Effects of acute reperfusion on regional myocardial function: serial two-dimensional echocardiography assessment

Serial two-dimensional echocardiography was performed in 23 patients with acute myocardial infarction who received intravenous thrombolytic therapy to evaluate the effect of acute reperfusion on regional wall motion abnormalities. Regional wall motion abnormalities improved in 4 of the 14 patients (29%) with successful reperfusion and in 1 of the 9 (11%) without successful reperfusion. In successfully reperfused patients, the main determinant of improvement in regional wall motion abnormalities was duration from the onset of chest pain to the time of reperfusion (3.3 vs. 6.3 h in successfully reperfused patients without recovery of regional wall motion abnormalities; P less than 0.001).     

Early intervention with propranolol after acute myocardial infarction: serial left ventricular function determined by M-mode and cross-sectional echocardiography

Fifty patients (mean age 48.6 +/- 9.4 years) with uncomplicated acute myocardial infarction were randomly assigned to propranolol therapy (n = 25) or placebo (n = 25) in a double-blind manner within 24 hours of their presentation with acute symptoms. M-mode and cross-sectional echocardiography were performed at one week and three months to evaluate the left ventricular function. A comparison of the two groups revealed that the group receiving propranolol had higher left ventricular ejection fraction (69% vs 52%, P less than 0.001), fractional shortening (32% vs 24%, P less than 0.01), lower mitral E-point septal separation (6 mm vs 14 mm, P less than 0.001) and wall motion abnormality score (2.5 vs 6.0, P less than 0.001) than the group receiving placebo therapy. At three months there was further significant improvement in wall motion abnormality score (1.1 vs 2.5, P less than 0.001) in the propranolol-treated group as compared to the placebo group, whereas the other parameters remained unchanged. We conclude that the left ventricular function detected by M-mode and cross-sectional echocardiography showed significant improvement in patients with acute myocardial infarction after early intervention with propranolol. This is possibly due to a reduction in the size of infarction.     

Simultaneous assessment of segmental and global left ventricular function by two-dimensional echocardiography in acute myocardial infarction

Both segmental and global left ventricular performance were assessed simultaneously in 29 patients with acute myocardial infarction using two-dimensional echocardiography. Comparisons were made between left ventricular wall motion versus peak CK-MB, site of infarction, and occurrence of heart failure. Two-dimensional echocardiography identified areas of dyssynergy which corresponded to electrocardiographic areas of infarction in 89% of all cases. Patients with heart failure had more dyssynergic segments, and these segments manifested more severe dyssynergy than patients without heart failure. Patients with severe global dysfunction manifested higher peak CK-MB values, and those with anterior infarction had more global dyssynergy than did those patients with inferior infarction. These observations suggest that two-dimensional echocardiography is a useful technique for localization and assessment of segmental and global dyssynergy in acute myocardial infarction. Information so derived correlates with the clinical status of patients with acute myocardial infarction, and may offer important insights into both prognosis and treatment.     

急性心肌梗塞静脉溶栓治疗改善左心室功能的作用

为评价急性心肌梗塞（ＡＭＩ）静脉溶栓再灌注对左心室功能及重塑的影响，应用二维超声心动图（２ＤＥ）对６１例ＡＭＩ接受静脉溶栓治疗的患者，分别在急性期及６个月后随访时测量并计算左心室容积（ＥＳＶ和ＥＤＶ），射血分数（ＥＦ），左心室内膜弧长（ＡＳＬ和ＰＳＬ）以及室壁运动指数（ＧＷ－ＭＩ和ＲＷＭＩ）。结果显示，以上各项指标急性期时两组比较差异均无显著性，在６个月后的随访中，再通组ＥＦ值明显高于未通组，再通组左室容量减小、变形减轻。急性期两组的心功能无差异，随访时再通组心功能较未通组显著改善。提示溶栓再灌注能明显减轻左心室的扩张及抑制左心室重塑，改善患者的心功能和预后。     

Rescue use of abciximab improves regional left ventricular function after early incomplete reperfusion in acute myocardial infarction

BACKGROUND: Abciximab was shown to have important beneficial effects beyond the maintenance of epicardial coronary artery patency. However, it remains uncertain whether abciximab may lead to a better functional outcome in patients with acute myocardial infarction (AMI) and with incomplete reperfusion after primary angioplasty (PA). HYPOTHESIS: The study aimed to evaluate whether rescue use of abciximab may lead to a better functional outcome in such patients. METHODS: The study included 25 patients with first AMI who met the following criteria: (1) total occlusion of the infarct-related artery, (2) PA within 12 h of symptom onset, (3) postprocedural diameter stenosis < 30%, and final Thrombolysis in Myocardial Infarction (TIMI) flow grade 2. Echocardiographic examination was performed before and on Days 7 and 30 after PA. The study population was divided into two groups: Group 1 (usual care, n = 13) and Group 2 (rescue use of abciximab, n = 12). Baseline characteristics were similar between the two groups. RESULTS: Peak level of creatine kinase was higher in Group 1 than in Group 2 (5,800+/-2,700 vs. 3,800+/-2,000 U/I, p < 0.05). At 1 month follow-up, infarct zone wall motion score index (2.71+/-0.26 vs. 2.05+/-0.63, p < 0.01) and left ventricular (LV) volume indices were smaller in Group 2 than in Group 1, whereas LV ejection fraction was higher in Group 2 than in Group 1 (52.1+/-7.8 vs. 42.1+/-6.4, p < 0.01). At 1-month, abciximab was the only independent predictor of wall motion recovery index by multiple regression analysis. CONCLUSIONS: Rescue use of abciximab may reduce the infarct size in patients with AMI and TIMI grade 2 flow after PA, which may improve the recovery of regional LV function.     

Early identification of left ventricular remodelling after myocardial infarction, assessed by transthoracic 3D echocardiography.

AIMS: The usefulness of 3D echocardiography (3DE) for accurate evaluation of left ventricular (LV) remodelling after acute myocardial infarction (AMI), and early identification of remodelling in the subacute phase, was assessed. METHODS AND RESULTS: Thirty-three AMI patients (21 anterior AMIs) underwent 3DE prospectively at baseline (6+/-4 days) and at 3, 6, and 12 months post-AMI. Remodelling was defined as >20% increase in end-diastolic volume (EDV) at 6 or 12 months in relation to baseline. In patients with remodelling (n = 13) at baseline, EDV and end-systolic volume (ESV), but not ejection fraction (EF), were significantly increased compared to patients without subsequent remodelling (n = 20). At 12 months, EDV and ESV increased further and significantly, and EF was unchanged in patients with remodelling, whilst LV volumes were unchanged and EF slightly increased in patients without remodelling. Clinical, electrocardiographic, and echocardiographic variables were analysed for the early identification of LV remodelling. Of these, at baseline the 3D sphericity index (EDV divided by the volume of a sphere, the diameter of which is the LV major end-diastolic long axis) was, by far, the most predictive variable with a sensitivity, specificity, and positive and negative predictive value for a cutoff value of >0.25 of 100%, 90%, 87% and 100%, respectively. CONCLUSIONS: Three-dimensional echocardiography can differentiate patients with and without subsequent development of LV remodelling accurately and early on the basis of the 3D sphericity index, a new and highly predictive variable.     

链激酶溶栓治疗急性心肌梗死对左心室功能的改善作用

为评价链激酶溶栓治疗急性心肌梗死（ＡＭＩ）对左心室功能的影响，应用二维超声心动图对２６例接受链激酶溶栓治疗的ＡＭＩ患者和２７例未溶栓的ＡＭＩ患者，分别在急性期及６个月后随访时测量并计算左心室容积（ＥＤＶ和ＥＳＶ），射血分数（ＥＦ）以及室壁运动指数（ＧＷＭＩ和ＲＷＭＩ）。以上各项指标在急性期时比较各组无显著性差异；在随访期再通组ＥＦ值明显高于未通组和未溶栓组，再通组左室容量减小。急性期各组心功能无差异，随访时再通组心功能较未通组显著改善。提示:链激酶溶栓能明显减轻ＡＭＩ患者的左心室扩张，改善左心室功能和长期预后     

Regional left ventricular function assessed by contrast angiography in acute myocardial infarction.

The relationship of segmental left ventricular (LV) wall motion abnormalities to LV function 2-6 days after acute transmural myocardial infarction (MI) was investigated in 45 patients by quantitative contrast ventriculography. Patients were divided into four classes according to the MIRU criteria. Segmental wall motion was assessed by determining the percentage of systolic shortening (deltaS) along nine hemiaxes and the extent of akinetic or dyskinetic abnormally contracting segments (% ACS) expressed as a percentage of end-diastolic perimeter. When compared with that in 17 normal control-subjects, the LV end-diastolic volume was increased only in patients in class III and class IV; the LV end-systolic volume increased progressively from normal through class IV. Ejection fraction had a negative linear correlation with %ACS (r = 0.97). The size of ACS was larger in anterior (34 +/- 14%) than in inferior MIs (23 +/- 7%), resulting in greater LV dysfunction. However, for a comparable size of ACS, infarct location alone did not influence LV function parameters. In the noninfarcted zone, deltaS was increased when the size of ACS was less than 25% and reduced when the size of ACS was greater than 25%. Thus, the size of ACS is a major determinant of LV dysfunction in acute MI. The compensatory mechanisms operate either through an augmented mechanical function of residual myocardium when the infarct is small, or through the Frank-Starling mechanism when the infarct is large.     

多普勒超声心动图评价急性心肌梗塞后左室重构及心功能改变

应用多普勒超声心动图对56例不同部位急性心肌梗塞（AMI）后患者及40例正常人左室结构（LVR）、收缩舒张功能参数进行对比分析研究。结果显示AMI后患者左室舒张及收缩末期内径、左心室舒张末期容积、左心室收缩末期容积、左室射血前期与射血时间比、舒张晚期峰值血流速度、A峰面积增大；射血分数、短轴缩短率、舒张早期峰值血流速度、E峰／A峰面积则降低，两组间比较有极显著性差异（P＜0．01）。认为AMI后患者心脏不同程度的发生了LVR及收缩舒张功能减退。     

Effects of intravenous metoprolol on global and regional left ventricular function after coronary arterial reperfusion in acute myocardial infarction

Coronary reperfusion in myocardial infarction improves infarct zone motion, but its effect on the global ejection fraction has been less consistent. The directional movement of the ejection fraction is determined by the opposing influences of improved infarct zone motion and diminishing hyperkinesia in the noninfarct zone. Noninfarct zone hyperkinesia has been attributed to catecholamine stimulation, the Frank-Starling mechanism or intraventricular interactions that unload noninfarcted segments. To investigate the influence of catecholamine stimulation, 9 men presenting with a first myocardial infarction (mean age 53 +/- 13 years) were studied. Coronary reperfusion was accomplished less than 4 hours after the onset of myocardial infarction. Radionuclide ventriculography was then performed before and immediately after the intravenous administration of 15 mg of metoprolol. End-diastolic volume did not change, but end-systolic volume increased 28% after metoprolol (p = 0.041). The ejection fraction decreased from 55 +/- 13% before metoprolol to 45 +/- 14% after its administration (p = 0.002). There was no effect of intravenous metoprolol on infarct zone motion, whereas motion in the noninfarcted segment decreased (p = 0.002). The patients underwent repeat ventriculography after receiving metoprolol, 100 mg orally twice a day for 9 days. Infarct zone motion improved (p less than 0.002) and the ejection fraction increased to 55 +/- 12% (p less than 0.02). Normal zone motion did not change. Thus, compensatory hyperkinesia is at least in part caused by catecholamine stimulation. Conclusions regarding the effects of reperfusion on global ventricular performance can be influenced by the timing of ejection fraction determinations relative to metoprolol therapy.     

Radionuclide assessment of regional left ventricular function in acute myocardial infarction

To determine changes in global and regional left ventricular function following acute myocardial function, 17 patients underwent radionuclide angiography at 3 and 10 days post infarction. Five patients had nontransmural myocardial infarction and 12 had transmural infarction (six anterior and six inferior). There were no previous infarctions in 16 (94%) patients. Regional ejection fractions were calculated by dividing the left ventricle into four quadrants using the geometric center of the left ventricle on the end-diastolic frame as a reference point. At 3 days post infarction, 8 of 17 (47%) patients had an abnormality of global left ventricular ejection fraction (LVEF), whereas 16 of 17 (94%) patients had abnormalities of one or more regional ejection fractions (p less than 0.01). Between 3 and 10 days, global LVEF did not change (51% to 49%, p = NS). However, there were significant changes in 23 of 68 (34%) regional LVEFs. These changes did not relate to type, ECG location, creatine kinase (CK) size of infarction, or initial global LVEF. These data suggest that regional LVEF is a sensitive technique for identifying segmental dysfunction associated with myocardial infarction. In addition, significant changes occur in regional LV function during acute myocardial infarction despite stable serial global LV performance.     

Real time myocardial contrast echocardiography to predict left ventricular wall motion recovery after reperfused acute myocardial infarction

INTRODUCTION AND OBJECTIVES: Real time myocardial contrast echocardiography (RTMCE) is a recently developed method. We sought to determine: a) whether RTMCE predicts recovery of left ventricular function after acute myocardial infarction (AMI), and b) whether data obtained with this method are comparable to those obtained with 99mTc-sestamibi single photon emission computed tomography (SPECT) and magnetic resonance. PATIENTS AND METHOD: We studied 85 patients with AMI who underwent angioplasty. RTMCE was performed 7 (4) days after AMI. Two-dimensional echocardiography was performed at the time of the RTMCE study and at follow-up (10 [4] weeks). SPECT and magnetic resonance were performed after AMI in 18 and 32 patients, respectively. RESULTS: Follow-up two-dimensional echocardiography results were available for 82 patients, who were subdivided into 2 groups: recovery (n=49) and no recovery (n=33). Regional (AMI-related) wall motion score index improved from 1.75 (0.49) to 1.32 (0.36) (P< .001) in the recovery group, and worsened from 1.85 (0.39) to 1.95 (0.36) in the no recovery group (P< .001). RTMCE perfusion score was 0.8 (0.3) in the recovery group, and 0.6 (0.4) in the no recovery group (P< .001). Concordance between RTMCE and SPECT in a segmental analysis was 78% (P< .001; kappa=0.49), whereas concordance between RTMCE and hyperenhancement with delayed contrast magnetic resonance findings was 70% (P< .001; kappa =0.35). Independent predictors of recovery were peak creatine kinase (OR=1.4 per 1000 UI; 95% CI, 1.0-1.9; P< .05) and RTMCE score (OR=8.8; 95% CI, 1.9-39.3; P< .01). A RTMCE score > or = 0.60 had a positive predictive value of 73% and a negative predictive value of 69% (P< .001; area under the curve 0.70). CONCLUSION: RTMCE showed a modest predictive value for recovery of left ventricular function after reperfused AMI.     

Comparison of contrast angiography and two-dimensional echocardiography for the evaluation of left ventricular regional wall motion abnormalities after acute myocardial infarction

Regional left ventricular wall motion abnormalities were assessed using 2-dimensional echocardiography and contrast ventriculography within 12 hours of the onset of chest pain in 20 patients with acute myocardial infarction (AMI); 10 patients had anterior infarctions and 10 had inferior. End-diastolic and end-systolic sinus beats from right anterior oblique contrast ventriculograms were analyzed using the center-line chord technique with both a standard overlap method of chord assignment and a nonoverlap method. Echocardiograms were obtained in parasternal long- and short-axis and apical 2- and 4-chamber views and analyzed using a 16-segment scoring system to derive anterior and infero-posterolateral wall motion indexes using both overlap (10 segments for anterior, 8 inferior) as well as nonoverlap (9 segments anterior, 7 inferior) methods of segment assignment. There was a significant inverse correlation between the standard (nonoverlap) echocardiographic analysis and the standard (overlap) angiographic analysis for infarct regions (y = -0.43 X +1.11, r = -0.59, p less than 0.05). Fifteen of 18 patients with angiographic infarct regional score less than or equal to -1 standard deviation/chord had an echocardiographic index greater than or equal to 1.5, while 15 of 16 patients with echocardiographic regional infarct index greater than or equal to 1.5 had an angiographic score less than or equal to -1 standard deviation/chord. Correlation between the 2 methods for noninfarct territories was poor (r = -0.34) because the angiographic method assesses hyperkinesis while the echocardiographic method does not.(ABSTRACT TRUNCATED AT 250 WORDS)     

Usefulness of myocardial contrast echocardiography in predicting global left ventricular functional recovery after anterior wall acute myocardial infarction

Although multiple recent studies have shown that myocardial contrast echocardiography (MCE) reliably differentiates between regional stunning and necrosis after acute myocardial infarction (AMI), prognosis is more closely related to measures of global left ventricular systolic function. One hundred fifteen patients underwent baseline wall motion assessment and MCE 2 days after admission and follow-up echocardiography a mean of 69 days later. Good agreement was found between perfusion score index and follow-up wall motion score index, indicating that MCE performed early after anterior wall AMI may be clinically useful in routine post-AMI risk stratification.     

Early reperfusion therapy improves left ventricular function after acute inferior myocardial infarction associated with right coronary artery disease

Quantitative global and regional ventriculographic analysis was performed acutely and 1 week later in 46 patients undergoing reperfusion procedures within 6 hours of acute inferior myocardial infarction due to right coronary artery disease. While serial improvement in global left ventricular ejection fraction was not demonstrated for the group, infarct zone regional wall motion did improve (-2.7 +/- 0.9 vs -2.3 +/- 1.4 SD/chord, p less than 0.007). Serial improvement in global ejection fraction was demonstrated in the subgroup of patients treated within 2 hours of symptom onset (55 +/- 10 vs 62 +/- 10%; n = 5; p less than 0.03). Infarct zone regional wall motion improved serially only in the subgroup of patients treated within 3 hours of symptom onset (-2.4 +/- 1.1 vs -1.3 +/- 1.7 SD/chord; n = 11; p less than 0.007). Patients with initially patent arteries had a higher ejection fraction on follow-up catheterization than did those with initially occluded vessels (61 +/- 11 vs 55 +/- 7%; p less than 0.02), and patients with patent arteries at follow-up had a higher ejection fraction than did those whose arteries were occluded (60 +/- 9 vs 48 +/- 4%; p less than 0.0001). We conclude that significant improvement in global and regional left ventricular function in patients with inferior myocardial infarction is possible when reperfusion therapy is begun early or when arterial patency is achieved.     

Early prediction of left ventricular function in streptokinase-treated acute myocardial infarction

We administered 750,000 units of intravenous streptokinase to 121 consecutive patients experiencing their first acute myocardial infarction within 4 h of pain onset. The following information was collected: hours between pain onset and streptokinase administration (TS), hours of pain after streptokinase administration (DP), initial and peak creatine phosphokinase levels (ICK and PCK), time to peak creatine phosphokinase, time to electrocardiographic ST segment resolution. Six days after the infarction, catheterization was performed to calculate ejection fraction, infarct-related regional ejection fraction, and dysfunction index. Data was analyzed using stepwise multiple regression. In patients experiencing anterior infarctions, the following equation was obtained predicting the ejection fraction (EF) with a correlation coefficient of 0.86: EF = 69 - 0.0050(PCK) - 3.7(TS) - 1.8(DP). In anterior infarctions the infarct-related ejection fraction and dysfunction index were similarly predictable. We were slightly less accurate in forecasting the outcome of inferior infarctions. The outcome of intravenous streptokinase therapy can be predicted early in the evolution of acute myocardial infarction using routinely available information.     

Global and regional right ventricular function after acute myocardial infarction: dependence upon site of left ventricular infarction

The relation of global and regional right and left ventricular function during the acute phase after a first myocardial infarction was assessed by first pass radionuclide angiography in 20 patients (10 after anterior and 10 after inferior myocardial infarction). The right ventricular ejection fraction did not differ significantly between the groups, but left ventricular ejection fraction was significantly depressed after anterior myocardial infarction. There was evidence of right ventricular dilatation and impaired transit in the group with inferior infarction. Five patients with anterior infarction and six with inferior infarction had abnormal right ventricular ejection fractions. Right ventricular wall motion abnormalities affected the septal wall in the group with anterior infarction and the free wall in the group with inferior infarction. The relation between right and left ventricular ejection fractions was markedly different in the two groups. In the group with anterior infarction there was a significant linear relation between right and left ventricular ejection fraction, whereas in the group with inferior infarction there was not. Thus right ventricular dysfunction commonly occurs after both anterior and inferior myocardial infarction. Right and left ventricular impairment are related after anterior myocardial infarction, but are independent after inferior myocardial infarction. Finally, the different effects of anterior and inferior myocardial infarction on right ventricular function may be explained by differences in septal and free wall involvement.     

Spontaneous recovery of left ventricular function following acute anterior myocardial infarction

Four patients with acute anterior wall myocardial infarction showing spontaneous and marked improvement in systolic left ventricular function are described. All 4 patients showed abnormal Q waves and severe wall motion abnormalities soon after acute infarction. In all 4 patients, at least some regeneration of R-wave forces occurred and the regional wall motion in the involved area of the left ventricle improved dramatically without coronary angioplasty or surgical revascularization during the intervening period. The improvement in left ventricular function was attributed to spontaneous increase in nutrient flow to the involved area. It is concluded that Q waves and severe wall motion abnormalities do not necessarily indicate irreversible scar formation.     

Markers of myocardial reperfusion as predictors of left ventricular function recovery in acute myocardial infarction treated with primary angioplasty

BACKGROUND: Myocardial blush grade (MBG), corrected TIMI frame count (cTFC), and ST-segment reduction are indices of myocardial reperfusion. HYPOTHESIS: We evaluated their predictive value for left ventricular (LV) function recovery by gated single-photon emission computed tomography (SPECT) after acute myocardial infarction (AMI) treated with primary percutaneous coronary intervention (PCI). METHODS: In 40 patients with AMI, gated SPECT was performed at admission and repeated 7 and 30 days after PCI. Left ventricular function recovery was defined as an increase > or = 10 points in SPECT LV ejection fraction from baseline to 1 month. The MBG, cTFC, and ST-segment elevation index 1 h after PCI were determined to evaluate reperfusion. RESULTS: Twenty-four patients (Group 1) had LV function recovery and 16 (Group 2) did not. A significant correlation was found between LV function recovery and MBG (r = 0.66; p = 0.0001), and ST-segment elevation index at 1 h (r = -0.55; p = 0.0001), but not with cTFC. Univariate predictors of LV function recovery were MBG (p = 0.0003) and ST-segment elevation index 1 h after intervention (p = 0.0026), but not cTFC. In a multivariate analysis, MBG was the only predictor of LV function recovery. Myocardial blush grade > or = 2 and ST-segment elevation index reduction had the same accuracy (88%) for predicting LV function recovery. Lower accuracy (75%) was shown by fast cTFC (< 23 frames). Myocardial blush grade > or = 2 showed the better negative likelihood ratio, and ST-segment elevation index reduction had the higher positive likelihood ratio in predicting LV function recovery. CONCLUSIONS: Myocardial blush grade was the best parameter for prediction of LV function recovery: MBG > or = 2 and ST-segment elevation index reduction showed good accuracy in predicting LV function recovery. The cTFC failed to be a significant predictor.