Electrocardiographic evolution of posterior acute myocardial infarction: importance of early precordial ST-segment depression

Precordial ST-segment depression is typically observed in anterior non-Q-wave acute myocardial infarction (AMI), and is generally not regarded as an indication for acute thrombolytic therapy. Of 544 patients with creatine kinase (CK)-MB-confirmed non-Q-wave AMI randomized to the prospective multicenter Diltiazem Reinfarction Study, 50 patients (9.2%) had isolated precordial ST-segment depression of 1 mm or more in 2 or more contiguous precordial electrocardiographic leads (V1-V4). Serial electrocardiograms recorded at study entry (mean 50.5 hours after onset of chest pain), on study day 2, study day 3 and at predischarge showed that in 23 of 50 patients (40%) electrocardiographic evidence of posterior AMI evolved, defined as an R wave of 0.04 second or more in lead V1 and an R:S greater than or equal to 1 in lead V2. In 18 of these 23 patients (78%), posterior AMI had evolved by study day 3, and none had an abnormal reelevation of CK-MB (every 12-hour sampling) for up to 14 days of hospitalization. Compared with the remaining 27 patients who had electrocardiographic features of anterior non-Q-wave AMI only, the 23 with initial precordial ST segment depression in whom posterior AMI developed had significantly higher mean peak CK values (1,051 +/- 172 vs 663 +/- 89 IU, p less than 0.009) and greater mean precordial ST-segment depression in lead V1 (0.28 vs + 0.19 mm, p = 0.01), in lead V2 (1.3 vs 0.26 mm, p = 0.003) and in lead V3 (2.0 vs 0.93 mm, p = 0.0004).(ABSTRACT TRUNCATED AT 250 WORDS)     

The distinction between coronary and myocardial reperfusion after thrombolytic therapy by clinical markers of reperfusion

Objectives. We sought to examine the hypothesis that rapid resolution of ST-segment elevation in acute myocardial infarction (AMI) patients with early peak creatine kinase (CK) after thrombolytic therapy differentiates among patients with early recanalization between those with and those without adequate tissue (myocardial) reperfusion.Background. Early recanalization of the epicardial infarct-related artery (IRA) during AMI does not ensure adequate reperfusion on the myocardial level. While early peak CK after thrombolysis results from early and abrupt restoration of the coronary flow to the infarcted area, rapid ST-segment resolution, which is another clinical marker of successful reperfusion, reflects changes of the myocardial tissue itself.Methods. We compared the clinical and the angiographic results of 162 AMI patients with early peak CK (≤12 h) after thrombolytic therapy with (group A) and without (group B) concomitant rapid resolution of ST-segment elevation.Results. Patients in groups A and B had similar patency rates of the IRA on angiography (anterior infarction: 93% vs. 93%; inferior infarction: 89% vs. 77%). Nevertheless, group A versus B patients had lower peak CK (anterior infarction: 1,083 ± 585 IU/ml vs. 1,950 ± 1,216, p < 0.01; and inferior infarction: 940 ± 750 IU/ml vs. 1,350 ± 820, p = 0.18) and better left ventricular ejection fraction (anterior infarction: 49 ± 8, vs. 44 ± 8, p < 0.01; inferior infarction: 56 ± 12 vs. 51 ± 10, p = 0.1). In a 2-year follow-up, group A as compared with group B patients had a lower rate of congestive heart failure (1% vs. 13%, p < 0.01) and mortality (2% vs. 13%, p < 0.01).Conclusions. Among patients in whom reperfusion appears to have taken place using an early peak CK as a marker, the coexistence of rapid resolution of ST-segment elevation further differentiates among patients with an opened culprit artery between the ones with and without adequate myocardial reperfusion.     

Usefulness of electrocardiographic findings and creatine kinase levels on admission in predicting the accuracy of the interval between onset of chest pain of acute myocardial infarction and initiation of thrombolytic therapy

Patients with chest pain lasting greater than 6 hours and suggesting acute myocardial infarction (AMI) are often excluded from thrombolytic therapy, because myocardial necrosis is believed to be largely irreversible beyond that time. To evaluate the relation between time of onset of chest pain and enzymatic evidence of myocardial necrosis, enzymes on admission were analyzed in 221 consecutive patients with greater than or equal to 2 mm ST-segment elevation by electrocardiography on admission and no contraindications to thrombolytic therapy. Patients with symptoms within 6 hours (n = 170, early) received thrombolytic therapy, but those with symptoms after 6 hours did not (n = 51, late). Eventually, 219 (168 early, 51 late) patients had enzymatically proven AMI within 24 hours. Creatine kinase levels on admission less than twice the upper normal limit were found in 155 (91%) early patients, but surprisingly, also in 30 (59%) late patients. By electrocardiography on admission, ST-segment elevation per lead was 2.1 +/- 1.1 mm in late patients with low initial enzymes versus 1.1 +/- 0.3 mm in those with elevated initial enzymes (p less than 0.0001). Concomitantly, Q waves in leads with ST-segment elevation were present in 17 (57%) late patients with low enzymes on admission versus 17 (81%) with elevated enzymes on admission (p = 0.06). Eventually, maximal creatine kinase levels were similar in all late patients irrespective of enzyme levels on admission. Therefore, many patients with symptoms of AMI after 6 hours have low enzymes on admission and may still be eligible for thrombolytic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

院前、院内小剂量重组组织型纤溶酶原激活剂静脉溶栓治疗急性心肌梗死的临床研究

目的 :评价静脉小剂量重组组织型纤溶酶原激活剂 (rt PA)院前救治急性心肌梗死的临床疗效 ,及其安全性和可行性。　　方法 :所有确诊为急性心肌梗死的患者 ,院前给予小剂量rt PA (5 0mg)进行静脉溶栓治疗 (院前组 ,n =60 ) ,与院内应用小剂量rt PA (5 0mg)进行静脉溶栓的患者 (院内组 ,n =5 7)进行比较 ,观察发病—溶栓时间延迟对rt PA静脉溶栓疗效的影响。　　结果 :院前组的冠状动脉总再通率为 91 7% ,明显高于院内组的 80 7% (P <0 0 5 ) ;病死率两组相比无显著性差异 (3 3 %vs 3 5 % ,P >0 0 5 ) ;两组患者均无需要输血的严重出血并发症 ;两组轻度出血的发生率 ,分别占病例总数的3 3 %和 3 5 % ,无显著性差异。　　结论 :院前小剂量rt PA (5 0mg)静脉溶栓治疗急性心肌梗死 ,只要适应证选择适当 ,能争取最大限度地挽救濒危的心肌组织 ,方法快速、简单、安全、有效 ,是可行的 ,并可能提高再通率。     

Acute myocardial infarction with simultaneous ST-segment elevation in the precordial and inferior leads: evaluation of anatomic lesions and clinical implications

BACKGROUND: Simultaneous ST-segment elevation in the precordial and inferior leads is a rare ECG finding in patients with acute myocardial infarction (AMI) and its clinical implications rarely have been reported. The purpose of this study was to evaluate the clinical features of this distinctive ECG manifestation and its impact on clinical outcome. METHODS AND RESULTS: Between May 1993 and July 2001 in our hospital, direct percutaneous coronary intervention (dPCI) was performed in 924 patients with AMI. Of these 924 consecutive patients, 37 patients (4.0%) who had simultaneous ST-segment elevation (> or = 1 mm) in the precordial and inferior leads were retrospectively analyzed. Eight of these 37 patients who had a wrapped left anterior descending artery (LADA) occlusion were placed into group 1 (ie, wrapped LADA). Twenty-nine of the 37 patients who had anatomic lesions other than a wrapped LADA in the coronary arteries were placed into group 2 (ie, "nonwrapped" LADA). Group 2 patients had significantly higher incidences of cardiogenic shock (58.6% vs 0%, respectively; p = 0.004), pulmonary edema (43.8% vs 0%, respectively; p = 0.02), and sustained sudden cardiac death due to malignant ventricular tachyarrhythmias (44.8% vs 0%, respectively; p = 0.03) than did group 1 patients. Group 1 patients usually had ST-segment elevations of < 2 mm the inferior leads. However, group 2 patients always had ST-segment elevations of > or = 2 mm in the inferior leads. Univariate analysis demonstrated that the mean (+/- SD) ST-segment elevation in the inferior leads was significantly higher in group 2 patients than in group 1 patients (11.08 +/- 4.18 vs 2.95 +/- 0.92 mm, respectively; p = 0.0001). Coronary angiography demonstrated that the incidence of multivessel disease (93.1% vs 37.5%, respectively; p = 0.002) and the incidence of severe obstructive two-vessel disease (ie, stenosis of > 85%) [93.1% vs 0%, respectively; p = 0.0001] were significantly higher in group 2 than in group 1 patients. Although there was no significant difference in the rate of unsuccessful reperfusion (24% vs 13%, respectively; p = 0.38) between group 2 and group 1 patients, the 30-day mortality rate was significantly higher in group 2 patients than in group 1 patients (48.3% vs 0%, respectively; p = 0.015). CONCLUSIONS: AMI with ECG manifestation of simultaneous ST-segment elevation in precordial and inferior leads can be caused by either a wrapped LADA occlusion or a nonwrapped LADA occlusion. While patients with wrapped LADA occlusions usually have favorable clinical outcomes, patients with nonwrapped LADA occlusions usually have serious clinical presentations and unfavorable clinical outcomes. Specific clinical and ECG features identifying high-risk patients in this clinical setting would be extremely important for early, aggressive, and appropriate management.     

Factors that determine the direction and magnitude of precordial ST-segment deviations during inferior wall acute myocardial infarction

Sixty-one patients with inferior acute myocardial infarction (AMI) and no evidence of prior AMI were studied to determine which factors influence the magnitude of precordial ST-segment depression. In the total study group, there was a significant but weak correlation between the magnitude of precordial ST-segment depression and the magnitude of inferior ST-segment elevation (r = -0.46, p less than 0.001). In the 29 patients with evidence of concomitant right ventricular (RV) involvement, precordial ST-segment depression was significantly smaller both in absolute terms (-1.3 +/- 1.8 vs -2.8 +/- 1.9 mm, p less than 0.01) and relative to the magnitude of inferior ST-segment elevation (ratio of -0.2 +/- 1.0 vs -1.1 +/- 0.5, p less than 0.01), whereas in the 15 patients with lateral ST-segment elevation (greater than or equal to 1 mm in lead V6), precordial ST-segment depression was significantly greater both in absolute terms (-3.5 +/- 2.3 vs -1.6 +/- 1.7 mm, p less than 0.01) and relative to the magnitude of inferior ST-segment elevation (ratio of -1.1 +/- 0.8 vs -0.5 +/- 0.9, p less than 0.02). Consistent with these findings, the correlation between the magnitudes of precordial and inferior ST-segment deviations was considerably improved when only the 24 patients with neither evidence of RV involvement nor lateral ST-segment elevation were analyzed (r = 0.89, p less than 0.001, n = 24). These data suggest that in patients with inferior AMI, there is a reciprocal relation between precordial and inferior ST-segment deviations, which is distorted by concomitant RV involvement and by concomitant lateral left ventricular wall involvement.     

Electrocardiographic comparison of myocardial salvage with primary revascularization versus thrombolysis in inferior myocardial infarction.

Primary revascularization (PR) and thrombolytic therapy (TT) reduce infarct size and mortality in patients with ST-segment elevation acute myocardial infarction (AMI). Electrocardiogram methods can determine the extent of myocardial salvage with different AMI therapies by comparing infarct size predicted by initial ST-segment changes and infarct size estimated by later quantitative QRS scores. In a community hospital setting, we used quantitative electrocardiogram methods to estimate infarct size and myocardial salvage associated with TT and PR amongst 50 patients presenting with inferior ST-segment elevation AMI. Baseline and electrocardiogram characteristics did not differ between TT (n = 29) and PR (n = 21) patients. There was no difference in median myocardial salvage (%) between TT vs. PR groups, (38.3% vs. 44.9% respectively, P =.66). Among patients with inferior AMI, myocardial salvage was achieved with both TT and PR therapy and did not differ significantly between reperfusion strategies.     

Changes in standard electrocardiographic ST-segment elevation predictive of successful reperfusion in acute myocardial infarction

The ability of the electrocardiographic ST segment to predict successful reperfusion after thrombolytic therapy remains controversial. To evaluate whether angiographically determined reperfusion could be predicted from changes in ST-segment elevation, the sum of ST-segment elevation in affected leads of the electrocardiogram was compared before and after thrombolytic therapy in 53 patients with acute myocardial infarction (AMI). Reperfusion status of the infarct-related artery was determined angiographically less than 8 hours from onset of symptoms. According to the Thrombolysis in Myocardial Infarction trial (TIMI) criteria, 33 patients had successful reperfusion (TIMI grade 2 to 3 flow) after thrombolytic therapy and 20 patients did not (TIMI grade 0 to 1 flow). Logistic multiple regression analysis showed that the proportional value for the shift in the sum of ST elevation, termed the "% ST change," was more strongly associated with reperfusion than the absolute measured difference in millimeters (chi-square = 11.34 vs 9.22). The entire spectra of sensitivities and specificities were determined to identify a level of the percent ST change with simultaneous high sensitivity and specificity. A 20% decrease in ST elevation provided such a level (88% sensitivity, 80% specificity). The positive and negative predictive values of a 20% decrease in ST elevation were 88 and 80%, respectively. These results suggest that a decrease of only 20% in the sum of ST elevation in the standard electrocardiogram after thrombolytic therapy is a useful noninvasive predictor of reperfusion status in patients with evolving AMI.     

In hospital observation of patients with acute coronary syndrome without ST elevation and multivessels coronary artery disease treated with early invasive strategy. Comparison of results of percutaneous coronary intervention and coronary artery by-pass grafting

Acute coronary syndromes (ACS) without persistent ST-segment elevation are the main cause of hospitalization, morbidity and mortality. The objective of this study was to compare clinical and angiographic parameters as well as in-hospital results of treating 307 consecutive patients with ACS without persistent ST-segment elevation with either PCI or CABG. Inclusion criteria were: rest angina within the last 24 hours, ST-segment depression (> 0.5 mm), T-wave inversion (> 1 mm) in at least two leads, positive serum cardiac markers. PCI was performed in 75.9% of patients and 24.1% of patients underwent CABG. Both groups did not differ as to age, sex, history of diabetes, arterial hypertension, heart failure, smoking and ejection fraction. Positive troponin was significantly more frequent in the PCI group. 51% of PCI patients and 80% of CABG patients had complete revascularization (p = 0.00001). Independent predictors of in-hospital death in the CABG group were: inability to determine culprit vessel during coronary angiography due to lesions' severity (OR 13.65; 95% CI 9.40-15.20; p = 0.007) and heart failure (OR 15.58; 95% CI 12.29-18.01; p = 0.003). In the PCI group these independent predictors were: Braunwald's IIIC unstable angina (OR 5.48; 95% CI 3.10-7.17; p = 0.04) and diabetes (OR 2.22; 95% CI 1.07-3.90; p = 0.003). In-hospital mortality rate was significantly higher in the CABG group (8.1% vs 1.7% p < 0.01). Patients with multivessel coronary artery disease and ACS without ST-segment elevation treated with PCI have better in-hospital outcome than patients assigned to CABG, but the rate of complete revascularization is lower.     

ST-segment deviation analysis of the admission 12-lead electrocardiogram as an aid to early diagnosis of acute myocardial infarction with a cardiac magnetic resonance imaging gold standard.

OBJECTIVES: The purpose of this study was to validate existing 12-lead electrocardiographic (ECG) ST-segment elevation myocardial infarction (STEMI) criteria in the diagnosis of acute myocardial infarction (AMI) and the application of similar ST-segment depression (STEMI-equivalent) criteria with contrast-enhanced cardiac magnetic resonance imaging (ceMRI) as the diagnostic gold standard. BACKGROUND: The admission ECG is the cornerstone in the diagnosis of AMI, and ceMRI is a new diagnostic gold standard that can be used to validate existing and novel 12-lead ECG criteria. METHODS: One hundred fifty-one consecutive patients with their first hospital admission for chest pain underwent ceMRI. The 116 patients without ECG confounding factors were included in this study, and AMI was confirmed in 58 (50%). The admission ECG was evaluated on the basis of the lead distribution of ST-segment deviation according to current American College of Cardiology/European Society of Cardiology (ACC/ESC) guidelines. RESULTS: A sensitivity of 50% and specificity of 97% for AMI were achieved with the currently applied ST-segment elevation criteria. Consideration of ST-segment depression in addition to elevation increased sensitivity for detection of AMI from 50% to 84% (p < 0.0001) but only decreased specificity from 97% to 93% (p = 0.50). There were no significant differences in AMI location or size between patients meeting the 12-lead ACC/ESC ST-segment elevation criteria and those only meeting the ST-segment depression criteria. CONCLUSIONS: In patients admitted to hospital with possible AMI, the consideration of both ST-segment elevation and depression in the standard 12 lead-ECG recording significantly increases the sensitivity for the detection of AMI with only a slight decrease in the specificity.     

Effect of primary percutaneous coronary intervention versus thrombolysis on ventricular arrhythmias and heart rate variability in acute myocardial infarction.

BACKGROUND: Several studies showed that thrombolysis reduces ventricular arrhythmias and improves heart rate variability (HRV) in patients with acute myocardial infarction (AMI). Primary percutaneous coronary intervention (PCI) has recently become the treatment of choice for AMI, but it is still unknown whether it has favorable effects on these prognostic variables. METHODS: We studied a group of 44 consecutive AMI patients (39 males, 5 females, mean age 59 +/- 9 years) submitted to primary PCI and 93 consecutive AMI patients (80 males, 13 females, mean age 61.0 +/- 11 years) treated with thrombolytic therapy within 6 hours of symptom onset. All patients underwent 24-hour Holter recording before discharge. RESULTS: The number of premature ventricular beats and the prevalence of non-sustained ventricular tachycardia in the 24 hours were lower in the PCI group (162 +/- 474 and 9%, respectively) than in the thrombolysed group (334 +/- 1730 and 14%, respectively), but the difference did not achieve statistical significance (p = 0.62 and p = 0.58, respectively). There were also no significant differences in HRV variables between the two groups, although a lower proportion of PCI patients tended to have bottom quartile values of HRV variables. The favorable trend for arrhythmias and HRV in PCI patients, however, seemed to be related to a worse basal clinical profile of thrombolysed patients, including a higher prevalence of previous AMI (14 vs 2%, p = 0.065), diabetes (27 vs 18%, p = 0.14) and, in particular, a lower use of beta-blockers (35 vs 93%, p < 0.001). CONCLUSIONS: In this study, we failed to show any significant benefit of primary PCI compared to thrombolysis on ventricular arrhythmias and HRV in patients with ST-segment elevation AMI. The clinical implications of these findings deserve investigation in future studies.     

Strict reliance on a computer algorithm or measurable ST segment criteria may lead to errors in thrombolytic therapy eligibility

BACKGROUND: There is accumulating evidence that thrombolytic therapy is underused among eligible patients with acute myocardial infarction. We sought to determine whether potential errors in electrocardiographic diagnosis might be a contributing factor. METHODS: Seventy-five electrocardiograms were interpreted on 2 separate occasions by 3 cardiologists. Two criteria were compared for thrombolysis eligibility: (1) measurement of > or =1 mm ST-segment elevation in 2 contiguous leads (measured) and (2) criterion 1 plus the subjective opinion that the changes represented acute transmural injury (interpretive). The results were compared with computerized interpretations by the Marquette 12SL system. RESULTS: Raw agreement and agreement corrected for chance between raters for both criteria were excellent and tended to be better for interpretive compared with measured criteria (kappa = 0.89 vs 0.78, respectively). Strict reliance on measured electrocardiographic criteria alone would have resulted in overuse of thrombolysis among all 3 raters. Based on the consensus opinion, the absolute overuse of thrombolysis would have been approximately 15% (P <.0034). The computer algorithm had a specificity of 100% and a sensitivity of 61.5%. Reliance on the computerized interpretation alone would have lead to underuse of thrombolytic therapy compared with consensus opinion (21.3% vs 34. 6%; P <.005). CONCLUSION: Agreement for suspected acute myocardial infarction tended to be better when the appearance of the ST segments was added to measurable ST elevation criteria. Strict reliance on measurable criteria may lead to the inappropriate overuse of thrombolysis. Although the Marquette 12SL system has excellent specificity, it has poor sensitivity for the diagnosis of thrombolysis-eligible AMI. Reliance on computerized electrocardiographic interpretation would lead to the inappropriate underuse of thrombolytic therapy in situations in which qualifying electrocardiographic criteria are actually met.     

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.     

Persistent ST-segment elevation after primary stenting for acute myocardial infarction: its relation to left ventricular recovery

BACKGROUND: Early restoration of coronary artery patency in acute myocardial infarction (AMI) has been linked to improvement in survival. However, early recanalization of an occluded epicardial coronary artery by either thrombolytic agents or percutaneous transluminal coronary angioplasty (PTCA) does not necessarily lead to left ventricular (LV) function recovery. HYPOTHESIS: The aim of this study was to evaluate the relation between persistent ST elevation shortly after primary stenting for acute myocardial infarction (AMI) and LV recovery. METHODS: Thirty-one patients with primary stenting for AMI were prospectively enrolled. To evaluate the extent of microvascular injury, serial ST-segment analysis on a 12-lead electrocardiogram recording just before and at the end of the coronary intervention was performed. Persistent ST-segment elevation (Persistent Group, n = 11) was defined as > or = 50% of peak ST elevation and resolution (Resolution Group, n = 20) was defined as < 50% of peak ST elevation. Echocardiography was performed on Day 1 and 3 months after primary stenting. RESULTS: At 3 months, infarct zone wall-motion score index (WMSI, 2.1 +/- 0.6 vs. 2.7 +/- 0.3, p < 0.05) was smaller in the Resolution Group than in the Persistent Group, whereas wall motion recovery index (RI, 0.4 +/- 0.3 vs. 0.1 +/- 0.2, p < 0.05) and ejection fraction (58 +/- 5 vs. 43 +/- 10%, p < 0.05) were larger in the Resolution Group than in the Persistent Group. The extent of persistent ST elevation (% ST) shortly after successful recanalization of the infarct-related artery was significantly related to RI at 3 months (r = -0.4, p < 0.05). However, time to reperfusion was not related to RI at 3 months. There was also significant correlation between corrected TIMI frame count and %ST (r = 0.4, p < 0.05). CONCLUSIONS: Persistent ST-segment elevation shortly after successful recanalization (> or = 50% of the peak value), as a marker of impaired microvascular reperfusion, predicts poor LV recovery 3 months after primary stenting for AMI.     

ST-segment resolution 60 minutes after combination treatment of abciximab with reteplase or reteplase alone for acute myocardial infarction (30-day mortality results from the resolution of ST-segment after reperfusion therapy substudy)

The combination of abciximab with thrombolytic therapy when treating acute ST-elevation myocardial infarction has been hypothesized to enhance microvascular perfusion. Resolution of ST-segment elevation after thrombolytic therapy is believed to be a marker of myocardial reperfusion and to predict mortality rate. Among 16,588 patients enrolled in the Fifth Global Use of Strategies to Open Occluded Arteries in Acute Myocardial Infarction trial, 1,764 consecutive patients from selected centers had their study electrocardiograms evaluated by a core laboratory for ST-segment deviation resolution 60 minutes after treatment. Patients were categorized into 4 groups: complete resolution (>70%), partial resolution (<70% to 30%), no resolution (<30%), and worsening ST-segment deviation. Patients treated with reteplase or a combination of reteplase plus abciximab had similar rates of complete resolution (32% vs 34%), partial resolution (29% vs 27%), no resolution (15% vs 16%), and worsening ST-segment elevation (23 vs 23%; p = 0.59). The 30-day mortality rates in these 4 groups were 2.1%, 5.2%, 5.5%, and 8.1% (p <0.001). Even after accounting for baseline variables, incomplete ST-segment resolution (<70%) was associated with an increased risk of death within 30 days (adjusted hazard ratio 2.41, 95% confidence interval 1.25 to 4.63, p <0.008). Thus, ST-segment resolution at 60 minutes was no different in patients treated with full-dose reteplase from those treated with a combination of abciximab and reteplase. Patients with >70% ST-segment resolution within 60 minutes had markedly decreased mortality rates, irrespective of treatment.     

Additional ST segment elevation during the first hour of thrombolytic therapy: an electrocardiographic sign predicting a favorable clinical outcome.

OBJECTIVES. The aim of this study was to investigate the significance of further ST elevation that occurs during the 1st h of thrombolytic therapy before the expected resolution. BACKGROUND. Early resolution of ST segment elevation is commonly accepted as a marker of clinical reperfusion during thrombolytic therapy for acute myocardial infarction. Using frequent electrocardiographic recordings, we observed in some patients further ST elevation that occurred during hour 1 of thrombolysis before the expected resolution. METHODS. To investigate the significance of this pattern, we classified 177 consecutive patients with a first acute myocardial infarction into two groups: Group A, 98 patients with ST elevation > or = 1 mm above the initial ST elevation during the 1st h of thrombolytic therapy, and Group B, 79 patients without this finding. RESULTS. Although the presence or absence of additional ST elevation was not associated with a clinical or prognostic difference in patients with a first inferior or posterior acute myocardial infarction, its presence indicated a more favorable clinical outcome and prognosis in patients with anterior infarction. Among the patients with anterior infarction the 65 patients in Group A had a higher ejection fraction (44 +/- 9% vs. 35 +/- 11%, p < 0.01), less heart failure (15% vs. 35%, p = 0.02) and a lower in-hospital mortality rate (0% vs. 8%, p = 0.04) than did the 37 patients from Group B. CONCLUSIONS. Additional ST elevation early during thrombolytic therapy in patients with anterior infarction suggests a favorable clinical outcome and thus may be indicative of successful reperfusion.     

Prognostic value of angiographic markers of myocardial reperfusion in patients treated with primary coronary angioplasty for anterior wall acute myocardial infarction

BACKGROUND: Modern therapy of acute myocardial infarction (AMI) is aimed at rapid and persisting restoration of blood flow in an infarct-related artery (IRA). However, in some patients myocardial reperfusion is not achieved in spite of effective IRA recanalisation. Myocardial Blush Grade (MBG) is one of the angiographic markers useful for the detection of this phenomenon. AIM: To assess the prognostic value of MBG in patients with anterior AMI treated with primary angioplasty. METHODS: The study group consisted of 104 patients (74 males, 30 females, mean age 62+/-13 years) treated with primary angioplasty due to anterior ST-segment elevation AMI. MBG was assessed after the procedure. The mortality and major cardiovascular event (MACE) rates were analysed one and six months after AMI. RESULTS: Patients with preserved myocardial reperfusion following angioplasty (MBG 2-3, n=64 (61.5%)) had a trend towards lower one-month mortality and significantly reduced six-month mortality compared with 40 (38.5%) patients with an impaired (MBG 0-1) myocardial reperfusion (3% vs 12.5%, NS; and 6.25% vs 20%, p<0.05, respectively). The rate of MACE was significantly lower in patients with rather than without reperfusion both after one and six months of follow-up (9.4% vs 27.5%, p=0.027 and 12.5% vs 42.5%, p<0.001, respectively). Compared with patients with a high MBG score, patients with altered reperfusion more frequently had diabetes (30% vs 12.5%, p=0.04), hypertension (67.5% vs 45%, p=0.043), longer time from the onset of symptoms to balloon inflation (355.9+/-199 min vs 215.5+/-113 min, p<0.001) and lower left ventricular ejection fraction, measured 3 days after AMI (43.3%+/-8 vs 47.4%+/-9, p=0.02). CONCLUSIONS: MBG has a significant prognostic value in patients with anterior AMI treated with primary angioplasty. Diabetes, hypertension and long delay of treatment are associated with the impairment of myocardial reperfusion.     

Acute Myocardial Infarction with Hyperoxemic Therapy (AMIHOT): a prospective, randomized trial of intracoronary hyperoxemic reperfusion after percutaneous coronary intervention.

OBJECTIVES: This study sought to determine whether hyperoxemic reperfusion with aqueous oxygen (AO) improves recovery of ventricular function after percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI). BACKGROUND: Hyperbaric oxygen reduces myocardial injury and improves ventricular function when administered during ischemia-reperfusion. METHODS: In a prospective, multicenter study, 269 patients with acute anterior or large inferior AMI undergoing primary or rescue PCI (<24 h from symptom onset) were randomly assigned after successful PCI to receive hyperoxemic reperfusion (treatment group) or normoxemic blood autoreperfusion (control group). Hyperoxemic reperfusion was performed for 90 min using intracoronary AO. The primary end points were final infarct size at 14 days, ST-segment resolution, and delta regional wall motion score index of the infarct zone at 3 months. RESULTS: At 30 days, the incidence of major adverse cardiac events was similar between the control and AO groups (5.2% vs. 6.7%, p = 0.62). There was no significant difference in the incidence of the primary end points between the study groups. In post-hoc analysis, anterior AMI patients reperfused <6 h who were treated with AO had a greater improvement in regional wall motion (delta wall motion score index = 0.54 in control group vs. 0.75 in AO group, p = 0.03), smaller infarct size (23% of left ventricle in control group vs. 9% of left ventricle in AO group, p = 0.04), and improved ST-segment resolution compared with normoxemic controls. CONCLUSIONS: Intracoronary hyperoxemic reperfusion was safe and well tolerated after PCI for AMI, but did not improve regional wall motion, ST-segment resolution, or final infarct size. A possible treatment effect was observed in anterior AMI patients reperfused <6 h of symptom onset.     

Value of t-wave direction with lead iii st-segment depression in acute anterior wall myocardial infarction: Electrocardiographic prediction of a “wrapped” left anterior descending artery

Background: Lead III ST-segment depression during acute anterior wall myocardial infarction (AMI) has been attributed to reciprocal changes. However, the value of the T-wave direction (positive or negative) in predicting the site of obstruction and type of the left anterior descending (LAD) artery is not clear and has not been studied before. Hypothesis: The aim of the study was to assess retrospectively the correlation between two patterns of lead III ST-segment depression, and type of LAD artery and its level of obstruction during first AMI. Methods: The study group consisted of 48 consecutive patients, admitted to the coronary care unit for first AMI, who showed ST-segment elevation in lead aVL and ST-segment depression in lead III on admission 12-lead electrocardiogram. The patients were divided by T-wave direction into Group 1 (n = 31), negative T wave, and Group 2 (n = 17), positive T wave. The coronary angiogram was evaluated for type of LAD (“wrapped”, i.e., surrounding the apex or not), site of obstruction (pre- or postdiagonal branch), and other significant coronary artery obstructions. Results: Mean lead III ST-segment depression was 1.99 ± 1.32 mm in Group 1 and 1.13 ± 0.74 mm in Group 2 (p = 0.004); mean ST-segment elevation in aVL was 1.35 ± 0.84 mm and 1.23 ± 0.5 mm, respectively (p = 0.5). A wrapped LAD was found in 12 patients (38.7%) in Group 1 and in 13 in Group 2 (76.4%) (p = 0.02). The sensitivity of lead III ST-segment depression with positive T wave to predict a wrapped LAD was 52%, and the specificity was 82% with a positive predictive value of 76%. On angiography, 25 patients (80%) in Group 1 and 13 (76%) in Group 2 had prediagonal occlusion of the LAD (p = 0.77 ). No significant difference between groups was found for right and circumflex coronary artery involvement or incidence of multivessel disease. Conclusions: The presence of lead III ST-segment depression with positive T wave associated with ST-segment elevation in aVL in the early course of AMI can serve as an early electrocardiographic marker of prediagonal occlusion of a “wrapped” LAD.     

Identification of the optimal electrocardiographic leads for detecting acute epicardial injury in acute myocardial infarction

Current coronary care electrocardiographic (ECG) monitoring techniques are aimed at detection of cardiac arrhythmias rather than myocardial ischemia. However, in patients with acute myocardial infarction (AMI) who undergo reperfusion therapy, monitoring ST-segment deviation could provide an early noninvasive indicator of coronary artery reocclusion. In this study, the admission 12-lead ECGs of patients with initial AMI were used to propose optimal lead locations for ST-segment monitoring. The study population was selected from consecutive Duke University Medical Center admissions during 1965 to 1981 who met the following inclusion criteria: chest pain for no more than 8 hours, initial AMI documented by ECG and 3 of 4 enzyme criteria, greater than or equal to 0.1 mV (1 mV = 10 mm) of ST elevation in at least 1 of the standard 12 leads (not aVR) on admission ECG, and no ECG evidence of conduction disturbances, ventricular hypertrophy or tachycardia. ST-segment deviation was quantified; AMI location was assigned based on the lead with maximal deviation. Of the 80 patients who had an inferior AMI, lead III was both the most frequent location for ST elevation (94%) and the most common site with maximal ST deviation. Lead V2 had the highest incidence of ST-segment depression (60%). In the 68 patients who had an anterior AMI, lead V2 had the highest frequency of ST elevation (99%). Leads V2 and V3 were the most common sites of maximal elevation. Thus, for monitoring ST deviation, leads III and V2 may be superior to leads II and V1, which are commonly used in arrhythmia monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)