Reliability of resolution of ST-segment elevation after coronary reperfusion in predicting myocardial salvage in anterior wall acute myocardial infarction

Resolution of ST-segment elevation (ST resolution) after reperfusion therapy has been shown to correlate with improved left ventricular (LV) function in patients with acute myocardial infarction (AMI). However, not all patients with ST resolution have preserved LV function. We evaluated the clinical significance of ST resolution in 129 patients with anterior wall AMI who underwent successful coronary recanalization within 6 hours after symptom onset by studying the relation to myocardial blush grade, another angiographic marker of myocardial reperfusion. A reduction of > or =50% in ST-segment elevation after recanalization was defined as ST resolution. Ninety-eight patients had ST resolution and 31 patients did not. Patients with ST resolution were subdivided into 2 groups according to myocardial blush grade after recanalization: 67 patients with blush grade 2 or 3, and 31 with blush grade 0 or 1. The QRS score after recanalization was higher (5.9 +/- 1.9 vs 3.4 +/- 2.0, p <0.01) and predischarge LV ejection fraction was lower (39 +/- 8% vs 57 +/- 9%, p <0.01) in patients with blush grade 0 or 1 than in those with blush grade 2 or 3. However, the QRS score after recanalization and the predischarge LV ejection fraction were similar in patients who had ST resolution with blush grade 0 or 1 and in those without ST resolution. Our findings suggest that ST resolution after recanalization does not consistently predict myocardial salvage in patients with anterior AMI.     

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.     

Impact of the magnitude of the initial ST-segment elevation on left ventricular function in patients with anterior acute myocardial infarction.

BACKGROUND: In the percutaneous coronary intervention (PCI) era, the impact of initial ST-segment elevation magnitude on left ventricular (LV) function in patients with acute myocardial infarction (AMI) remains unclear. METHODS AND RESULTS: In the present study, 239 patients with total occlusion and 81 patients with spontaneous reperfusion within 12 h of their first anterior AMI were evaluated. The sum of ST-segment elevation (SigmaST) was measured in leads I, aV(L) and V(1-6) shortly before angiography. Predischarge LV ejection fraction (LVEF) was obtained at 15+/-5 days. In total occlusion, the predischarge LVEF was significantly lower in patients with SigmaST >/=10 mm than in those with SigmaST <10 mm (51+/-14% vs 57+/-14%, p<0.01). However, in spontaneous reperfusion, there was no significant difference between patients with ST >/=10 mm and those with SigmaST <10 mm (61+/-13 vs 62+/-14 %, p=NS). Predischarge LVEF significantly correlated with SigmaST in total occlusion (r=-0.25, p<0.01), but not in spontaneous reperfusion (r=0.03, p=NS). CONCLUSION: The results suggest that initial SigmaST is an important predictor of LV function in patients with total occlusion, but not in those with spontaneous reperfusion.     

ST-segment re-elevation unrelated to left ventricular ejection fraction or volume after anterior wall acute myocardial infarction treated with successful reperfusion

Ventricular remodeling is a major determinant of the long-term prognosis of patients with acute myocardial infarction (AMI). No previous study examined the relation of ST-segment re-elevation to left ventricular (LV) volume and function in patients with successful reperfusion. We examined the relation of ST-segment re-elevation to LV function and volume indices in 51 patients with anterior wall AMI who underwent successful reperfusion by direct coronary angioplasty. A 12-lead electrocardiogram was recorded once a day until 7 days after the onset of AMI. ST-segment shift was measured and Sigma ST was defined as the sum of ST-segment elevation obtained from leads V2, V3, and V4. ST-segment re-elevation was defined as present when the difference between maximal and minimal Sigma ST (Delta ST) was >0.3mV. LV indices were obtained from left ventriculography performed approximately 1 month after the onset of AMI. ST-segment re-elevation was observed in 15 patients (29%). No significant differences were observed between the ST- re-elevation group and non-ST-re-elevation group in LV ejection fraction (49.4+/-14.0 vs. 51.2+/-11.5%), LV end-systolic volume index (35.8+/-13.1 vs. 33.8+/-12.5 mL/m(2)) or LV end-diastolic volume index (69.7+/-12.8 vs. 68.3+/-14.4 mL/m(2)). The difference between maximal and minimal Sigma ST (Delta ST) was not significantly correlated with any LV index examined. In conclusion, the present study revealed that ST-segment re-elevation after successful reperfusion in anterior wall AMI patients was not related to LV volume or function, indicating that ST-re-elevation is not a clinically meaningful indicator of LV remodeling.     

Clinical and angiographic characteristics of patients with combined anterior and inferior ST-segment elevation on the initial electrocardiogram during acute myocardial infarction

Objective

We evaluated the significance of combined anterior and inferior ST-segment elevation on the initial electrocardiogram (EKG) in patients with acute myocardial infarction (AMI) and correlated it with AMI size and left ventricular (LV) function.

Methods

We analyzed admission EKGs of 2996 patients with AMI from the GUSTO-I angiographic substudy and the GUSTO-IIb angioplasty substudy who underwent immediate angiography. In all, we identified 1046 patients with anterior ST elevation (ST-segment elevation in ≥2 of leads V₁-V₄) and divided them into 3 groups: Group 1, anterior + inferior ST elevation (ST elevation in ≥2 of leads II, III, aVF, n =179); Group 2, anterior ST elevation only (<2 of leads II, III, aVF with ST elevation or depression, n = 447); Group 3, anterior ST elevation + superior ST elevation (ST depression in ≥2 of leads II, III, aVF, n = 420).

Results

Cardiac risk factors, prior AMI, prior percutaneous transluminal coronary angioplasty or coronary artery bypass graft, Killip class, and thrombolytic therapy assignment did not differ among the 3 groups. Group 1 patients had greater number of leads with ST elevation compared to Groups 2 and 3 (ST elevation in ≥6 leads 83% vs 22% vs 49%, P = .001). Despite greater ST-segment elevation, Group 1 patients had a lower peak CK level (median baseline peak CK 1370 vs 1670 vs 2381 IU, P = .0001) and less LV dysfunction (median ejection fraction 0.53 vs 0.49 vs 0.45, P = .0001; median number of abnormal chords 21 vs 32 vs 40, P = .0001). Angiographically, Group 1 had 2 distinct subsets of patients with either right coronary artery (RCA) (59%) or left anterior descending coronary artery (LAD) (36%) occlusion. In contrast, the infarct-related artery (IRA) was almost entirely the LAD in Groups 2 and 3 (97%). Further, the site of IRA occlusion in Group 1 was mostly proximal RCA (67%) in the RCA subgroup and mid or distal LAD (70%) in the LAD subgroup. ST-segment elevation in lead V₁ ≥ V₃ and absence of progression of ST elevation from lead V₁ to V₃ on the EKG differentiated IRA-RCA from IRA-LAD in patients with combined anterior and inferior ST elevation.

Conclusions

The AMI size and LV dysfunction in patients with anterior ST elevation is directly related to the direction of ST segment deviation in the leads II, III, aVF; least with inferior ST elevation, intermediate with no ST deviation, and maximal with superior ST elevation (inferior ST depression). Despite greater ST-segment elevation, patients with combined anterior and inferior ST elevation have limited AMI size and preserved LV function. Angiographically, they comprise 2 distinct subsets with either proximal RCA or mid to distal LAD occlusion. A predominant right ventricular and limited inferior LV AMI from a proximal RCA occlusion, or a smaller anterior AMI from a more distal occlusion of LAD may explain their limited AMI size despite greater ST elevation.     

Reperfusion arrhythmias during coronary angioplasty for acute myocardial infarction predict ST-segment resolution

BACKGROUND: Despite early recanalization of an occluded infarct-related artery, myocardial reperfusion may remain impaired due to microvascular injury. Reperfusion arrhythmias may indicate successful microvascular reperfusion. METHODS: Microvascular reperfusion was assessed prospectively in 42 consecutive patients with ST-segment elevation acute myocardial infarction (AMI) by evaluation of the resolution of ST-segment elevation (<50% of initial level) immediately after successful coronary angioplasty. Patients were divided into two groups: those with ST resolution (n=24) and those without ST resolution (n=18). The presence of reperfusion arrhythmias immediately after recanalization was recorded. RESULTS: Patients with ST resolution were younger (54+/-12 years compared with 64+/-17 years, P=0.04), their pain-to-recanalization time was shorter (195+/-87 min compared with 294+/-179 min, P=0.05), they were less often diabetic (13% compared with 24%, P=0.05) and were more often given IIb/IIIa inhibitors (58% compared with 22%, P=0.02). Reperfusion arrhythmias were observed in 15 out of 24 patients with ST resolution (62%) but in only one out of 18 without ST resolution (5%) (P<0.01). Reperfusion arrhythmias included accelerated idioventricular rhythm, 13 (81%); multifocal ventricular premature beats, two (13%); and ventricular tachycardia, one (6%). The sensitivity and specificity of reperfusion arrhythmias for ST resolution were 62 and 95%, respectively. In a logistic regression model including age, time to treatment, diabetes, use of IIb/IIIa inhibitors and reperfusion arrhythmias, only the latter was found to be an independent predictor of ST resolution (P<0.01). CONCLUSION: Reperfusion arrhythmias following coronary angioplasty for AMI are a highly specific marker for ST resolution and may indicate successful microvascular reperfusion.     

急性前壁心肌梗死伴不同下壁导联ST段改变的临床特点

目的探讨ST段抬高急性前壁心肌梗死(简称心梗)伴不同下壁导联ST段改变患者的梗死相关血管以及梗死面积及心功能情况。方法73例急性前壁心梗患者,根据入院时心电图下壁导联ST段改变情况将患者分为3组:A组为Ⅱ、Ⅲ、aVF中至少两个导联ST段抬高;B组为Ⅱ、Ⅲ、aVF中至少两个导联ST段压低,C组为Ⅱ、Ⅲ、aVF中少于两个导联ST段有改变。比较三组CK最大值,左室射血分数以及梗死相关血管(IRCA)。结果CK最大值3组比较A组最低(1280±531IU/Lvs2034±911,1677±630IU/L,P<0.01);左室射血分数A组最高(0.54±0.09vs0.48±0.07,0.47±0.08,P<0.01);三组IRCAA组中85.7%的患者位于“绕过心尖的左前降支(LAD)”的中远段,有14.3%的患者位于右冠状动脉(RCA)的近段;B组的患者中全部为非“绕过心尖的LAD”,其中有70.4%的患者位于非“绕过心尖的LAD”的近段;C组中有96.7%的患者为非“绕过心尖的LAD”,其中有73.3%的患者位于非“绕过心尖的LAD”的近中段,三组比较差异有显著性(P<0.01)。结论IRCA为LAD的急性前壁心梗时下壁ST段改变可能与LAD长度和病变部位有关;前壁合并下壁ST段同时抬高的患者若IRCA为“绕过心尖的LAD”,其梗死面积较小,心功能较好。     

Clinical implications of serial changes in ST-segment elevation after reperfusion in patients with anterior acute myocardial infarction.

BACKGROUND: In patients with acute myocardial infarction (AMI), the relationship of serial changes in ST-segment elevation after reperfusion to left ventricular (LV) function remains unclear. METHODS AND RESULTS: The study group comprised 164 patients with reperfused anterior AMI within 6 h of symptom onset. The sum of ST-segment deviation was calculated on admission (SigmaST-admission), and 1 h (SigmaST-1 h) and 24 h (SigmaST-24 h) after reperfusion. ST resolution was defined as a reduction in SigmaST-1 h of > or =50% as compared with SigmaST-admission. Patients were classified into 3 groups: group A, 82 patients with ST resolution in whom SigmaST-1 h > or = SigmaST-24 h; group B, 37 patients with ST resolution in whom SigmaST-1 h < SigmaST-24 h; group C, 45 patients without ST resolution. Peak creatine kinase were higher in groups B and C than in group A (4,578+/-2,176, 4,236+/-2,638, 2,222+/-1,926 mU/ml, p<0.01). At 6 months follow-up, the LV ejection fraction were lower in groups B and C than in group A (53+/-8, 54+/-12, 62+/-9%, p<0.01). CONCLUSIONS: An increase in ST-segment elevation 1-24 h after reperfusion, despite ST resolution, is associated with a larger infarction and poorer LV function in patients with reperfused anterior AMI.     

Effect of preinfarction angina pectoris on ST-segment resolution after primary coronary angioplasty for acute myocardial infarction

The presence of preinfarction angina has been shown to exert a favorable effect on left ventricular function after acute myocardial infarction (AMI). Whether or not preinfarction angina is beneficial for myocardial tissue reperfusion, however, remains to be determined. We sought to evaluate the influence of preinfarction angina on resolution of ST-segment elevation, which could be affected by microcirculatory damage after recanalization therapy. We studied 96 patients with a first AMI in whom Thrombolysis In Myocardial Infarction (TIMI)-3 flow in the infarct-related artery was established by primary angioplasty. Percent reduction in the sum of ST elevation from baseline to 1 hour after angioplasty (percent delta summation operator ST) was examined. Poor ST resolution, defined as percent delta summation operator ST <50%, was observed in 25 patients, who had a worse clinical outcome, larger infarct size, and poorer left ventricular function. On multivariate analysis, the absence of preinfarction angina, as well as anterior wall infarction, were major independent predictors of poor ST resolution, whereas age, sex, coronary risk factors, ischemic time, Killip class on admission, multivessel disease, initial TIMI flow grade, and extent of collaterals were not significant. Patients with preinfarction angina had a greater degree of ST-segment resolution than those without angina (71 +/- 21% vs 49 +/- 43%, p = 0.02). Additional ST elevation after reperfusion was noted exclusively in patients without preinfarction angina (p = 0.02). Preinfarction angina is associated with a greater degree of ST-segment resolution in patients with TIMI-3 flow after primary angioplasty, suggesting a protective effect of preinfarction angina against microcirculatory damage after reperfusion.     

Relation of lateral ST-segment elevation pattern to myocardial salvage in patients with recanalized anterolateral acute myocardial infarction

BACKGROUND: Although anterior acute myocardial infarction (AMI) with ST-segment elevation in lateral leads is associated with a poor prognosis, the significance of the pattern of lateral ST-segment elevation has not been examined. HYPOTHESIS: The aim of the study was to examine the relation of the pattern of lateral ST-segment elevation to myocardial reperfusion and infarct size in patients with AMI. METHODS: We studied 111 patients who had a first AMI presenting with anterolateral ST-segment elevation and Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow of the left anterior descending coronary artery within 6 h from symptom onset. Patients were classified into two groups according to the pattern of lateral ST-segment elevation on the admission electrocardiogram: Group 1, 42 patients with equivalent or greater ST-segment elevation in lead I than in lead aVL, and Group 2, 69 patients with lesser ST-segment elevation in lead I in than in lead aVL. Left ventricular ejection fraction (LVEF) was measured by predischarge left ventriculography. RESULTS: There were no differences between the two groups in age, gender, time from onset to recanalization, culprit lesion, or collateral development. Group 1 patients had a higher probability of impaired myocardial reperfusion as indicated by a myocardial blush grade of 0 or 1 after recanalization, a higher peak creatine kinase level, and a lower LVEF than Group 2 patients (p = 0.0001, respectively). CONCLUSIONS: We conclude that equivalent or greater ST-segment elevation in lead I than in lead aVL is associated with impaired myocardial reperfusion and less myocardial salvage in patients with recanalized AMI who present with anterolateral ST-segment elevation on the admission electrocardiogram.     

Pressure-derived fractional collateral blood flow: a primary determinant of left ventricular recovery after reperfused acute myocardial infarction

OBJECTIVES: We evaluated the relation between pressure-derived fractional collateral flow (PDCF) and left ventricular (LV) recovery after reperfused acute myocardial infarction (AMI). BACKGROUND: The functional significance of collateral flow remains uncertain in AMI. METHODS: The PDCF was measured in 70 patients with first AMI (pain onset <12 h) treated with primary angioplasty (PA), being determined by simultaneous measurement of mean aorta pressure (Pa), distal coronary pressure during the balloon occlusion (Poc), and central venous pressure (CVP): (Poc - CVP)/(Pa - CVP)*100. Sufficient collateral (group I) was defined as PDCF index >24% and insufficient collateral (group II) as PDCF index <24%. Echocardiography was performed before, and on day 3, day 7, and day 30 after PA. Wall-motion recovery index (RI) was obtained by dividing the number of improved wall-motion segments (>grade 1) at follow-up by the number of abnormal wall-motion segments within the infarct zone at baseline. RESULTS: Baseline characteristics were similar between both groups. Peak levels of creatine kinase were lower in group I than in group II (2,600+/-1,900 U/liter vs. 4,100+/-3,000, p < 0.05). At one month, infarct zone wall-motion score index (1.65+/-0.54 vs. 2.31+/-0.46, p < 0.01) and LV volume indexes were smaller in group I than in group II, whereas, LV ejection fraction was higher in group I than in group II (52.8+/-8.3 vs. 45.9+/-9.0, p < 0.01). The PDCF index was the strongest predictor of RI at one month (r = 0.61, p < 0.01). Time to reperfusion was not related to RI at one month. However, it was significantly related to RI in group II (r = -0.34, p < 0.05). CONCLUSIONS: The LV recovery after reperfused AMI is primarily determined by PDCF and is less dependent on time to reperfusion in patients with sufficient collaterals.     

Transient increase in ST-segment elevation immediately after reperfusion in acute myocardial infarction]

The significance of transient increase in ST-segment elevation immediately after reperfusion in acute myocardial infarction (AMI) was assessed by 12-lead electrocardiography. The study population consisted of 18 patients with initial anterior AMI, whose totally-occluded left anterior descending arteries were reperfused within 6 hours after the onset of symptoms. The ST-segment elevation was defined as that of more than 0.2 mV in the V3 lead immediately after reperfusion. Collateral circulation, timing of reperfusion, CPK release, left ventricular ejection fraction and mean % 201Tl uptake in the infarct regions were compared between patients with and without ST elevation. Eleven patients (61%) had ST-segment elevation (0.61 +/- 0.29 mV). Well-developed collaterals were observed in 43% of patients without ST-segment elevation (p < 0.05) but not in those with ST elevation. ST-segment elevations were accompanied by delays in timing of reperfusion (3.7 +/- 1.2 hrs vs 2.5 +/- 0.9 hrs, p < 0.05), higher peak CPK values (6,190 +/- 3,156 IU/l vs 3,222 +/- 2,053 IU/l, p < 0.05) and lower mean % 201Tl uptake (54.2 +/- 11.4% vs 73.9 +/- 11.3%, p < 0.01). We concluded that transient increase in ST-segment elevation immediately after reperfusion may relate to poorly-developed collaterals and prolongation of ischemia; i.e., severe ischemia before reperfusion, and therefore may reflect myocardial reperfusion injuries.     

Persistent ST segment depression in precordial leads V5-V6 after Q-wave anterior wall myocardial infarction is associated with restrictive physiology of the left ventricle

OBJECTIVES: To examine the relationship between the persistence of ST segment depression in leads V5-V6 after Q-wave anterior wall myocardial infarction (MI) and the filling pattern of the left ventricle (LV). BACKGROUND: Precordial ST segment depression predominantly in leads V5-V6 is associated with increased in-hospital morbidity and mortality after acute myocardial ischemia, perhaps due to reduced diastolic distensibility of the LV. METHODS: We prospectively studied 19 patients after Q-wave anterior wall MI (>6 months). All patients underwent 12-lead ECG recording, symptom-limited treadmill exercise testing with single photon emission computed tomography thallium-201 imaging, transthoracic Doppler echocardiography, cardiac catheterization and measurement of circulating atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels. Patients were classified based on the presence of ST segment depression in leads V5-V6: Group I = ST segment depression <0.1 mV (n = 10); Group II = ST segment depression > or =0.1 mV (n = 9). RESULTS: Patients in Group II had greater LV end diastolic pressures (32.4 +/- 6.5 mm Hg vs. 14.8 +/- 6.1 mm Hg; p = 0.0001), higher plasma ANP (44.4 +/- 47.1 pg/ml vs. 10.7 +/- 14 pg/ml; p = 0.04) and BNP levels (89.4 +/- 62.7 pg/ml vs. 23.6 +/- 33.1 pg/ml; p = 0.01), greater left atrium area (20.6 +/- 3.1 cm2 vs. 17.8 +/- 2.4 cm2; p = 0.05), lower peak atrial (A), higher early (E) mitral inflow velocities, a higher E/A ratio and a lower deceleration time (167 +/- 44 ms vs. 220 +/- 40 ms; p = 0.05). Lung thallium uptake during exercise was more common in Group II (78% vs. 10%, p = 0.04). CONCLUSIONS: Persistent ST segment depression in leads V5-V6 in survivors of Q-wave anterior wall MI is associated with increased LV filling pressure and a restrictive LV filling pattern.     

The effect of ST resolution on QT dispersion after interventional treatment in acute myocardial infarction

BACKGROUND: It has been reported that reperfusion treatment reduces QT dispersion (QTD) in cases of acute myocardial infarction (AMI). Successful myocardial perfusion is not synonymous with Thrombolysis in Myocardial Infarction (TIMI) III flow. It has been demonstrated that in AMI, the grade of ST-resolution correlates strongly with left ventricular (LV) function, enzyme elevation, and mortality after primary angioplasty. HYPOTHESIS: This study investigated the relation between ST-resolution grade and QTD and the feasibility of using QTD as a determinant of successful myocardial tissue perfusion in patients in whom TIMI III flow in the infarct-related artery (IRA) is restored by interventional treatment for AMI. METHODS: The study included 57 patients (38 men, 19 women, average age 54.4 +/- 11.6 years), whose IRA was perfused by primary angioplasty after the diagnosis of anterior AMI with ST elevation. Electrocardiograms of patients were taken 45 +/- 12 min post procedure, and patients were divided into three groups depending on the grade of ST resolution: Group 1, full ST resolution; Group 2, partial ST resolution; and Group 3, unsuccessful ST resolution. RESULTS: Full ST resolution was seen in 19 cases (33%), partial resolution in 26 cases (47%), and unsuccessful resolution in 12 cases (20%). There were no differences among groups in terms of risk factors, stent diameters, symptom onset-balloon time, LV function, and preprocedure corrected QTD (QTcD) (p = 0.274). After the procedure, a significant reduction in QTcD was found within the groups (p = 0.0001 in Group 1, p = 0.004 in Group 2, and p = 0.011 in Group 3). Reductions in QTcD post procedure were 24.21 +/- 14.27, 11.85 +/- 16.18, and 12.50 +/- 11.58 ms in Groups 1, 2, and 3, respectively. There was a statistically significant difference of p = 0.015 between Groups 1 and 2 and a difference of p = 0.028 between Groups 1 and 3. There was no statistically significant difference between Groups 2 and 3 (p = 0.916). CONCLUSION: In acute MI, TIMI III flow led to a reduction in QTcD, and full myocardial perfusion made an additional contribution to the electrical stability of the myocardium.     

急性心肌梗死再灌注后心电图ST段抬高的意义

目的：探讨急性心肌梗死（AMI）患者接受经皮冠状动脉腔内成形术（PTCA）治疗心电图ST段持续高与临床预后的关系。方法：AMI患者共30例,比较PTCA前及术后1h12导联心电图抬高ST的总和,按ST段下降幅度分为两组,A组：AT段下降≥50％,B组：ST段下降＜50％。行小剂量多巴酚丁胺负荷超声心动图检查并随访复查超声心动图。结果：AMI发病早期基础状态和负荷状态及发病后第1、2、3个月左室射血分数（LVEF）A组均明显大于B组。多巴酚丁胺负荷状态下主动脉峰值血流加速度、每搏输出量及每搏指数A组明显大于B组。基于状态和负荷状态下总室壁运动积分指数（GWMSI）和梗死区室壁运动积分指数（IWMSI）A组均明显小于B组,AMI发病后1、2、3个月GWMSI A组均明显小于B组。发病第1、2个月IWMSI两组间差异无统计学意义。发病第3个月IWMSI A组明显小于B组。AMI直接PTCA后心电图ST段持续抬高的患者左室收缩功能及收缩储备功能以及梗死区室壁运动的恢复明显低于ST段迅速下降者。     

Early identification of impaired myocardial reperfusion with serial assessment of ST segments after percutaneous transluminal coronary angioplasty during acute myocardial infarction.

To evaluate the relation between ST-segment analysis and microvascular reperfusion in patients with acute myocardial infarction (AMI), we studied 51 patients with first AMI who were successfully treated by percutaneous transluminal coronary angioplasty (PTCA). The lead showing the greatest ST-segment elevation on the 12-lead electrocardiogram (ECG) was serially investigated until 24 hours after PTCA. Successful reperfusion was determined by technetium-99m tetrofosmin single-photon emission computed tomography. Impaired reperfusion (group 1: < 4 change in the sum of the defect score from before to immediately after PTCA) was observed in 24 patients, and successful reperfusion (group 2) was observed in 27 patients. Although ST-segment elevation was reduced significantly at 30 minutes after PTCA in group 2 (2.2 +/- 1.4 to 1.7 +/- 1.3 mm, p = 0.01), there was no significant change in group 1 (1.9 +/- 1.9 to 2.4 +/- 1.7 mm). Ten of 14 patients (71%) with persistent ST-segment elevation (DeltaST > 0 mm change in ST segment from before to 30 minutes after PTCA > 0) were in group 1, whereas 23 of 37 patients (62%) with ST-segment resolution (DeltaST < or = 0) were in group 2. The sensitivity and specificity of persistent ST-segment elevation for predicting impaired microvascular reperfusion were 42% and 85%, respectively. Thus, persistent ST-segment elevation 30 minutes after primary PTCA was a highly specific electrocardiographic marker of impaired reperfusion in patients with AMI.     

Feasibility and safety of thrombectomy with TVAC aspiration catheter system for patients with acute myocardial infarction

Early reperfusion with angioplasty and stenting is established as a central, effective treatment for acute myocardial infarction (AMI). The role of thrombectomy prior to angioplasty remains to be elucidated. To evaluate its feasibility, safety, and efficacy, thrombectomy using a TVAC aspiration catheter system was attempted prior to angioplasty and stenting in 40 consecutive patients with AMI. Fifty consecutive patients with AMI in whom angioplasty and stenting were performed without prior thrombectomy served as controls. Neither distribution of Killip classification nor culprit lesion was different between the two groups. In patients treated with the TVAC system, the procedure was successful in 39/40 patients (98%) and there were no procedure-related complications. In the final coronary angiogram, TIMI-3 (Thrombolysis in Myocardial Infarction) flow was obtained in 37/40 (93%) in patients treated with the TVAC system and 43/50 (86%) in control patients. Electrocardiograms before and after coronary intervention were analyzed in patients with ST elevation AMI (35 patients treated with the TVAC system and 41 control patients). ST elevation recovery >50% of the initial value was observed after coronary intervention in 26/35 (74%) in patients treated with the TVAC system and 26/41 (63%) in control patients (P = 0.33). In the case of anterior AMI, ST elevation recovery >50% of the initial value was observed in 13/17 (76%) in patients treated with the TVAC system and 8/20 (40%) in control patients (P = 0.045). Thus, thrombectomy using a TVAC system is feasible, safe, and may have the potential to enhance ST-segment resolution in patients with anterior AMI.     

Intracoronary ST segment evolution during primary coronary stenting predicts infarct zone recovery

In patients with acute myocardial infarction (AMI), early ST segment elevation resolution on ECG predicts myocardial reperfusion and LV recovery. Intracoronary ECG is more sensitive than surface ECG to detect regional ischemia. In patients undergoing primary percutaneous coronary intervention (PCI), we investigated if failed myocardial reperfusion, despite successful infarct vessel recanalization, could be rapidly and easily identified by intracoronary ST segment monitoring from guidewire recording. We recorded intracoronary and standard ECG during primary coronary stenting (PCI) in 50 patients with AMI (59 ± 11 years; anterior AMI in 66%). All patients had a successful PCI and underwent 2D echocardiography soon after PCI and 6 months later. Following PCI, intracoronary ST resolution ≥ 50% from baseline was documented in 39 patients (78%; group A; from 11 ± 8 to 1 ± 2 mm) but not in 11 (22%; group B; from 11 ± 8 to 8 ± 5 mm). Group A had slightly shorter ischemic time (202 ± 94 vs. 238 ± 112 min in B; P = 0.2) and smaller peak CK values (2,752 ± 2,038 vs. 4,802 ± 3,671 U/L in B; P = 0.02). After PCI, ST resolution was found on standard ECG in 34 (87%) group A and in 3 (27%) group B patients. At 6‐month follow‐up, left ventricular ejection fraction was greater in group A (47% ± 8% vs. 39% ± 8% in B; P < 0.001) with improved wall motion score index (from 2.2 ± 0.3 to 1.7 ± 0.3 in A; from 2.3 ± 0.4 to 2.1 ± 0.4 in B; P < 0.001). There were no significant differences between intracoronary and standard ECG for sensitivity (92% vs. 86%) and specificity (62% vs. 57%) to predict improved infarct zone recovery after 6 months. ST elevation resolution on intracoronary recording during PCI predicts infarct zone recovery. Monitoring ST segment evolution by intracoronary ECG allows prompt and inexpensive identification in the catheterization laboratory of those patients without myocardial reperfusion, who may require adjunctive therapeutic interventions after successful infarct vessel recanalization. Catheter Cardiovasc Interv 2005;64:53–60. © 2004 Wiley‐Liss, Inc.     

New diagnostic criteria for acute myocardial infarction and in-hospital mortality.

BACKGROUND: The recent introduction of new diagnostic criteria for acute myocardial infarction (AMI), with troponin measurement, has increased the number of patients admitted with this diagnosis. OBJECTIVE: To evaluate the epidemiologic and prognostic implications of the new diagnostic criteria for AMI. METHODS: This was a retrospective study of 586 patients admitted for acute coronary syndrome (ACS) to the coronary care unit of our hospital, between 2002 and 2003. Data were collected from RECIMA, the Madeira Ischemic Heart Disease Registry. The population was analyzed following two different definitions of ACS: 1 - old criteria (Group I): AMI with ST elevation (typical symptoms or ECG with ST-segment elevation and raised CK-MB >2x), AMI without ST elevation (typical symptoms or ECG without ST elevation and raised CK-MB >2x) and unstable angina (UA) (symptoms or ECG indicative of ischemia, with normal CK-MB, regardless of troponin status); 2 - new criteria (Group II): AMI with ST elevation (typical symptoms or ECG with segment ST elevation and raised CK-MB >2x or troponin), AMI without ST elevation (typical symptoms or ECG without ST-segment elevation and raised CK-MB >2x or troponin) and UA (symptoms or ECG indicative of ischemia, with normal enzymes). We evaluated whether this change in criteria had any influence on in-hospital mortality. RESULTS: The new criteria significantly (by 11.9 %) increased the total number of patients admitted with AMI. This was due to an increase in AMI without ST elevation (p < 0.001) and a decrease in patients with UA (p < 0.001), with no changes in AMI with ST elevation. In-hospital mortality was lower in patients with AMI diagnosed by the new criteria and in those with UA. CONCLUSION: The overall increase in AMI resulting from the new diagnostic classification was accompanied by a decrease, although not statistically significant, of in-hospital mortality, probably due to the lower risk of the population analyzed.     

Comparison of real-time contrast echocardiography and low-dose dobutamine stress echocardiography in predicting the left ventricular functional recovery in patients after acute myocardial infarction under different therapeutic intervention

BACKGROUND: Early prediction of left ventricular (LV) functional recovery after acute myocardial infarction (AMI) remains challenging. This prospective study aims to compare real-time myocardial contrast echocardiography (MCE) with low-dose dobutamine stress echocardiography (LDDSE) in predicting the LV functional recovery in patients after AMI who underwent different therapeutic interventions. METHODS: Ninety-two patients with AMI were divided into 3 groups: primary coronary intervention group (n=34), thrombolysis group (n=30) and conservative therapy group (n=28). MCE was performed 2.3+/-0.7 days after chest pain onset. LDDSE was done within 2 days of MCE study. Follow-up echocardiography was performed 4 months later. RESULTS: Patients treated by primary coronary intervention or thrombolysis had significantly lower regional perfusion score (0.65+/-0.53 vs. 1.01+/-0.49, p=0.008; 0.78+/-0.55 vs. 1.01+/-0.49, p=0.03), better contractile reserve (regional dobutamine Deltawall motion score -1.12+/-0.39 vs. -0.80+/-0.43, p=0.01; -0.99+/-0.50 vs. -0.80+/-0.43, p=0.08) and LV function recovery (regional Deltawall motion score -1.67+/-0.53 vs. -1.02+/-0.46, p=0.003; -1.42+/-0.58 vs. -1.02+/-0.46, p=0.03) than those of conservative therapy group. MCE and LDDSE showed good concordance for predicting LV functional recovery (kappa=0.63, p<0.001). Perfusion score index had a good correlation with LV functional recovery (r=-0.75, p<0.001). CONCLUSIONS: This study demonstrates that perfusion score index obtained from real-time MCE is comparable to LDDSE in predicting the LV functional recovery even under different therapeutic interventions. Revascularization results in better preservation of myocardial microvascular integrity, regional contractile reserve and LV functional recovery.