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。     

老年急性心肌梗塞溶栓治疗对左心室功能的改善作用

目的 :评价链激酶溶栓治疗老年急性心肌梗塞 (AMI)对左心室功能的影响。方法 :应用二维超声心动图对 2 9例 AMI接受链激酶溶栓治疗和 2 1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)等参数。结果 :急性各组心功能无差异。随访期再通组 EF值明显增加 ,且明显高于未通组和未溶栓组。结论 :链激酶溶栓能明显减轻老 AMI患者的左心室扩张 ,改善左心室功能和长期预后     

Determinants of improved left ventricular function after thrombolytic therapy in acute myocardial infarction

Many studies have been performed to evaluate the efficacy of thrombolytic therapy in achieving reperfusion, salvaging myocardium and enhancing survival. This review discusses the concordance between the results of these clinical studies and the observations made in experimental animals of the effect of reperfusion on the recovery of left ventricular function. The evaluation of functional recovery is affected by the timing of the measurement and the sensitivity of the method for detecting regional abnormalities. In addition, the underlying coronary anatomy also determines outcome, so that infarct location, collateral circulation and the degree of coronary obstruction merit consideration. Two factors are of paramount importance in determining the amount of myocardium salvaged, the recovery of left ventricular function and the reduction in mortality. These factors are: the time delay until reperfusion is achieved and the adequacy of the coronary reflow. The close agreement between studies measuring the effect of reperfusion on left ventricular function and studies with mortality as the end point provides indirect evidence that enhancement of survival in patients treated with thrombolytic agents is mediated by recovery of ventricular function.     

The influence of thrombolytic therapy on selected parameters of left ventricular function in acute myocardial infarction

Our study aimed to evaluate the influence of thrombolytic therapy on some left ventricle (LV) function parameters in patients with acute myocardial infarction. The study was performed on 44 pts admitted to hospital due to acute myocardial infarction. The patients were divided into two groups: I group--30 pts (26 male, 4 female) at average age 57 +/- 10 who were treated with tissue plasminogen activator (t-PA) routinely and II group--14 pts (9 male, 5 female) at average age 62 +/- 10 in whom thrombolytic therapy was contraindicated for various reasons. Transthoracic echocardiography was performed just before treatment (0), 3.5 hours after the onset of drug administration (2 hours after the end of t-PA injection) (1) and on the 10th day of hospitalization (2). Control group consisted of 16 clinically healthy individuals (12 male, 4 female) at average age 54 +/- 9. The following parameters were evaluated: DT-E--wave of early diastolic transmitral flow deceleration time, IVRT--isovolumic relaxation time, E/A--early/atrial peak flow velocity ratio of transmitral flow, LATEF%--left atrial total emptying fraction, EF--left ventricle ejection fraction. In patients with acute myocardial infarction shortening of DT, prolongation of IVRT, lower E/A ratio and decrease of LATEF% compared to controls were observed. In group I EF was less than in clinically healthy individuals. E/A ratio was higher in pts from group I than from group II. In patients treated with t-PA 2 hours after treatment as well as on the 10th day significant prolongation of DT, shortening of IVRT and increase of LATEF% were observed. These changes were accompanied by the increase of EF. In patients with acute myocardial infarction not treated with t-PA significant increase in E/A ratio and EF on 10th day were observed. On the basis of the results were conclude: In patients with acute myocardial infarction LV diastolic function and with unproper relaxation as well as unproper compliance of LV myocardium is present. In patients with thrombolytic therapy LV filling pattern improves just two hours after t-PA administration (DT prolongation, IVRT shortening, LATEF% increase). Such tendency remains on the 10th day after treatment. In patients without thrombolytic therapy slight improvement occurs no sooner than on the 10th day of the MI.     

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     

Effects of intracoronary thrombolysis therapy on left ventricular function after acute myocardial infarction

To treat the acute phase of myocardial infarction, nitroglycerin and urokinase were injected directly into the infarct-related coronary artery. Left ventricular ejection fraction and regional ejection changes were significantly preserved in the chronic phase, compared with conventional therapy in patients with obstruction at the same site. Comparing left ventricular function in the acute and chronic phases, left ventricular ejection fraction, regional ejection changes and left ventricular end-diastolic pressure were significantly improved in the chronic phase in patients with reperfusion within 6 hours. On the other hand, in patients who had no reperfusion in either the acute or chronic phase, left ventricular ejection fraction deteriorated in the chronic phase. Even in patients with reperfusion in the acute phase, reocclusion later meant a worse left ventricular ejection fraction in the chronic phase. These results suggest that intracoronary thrombolysis with urokinase within 6 hours gives a good chance of recovery from myocardial damage in patients with myocardial infarction.     

Long-term effect of thrombolytic therapy on left ventricular ejection fraction after acute myocardial infarction

To assess the long-term effect of thrombolytic therapy on left ventricular (LV) systolic function, 222 patients with acute myocardial infarction treated with intravenous tissue plasminogen activator within 4 hours of symptom onset underwent assessment of LV ejection fraction (EF) by radionuclide equilibrium angiography at hospital discharge and 1 year later. Mean EF at hospital discharge (46 ± 12) was similar to that at 1 year (45 ± 13). Stepwise multivariate linear regression analysis identified EF at discharge and patency of the infarct-related artery before discharge as independent predictors of EF change at 1 year (p = 0.0002 and 0.003, respectively). Random assignments to invasive versus conservative treatment strategies or to early versus delayed β-blocker therapy did not affect EF change during follow-up. No significant deterioration of EF was observed in patients with larger infarcts. However, EF decreased from 45 ± 10 at hospital discharge to 39 ± 12 (p = 0.005) at 1-year follow-up in a subgroup of patients with history of prior infarction.

Thus, patients with acute myocardial infarction, treated with intravenous tissue plasminogen activator early after onset of symptoms, appear to have stable LV function between hospital discharge and 1 year follow-up. The change in EF between hospital discharge and 1 year can be predicted from the EF value at discharge, patency of the infarct-related artery before discharge and history of previous myocardial infarction.     

Effect of successful thrombolytic therapy on right ventricular function in acute inferior wall myocardial infarction

In 19 patients undergoing intracoronary fibrinolytic therapy for acute myocardial infarction, the site of coronary obstruction was in the proximal right coronary artery. Time between onset of symptoms and hospitalization was less than 4 hours. These patients were studied prospectively by radionuclide techniques immediately after admission, 48 hours and 4 weeks after AMI. Right and left ventricular (RV and LV) ejection fractions (EF) were calculated from gated blood pool scintigrams and the size of the LV perfusion defect was assessed by thallium-201 scintigraphy. Before the intervention, RV performance was significantly lower (RVEF 29 +/- 8%) than normal (53 +/- 7%). The size of the LV perfusion defect was relatively small (less than 25% of LV circumference), and as a consequence, LV pump function was only marginally impaired (LVEF 54 +/- 11%). Recanalization of the infarct artery was achieved in 12 patients (group A); in 7 patients the infarct artery remained occluded (group B). Early after the intervention (48 hours), RV performance in group A recovered significantly (RVEF: 30 +/- 9% vs 39 +/- 7%, p less than 0.01), and further improvement was noted at 4 weeks (RVEF 43 +/- 5%, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Silent left ventricular dysfunction during routine activity after thrombolytic therapy for acute myocardial infarction

To investigate prospectively the occurrence and significance of postinfarction transient left ventricular dysfunction, 33 ambulatory patients who underwent thrombolytic therapy after myocardial infarction were monitored continuously for 187 +/- 56 min during normal activity with a radionuclide left ventricular function detector at the time of hospital discharge. Twelve patients demonstrated 19 episodes of transient left ventricular dysfunction (greater than 0.05 decrease in ejection fraction, lasting greater than or equal to 1 min), with no change in heart rate. Only two episodes in one patient were associated with chest pain and electrocardiographic changes. The baseline ejection fraction was 0.52 +/- 0.12 in patients with transient left ventricular dysfunction and 0.51 +/- 0.13 in patients without dysfunction (p = NS). At follow-up study (19.2 +/- 5.4 months), cardiac events (unstable angina, myocardial infarction or death) occurred in 8 of 12 patients with but in only 3 of 21 patients without transient left ventricular dysfunction (p less than 0.01). During submaximal supine bicycle exercise, only two patients demonstrated a decrease in ejection fraction greater than or equal to 0.05 at peak exercise; neither had a subsequent cardiac event. These data suggest that transient episodes of silent left ventricular dysfunction at hospital discharge in patients treated with thrombolysis after myocardial infarction are common and associated with a poor outcome. Continuous left ventricular function monitoring during normal activity may provide prognostic information not available from submaximal exercise test results.     

Improved left ventricular function in myocardial infarction following intravenous thrombolytic therapy with acylated plasminogen activator

Forty-six patients with acute myocardial infarction (MI) were treated within three hours of the onset of chest pain with an intravenous bolus (IV) of 30 units of anisolated plasminogen activator streptokinase complex (APSAC). Reperfusion was detected in 31 patients (67%) by clinical, electrocardiographic, and enzymatic criteria. The mean time elapsed between the onset of the chest pain to thrombolytic therapy was 114 +/- 53 minutes. Left ventricular ejection fraction (LVEF) was significantly better in patients with anterior and inferior myocardial infarction who had successful reperfusion, as compared with those who did not (48.8 +/- 13.0 vs 35.3 +/- 10.9, p less than 0.05 and 59.7 +/- 12.6 vs 47.9 +/- 15.3, p less than 0.05, respectively). The rate of reocclusion within three weeks was 22%. The overall one-year mortality was 4%. There were no serious adverse reactions following the thrombolytic treatment. Thus bolus IV injection of 30 units of APSAC is both safe and effective in preserving left ventricular function when given early in the course of acute myocardial infarction.     

Early recovery of left ventricular function after thrombolytic therapy for acute myocardial infarction: an important determinant of survival

Thrombolytic therapy for acute myocardial infarction reduces early mortality, but full recovery of left ventricular function after reperfusion is delayed. Therefore, the relations among reperfusion, survival and the time course of left ventricular functional recovery were examined in 226 patients treated with intracoronary streptokinase; 77% (134 patients) had sustained reperfusion and 31 patients had no reperfusion or had reocclusion by day 3. Wall motion was measured from contrast ventriculograms performed in the acute period and 3 days later in the central and peripheral infarct regions and the noninfarct region by the centerline method in 165 patients. Patients with reperfusion had better survival (p less than 0.05, mean follow-up 4.5 years) and a higher ejection fraction at 3 days (52 +/- 12 versus 46 +/- 10%, p less than 0.02) attributable to a significantly different change in peripheral infarct region function between the acute and 3 day studies (0.1 +/- 1.0 versus -0.3 +/- 0.9 SD, p less than 0.05). These early functional changes were significant in patients with anterior myocardial infarction and showed similar trends in those with inferior myocardial infarction. On Cox regression analysis, function measured at 3 days was more predictive of survival than was function measured acutely (chi square for acute ejection fraction = 11.48 versus 24.59 at 3 days). Although, as previously reported, greater than 45% of total recovery of left ventricular function occurs later, the ejection fraction achieved by day 3 is already predictive of survival. Thus, the mechanism by which successful thrombolytic therapy enhances survival is improvement of regional and global left ventricular function early after acute myocardial infarction.     

Effects of early myocardial reperfusion on left ventricular function in patients with acute myocardial infarction

The effect of early myocardial reperfusion (within six hours after the onset of symptoms) on left ventricular (LV) function in 106 patients with acute myocardial infarction was studied. The subjects consisting of 26 with conventional therapy, 19 with percutaneous transluminal coronary recanalization (PTCR), 16 with percutaneous transluminal coronary angioplasty (PTCA) after PTCR, 32 with direct-PTCA and 13 with coronary artery bypass graft (CABG) were randomly observed after 1981. In these patients, left ventricular ejection fraction (LVEF), regional wall motion, end-diastolic pressure and the contractility index were measured as the indices of LV function. 1. Compared to the conventional therapy group, LVEF and regional wall motion improved significantly in all groups with reperfusion therapy except in the PTCR group. This LV function in patients with subtotal obstruction or good initial collaterals significantly improved compared to patients with total obstruction and no collateral circulation. Patients with a 75 percent or more residual stenosis after reperfusion therapy had significantly decreased LV function compared to those with residual stenosis of less than 75 percent. These findings support the potential role for reperfusion therapy in patients with acute myocardial infarction.     

Prognostic significance of the evolution of left ventricular ejection fraction in patients with acute myocardial infarction not treated with thrombolytic therapy

Several controlled trials on the thrombolytic treatment of acutemyocardial infarction (AMI) have failed to demonstrate thatthrombolysis has a simultaneous positive effect on left ventricularfunction and survival. One explanation may be that spontaneouschanges in left ventricular function occurred during the progressionof AMI in control patients. The aim of this study was to evaluatethe spontaneous evolution of left ventricular ejection fraction(LVEF) and its prognostic influence on early (1 month) and late(1 year) mortality in patients with AMI. We studied 216 patientsadmitted to our CCU within 24 h of the onset of symptoms. LVEFwas determined by radionuclide ventriculography on admission(RNV1) and at the end of the necrotic phase (RNV2). Fourteenpatients died before RNV2. On the basis of LVEF values at RNV1,the remaining 202 patients were divided into two groups: thosewith a normal LVEF (55%), and those with an abnormal LVEF (<55%). Among patients with a normal LVEF at RNV1 (64 patients) a significantincrease (>12%) in LVEF at RNV2 was observed in 12.5%, asignificant decrease (>12%) in 12.5% and no change at allin 75%. All of these patients survived, regardless of the evolutionof LVEF. In patients with an abnormal LVEF at RNV1 (138) a significantincrease (>5%) in LVEF at RNV2 was observed in 72.5%, a significantdecrease (>5%) in 6.5% and no change at all in 21%. In patientswith a LVEF increase, both early and late mortality were significantlylower than in patients with a LVEF decrease: (early mortality4% vs 55.5%, P<0.001; late mortality 6% vs 66.6%, P<0.001)respectively. In patients without any LVEF change, mortalitywas significantly lower than in patients with a LVEF decrease:(early mortality 10% vs 55.5%, P = 0.01; late mortality 14%vs 66.6%, P=0.004) respectively. In conclusion, our data demonstrate that a significant increasein LVEF occurs in most patients with an early depression ofleft ventricular function. This behaviour is associated witha low early and late mortality in comparison with the patientswith a LVEF decrease and is independent of thrombolytic treatment.When the early measurement of LVEF is normal the prognosis isnot influenced by LVEF evolution. These findings must be keptin mind when LVEF is used as a prognostic index and as an end-pointfor the evaluation of the effects of thrombolytic therapy.     

Effects of early high-dose streptokinase intravenously on left ventricular function in acute myocardial infarction

One hundred seven patients who recently had acute myocardial infarction were randomly assigned either to standard heparin therapy or to intravenous streptokinase within 5 hours after the onset of symptoms in 7 hospitals without catheterization facilities. In the third week, the patients were referred to a university hospital, where the patency rate of the infarct-related artery was studied by selective coronary arteriography and left ventricular function by radionuclide angiography. Fifty-five patients received heparin and 52 streptokinase within a mean period of 190 minutes after the onset of symptoms. Seven patients in the heparin group and 4 in the streptokinase group died in hospital. The patency rate of the infarct-related artery was identical in both groups (69% in the heparin group vs 68% in the streptokinase group). Left ventricular ejection fraction was not statistically different (0.44 +/- 0.13 in the heparin group vs 0.45 +/- 0.12 in the streptokinase group). Left ventricular ejection fraction was significantly higher in patients with a patent infarct-related artery than in patients with an obstructed infarct-related artery (0.49 +/- 0.12 vs 0.41 +/- 0.15, p less than 0.01). In patients with inferior wall infarction, left ventricular ejection fraction was identical (0.50 +/- 0.10 in the heparin group vs 0.52 +/- 0.09, in the streptokinase group). In patients with anterior wall infarction, left ventricular ejection fraction was significantly higher in the streptokinase group than in heparin group (0.40 +/- 0.10 vs 0.33 +/- 0.09, p less than 0.05). Analysis of regional wall motion revealed that improvement occurred in the lateral wall of the left ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of thrombolytic therapy in acute inferior myocardial infarction with or without right ventricular involvement

Objectives. This study assessed the prognostic impact of right ventricular involvement (RVI) in streptokinase-treated patients with inferior acute myocardial infarction (AMI) stratified for small or large AMI.Background. Only scant data exist from small studies about the impact of reperfusion therapy on survival in patients with RVI during inferior AMI.Methods. Right ventricular involvement was assessed by ST-segment elevation ≥0.1 mV in lead V₄R and infarct size by the extent of ST-segment deviation on the baseline electrocardiogram: small AMI = sum ST-segment elevation ≤0.8 mV and no precordial ST-segment depression (small ST); large AMI = presence of precordial ST-segment depression or sum ST-segment elevation >0.8 mV (large ST) in 522 inferior AMI patients of the Hirudin for Improvement of Thrombolysis (HIT-4) Trial. In 187 patients, 90-min coronary angiography was performed.Results. Right ventricular involvement was present in 169 patients (32%). Higher 30-day cardiac mortality rates with RVI (5.9% vs. 2.5%) were related to larger infarct size rather than to RVI. For large ST, a proximal right coronary artery lesion was observed in 52% with and in 23% without RVI. Patency rates at 90 min were similar (54% vs. 52%). In the 28% of patients who had small ST, cardiac mortality was less than 1% irrespective of the presence of RVI. Coronary artery lesions were mostly located distally. Patency rates were 27% with and 80% without RVI.Conclusions. ST-segment elevation of ≥0.1 mV in V₄R in inferior AMI patients is associated with larger infarct size and higher 30-day mortality rates. Right ventricular involvement is not an independent predictor of survival. In patients with small ST, cardiac mortality is low, even if ST V₄R is ≥0.1 mV.