Hypokinetic Segments Research Articles

Conventional and segmental myocardial Tei indices measurement in patients with acute ST-segment elevation myocardial infarction: Is there a relation?

Background: Myocardial infarction (MI) results in impairment of left ventricular (LV) systolic and diastolic functions to various degrees. The tissue Doppler image derived Tei index (TDI-Tei index) has recently been used to assess LV function, and like the conventional Tei index, it was also found to be useful for global function. There are a small number of studies which apply TDI-Tei index to assess regional function and whether it varies according to the degree of changes in wall motion in various LV segments. Objectives: This study was conducted to assess the changes of segmental myocardial Tei index by TDI according to the degree of changes of wall motion in the patient with acute ST-segment elevation myocardial infarction (STEMI) and its correlation with Tei index derived by conventional Doppler. Patients and methods: This study was carried out on thirty patients with acute STEMI selected from Coronary Care Unit, Cardiology Department, Mansoura Specialized Hospital, Mansoura University, Egypt. The study group was subjected to clinical assessment, electrocardiography (ECG), routine laboratory profile and Doppler echocardiography (conventional and pulsed wave tissue Doppler imaging “PW-TDI”). Tei index was calculated from the sum of isovolumetric contraction time (IVCT) and isovolumetric relaxation time (IVRT), divided by ejection time (ET) which were measured from pulsed wave Doppler imaging of the trans-mitral inflow and LV outflow tracts. Myocardial velocities and TDI-Tei index were measured at basal and mid-segments of LV walts from apical 4, 2 and 5-chamber views using 16-segment model. Average values of myocardial velocities and TDI-Tei indices were obtained from normal, hypokinetic and akinetic segments then compared. Results: The mean values of left ventricular ejection fraction (LVEF), mitral E/A ratio and conventional Tei index were 51.83 ± 5.15%, 1.18 ± 0.15 and 0.63 ± 0.07 ms, respectively. Segmental myocardial TDI-Tei index was correlated positively with conventional Tei index ( r = 0.648, P < 0.001). TDI-Tei indices were significantly higher in akinetic and hypokinetic segments than those of normal segments (0.70 ± 0.09, 0.64 ± 0.05 vs 0.63 ± 0.05, P < 0.001). Conclusions: Tei index (either conventional or TDI) is superior to EF in evaluation of LV performance in patients with acute STEMI. Tei index derived by myocardial segments by TDI is correlated with conventional Tei index. Segmental TDI-Tei index values differ according to the grade of dysfunctional wall motion.

Evaluation of left ventricular regional systolic functions in patients with coronary artery disease by two-dimensional strain imaging: a velocity vector imaging study

The aim of the study was to assess left ventricular (LV) regional systolic functions in coronary artery disease (CAD) using a novel strain imaging method, namely, velocity vector imaging (VVI). The study included 69 patients (51 men, 18 women; mean age 52.9±10.3 years) with CAD and 30 healthy volunteers (22 men, 8 women; mean age 58.1±13.8 years). Thirty-three patients had previous myocardial infarction (MI). In all the patients, LV wall motions were analyzed as akinetic, hypokinetic, or normokinetic using the 16-segment model of the American Heart Association. In addition, LV peak systolic strain, strain rate (SRs), and segmental ejection fraction (SEF) of all the segments were calculated by using VVI. Patients with MI had significantly lower mean peak systolic strain, SRs, and SEF compared to patients without MI and controls (p=0.0001). The presence of multivessel disease was accompanied by significantly decreased peak systolic strain (p=0.04), SRs (p=0.02), and SEF (p=0.0001). Myocardial segments affected by subtotal/total occlusion (≥99%) had lower peak systolic strain (p=0.02), SRs (p=0.001), and SEF (p=0.0001) values compared to segments with less severe occlusion. In segmental analysis, longitudinal deformation was most significant in akinetic segments (p=0.0001), but hypokinetic and normokinetic segments also differed significantly with respect to deformation (for strain, p=0.01; for SRs and SEF, p=0.0001). Moreover, deformation in the normokinetic segments was more significant than normal segments of the controls (for strain, p=0.02; for SRs and SEF, p=0.0001). Velocity vector imaging allows regional deformation analysis for quantitative assessment of regional LV systolic functions; this technique may be more reliable than conventional echocardiography in determining wall motion abnormalities.

Validation of Longitudinal Peak Systolic Strain by Speckle Tracking Echocardiography With Visual Assessment and Myocardial Perfusion SPECT in Patients With Regional Asynergy

Automated function imaging (AFI) is a recently developed method of calculating the longitudinal peak systolic strains (LS) of the regional left ventricular (LV) wall using speckle tracking echocardiography and displaying them on a single bull's-eye map. The feasibility of AFI in patients with regional LV wall motion abnormalities caused by myocardial infarction (MI) was evaluated by comparison with visual assessment and myocardial perfusion single-photon emission computed tomography (SPECT). Segmental LS was measured by AFI in 60 patients with MI (67 ± 11 years) and 58 controls (71 ± 9 years). Wall thickening (WT) was measured by SPECT in 20 patients with MI. There was a strong positive linear relationship between the wall motion score index by expert visual assessment and global LS. The receiver-operating characteristic analysis revealed the best cutoff value of 11% < LS to identify hypokinetic segments. The overall accuracy of wall motion scoring by LS in the 2,006 segments was 96.8% (κ = 0.90) compared with visual assessment. The correlation coefficient between LS and WT was R² = 0.65 in the 340 segments. Assessment of LV regional asynergy by AFI showed good agreement with visual and SPECT assessments. AFI is clinically useful for quantitative assessment of LV regional wall motion abnormalities.

Detection and Quantification by Deformation Imaging of the Functional Impact of Septal Compared to Free Wall Preexcitation in the Wolff-Parkinson-White Syndrome

Pacing experiments in healthy animal hearts have suggested a larger detrimental effect of septal compared to free wall preexcitation. We investigated the intrinsic relation among the site of electrical preexcitation, mechanical dyssynchrony, and dysfunction in human patients. In 33 patients with Wolff-Parkinson-White (WPW) syndrome and 18 controls, regional myocardial deformation was assessed by speckle tracking mapping (ST-Map) to assess the preexcitation site, shortening sequences and dyssynchrony, and the extent of local and global ejecting shortening. The ST-Map data in patients with accessory atrioventricular pathways correctly diagnosed as located in the interventricular septum (IVS) (n = 11) or left ventricular free wall (LFW) (n = 12) were compared to the corresponding control values. A local ejecting shortening of <2 SD of the control values identified hypokinetic segments. The localization of the atrioventricular pathways by ST-Map matched with the invasive electrophysiology findings in 23 of 33 patients and was one segment different in 5 of 33 patients. In both WPW-IVS and WPW-LFW, local ejecting shortening was impaired at the preexcitation site (p <0.01). However, at similar electrical and mechanical dyssynchrony, WPW-IVS had more extensive hypokinesia than did WPW-LFW (3.6 +/- 0.9 vs 1.8 +/- 1.3 segments, p <0.01). Compared to controls, the left ventricular function was significantly reduced only in WPW-IVS (global ejecting shortening 17 +/- 2% vs 19 +/- 2%, p = 0.01; ejection fraction 55 +/- 5% vs 59 +/- 3%, p = 0.02). In conclusion, preexcitation is associated with local hypokinesia, which at comparable preexcitation is more extensive in WPW-IVS than in WPW-LFW and could adversely affect ventricular function. ST-Map might have a future role in detecting and guiding treatment of septal pathways with significant mechanical effects.

Reliability of Visual Assessment of Global and Segmental Left Ventricular Function: A Multicenter Study by the Israeli Echocardiography Research Group

The purpose of this multicenter study was to determine the reliability of visual assessments of segmental wall motion (WM) abnormalities and global left ventricular function among highly experienced echocardiographers using contemporary echocardiographic technology in patients with a variety of cardiac conditions. The reliability of visual determinations of left ventricular WM and global function was calculated from assessments made by 12 experienced echocardiographers on 105 echocardiograms recorded using contemporary echocardiographic equipment. Ten studies were reread independently to determine intraobserver reliability. Interobserver reliability for visual differentiation between normal, hypokinetic, and akinetic segments had an intraclass correlation coefficient of 0.70. The intraclass correlation coefficient for dichotomizing segments into normal versus other abnormal was 0.63, for hypokinetic versus other scores was 0.26, and for akinetic versus other scores was 0.58. Similar results were found for intraobserver reliability. Interobserver reliability for WM score index was 0.84 and for left ventricular ejection fraction was 0.78. Similar values were obtained for the intraobserver reliability of WM score index and ejection fraction. Compared to angiographic data, the accuracy of segmental WM assessments was 85%, and correct determination of the culprit artery was achieved in 59% of patients with myocardial infarctions. Among experienced readers using contemporary echocardiographic equipment, interobserver and intraobserver reliability was reasonable for the visual quantification of normal and akinetic segments but poor for hypokinetic segments. Reliability was good for the visual assessment of global left ventricular function by WM score index and ejection fraction.

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 …

Segmental Tissue Doppler Image-Derived Tei Index in Patients With Regional Wall Motion Abnormalities

Background and ObjectivesAlthough the Tei index is a useful predictor of global ventricular function, it has not been investigated at the level of regional myocardial function. We therefore investigated the segmental tissue Doppler image derived-Tei index (TDI-Tei index) in patients with regional wall motion abnormalities.Subjects and MethodsWe prospectively studied 17 patients (mean age 62±9 years, 5 women) with left ventricular (LV) regional wall motion abnormalities. The Tei index, defined as the sum of isovolumetric contraction time (IVCT) and isovolumetric relaxation time (IVRT) divided by ejection time (ET), was measured in the basal and mid segments of the LV walls from standard apical views (4-, 2-, and 5-chamber views). We also obtained TDI velocity data in each segment. LV wall motion was classified as normal, hypokinetic, or akinetic, based on visual analysis. The TDI-Tei index, peak systolic myocardial velocity (Sm), early diastolic myocardial velocity (Em), and late diastolic myocardial velocity (Am) were analyzed in a total of 203 segments.ResultsMean LV ejection fraction was 41.8±8.5%. TDI-Tei indices of dysfunctional segments (akinesis or hypokinesis, n=63) were significantly higher than those of normal segments (n=140) (0.714±0.169 vs. 0.669±0.135, p=0.041, respectively). Average values of TDI-Tei index, Sm, Em, and Am were 0.742±0.201, 4.206±1.336, 5.258±1.867, and 5.578±2.354 in akinetic segments; 0.677±0.101, 4.908±1.615, 5.369±2.121, and 5.542±2.492 in hypokinetic segments; and 0.669±0.135, 5.409±1.519, 6.108±2.356, and 6.719±2.466 in normal segments, respectively. A significant negative correlation was apparent between the TDI-Tei index and Sm (r=-0.302, p<0.001).ConclusionThese data suggest that the value of the segmental TDI-Tei index differs significantly according to regional function grade.

Evaluating global and regional left ventricular function in patients with reperfused acute myocardial infarction by 64-slice multidetector CT: A comparison to magnetic resonance imaging

A number of studies have compared 64-slice multidetector row computed tomography (MDCT) and magnetic resonance imaging (MRI) for left ventricular (LV) function; however, none were performed in patients with reperfused acute myocardial infarction. We compared global and regional LV function assessment by 64-slice CT (MDCT) with cardiac magnetic resonance (CMR) after reperfused ST elevation myocardial infarction. Twenty-one patients were scanned after reperfusion with contrast-enhanced CMR and MDCT. Reconstructed short axis images were used to assess global (quantitative assessment of LF end-diastolic volume [LVEDV], end-systolic volume [LVESV], stroke volume [LVSV], ejection fraction [LVEF], and mass, by Simpson's method) and regional cardiac function (qualitative assessment on a 4-point scale [4=normal, 3=hypokinesia, 2=dyskinesia, 1=akinesia]) in a standard 17-segment myocardial model. We scanned 21 persons (age, 60+/-10 years; 19 men) with CMR and MDCT. Good correlation was observed for all global parameters between MDCT and CMR (LVEF, r=0.90; LVEDV, r=0.91; LVESV, r=0.94; LVSV, r=0.84; LV mass, r=0.91). Interobserver agreement for regional function was excellent (weighted kappa, 0.81). The interobserver agreement for regional function on MDCT and CMR were comparable (weighted kappa of 0.86 and 0.88, respectively). MDCT had a better sensitivity, specificity, positive predictive value, and negative predictive value for akinetic segments on CMR than did hypokinetic segments (71%, 91%, 68%, and 93% versus 84%, 97%, 81%, and 98%, respectively). MDCT provides an accurate and reproducible measurement of regional and global LV function in patients with reperfused acute myocardial infarction.

Which Protocol for Which Segment: A Comparative Study of Different Pharmacological Stress Echocardiography Protocols for Predicting Viability in Segments with Varying Degrees of Dyssynergy

Pharmacological stress echocardiography is widely accepted for identifying potential contractile recovery after revascularization. We sought to compare the prognostic power of three pharmacological stress protocols for predicting contractile recovery of myocardial segments at varying degrees of dyssynergy. We enrolled 100 consecutive patients with significant coronary stenosis amenable for revascularization and regional wall motion abnormality in the distribution of the affected artery. All patients underwent an assessment of regional wall motion according to the standard 16-segment model. The patients underwent three stress echocardiography protocols in separate sessions: low-dose dobutamine, infra-low-dose dipyridamole, and combined protocol. The patients underwent thereafter coronary revascularization either by percutaneous coronary angioplasty or by surgical bypass grafting. A follow-up echocardiography was performed 8 weeks after revascularization to assess regional wall motion abnormality. The predicted recovery by any of the three protocols for each category of segments was compared with actual contractility improvement. The combined protocol had a significantly higher sensitivity for predicting contractility recovery in all segment categories compared with the other two protocols. In addition, it had a similar specificity in hypokinetic and dyskinetic segments, though with a lower specificity in akinetic segments when compared with the low-dose dobutamine protocol, and a similar specificity in dyskinetic segments, though with a lower specificity in hypokinetic and akinetic segments when compared with the infra-low-dose dipyridamole protocol. In patients with predominantly akinetic/dyskinetic segments, the combined pharmacological stress protocol would better predict functional recovery after revascularization, as compared with the low-dose dobutamine and the infra-low-dose dipyridamole protocols.

Quantitative Evaluation of Regional Left Ventricular Function by Multidetector Computed Tomography

: Because most contemporary workstations offer quantitative analysis of regional function by multidetector computed tomography, we aimed to establish typical values for normal, hypokinetic, and akinetic regions, and to establish optimal thresholds to differentiate between normal and abnormal values. : For 33 patients, quantitative regional functional parameters were compared with visual analysis by both multidetector computed tomography and echocardiography. Normal values were established to normalize for segmental variability. Optimal thresholds were established to differentiate between normal and abnormal segments by receiver operating characteristic analysis. : Akinetic, hypokinetic, and normokinetic segments demonstrated significant differences (P < 0.0001) for end-systolic thickness (mean [95% confidence interval], 9.4 [4.5-14.3], 11.7 [7.2-16.2], and 14.3 mm [8.2-20.3 mm]), respectively; thickening, 24% [-22% to 71%], 45% [-16% to 106%], and 82% [10%-154%]), respectively; and motion, 3.5 [-2.0 to 8.9], 6.1 [-0.2 to 12.4], and 8.5 mm [1.8-15.3 mm], respectively). Thickening performed best with area under the curve of 0.87 and sensitivity equal to specificity of 82%. Intraobserver variability was good, but interobserver variability was only moderate. : Quantification of regional myocardial function can be performed to assist the physician in mapping left ventricular function.

Combined rest redistribution thallium-201 SPECT and low-dose dobutamine contractility assessment in a simple and practical new viability protocol

Rest-redistribution (RR) thallium-201 (Tl-201) imaging is commonly used for myocardial viability evaluation. Contractile reserve (CR) assessment with low-dose dobutamine (LDD) is another method that highly predicts functional recovery following revascularization. In this study, we investigate the feasibility of a new protocol that provides combined Tl-201 uptake, resting and CR functional regional myocardial information in a single examination. A total of 41 patients underwent RR-gated-SPECT Tl-201 myocardial perfusion imaging. The LDD infusion was maintained during delayed imaging. Segmental Tl-201 uptake was classified into normal, fixed decrease (mild to absent) and reversible, and sub-classified by wall motion (WM)/thickening (WT) changes between early resting and delayed LDD gated images into normal, fixed or improved dysfunctional (CR present) segments. Out of 820 examined segments, 33 showed no appreciable Tl-201 uptake to evaluate WM/WT. In a dysfunctional myocardium, CR was significantly higher (P < 0.001) in reversible and fixed than in normal Tl-201 segments. The CR in dysfunctional segments with fixed decrease Tl-201 uptake was significantly higher (P < 0.05) in mild and moderate than in severe fixed defects. Both fixed Tl-201 defects and lack of CR were observed more (P < 0.05) in akinetic/dyskinetic than in hypokinetic segments. Simultaneous assessment of myocardial viability by RR Tl-201 uptake, resting and CR functional regional information is feasible and can be easily attained using this new protocol. Moreover, this protocol requires no additional time or radioactivity when compared with the usual RR Tl-201 protocol. Validation of this protocol with patients' revascularization data is needed.

Significance of Plasma Levels of N-Terminal Pro-B-Type Natriuretic Peptide on Left Ventricular Remodeling in Non-Obstructive Hypertrophic Cardiomyopathy Attributable to the Asp175Asn Mutation in the α-Tropomyosin Gene

Hypertrophic cardiomyopathy (HC) is an inherited heart disease characterized by left ventricular (LV) remodeling. The present study was conducted to investigate the association of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) levels with LV remodeling on magnetic resonance imaging and procollagen formation in 17 healthy controls and 24 patients with nonobstructive HC attributable to an identical Asp175Asn (aspartic acid to asparagine at codon 175) mutation in the alpha-tropomyosin gene. None of the patients had history of decompensated heart failure, and all patients had normal LV ejection fraction. Patients with HC had higher NT-pro-BNP levels compared with controls (median 60 pmol/L, range <40 to 359, vs <40 pmol/L; p <0.001), but 9 patients with HC had normal NT-pro-BNP levels (<40 pmol/L). In patients with HC, levels of NT-pro-BNP were correlated significantly with LV end-systolic volume index (r = 0.50, p <0.05), LV mass index (r = 0.47, p <0.05), proportion of hypokinetic segments (r = 0.50, p <0.05), and levels of serum aminoterminal propeptide of type III procollagen (r = 0.52, p <0.01). When patients with HC were divided into 3 groups on the basis of their NT-pro-BNP levels, there were statistically significant linear associations of LV end-systolic volume (test for linearity p = 0.034), LV mass index (p = 0.009), proportion of hypokinetic segments (p = 0.016), and levels of serum aminoterminal propeptide of type III procollagen (p = 0.020) with NT-pro-BNP levels over the 3 groups, suggesting a tight relation between LV remodeling and levels of NT-pro-BNP. In conclusion, in patients with nonobstructive HC attributable to an Asp175Asn mutation in the alpha-tropomyosin gene, elevated NT-pro-BNP levels are associated with incipient LV remodeling, suggesting that NT-pro-BNP could be used to diagnose insidious unfavorable LV remodeling in HC.

Efficacy of Intramyocardial Injection of Angiogenic Cell Precursors for Ischemic Cardiomyopathy

: The objective of this study is to determine the efficacy of intramyocardial angiogenic cell precursors (ACPs) injection in ischemic cardiomyopathy (ICM). : Twenty-five ICM patients (cell group) underwent intramyocardial ACPs injection. Seventeen ICM patients (control group) treated by medical means were matched with cell group. There was no statistically significant difference between cell and control groups in relation to left ventricular ejection fraction (LVEF) and comorbidities. In the cell group, mean age was 58.4 ± 13.7 years. Mean LVEF was 26.1% ± 7.4%. New York Heart Association (NYHA) class was 2.9 ± 0.6. The ACPs were derived and expanded from autologous blood. The number of cells before injection was 27.4 ± 18.8 million cells. The cells were injected into the nonviable myocardium and hypokinetic segments in the cell group. : There was no new ventricular arrhythmia. NYHA was improved by 0.9 ± 1.0 (P < 0.001) at 229.9 ± 98.8 days. Six-minute walk test and quality of life assessed by short form-36 improved in the cell group. LVEF was improved in 72% of patients (18 of 25). LVEF improved by 6.4 ± 9.9 points % (P = 0.003) at 290.4 ± 210.3 days. The percentage of infarction area decreased 21.9 ± 17.4 points % at 159 ± 54 days postoperatively. There was no significant improvement of NYHA and LVEF in the control group. : For this efficacy study, the NYHA class, quality of life, and six-minute walk test were improved after cell transplantation. The LVEF was also significantly improved in the cell treated group.

CT17P IMAGES OF AN INFARCT RELATED INCOMPLETE LEFT VENTRICULAR RUPTURE MANAGED WITH PERICARDIAL PATCH REPAIR

Introduction A 54‐year‐old woman presented with an inferior MI &amp; post infarction pericarditis. Incomplete LV rupture was confirmed by MRI. She was managed with pericardial patch repair of her LV.Case Our patient presented with 1 week of chest pain, elevated Troponin T &amp; ECG suggesting a recent inferior MI. Angiography showed an occluded obtuse marginal artery, left ventriculogram a 1 cm endocardial defect in a hypokinetic segment of the infero‐lateral LV &amp; transthoracic echo a small LV wall defect with a haemodynamically insignificant pericardial effusion. Cardiac MRI confirmed an infero‐lateral infarct &amp; an anatomical defect suggesting incomplete rupture of the LV free wall. Operatively straw colored pericardial fluid &amp; a shaggy pericarditis were noted. Myocardium supplied by the obtuse marginal artery had appearances of recent infarction &amp; on cardiopulmonary bypass a pericardial patch was glued over this area. The patient required elective drainage of a persistent pericardial effusion and was discharged on the 13th post‐operative day. 4 weeks after discharge she was asymptomatic with echo showing a resolving pericardial effusion.Discussion Incomplete LV rupture following MI is rare &amp; caused by haemorrhagic dissection of the ventricular wall leaving a defect lined by epicardium alone. The natural history is not well described but may include free wall rupture with an in‐hospital mortality of 70%. Pericardial patch augmentation of the LV may reduce the risk of free wall rupture.Conclusion Management of incomplete LV rupture is poorly described but reinforcement of the area with a pericardial patch may be performed safely to reduce the risk of free wall rupture.

Attenuation of cardiac remodelling by endocardial injection of erythropoietin: ultrasonic strain-rate imaging in a model of hibernating myocardium

The aim of this study was to investigate whether erythropoietin (EPO) has cardioprotective effects in a chronic myocardial ischaemia model regarding strain-rate imaging parameters during dobutamine stress echocardiography (DSE). An ameroid constrictor was placed around the circumflex artery in 13 pigs to induce hibernating myocardium by a chronic vessel occlusion. The pigs were randomized 14 days later: seven pigs receiving 10,000 U EPO and six pigs receiving placebo injected into the ischaemic region using a NOGAtrade mark-guided transendocardial catheter. At weeks 2 and 6, animals were examined by DSE, electromechanical mapping, and coronary angiography. During incremental dobutamine infusion, regional radial function was monitored by measuring peak systolic strain-rates (SRsys), systolic strains (epsilonsys), and post-systolic strains (epsilonps). At week 6, the animals were pathohistologically investigated. Echocardiography revealed 2.2+/-0.8 hypokinetic segments in the EPO-treated animals in comparison with 3.3+/-0.9 akinetic segments per animal in the controls. The mean ejection fraction was reduced in the control group (55+/-3 vs. 66+/-4%, P=0.057). Strain-rate imaging revealed ischaemic myocardium in EPO-treated animals and non-viable myocardium in the controls (P=0.0001). Histological analysis of the ischaemic region revealed a reduction of myocardial fibrosis (8+/-1 vs. 27+/-5%) in the EPO-treated group. The transmural extension of fibrosis and the echocardiographic deformation data correlated in the posterior walls (EPO group): epsilonsys at rest r=0.83; peak SRsys during dobutamine stimulation r=0.92, P=0.01. Endocardial EPO injection may induce cardioprotective effects in chronic ischaemic myocardium and helps to obtain the myocardial contractile reserve, objectified by ultrasonic strain-rate imaging.

Clinical Significance of Late Gadolinium Enhancement on Cardiac Magnetic Resonance in Patients With Hypertrophic Cardiomyopathy

In patients with hypertrophic cardiomyopathy, myocardial fibrosis can be detected by late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging. We investigated the relationships between the extent of LGE, left ventricular morphology and function, and clinical characteristics. Both cine and gadolinium-enhanced magnetic resonance imaging were performed in 104 patients with hypertrophic cardiomyopathy. Fifty patients (48%) showed LGE (range: 1-11 segments). The extent of LGE was positively correlated with maximum left ventricular wall thickness (r=0.53, P< .001), left ventricular mass (r=0.41, P< .001), and the number of hypokinetic segments (r=0.51, P< .001), and inversely correlated with ejection fraction (r=-0.32, P=.001), the magnitude of the subaortic gradient increase during exercise echocardiography (r=-0.26, P=.023), and age at diagnosis (r=-0.20, P=.04). Four of the five patients with an ischemic response on exercise echocardiography had > or =3 segments showing LGE (P=.003). Severe hypertrophy (i.e., > or =30 mm) and nonsustained ventricular tachycardia occurred more frequently as the number of LGE segments increased (P< .001 and P=.04, respectively). Extensive LGE reflects greater disease expression. It is associated with more severe myocardial damage (i.e., a lower ejection fraction and a larger number of hypokinetic segments) and with adverse clinical characteristics (e.g., young age at diagnosis, severe hypertrophy, nonsustained ventricular tachycardia, and an ischemic response on exercise), suggesting that it may be closely linked to prognosis.

Percutaneous endocardial injection of erythropoietin: Assessment of cardioprotection by electromechanical mapping

Apart from its well-known stimulation of erythropoiesis, erythropoietin (EPO) exhibits angiogenic and anti-apoptotic effects. These cellular protective effects have also been described in experimental acute myocardial infarction models. We investigated the effects of EPO in a porcine model of chronic progressive myocardial ischaemia. At weeks 2 and 6 after implantation of a circumflex ameroid constrictor, endocardial electromechanical NOGA system (Biosense Webster, Inc., California, USA) mapping of the left ventricle, coronary and ventricular angiography, as well as echocardiography were performed. Two weeks after ameroid placement, 13 pigs were randomized with 7 pigs receiving 10.000 U EPO and 6 pigs receiving placebo into the ischaemic region using a NOGA guided percutaneous transendocardial injection catheter, MYOSTAR. After 6 weeks, histology (Masson's Trichrome) was analyzed. Endocardial electromechanical mapping showed an increase of mean unipolar voltage (UV) amplitude in the ischaemic myocardial segments in the EPO-treated animals (8.5 mV pre and 10.6 mV post treatment) and a significantly reduced ischaemic surface area compared to the control group (19% vs. 41%) suggesting a decline in ischaemic injury. Echocardiography revealed 2,2 hypokinetic segments of the lateral wall in the EPO group vs. 3,3 in the control groups. The mean ejection fraction was 64% in the EPO group and 55% in the placebo group. Quantitative histological analysis of the ischaemic regions revealed a reduction of myocardial fibrosis (8% vs. 28%) in the EPO group. Endocardial EPO injection may induce cardioprotective effects in hibernating myocardium and may attenuate the progression of ischaemic tissue damage.

Do mechanical markers of myocardial ischaemia predict the transmural extent of myocardial infarction in man?

The present study aimed to explore the relationship between the transmural extent of myocardial necrosis and mechanical markers of myocardial ischaemia in man. A group of 40 patients with previous Q-wave myocardial infarction and a left ventricular ejection fraction (LVEF) of 27 +/- 11% was studied by cine and contrast-enhanced magnetic resonance imaging. Necrotic areas of delayed contrast enhancement were present in every patient and involved 20 +/- 8% of left ventricular myocardium. In involved segments, the transmural extent of contrast enhancement varied from 5% to 100%, being on average 38 +/- 25% of the wall thickness. End-diastolic left ventricular wall thickness and systolic wall thickening were lower in contrast-enhanced segments than in the other segments (P < 0.001). Furthermore, although left ventricular wall thickness and systolic wall thickening decreased as the transmural extent of contrast enhancement increased, the correlations were weak (r = -0.382 and -0.45, respectively). Finally, a delayed contrast enhancement was present in 89% of akinetic and in 94% of dyskinetic segments; however, contrast enhancement was also present in 18% of the segments with normal wall motion and in 56% of hypokinetic segments. Although mechanical markers of myocardial ischaemia substantially reflect the transmural extent of myocardial infarction, none of them can be considered as a substitute for the direct observation of necrotic tissue and its transmural extent, as provided by contrast-enhanced magnetic resonance imaging.

Magnetic Resonance Imaging of Delayed Enhancement in Hypertrophic Cardiomyopathy

The aim of the study was to analyze the relationship between myocardial delayed enhancement, first-pass perfusion, and contractile function in hypertrophic cardiomyopathy (HCM) patients, using MR. Fifty-three patients diagnosed with HCM were prospectively examined using a 1.5-T MR unit. Multiphase gradient-echo sequences were performed to study global left ventricular function, wall thickness, and left ventricular mass. Myocardial tissue tagging was conducted to evaluate contractile function. T1-weighted inversion-recovery sequences were obtained at rest to study myocardial contrast enhancement at first pass and delayed enhancement 10 minutes later. Delayed enhancement found in 30 patients (56.6%) was most commonly seen in hypertrophic segments. Nine patients exhibited delayed enhancement in segments with normal wall thickness (<15 mm). Sixteen patients (30.1%) showed first-pass perfusion defects at rest, which were associated with significantly lower stroke volume (P<0.05) and lower cardiac output (P<0.01). The hypokinetic segments found in 16 patients (30.1%) were significantly thicker at end diastole (P<0.01). Delayed enhancement correlated positively with perfusion defects (r=0.5, P<0.01) and hypokinetic segments (r=0.3, P<0.05). Delayed myocardial enhancement is most commonly found in hypertrophic segments but also can be seen in segments with normal wall thickness. Perfusion defects at rest and impaired contractile function are related abnormalities with delayed myocardial enhancement. Further studies are necessary to assess the role of myocardial tagging, first-pass perfusion, and delayed enhancement in risk stratification for patients with HCM.

Long-term Follow-up of Intramyocardial Dissecting Hematomas Complicating Acute Myocardial Infarction

Intramyocardial dissecting hematoma is a form of subacute cardiac rupture complicating acute myocardial infarction. Initially contained within the myocardial wall, the hematoma may expand, rupture into adjacent structures, or spontaneously resolve. However, long-term follow-up is unknown because clinical and serial imaging data are lacking. The purpose of this study was to characterize the early and late myocardial wall changes after transmural myocardial infarction using serial ultrasound examinations of the infarct-related segments. Clinical, electrocardiographic, and echocardiographic features of 8 patients (7 men, mean age 59 years) who presented with acute myocardial infarction and echocardiographically documented intramyocardial dissecting hematoma were analyzed. All patients had precordial echocardiography and 6 underwent transesophageal echocardiography. Differentiating hematoma from trabeculations, thrombus, or pseudoaneurysm was done with contrast and color flow Doppler. Seven patients presented with S-T elevation in V1 to V4, and in 3 the elevation extended to V5, V6, I, and aVL. One patient presented with S-T elevation in II, III, aVF, V3R, and V4R. The most striking feature was persistent S-T elevation of more than 72 hours in all patients. Hematoma consisted of a cysticlike, echolucent cavity variable in size, adjacent to severely hypokinetic or dyskinetic infarct-related segments. Hematoma acoustic characteristics depended on time of evolution. Two patients underwent elective revascularization and the rest were medically treated. Two patients died and 6 were alive at the mean follow-up of 12 months. In conclusion, persistent S-T elevation is an important clue in suggesting intramyocardial dissecting hematoma, which is confirmed by its unique ultrasound appearance. Serial echocardiography is useful in determining its evolving nature, and may guide outcome.