Recovery Of Global Function Research Articles

Stunning, Hibernation, and Assessment of Myocardial Viability

The last 3 decades have witnessed an unprecedented improvement in the outcome of patients with acute coronary syndromes. The widespread use of thrombolytic therapy and percutaneous coronary interventions, in association with increasingly potent antithrombotic agents, has contributed to significant reductions in mortality and morbidity in these patients. Although overall survival has improved, a downside of this success has been the greater number of patients with residual left ventricular (LV) dysfunction undergoing progressive LV remodeling and congestive heart failure. This problem is compounded by the rising age of our population and the higher prevalence of comorbidities such as diabetes mellitus that confer an increased risk of coronary artery disease (CAD) and congestive heart failure. Patients with CAD represent by far the most numerous cohort among those with congestive heart failure, and their treatment remains a partial success.1 Typically, these patients have multivessel disease, increased LV volumes, and variable degrees of regional and/or global systolic dysfunction, although more cases of isolated diastolic dysfunction have been reported recently.2–4 In these patients, coronary revascularization may lead to symptomatic and prognostic improvement, and these clinical benefits are accompanied by evidence of reverse LV remodeling. In this context, the concept of myocardial viability was developed and a number of different techniques have been used to demonstrate the presence of viable tissue before coronary revascularization. The aim of this review article is to summarize our current understanding of the concept of myocardial viability and its clinical implications in patients with CAD and chronic LV dysfunction. Throughout this review, we use the term viability to describe dysfunctional myocardium subtended by diseased coronary arteries with limited or absent scarring that therefore has the potential for functional recovery. Viability is a prospective definition, but it does not imply evidence of functional recovery after interventions. The term hibernation, which …

Early predictors of left ventricular function improvement late after myocardial infarction

Prognosis after acute myocardial infarction (AIM) depends on the extent of irreversibly damaged myocardium and viable tissue due to stunning or hibernation. The aim of the study was to assess the prognostic significance of early echocardiographic parameters of myocardial viability in prediction of late recovery of regional and global ventricular function. The study prospectively included 40 patients after the first, uncomplicated univessel AIM treated with percutaneous coronary intervention (PCI). Low dose dobutamine echocardiography (LDDE) was preformed 7-10 days after AIM and follow-up resting echocardiography from 7 to 12 months later. The sensitivity and specificity for the prediction of post revascularisation regional, dys synergy improvement were 61.29% and 94.59% respectively. The positive and negative predicative values were 90.48% and 74.47% re spectively. The number of viable segments (p = 0.01) and extent of contractile reserve (p = 0.01) were univariate, independent predictors of improvement in ejection fraction (EF). From the multivariate stepwise regression analysis contractile reserve was selected as most powerful predictor of late recovery of left ventricular contractile function (p = 0.007). Receiving-operator characteristic curve (ROC) analysis demonstrated that three or more recovered segments were necessary for an improvement of left ventricular ejection fraction (LVEF) > or = 5% after the revascularisation, with the highest sensitivity, 100% and specificity 56% (p = 0.01). Low-dose dobutamine echocardiography is a powerful predictor of the regional dys synergy recovery late after AIM treated with PTCA with implantation stent. Late full functional improvement of the left ventricle is related to the extent of contractile reserve and amount of viable tissue. At least three recovered segments are necessary for a significant recovery of the global left ventricular contractility.

Real-time myocardial contrast echocardiography can predict functional recovery and left ventricular remodeling after revascularization in patients with ischemic heart disease

Previous studies showed that preservation of microvascular integrity after myocardial ischemia was associated with myocardial viability. Real-time myocardial contrast echocardiography (RT-MCE) is a promising modality for non-invasive evaluation of microcirculation perfusion. Thus, it provides a unique tool to detect myocardial viability. We sought in this study to investigate the role of RT-MCE in predicting left ventricular (LV) functional recovery and remodeling after revascularization in patients with ischemic heart disease. Thirty-one patients with ischemic heart disease and resting regional LV dysfunction were included. LV volume, global and regional function were evaluated by echocardiography before and 6 - 9 months after revascularization. RT-MCE was performed before revascularization using low mechanical index power modulation imaging. Myocardial contrast opacification of dysfunctional segments was scored on a 3-point scale and mean contrast score in dysfunctional segments was calculated. Patients were divided into 2 groups according to mean contrast score in dysfunctional segments: group A, patients with mean contrast score = 0.5 (n = 19); group B, patients with mean contrast score < 0.5 (n = 12). Wall motion improvement was found to be 94.5%, 45.5% and 16.1% respectively (P < 0.01) in homogenous, patchy and absent contrast opacification segments. At baseline, there was no significant difference in LV volume and global function between the two groups. After revascularization, group B had significantly larger LV end-diastolic volume (LVEDV) and LV end-systolic volume (LVESV), lower LV ejection fraction (LVEF) and higher wall motion score index (WMSI) than those of group A (all P < 0.05). Revascularization was followed by significant improvement of LV volume and recovery of global LV function in group A (all P < 0.01); however, in group B, after revascularization, deterioration of LVEDV (P < 0.05) was observed, moreover LVESV, WMSI and LVEF did not change significantly. The maintenance of myocardial microcirculation detected by RT-MCE can predict functional recovery and LV remodeling after revascularization in patients with ischemic heart disease, which might be helpful in clinical decision-making and risk stratification.

Long-lasting cognitive injury in rats with apparent full gross neurological recovery after short-term cardiac arrest

The long-term behavioral effects of mild global ischemia have not been well described. We used short (5 min) asphyxic-cardiac arrest that resulted in no apparent gross neurological deficits to study the long-term effects of mild hypoxic ischemia on the neurobehavioral status of rats. Fifteen adult, male Wistar rats were studied. One group was given asphyxic-cardiac arrest (CA) for 5 min (n=10) and the other group had Sham procedure (n=5). Neurobehavioral testing was performed before and 2 weeks after CA. The neurobehavioral evaluations were: neurological deficit score (NDS), Y Maze, open field, pre-pulse inhibition (PPI) of acoustic startle reflex (ASR), wire hanging, and inclined screen. At 24h post-CA, all of the rats regained normal neurological function as measured by NDS, an integral score for consciousness, brainstem reflexes, sensorimotor function and simple behavioral reflex tests. However, 1 week after CA, the rats exhibited significant activity reductions in the open field and in spontaneous alternation in the Y maze. The CA rats also showed a significant decrease in startle reaction amplitude and startle inhibition in the PPI tests. Two weeks after CA, the changes in motor activity and deficits in PPI remained significant, but the spontaneous alternation recovered. The muscle strength test of wire hanging and inclined screen tests did not exhibit significant change. We present a rodent model of mild CA that, despite apparent full recovery of global neurological function at 24h post-resuscitation, exhibited long-term cognitive injury lasting for at least 2 weeks after CA. This model may help understand better the injury associated with CA and develop management strategies for mild brain injury.

The function of left ventricular basal segments is most important for long-term recovery

Adrenergic beta-blockade is the most potent pharmacological therapy for the improvement of global left ventricular (LV) function in heart failure. A substantial portion of patients responds poorly to beta-blockers, but there is scarce information about LV regional function and recovery. We intended to evaluate the effects of beta-blockade on LV regional function and recovery, contractile reserve (CR) and response to long-term treatment. Methods Twenty-two patients with heart failure were investigated at rest and during dobutamine stress echocardiography (DSE), before and after 6 months of metoprolol treatment. LV function was evaluated by global ejection fraction (EF), and by regional function in basal, mid and apical segments. Results Recovery of LV global function (increase in EF > 5%) after metoprolol treatment was significantly and best correlated to CR in basal segments of the ventricle ( r = 0.79, p < 0.001), in comparison with function of mid and apical segments. The correlation between global recovery and global CR was r = 0.55, p = 0.007. In a multivariate logistic regression, including global and regional CR, age, gender, etiology of heart failure, ACE-inhibitor treatment, heart rate, and baseline EF, only basal CR was independently associated with recovery, OR 1.07 [95% CI, 1.01–1.21], p = 0.019. Conclusion The strongest association for prediction of LV recovery after metoprolol treatment was found regarding function of basal segments of the ventricle. Patients that responded favourably to beta-blockade had a significantly better CR, and treatment effect, in these segments. This gives further evidence for the importance of myocardial function in basal segments to the contribution of recovery and LV global function.

Contrast echocardiography for the assessment of myocardial viability

The availability of an accurate, non-invasive method for distinguishing viable from irreversibly damaged myocardium, after acute myocardial infarction or in chronic coronary artery disease, is important in clinical decision making. Such a tool would enable physicians to identify patients most likely to benefit from revascularization strategies in patients with coronary artery disease and left ventricular dysfunction. Myocardial contrast echocardiography is a new technique that utilizes acoustically active gas-filled microspheres (microbubbles), which remain exclusively in the intravascular space and allow the simultaneous assessment of global and regional myocardial structure, function, and perfusion. An increasing body of data supports its role in assessing myocardial viability and predicting the recovery of function. Myocardial contrast echocardiography accurately differentiates 'stunning' from necrosis, delineates transmural extent of infarction, predicts recovery of regional and global left ventricular systolic function in the recuperative phase, identifies patients at high risk of left ventricular remodelling, and provides incremental viability data when performed in conjunction with low-dose dobutamine echocardiography. Technological advances have positioned myocardial contrast echocardiography as a safe, practical bedside technique for the evaluation of myocardial viability. It has comparable accuracy with other non-invasive imaging techniques, such as dobutamine stress echocardiography, radionuclide scintigraphy and cardiac magnetic resonance imaging.

Recovery of global systolic function after primary angioplasty. Influence of coronary flow velocity reserve measured by transthoracic echocardiography

Background Our objective were to know whether coronary flow velocity reserve measured by transthoracic Doppler echocardiography, as marker of microvascular integrity, affects the recovery of global systolic function. Secondly, we intended to define the best cut-off point of coronary flow velocity reserve to predict recovery of global systolic function. Methods We studied 57 patients with coronary flow recorded by transthoracic Doppler echocardiography, after suffering a first anterior acute myocardial infarction and undergoing a successful primary percutaneous coronary intervention (TIMI 3 flow). We measured, at discharge and at 1 month: ejection fraction, volume indexes and anterior wall motion score index. Coronary flow in left anterior descending artery was detected by transthoracic Doppler echocardiography and coronary flow velocity reserve was calculated. Results After applying ROC curves, 1.54 was the best cut-off value of coronary flow velocity reserve for detection of recovery of global systolic function. Ejection fraction only increased significantly in patients with normal coronary flow velocity reserve. Only end-systolic volume index increased significantly at 1 month in patients with impaired coronary flow velocity reserve. Conclusion We showed that coronary flow velocity reserve, measured by transthoracic Doppler echocardiography, influence the recovery of global systolic function, mainly by ventricular dilation. Furthermore, a quite lower value of coronary flow velocity reserve than that used for diagnostic purpose should be used to predict improvement of systolic function.

Mitochondrial uncoupling, with low concentration FCCP, induces ROS-dependent cardioprotection independent of KATP channel activation

Both K(ATP) channel opening drugs and ischaemic preconditioning have been suggested to protect the ischaemic heart by acting on K(ATP) channels in the inner mitochondrial membrane, uncoupling the proton gradient and partially dissipating the mitochondrial membrane potential. The aim of these studies was to use low concentrations of FCCP, a mitochondrial protonophore, to bypass the mitochondrial K(ATP) channel and partially uncouple the mitochondria and establish whether this activates protective pathways within the rat heart analogous to K(ATP) channel openers or preconditioning. Isolated, Langendorff-perfused rat hearts were subjected to 25 min global zero-flow ischaemia and functional recovery assessed. Hearts were pretreated with FCCP (30-300 nM) in the presence or absence of glibenclamide (1 microM), 5-hydroxydecanoate (5-HD: 100 microM), N-acetyl cysteine (4 mM), or N-2-mercaptopropionyl glycine (1 mM). The metabolic consequences of FCCP perfusion in isolated hearts were studied using (31)P NMR, and reactive oxygen species (ROS) production was measured using DCF fluorescence in isolated rat ventricular myocytes. FCCP exerted a dose-dependent cardioprotective effect, with 100 nM FCCP being the optimal concentration. This effect could not be blocked by glibenclamide or 5-HD, but was completely attenuated by N-acetyl cysteine and N-2-mercaptopropionyl glycine. Perfusion with FCCP (100 nM) did not deplete bulk ATP during the pretreatment period but significantly depleted phosphocreatine. In ventricular myocytes, FCCP caused an antioxidant-sensitive increase in ROS production but diazoxide was without effect. In the isolated rat heart, partial mitochondrial uncoupling with low-dose FCCP significantly improves post-ischaemic functional recovery via a ROS-dependent pathway. This cardioprotection is not mediated via the depletion of cellular ATP or mitochondrial K(ATP) channel activation.

Mesenchymal lineage precursor cells induce vascular network formation in ischemic myocardium

Mesenchymal lineage precursors can be reproducibly isolated from adult mammalian bone marrow and grown in culture. Immunoselection with monoclonal antibodies against STRO-1 and vascular-cell-adhesion molecule 1 (VCAM1/CD106) prior to expansion results in a 1,000-fold enrichment of mesenchymal precursors compared to standard isolation techniques. Intramyocardial injection of human STRO-1-selected precursors in an athymic rat model of acute myocardial infarction results in induction of vascular network formation and arteriogenesis coupled with global functional cardiac recovery.

Stress cardiomyopathy mimicking acute coronary syndrome: case presentation and review of the literature

Stress cardiomyopathy is a novel clinical syndrome affecting predominantly elderly female patients. It is characterized by severe reversible left ventricular dysfunction demonstrating a peculiar pattern of extensive apical wall motion abnormality known as "apical ballooning". The syndrome is typically precipitated by acute severe emotional, psychological or physical stress. It mimics acute coronary syndrome exhibiting typical clinical and electrocardiographic features of acute myocardial infarction. At angiography, however, significant coronary artery disease is invariably excluded. In the acute phase, the syndrome may be complicated by cardiogenic shock or ventricular fibrillation. Clinical data indicate that the disease is associated with an extensive increase of endogenous cathecholamine levels which may exhibit a direct toxic effect on the myocytes causing non-ischemic myocardial "stunning". This mechanism may have important implications for the management of patients in the acute phase of the disease. The prognosis of stress cardiomyopathy, however, seems favorable with recovery of global and regional myocardial function within a few weeks in the vast majority of patients. Yet, long-term outcome data in larger patient populations are lacking. We report the case of a female patient presenting with stress cardiomyopathy and review the current knowledge of the disease.

Autologous bone marrow-derived stem-cell transfer in patients with ST-segment elevation myocardial infarction: double-blind, randomised controlled trial

The benefit of reperfusion therapies for ST-elevation acute myocardial infarction (STEMI) is limited by post-infarction left-ventricular (LV) dysfunction. Our aim was to investigate the effect of autologous bone marrow-derived stem cell (BMSC) transfer in the infarct-related artery on LV function and structure. We did a randomised, double-blind, placebo-controlled study in 67 patients from whom we harvested bone marrow 1 day after successful percutaneous coronary intervention for STEMI. We assigned patients optimum medical treatment and infusion of placebo (n=34) or BMSC (n=33). Our primary endpoint was the increase in LV ejection fraction and our secondary endpoints were change in infarct size and regional LV function at 4 months' follow-up, all assessed by MRI. We assessed changes in myocardial perfusion and oxidative metabolism with serial 1-[11C]acetate PET. Analyses were per protocol. This study is registered with , number NCT00264316. Mean global LV ejection fraction 4 days after percutaneous coronary intervention was 46.9% (SD 8.2) in controls and 48.5% (7.2) in BMSC patients, and increased after 4 months to 49.1% (10.7) and 51.8% (8.8; OR for treatment effect 1.036, 95% CI 0.961-1.118, p=0.36). Compared with placebo infusion, BMSC transfer was associated with a significant reduction in myocardial infarct size (BMSC treatment effect 28%, p=0.036) and a better recovery of regional systolic function. Myocardial perfusion and metabolism increased similarly in both groups. We noted no complications associated with BMSC transfer and all but one patient in the BMSC group completed the 4 months' follow-up. Intracoronary transfer of autologous bone marrow cells within 24 h of optimum reperfusion therapy does not augment recovery of global LV function after myocardial infarction, but could favourably affect infarct remodelling.

Myocardial Contrast Echocardiographic Estimates of Infarct Size Predict Likelihood of Left Ventricular Remodeling After Acute Anterior Wall Myocardial Infarction

We sought to determine the utility of myocardial contrast echocardiography (MCE) in predicting left ventricular (LV) remodeling (LVR) in patients with a recent anterior wall myocardial infarction and residual regional LV akinesis. Although recent studies have shown that MCE predicts recovery of regional and global LV systolic function after myocardial infarction, the relationship between myocardial perfusion patterns and likelihood of subsequent LVR has not been extensively studied. In all, 50 patients (mean age 62 years) underwent contrast-enhanced echocardiography for determination of LV volumes and ejection fraction, and MCE, 2 days after admission, with follow-up contrast-enhanced echocardiography 6 months later. LVR was defined as greater than 15% increase in LV end-diastolic volume index at follow-up. LVR occurred in 19 patients (38%) (group 1), with stable LV volumes in 31 patients (62%) (group 2). Routine clinical and angiographic variables did not differ between groups 1 and 2. Both transmural extent of infarction and number of abnormally perfused myocardial segments (assessed by MCE) predicted LVR. LVR occurred in 55% of patients with transmural perfusion defects, and was less common in those with subendocardial perfusion defects or normal perfusion (31% and 21%, respectively). The mean percent increase in LV size was significantly greater for transmural infarcts (15 +/- 7%) versus subendocardial infarcts or normal perfusion (-1 +/- 8 and 8 +/- 8, respectively). When more than 5 myocardial segments were abnormally perfused, remodeling always occurred and was extensive. MCE markers of infarct size are useful in predicting subsequent risk of LVR after myocardial infarction. Routine performance of MCE studies in select patients early after infarction may be helpful in further refining risk stratification.

Incremental Value of Strain Rate Analysis as an Adjunct to Wall-Motion Scoring for Assessment of Myocardial Viability by Dobutamine Echocardiography

Assessment of myocardial viability based on wall-motion scoring (WMS) during dobutamine echocardiography (DbE) is difficult and subjective. Strain-rate imaging (SRI) is quantitative, but its incremental value over WMS for prediction of functional recovery after revascularization is unclear. DbE and SRI were performed in 55 stable patients (mean age, 64+/-10 years; mean ejection fraction, 36+/-8%) with previous myocardial infarction. Viability was predicted by WMS if function augmented during low-dose DbE. SR, end-systolic strain (ESS), postsystolic strain (PSS), and timing parameters were analyzed at rest and with low-dose DbE in abnormal segments. Regional and global functional recovery was defined by side-by-side comparison of echocardiographic images before and 9 months after revascularization. Of 369 segments with abnormal resting function, 146 showed regional recovery. Compared with segments showing functional recovery, those that failed to recover had lower low-dose DbE SR, SR increment (DeltaSR), ESS, and ESS increment (DeltaESS) (each P<0.005). After optimal cutoffs for the strain parameters were defined, the sensitivity of low-dose DbE SR (78%, P=0.3), DeltaSR (80%, P=0.1), ESS (75%, P=0.6), and DeltaESS (74%, P=0.8) was better though not significantly different from WMS (73%). The specificity of WMS (77%) was similar to the SRI parameters. Combination of WMS and SRI parameters augmented the sensitivity for prediction of functional recovery above WMS alone (82% versus 73%, P=0.015; area under the curve=0.88 versus 0.73, P<0.001), although specificities were comparable (80% versus 77%, P=0.2). The measurement of low-dose DbE SR and DeltaSR is feasible, and their combination with WMS assessment improves the sensitivity of viability assessment with DbE.

742 Predictive value of myocardial perfusion contrast ECHO, angiographic assessment of myocardial perfusion, ECG, and reperfusion arrhythmias for the assessment of global functional recovery of the LV

742 Predictive value of myocardial perfusion contrast ECHO, angiographic assessment of myocardial perfusion, ECG, and reperfusion arrhythmias for the assessment of global functional recovery of the LV

Hot or cold? Warm heart, cool brain

There is considerable interest in cooling as a therapy after acute brain injury. This is fuelled by laboratory evidence showing that a reduction in systemic temperature reduces neuronal loss and improves global functional recovery in models of acute brain injury of all aetiologies and in all species, and the strong association between pyrexia and poor neurological outcome in head injury (Jones et al, 1994) and stroke. Reproducing these positive results in clinical trials has been problematic and it can be argued that a more sophisticated approach might be necessary.

Short- and Long-Term recovery of left ventricular function predicted at the time of primary percutaneous coronary intervention in anterior myocardial infarction

ObjectivesThe aim of this study was to determine predictors of left ventricular (LV) function recovery at the time of primary percutaneous coronary intervention (PCI). BackgroundAngiographic, intracoronary Doppler flow, and electrocardiographic variables have been reported to be predictors of recovery of LV function after acute myocardial infarction (MI). We directly compared the predictive value of Thrombolysis In Myocardial Infarction (TIMI) flow grade, corrected TIMI frame count (cTfc), myocardial blush grade, coronary Doppler flow velocity analysis, and resolution of ST-segment elevation for recovery of LV function in patients undergoing primary PCI for acute MI. MethodsWe prospectively studied 73 patients who underwent PCI for an acute anterior MI. Recovery of global and regional LV function was measured using an echocardiographic 16-segment wall motion index (WMI) before PCI, at 24 h, at one week, and at six months. Directly after successful PCI, coronary flow velocity reserve (CFR), cTfc, TIMI flow grade, and myocardial blush grade were assessed. ResultsMean global and regional WMI improved gradually over time from 1.86 ± 0.23 before PCI to 1.54 ± 0.34 at six-month follow-up (p < 0.0001) and from 2.39 ± 0.30 before PCI to 1.87 ± 0.48 at six-month follow-up (p < 0.0001), respectively. Multivariate analysis revealed CFR as the only independent predictor for global and regional recovery of LV function at six months. ConclusionsDoppler-derived CFR is a better prognostic marker for LV function recovery after anterior MI than other currently used parameters of myocardial reperfusion.

Why do patients with ischemic cardiomyopathy and a substantial amount of viable myocardium not always recover in function after revascularization?

Objective In patients with ischemic cardiomyopathy and a substantial amount of dysfunctional but viable myocardium, myocardial revascularization may improve left ventricular ejection fraction. The aim of this study was to evaluate why not all patients with a substantial amount of viable tissue recover in function after revascularization. Methods A total of 118 consecutive patients with a depressed left ventricular ejection fraction (on average 29% ± 6%) due to chronic coronary artery disease underwent myocardial revascularization. Before revascularization all patients underwent dobutamine stress echocardiography to assess regional dysfunction, left ventricular volumes, and myocardial viability as well as radionuclide ventriculography to determine the left ventricular ejection fraction. Next, 3 to 6 months after revascularization, the left ventricular ejection fraction and regional contractile function were reassessed. Improvement of left ventricular ejection fraction ≥ 5% following revascularization was considered clinically significant. Results Dobutamine stress echocardiography revealed that 489 (37%) of the 1329 dysfunctional segments were viable. A total of 61 (52%) patients had a substantial amount of viable myocardium (≥4 viable segments). In these 61 patients the global function was expected to recover ≥ 5% after revascularization. However, left ventricular ejection fraction did not improve in 20 (33%) of 61 patients despite the presence of substantial viability. Clinical characteristics and echocardiographic data were comparable between patients with and without improvement. However, patients without improvement had considerably larger end systolic volumes (153 ± 41 mL vs 133 ± 46 mL, P = .007). The likelihood of recovery of global function decreased proportionally with the increase of end systolic volume ( P < .001, R = 0.43, n = 61). Receiver operating characteristic curve analysis demonstrated that an end systolic volume ≥ 140 mL had the highest sensitivity/specificity to predict the absence of global recovery. Conclusions In patients with ischemic cardiomyopathy not only the amount of dysfunctional but viable myocardium but also the extent of left ventricular remodeling determines the improvement in function following myocardial revascularization. Patients with a high end systolic volume due to left ventricular remodeling have a decreased likelihood of improvement of global function.

Multi-detector computed tomography for imaging of subendocardial infarction: prediction of wall motion recovery after reperfused anterior myocardial infarction.

After reperfusion therapy for acute myocardial infarction (AMI), evaluation of transmural myocardial microcirculation can indicate prognosis. The aim of the present study was to determine whether the evaluation of transmural myocardial microcirculation by newly developed 4-slice computed tomography (CT) can estimate the recovery of left ventricular function. Seventeen consecutive patients who had anterior AMI with a total occlusion in the proximal left anterior descending artery (LAD) and who had undergone successful balloon reperfusion therapy within 24 h of the onset of AMI were examined. Four-slice CT was performed 10-14 days after AMI onset. The median of the epicardial perfusion ratio (infarcted anterior epicardial CT number/intact lateral epicardial CT number ratio = 92%) was used to categorize the cases into 2 groups: the transmural infarction group (n=8) and the subendocardial infarction group (n=9). Although no significant difference was observed between myocardial enhancement by CT in the acute phase and anterior wall motion or ejection fraction in the acute phase, the transmural infarction group showed poor recovery of anterior wall motion at 6 months after AMI onset, whereas the subendocardial infarction group exhibited good recovery of regional and global left ventricular function. Transmural myocardial microcirculation imaged by 4-slice CT can predict wall motion recovery after AMI.

262 Pulse wave intensity discriminates between myocardial, conduit arterial and peripheral vascular influences on arterial wave travel — new ultrasonic insights from a study of heart failure

Objective: In patients with heart failure symptoms due to ischemic cardiomyopathy and a substantial amount of dysfunctional but viable myocardium, myocardial revascularization may improve left ventricular ejection fraction (LVEF). The aim of this study was to evaluate why not all patients with a substantial amount of viable tissue recover in function after revascularization. Methods: A total of 118 consecutive patients with a depressed LVEF (on average 29%± 6%) due to chronic coronary artery disease underwent myocardial revascularization. Before revascularization all patients underwent dobutamine stress echocardiography to assess regional dysfunction, LV volumes, and myocardial viability as well as radionuclide ventriculography to determine the LVEF. Next, 3 to 6 months after revascularization, the LVEF and regional contractile function were reassessed. Improvement of LVEF 3 5% following revascularization was considered clinically significant. Results: Dobutamine stress echocardiography revealed that 489 (37%) of the 1329 dysfunctional segments were viable. A total of 61 (52%) patients had a substantial amount of viable myocardium (3 4 viable segments). In these 61 patients the global function was expected to recover 3 5% after revascularization. However, LVEF did not improve in 20 (33%) of 61 patients despite the presence of substantial viability. Clinical characteristics and echocardiographic data were comparable between patients with and without improvement. However, patients without improvement had considerably larger end systolic volumes (153± 41 ml versus 133 ± 46 ml, P=0.007). The likelihood of recovery of global function decreased proportionally with the increase of end systolic volume (P<0.001, R=0.43, n=61). ROC curve analysis demonstrated that an end systolic volume 3 140 ml had the highest sensitivity/specificity to predict the absence of global recovery. Conclusions: In patients with ischemic cardiomyopathy not only the amount of dysfunctional but viable myocardium but also the extent of LV remodeling determines the improvement in function following myocardial revascularization. Patients with a high end systolic volume due to LV remodeling have a decreased likelihood of improvement of global function. 261 Quantitative myocardial contrast echo improves accuracy for prediction of ventricular recovery compared to qualitative assessment in patients with treated with primary angioplasty.

Stem cells and regeneration of the cardiovascular system: facts, fictions, and uncertainties

The data reviewed here support the view that bone marrow (BM) stem cells can migrate to infarcted myocardium and differentiate into mature, functional cardiomyocytes. Cytokines can mobilize BM stem cells from marrow leading to homing of progenitor cells to infarcted myocardium. Interestingly, contractile performance in these studies appears greater than the capacity of the regenerated cell mass and its biomechanial organization predict, suggesting that the function of the regenerated cell per se may not alone account for global functional recovery.