predict FMR severity.

Severity of regional myocardial dysfunction is not affected by cardiomyocyte apoptosis in non-ischemic heart failure

The role of myocardial apoptosis during the development of heart failure (HF), in the absence of coronary artery stenosis, is still debated. The aim of the study was to evaluate whether (similar to functional impairment) the activation of myocardial apoptosis follows a regional pattern in an established model of pacing-induced HF. HF was induced in adult male minipigs by rapid and sustained left ventricular (LV) epicardial pacing ( n = 8; n = 5 healthy controls). Progressive regional derangement of the contractile function and perfusion was assessed by magnetic resonance imaging as LV end-systolic wall thickening (LVESWT) and relative upslope of signal intensity (LVRUSI, %) in the anterior/anterior-lateral (pacing site, PS) and infero-septal LV region (opposite site, OS). LV tissue from PS and OS was analyzed for biomarkers of cell apoptosis and injury. After 21 days of LV pacing, LVESWT was lower in the PS compared to OS (7.6 ± 3.7 vs 24.16 ± 3.6%, p < 0.05), and LV ejection fraction was 24.0 ± 3.7 ( p < 0.05 vs control). The mRNA expression of caspase (Casp)-3 was significantly higher in the PS of HF hearts than in controls (1.28 ± 0.125 vs 0.82 ± 0.10), but not Casp-9. Bcl-2 and Hsp72 expression was significantly increased in PS compared to control (0.90 ± 0.60 vs 0.63 ± 0.033; 0.72 ± 0.10 vs 0.28 ± 0.098), in the presence of a TNF-α level increased by 50.7%. The regional myocardial apoptotic index, assessed by TUNEL, was unchanged in HF. In conclusion, the activators and inhibitors of cell apoptosis are equally expressed without affecting the survival of cardiomyocytes and the magnitude of regional myocardial dysfunction during development of non-ischemic HF.

E0698 Value of segmental myocardial strain by 2-dimensional strain echocardiography for assessment of scar area induced in a rat model of myocardial infarction

Backgrounds and ObjectivesTwo-dimensional strain echocardiography (2DSE) technique has enabled accurate quantification of regional myocardial function. This experimental study was aimed to investigate the value of 2DSE in detection of segmental...

The efficacy of tissue Doppler imaging in predicting myocardial iron load in patients with beta-thalassemia major: correlation with T2* cardiovascular magnetic resonance

Tissue Doppler imaging (TDI) can detect myocardial dysfunction related to iron load in patients with beta-thalassemia major (TM). We aimed to assess the efficacy of pulsed-wave TDI (PW-TDI) in predicting myocardial iron load in patients with TM using T2* magnetic resonance (MR) as the gold-standard non-invasive diagnostic test. 33 asymptomatic TM patients, mean aged 18 +/- 6 years (6-31) with normal left ventricular (LV) global systolic function were evaluated by conventional echocardiography and PW-TDI. Results were compared with 20 age and sex-matched controls. TDI measures included myocardial systolic (Sm), early (Em) and late (Am) diastolic velocities at basal and middle segments of septal and lateral LV wall. Myocardial iron deposition were measured in 29/33 patients by T2* MR. TM patients were also subgrouped according to those with iron load (T2* <or= 20 ms) and those without (T2* > 20 ms). Mean T2* was 12.3 +/- 7.8 ms (4-31.3). Abnormal myocardial iron load (T2* < 20 ms) was found in 25/29 (86%) patients. The following TDI measures were lower in patients than in controls: basal septal Em (P < 0.001) and Am (P < 0.05), mid-septal Am (P < 0.05), mid-lateral LV wall Sm (P < 0.05) and Am (P < 0.05). Regional myocardial dysfunction were more prominent in patients with T2* <or= 20 ms. Mid-septal Sm and Em significantly correlated with mid-septal T2*(r = 0.44, P = 0.023 and r = 0.54, P = 0.004, respectively). The PW-TDI parameters and the cut-off values for predicting presence of myocardial iron load were determined. PW-TDI technique was found both sensitive and specific in predicting presence of myocardial iron load in TM patients with normal LV global systolic function. Therefore, it can be used for screening of TM patients.

Regional Myocardial Dysfunction is Independently Associated with Regional Sympathetic Dysinnervation in Type 2 Diabetes

Regional Myocardial Dysfunction is Independently Associated with Regional Sympathetic Dysinnervation in Type 2 Diabetes

Adenosine transport, erythrocyte deformability and microvascular dysfunction: An unrecognized potential role for dipyridamole therapy

Reperfusion injury and no-reflow phenomenon are known entities that contribute to persistent impairment in myocardial perfusion and regional myocardial dysfunction following restoration of epicardial coronary blood flow after a myocardial infarction. Following prolonged ischemia, oxidative stress and inflammation-mediated alterations in erythrocyte mechanics and microvascular architecture play a major role in ischemia/reperfusion injury and no-reflow phenomenon. An increase in red cell rigidity is an important rheological aspect of RBCs, which facilitates platelet aggregation with the subendothelium. Dipyridamole inhibits the reuptake of adenosine which causes platelet inhibition and vasodilatation. Dipyridamole improves microvascular function by increasing RBC deformability and reducing blood viscosity. In addition, it has anti-oxidant and anti-inflammatory properties that provide protection to the microvasculature. This review discusses the potential role for dipyridamole therapy in the treatment of microvascular dysfunction.

Automated Versus Visual Segmental Scoring

Echocardiography is the most widely used noninvasive test for assessing the structure and function of the heart, accounting for 14% of overall Medicare expenditures for imaging in 2007.1 Despite the availability of a variety of validated quantitative methods for assessing chamber size and cardiac function, many elements of echocardiographic interpretation remain qualitative rather than quantitative. This is particularly true of the assessment of regional wall motion. Notwithstanding progress in the field of myocardial perfusion echocardiography2 and earlier efforts to quantitate regional function with acoustic quantitation3 and Doppler tissue imaging-based methods,4 echocardiographic assessment of regional wall motion remains the principal method by which echocardiographers make the diagnosis of coronary disease. Moreover, the ability to visually identify stress-induced regional wall motion abnormalities is the foundation for stress echocardiography. Article see p 47 The ability to reproducibly and reliably detect regional wall motion abnormalities is an essential skill for any physician interpreting echocardiograms and conceded to be one of the most difficult skills to acquire.5 Consequently, an automated quantitative approach to assessing regional function would be invaluable as a tool for the interpretation of echocardiograms for teaching and research and could prove useful in training echocardiographers. The study of Liel Cohen6 in this issue of Circulation: Cardiovascular Imaging proposes just such a tool. In their article, the authors report their evaluation of a semiautomated method of measuring regional longitudinal strain to develop segmental scores, classifying segments as normal, hypokinetic, or akinetic/dyskinetic/aneurysmal. As the authors note, strain analysis based on speckle tracking as opposed to angle-dependent Doppler tissue imaging methods is appealing because it avoids translation artifact and angle dependence. Twelve expert echocardiographers of the Israeli Echocardiography Research Group at 9 major Israeli cardiology centers used this approach as well as qualitative visual segmental scoring in 15 patients …

Assessment of cardiac twist in hypertrophic cardiomyopathy using velocity vector imaging

Objective To assess global and regional cardiac twist function in hypertrophic cardiomyopathy(HCM) patients by velocity vector imaging(VVl).Methods Thirty HCM patients and 33 normal subjects were enrolled into this study.Two dimensional echocardiographic images of parasternal left ventricular basal level,middle and apical level short axis plane,apical four-and two-chamber plane were obtained.Maximal rotation degree,peak rotation rate,circumferential strain (CS) and strain rate (CSR),radial strain(RS) and strain rate(RSR) in systole were measured using VVI offline software.In addition,diastolic peak un-rotation rate,untwisting rate(unTwR) were measured.Each parameters was analyzed both in subendocardial and subepicardial layer.Results There was no significant difference in left ventricular ejection fraction between two groups.EDV,ESV,SV were significantly decreased (P＜0.01) in HCM group.Left ventricular twist(LVtw),CS of subendocardial layer were higher in HCM group than control group(P＜0.05),while the peak rotation rate,un-rotation rate,CS,CSR were lower of subepicardial layer (P＜0.05).The RSR of each short axis level were significantly decreased in HCM group (P＜0.01).The diastolic unTwR was decreased in HCM group (P＜0.05).For further analysis of the two subgroups in HCM,more regional torsion deterioration occurred in patients with left ventricular outflow tract obstruction than those without obstruction.Conclusions The global cardiac twist angle of HCM was higher than normal person,but the circumferential deformation ability of regional myocardium was impaired,left ventricular outflow tract obstruction may aggravate the regional myocardial dysfunction. Key words: Echocardiography; Cardiomyopathy; hypertrophic; Torsion; Ventricular function; left; Velocity vector imaging

Transient Cardiac Ballooning—The Syndrome

Transient cardiac ballooning is usually a reversible clinical entity. A patient typically presents with chest pain, electrocardiogram (ECG) abnormalities like ST-segment elevation (most commonly reported) or depression, and elevated cardiac enzymes, but has no or nonobstructive coronary artery disease. Left ventriculography reveals transient akinesis of the involved portion of the myocardial wall with compensatory hyperkinesis of the remaining myocardium, leading to ballooning of the noncontracting myocardial wall during systole. Acute regional myocardial dysfunction ensues, which normalizes on average within 1 to 6 weeks. The hypotheses for these pathophysiologic changes range from direct cardiac myocyte injury to postischemic myocardial stunning to neurotransmitter actions. The objective of this article is to present a succinct description of a small case series accompanied with various recently reported presentations and morphology by left ventriculogram and a detailed review of available data on underlying pathophysiology. In addition, a discussion on current diagnostic guidelines, treatment, prognosis, and potential future investigations is included.

Did Jesus die of a ‘broken heart’?

Did Jesus die of a ‘broken heart’?

Impaired Myocardial Function in Hypertrophic Cardiomyopathy

Tissue Doppler imaging (TDI) parameters of peak myocardial velocities (S', E', and A') has been employed to assess the regional left ventricular myocardial function. The global function index (GFI) derived from TDI has been recently employed to distinguish the different etiologies of left ventricular hypertrophy. To analyze whether the GFI or individual TDI parameters of peak myocardial velocities (S', E', and A') allows detecting different degrees of regional myocardial dysfunction in the most frequent forms of hypertrophic cardiomyopathy (HCM). GFI = (E/E')/S' (where E is the peak transmitral flow velocity, E' is the early diastolic myocardial velocity, and S' is the peak systolic myocardial velocity) and TDI peak myocardial velocities was measured in the septal and lateral mitral annulus in 101 patients with HCM (mean age 47.5 +/- 14 years, 58 women) and in age-matched group of 30 healthy controls (mean age 46 +/- 6 years, 16 women). Forty-five patients had nonobstructive asymmetric septal HCM, 20 patients had a subaortic gradient >or= 30 mm Hg, 21 p. had apical HCM, and 15 p. had other forms of HCM (midventricular, symmetric, and biventricular). All patients with HCM exhibited a decrease in early diastolic (E') and systolic (S') myocardial velocities, both in the lateral and septal-mitral annulus border, but more pronounced in septal-mitral annulus. Septal GFI was higher in HCM patients than in healthy subjects (1.8 (1.1-2.5) and (0.57 (0.31-0.92), respectively, P < 0.001), but no differences were seen when different forms of HCM were compared. In a selected population of patients with HCM and a preserved left ventricular(LV) systolic function, GFI and individual TDI parameters of peak velocity (S', E', and A') and E/E' ratio were similar in different forms of HCM, indicating that in all patients with HCM there is regional systolic and diastolic myocardial dysfunction, regardless of the location of hypertrophy.

Echocardiographic study of left ventricular transmural radial displacement during acute myocardial ischemia in vivo:a canine model

Objective To evaluate the change of myocardial segment and the transmural peak radial displacement(RD) of left ventricular wall before and after acute myocardial isehemia. Methods Left anterior descending coronary artery was ligated to induce acute myocardial ischemia in 10 open-chest Beagle canine models. Two-dimensional gray-scale images with overlaid tissue Doppler velocity imaging in three short-axis views including mitral annulus(MV), papillary muscle(PM) and apical(AP) levels were acquired before and after acute myocardial ischemia in three complete cardiac cycles. Parameters including RD, RD peak time(RD-TC), standard deviation of RD peak time(RD-TSD) of anterior wall( AW), inferoseptal wall (IS) ,inferior wall(lW) and posterior wall(PW) at the 12 segments and different myocardial layers(i.e., subend,mid,subepi) of the same segment of left ventricle were measured and analyzed using quantification tissue Doppler imaging workstation and the difference and co-relationship among them were analyzed also. Results ①After acute myocardial ischemia, the segment and subend,mid, subepi RD of AW of MV, PW and AP were decreased,other counterpart segments were increased without significant difference(P>0.05). ②After acute myocardial ischemia, the existed RD co-relationship revealed between suhend, mid, subepi and the segment were changed(i, e. ,the co-relation in AM at PW and AP levels were vanished). ③Corrected by the heart rate, myocardial RD-Tc at all 12 segments and subend, mid, subepi after acute myocardial ischemia were longer than that before separately. ④ RD-TSD at the 12 segments, subend, mid, subepi were significantly wider after acute myocardial ischemia than that before(P<0.05). Conclusions The decreased RD,dis-connective spatial co-relationship of RD,delayed RD-Tc and wide RD-TSD can be used as potential mechanical parameters for the more sensitive evaluation of regional myocardial dysfunction during acute isehemia. Key words: Echocardiography; Myocardial ischemia ; Ventricular function,left ; Radial displacement

Clinical assessment of left ventricular rotation and strain: a novel approach for quantification of function in infarcted myocardium and its border zones

Left ventricular (LV) circumferential strain and rotation have been introduced as clinical markers of myocardial function. This study investigates how regional LV apical rotation and strain can be used in combination to assess function in the infarcted ventricle. In healthy subjects (n = 15) and patients with myocardial infarction (n = 23), LV apical segmental rotation and strain were measured from apical short-axis recordings by speckle tracking echocardiography (STE) and MRI tagging. Infarct extent was determined by late gadolinium enhancement MRI. To investigate mechanisms of changes in strain and rotation, we used a mathematical finite element simulation model of the LV. Mean apical rotation and strain by STE were lower in patients than in healthy subjects (9.0 +/- 4.9 vs. 12.9 +/- 3.5 degrees and -13.9 +/- 10.7 vs. -23.8 +/- 2.3%, respectively, P < 0.05). In patients, regional strain was reduced in proportion to segmental infarct extent (r = 0.80, P < 0.0001). Regional rotation, however, was similar in the center of the infarct and in remote viable myocardium. Minimum and maximum rotations were found at the infarct borders: minimum rotation at the border zone opposite to the direction of apical rotation, and maximum rotation at the border zone in the direction of rotation. The simulation model reproduced the clinical findings and indicated that the dissociation between rotation and strain was caused by mechanical interactions between infarcted and viable myocardium. Systolic strain reflects regional myocardial function and infarct extent, whereas systolic rotation defines infarct borders in the LV apical region. Regional rotation, however, has limited ability to quantify regional myocardial dysfunction.

Diagnostic Capability and Reproducibility of Strain by Doppler and by Speckle Tracking in Patients With Acute Myocardial Infarction

The objective of the present study was to investigate the ability of strain by Doppler and by speckle tracking echocardiography in the acute phase in patients with ST-segment elevation myocardial infarction (STEMI) to diagnose left ventricular (LV) infarct size. Furthermore, we wanted to study at which time during the cardiac cycle strain should be measured. The assessment of regional myocardial dysfunction may be an important diagnostic tool in the evaluation of acute myocardial injury. Strain by Doppler and speckle tracking were assessed in the acute phase and after 10 days in 36 patients (61 +/- 11 years) with STEMI treated with thrombolysis. In a 16-segment model of the LV, peak systolic, end systolic, and peak negative strain were validated against the corresponding myocardial segments measured by contrast-enhanced cardiac magnetic resonance. The 16 segments were averaged to assess LV global longitudinal strain. In addition, 6 segments were analyzed from parasternal short-axis recordings at the papillary muscle level to assess circumferential strain. Reproducibility was tested in 20 patients. The different segmental strain assessments separated significantly (p < 0.0001) between the different levels of infarct transmurality regardless of method, with better reproducibility for speckle strain. Circumferential strain separated better than longitudinal strain. With a cutoff value of -13.3% for segmental circumferential strain, sensitivity was 80% and specificity was 74% for prediction of transmural infarction. The LV global strain showed a good correlation with LV infarct size, with the best correlation for LV global peak systolic speckle strain (beta = 0.76, p < 0.0001). On a segmental level, circumferential strain separated transmural from subendocardial necrosis better than longitudinal strain in the acute phase in patients with STEMI. Our findings suggest that in the acute phase in patients treated with thrombolysis, LV global peak systolic speckle strain should be the preferred method for predicting final LV infarct size.