Sum Of ST-segment Elevation Research Articles

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.

Prediction of Early Complications in Patients With Acute Myocardial Infarction by Calculation of the ST Score

Study objective: To assess the relationship between the sum of ST-segment elevations (ST score) in the admission ECG and the occurrence of early complications in patients with acute myocardial infarction (MI). Methods: We conducted an observational study of patients who presented with acute anterior or inferior MI to the ED of a 2,000-bed inner-city hospital. Age, sex, time from onset of pain and the start of thrombolysis, and ST score were evaluated by the emergency physician. “Early complications” were defined as acute congestive heart failure or severe rhythm disturbances in the 24 hours after the start of thrombolysis. The outcome measures were the relationship between ST score and the occurrence of early complications; the influence of age, sex, or time between onset of pain and thrombolysis; and identification of a cutoff value with the highest sensitivity and specificity for prediction of complications. Results: We included 243 patients (194 men, 49 women; mean age, 56.6 years) with acute MI (anterior, 119; inferior, 124) who underwent thrombolysis in our analysis. ST score was significantly greater in patients with early complications, compared with patients without complications (anterior, 10.3 versus 19.4 mm [ P<.001]; inferior, 6.9 versus 10.4 mm [ P<.001]). Receiver-operator curve analysis revealed an ST score of 13 mm in patients with anterior MI and 9 mm in patients with inferior MI as the cutoff value with the greatest sensitivity and specificity for predicting early complications of MI. (For anterior MI, sensitivity was .79, specificity .73; for inferior MI, sensitivity was .64 and specificity .68.). On multivariate regression analysis, ST score was an independent predictor of the occurrence of at least one complication. (For anterior MI, the odds ratio [OR] was 9.7 and the 95% confidence interval [CI] 3.9 to 25.1; for inferior MI the OR was 5.0 and the 95% CI 2.0 to 12.8). Age, sex, and interval from onset of pain to treatment had no significant effect on the occurrence of early complications. Conclusion: The absolute ST score is useful in estimating the probability of early complications in patients with acute MI receiving thrombolytic therapy. A cutoff value of 13 mm for anterior MI and 9 mm for inferior MI stratifies patients into high- and low-risk subgroups for the development of acute congestive heart failure and severe rhythm disturbances during the first 24 hours of hospitalization. [Gwechenberger M, Schreiber W, Kittler H, Binder M, Hohenberger B, Laggner A, Hirschl MM: Prediction of early complications in patients with acute myocardial infarction by calculation of the ST score. Ann Emerg Med November 1997; 30:563-570.]

Prognostic value of clinical markers of reperfusion in patients with acute myocardial infarction treated by thrombolytic therapy

Patients who cannot be reperfused after thrombolytic therapy have a high mortality rate. Noninvasive clinical markers of reperfusion have been widely studied, yet their prognostic significance remains unclear. To assess the prognostic value of commonly used noninvasive clinical markers of early reperfusion we studied 327 patients who received intravenous thrombolytic treatment (1.5 MU streptokinase in 1 hour or 100 mg alteplase in 3 hours) within 6 hours of acute infarction. Successful clinical reperfusion (SCR) was defined as the presence of at least two of the following criteria at 2 hours after thrombolytic treatment: (1) significant relief of pain (a 5-point reduction on a 1 to 10 subjective scale), (2) ≥50% reduction of sum of ST segment elevation, and (3) abrupt initial increase of creatine kinase levels (more than twofold over the upper-normal or baseline elevated values). Clinical variables that were significantly associated by univariate analysis were tested by multivariate analysis to obtain independent predictors of 30-day mortality rate. SCR was present in 210 (64%) patients (group 1), and absent in 117 (36%) patients (group 2). The groups were similar for most baseline characteristics, although group 2 patients were slightly older (mean 60 vs 57 years, p < 0.02). Thirty-day outcomes for group 2 patients compared with group 1 patients were heart failure in 23.1% and 10.5% ( p < 0.005), progression to cardiogenic shock in 12.8% and 0.5%, ( p < 0.00001), and death in 16.2% and 3.8% ( p < 0.0001), respectively. By multivariate analysis the Killip class at admission ( p < 0.00001), the absence of SCR ( p = 0.017), anterior infarct location ( p = 0.021), and age ( p = 0.03) were independent predictors of mortality rate, and sex ( p = 0.051) had borderline significance. The absence of SCR defined a group of patients with significantly higher mortality rate (odds ratio 4.89, 95% confidence interval 2.07 to 11.57). Three simple noninvasive clinical criteria of successful reperfusion may be used to identify a group of patients with poor prognosis after thrombolytic therapy in whom alternative strategies could be applied. (Am Heart J 1997;134:631-8.)

Significance of initial ST segment changes for thrombolytic treatment in first inferior myocardial infarction.

OBJECTIVE: To evaluate the benefit to risk ratio of thrombolytic treatment in patients with small inferior acute myocardial infarction (AMI). Controlled studies relating the benefit from thrombolysis with initial electrocardiographic...

Sum of ST-segment elevations on admission electrocardiograms in acute myocardial infarction predicts left ventricular dilation

In summary, ST-segment elevations on the admission electrocardiogram not only diagnose acute myocardial infarction but also provide predictive information with respect to developing infarct size and left ventricular remodeling as well as survival.

Predicting postinfarction left ventricular dysfunction based on the configuration of the QRS complex and ST segment in the initial ECG of patients with a first anterior wall myocardial infarction.

The objective of the study was to identify patients with anterior wall acute myocardial infarction (AMI) at high risk of postinfarction left ventricular dysfunction (LVD). This study population included all patients admitted with a diagnosis of anterior wall AMI (ST segment elevation of > 1 mm in 2 or more precordial leads) without history or ECG evidence of antecedent AMI,who underwent assessment of left ventricular ejection fraction (LVEF) during emergency hospitalization. ST segment deviation from baseline was measured manually 0.08 s after the J point in all leads. Patients (n = 81) were classified into two groups based on the configuration of the QRS complex and ST segment: ST > 1 mm with preserved (pattern A; n = 60) or distorted terminal QRS (emergence of the J point at a level above the lower half of the R wave or disappearance of the S wave in leads with an Rs configuration; pattern B; n = 21). LVD (LVEF < 40%) was significantly more prevalent in patients with pattern B than pattern A (48 vs. 12%; p = 0.002). There was no correlation between the number of leads with ST segment elevation and LVD (p = 0.47). The sum of ST segment elevation in involved leads correlated weakly, yet significantly with LVEF (R = -0.22; p < 0.05). In conclusion, patients with anterior wall AMI and pattern B in the initial ECG are at high risk of post-AMILVD.

The initial electrocardiogram pattern is a strong predictor of outcome in acute myocardial infarction

We analyzed the significance of the initial electrocardiogram on the clinical outcome of 205 consecutive patients with a first myocardial infarction. Three different patterns of the electrocardiogram were defined: (A) Tall symmetric T waves in the involved leads; (B) ST segment elevation >0.1 mV in two or more adjacent leads; and (C) ST segment elevation together with distortion of the terminal portion of the QRS complex in two or more adjacent leads. Twelve patients were considered to have an initial ‘A’ electrocardiogram, 151 an initial ‘B’ electrocardiogram, and 42 an initial ‘C’ electrocardiogram. Four factors were significantly related to mortality: age, ST, Killip class and electrocardiographic pattern. The mortality rate was 0% in group A, 7.9% in group B, and 26.2% in group C ( P = 0.0019). Patients with type C electrocardiograms had a significantly worse Killip classification and a significantly higher sum of ST segment elevation. Among patients with inferior infarction, the mortality rate was 1.4% in type B vs. 24.1% in type C ( P = 0.0005). Among patients with anterior infarction, the mortality rate was 13% in type B vs. 30.8% in type C ( P = 0.089). We conclude that the pattern of the initial electrocardiogram is a strong predictor of outcome in acute myocardial infarction, especially if it is inferior.

Isoproterenol induces ST-segment elevation without wall motion aggravation and myocardial ischemia in experimental myocardial infarction

The mechanism of exercise-induced ST-segment elevation in previous myocardial infarction was investigated using isoproterenol infusion with atrial pacing to simulate exercise hemodynamics in seven closed chest dogs with myocardial infarction. The myocardial infarction was induced by cellulose embolization of the left anterior descending artery. One week after infarction, 1) isoproterenol 0.3 microgram/min infusion, 2) right atrial pacing alone, and 3) isoproterenol infusion after the injection of propranolol 0.5 mg/kg were performed. The heart rate was kept constant by atrial pacing during the examination. Precordial ST-segment deviation, left ventricular global and regional wall motions, lactate extraction ratio, and regional myocardial blood flow were measured. Isoproterenol induced a significant elevation of the ST-segment, i.e., the sum of ST-segment elevation at chest leads V2, V3 and V4, sigma STV234, increased from 0.32 +/- 0.11 (mean +/- SEM) to 0.82 +/- 0.22 mV (p < 0.01). However, pacing alone and isoproterenol with pretreated propranolol did not. During isoproterenol-induced ST-segment elevation, left ventricular ejection fraction increased (29.2 +/- 3.3 to 39.1 +/- 3.9%, p < 0.01), lactate extraction ratio decreased but within the normal range for lactate metabolism (30.2 +/- 7.0 to 16.7 +/- 4.2%, p < 0.01), and the inner/outer ratio of regional blood flow did not change significantly (0.81 +/- 0.18 to 0.97 +/- 0.13 in the non-infarct border area, NS; 0.37 +/- 0.04 to 0.42 +/- 0.07 in the infarct border area, NS). Isoproterenol enhanced ventricular wall motion in the border and non-infarct areas, but did not induce aggravation in the infarct area.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison using dynamic vectorcardiography and MIBI SPECT of ST-segment changes and myocardial MIBI uptake during percutaneous transluminal coronary angioplasty of the left anterior descending coronary artery

The quantitative relation between ST-segment changes and the severity and extent of myocardial ischemia during coronary occlusion remains unclear. This study assesses whether ST-segment changes during percutaneous transluminal coronary angioplasty (PTCA) correlate with the amount of myocardium at risk, measured with technetium-99m hexakis 2-methoxyisobutyl isonitrile (MIBI; also called sestamibi) single-photon emission computed tomography (SPECT). Quantitative continuous dynamic vectorcardiography was performed during PTCA of the left anterior descending coronary artery in 11 patients (mean age 64.3 years) without previous myocardial infarction. Change in the magnitude of the ST vector (STc-VM) was continuously recorded. A standardized protocol of balloon inflations was used and technetium-99m MIBI was injected intravenously at the onset of the third inflation. SPECT imaging was performed 60 minutes later and compared to a rest acquisition. SPECT was quantified by bull's-eye analysis using: (1) the change in the pathologic/normal area count ratio ( ΔP N ) as an index of the severity of ischemia; and (2) planimetered defect size during PTCA as an indicator of the size of the area at risk. The ΔP N from baseline to balloon occlusion (22 ± 11%) was correlated, albeit loosely, ta the maximum value of STc-VM (245 ± 186 μV, r = 0.62, p < 0.05), but there was no correlation between the size of the scintigraphic defect and STc-VM. Likewise, the sum of ST-segment elevation was correlated to ΔP N (r = 0.72, p < 0.02), but not ta the size of the scintigraphic defect. In conclusion, ST changes induced by coronary occlusion during PTCA are mostly related to the severity of ischemia rather than to the size of the area at risk. During coronary occlusion, ST changes provide only a crude estimate of the amount of jeopardized myocardium.

790-2 Baseline Electrocardiogram Predicts 30-day Mortality Among 32,812 Patients with Acute Myocardial Infarction Treated with Thrombolysis

To determine the initial electrocardiographic variables predictive of survival among patients with acute myocardial infarction, we analyzed the baseline 12-lead ECGs in 32,812 patients enrolled into the GUSTO trial. All patients had ≥ 0.1 mV of ST segment elevation in at least one lead and received thrombolytic therapy. Those with LBBB or ventricular rhythm were excluded from analysis. Clinical follow-up was &gt; 99.5% complete. 2218 (6.8%) patients died within 30 days of the initial ECG. Death within 30 days was more common in patients with RBBB (17%), LAFB (14%), and LPFB (17%), than in those with a normal conduction pattern (6%). Patients with ECG evidence of previous MI in a location distinct from the acute MI had a higher risk of death (9.8% vs. 5.9%) than those without prior infarction (p &lt; 0.0001). The variable having the greatest univariate predictive power for 30-day survival was the sum of the absolute ST-segment deviation in each lead ( x 2 = 341), as shown in the following mortality curve. Other ST segment variables that predicted 30-day survival were the sum of ST-segment elevation in each lead (x 2 = 287). the maximum ST elevation in anyone lead ( X 2 = 257), and the number of leads with ST elevation ( x 2 = 250). When multivariate modeling was performed the sum of the absolute ST deviations, number of leads with ST elevation, prior ECG MI, RBBB, and LAFB each added independent prognostic information. We conclude that an ECG at the time of presentation contains substantial prognostic information which can be used to help stratify risk among thrombelytic-treated patients with acute myocardial infarction.

QT dispersion does not predict early ventricular fibrillation after acute myocardial infarction.

Ventricular arrhythmias may be associated with increased QT dispersion (difference between maximum and minimum QT on standard 12-lead ECG). We performed a case control study to determine if QT dispersion on the admission ECG could predict early VF after acute myocardial infarction. The cases were 24 patients with acute myocardial infarction (14 inferior, 8 anterior, and 2 lateral) with VF within 12 hours of admission. There were 24 control patients without VF matched for site of infarction and ST segment score (sum of ST segment elevation). VF occurred a median of 153 minutes (interquartile range 93-245) after onset of chest pain and 33 minutes (range 7-104) after initial ECG. QT (399 +/- 37 and 394 +/- 37), QT corrected (440 +/- 38 and 429 +/- 29), and QT dispersion (68 +/- 20 and 66 +/- 27) were similar in patients and controls. By design, ST score was similar (11 +/- 9 vs 9 +/- 5 mV), although a good match could not be obtained for three patients with extreme ST elevation. Patients with VF presented to the hospital earlier after the onset of chest pain (median 95 min [range 65-188] compared to 150 min [range 80-270], P = 0.05) and had a lower serum sodium (138 +/- 2.4 vs 140 +/- 2.5, P = 0.05) than controls. Thus, QT interval and QT dispersion, measured on the presenting ECG, did not predict early VF after myocardial infarction.

Clinical Utility of Electrocardiographic ST-Segment Area for Predicting Unsatisfactory Outcomes Following Thrombolytic Therapy.

The bedside surface 12-lead electrocardiogram is a mainstay in the early diagnostic evaluation of patients with suspected acute myocardial infarction. The presence of ST-segment elevation exceeding 1.0 mm in two or more anatomically associated leads is a reliable marker of myocardial injury and, when considered along with concomitant ST-segment depression, reflects the extent of myocardial injury. Mounting evidence also suggests that prolonged repolarization is a marker of injury and predicts the likelihood of malignant ventricular arrhythmias. We questioned whether a measure of both ST-segment duration and deviation (ST-deviation area) would offer additional prognostic information. Methods/Results: Admission electrocardiograms from 200 consecutive patients with ischemic chest pain accompanied by ST-segment elevation in whom thrombolytic therapy was given within 6 hours from symptom onset were analyzed. The sum of ST-segment elevation (Sigma ST elevation) and ST-segment deviation (Sigma ST deviation) were calculated, as was the sum of ST-segment deviation area (Sigma ST deviation area). All ST measurements were performed 60 msec after the J point. Computerized planimetry was used to calculate ST-segment area. Sigma ST deviation and Sigma ST deviation area remained constant over time. Patients with large deviations (Sigma ST elevation > 20 mm (odds ratio 2.14, p = 0.02) and Sigma ST deviation area > 150 (odds ratio 1.92, p = 0.02) had a higher incidence of in-hospital unsatisfactory clinical outcome (defined as death, congestive heart failure, cardiogenic shock, recurrent myocardial infarction, or the need for coronary revascularization). These relationships were present for both inferior and anterior infarctions. Sigma ST deviation area correlated closely with Sigma ST elevation (r = 0.92; p = 0.0001) and significantly but much less strongly with the sum of Q waves (r = 0.18; p = 0.01). By univariate analysis, only site of infarction (p = 0.01), Sigma ST deviation area (p = 0.04), and the sum of Q waves (p = 0.005) were identified as predictors of a poor clinical outcome. The sum of Q waves was identified by multivariate analysis as the best independent predictor of an unsatisfactory clinical outcome. Conclusions: A clinician's ability to provide optimal care is influenced strongly by the availability of diagnostic and prognostic information. In the evaluation of patients with acute myocardial infarction, ST-segment deviation area derived from the admission surface electrocardiogram can be used to risk-stratify patients. The full clinical potential of this measure is unknown and will require further evaluation.

A simple electrocardiographic predictor of the outcome of patients with acute myocardial infarction treated with a thrombolytic agent: A Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-2)-derived analysis

Objectives. This analysis aimed to evaluate in a large patient cohort the relation between ST segment alterations after fibrinolytic therapy for acute myocardial infarction and 1) the combined end point of in-hospital mortality plus clinical congestive heart failure or extensive left ventricular damage, and 2) mortality 30 and 180 days after randomization.Background. Angina relief, enzyme release acceleration and ST segment normalization are related to coronary artery reperfusion and prognosis. Electrocardiographic (ECG) evaluation before and after fibrinolytic drug administration has been used to predict short-and long-term clinical outcome in acute myocardial infarction.Methods. Patients enrolled in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-2) trial underwent a standard ECG on admission and after 4 h of alteplase or streptokinase therapy; 7,426 recordings were suitable for ST segment analysis. A decrease ≥ 50% in the sum of ST segment elevation in all ECG leads was adopted as the cutoff for predicting coronary artery patency. Recanalization was deemed to have occurred in 4,951 patients (group A) versus 2,475 patients without reperfusion (group B).Results. Group A patients experienced a lower incidence of the combined end point than did group B patients (16.2% vs. 22.9%, respectively), as well as of all its components (death, clinical heart failure, ejection fraction < 35%, injured myocardial segment > 45%, QRS score > 10). Thirty- and 180-day mortality rates were lower in group A than group B (3.5% and 5.7% vs. 7.4% and 9.9%, respectively); relative risk (Cox) was 0.46 (95% confidence interval [CI] 0.37 to 0.57) for 30-day and 0.58 (95% CI 0.48 to 0.70) for 180-day mortality. Patients in group A had significantly less ventricular fibrillation and sustained ventricular tachycardia but more ischemic episodes (early recurrent angina plus myocardial infarction recurrence).Conclusions. A simple, inexpensive instrumental evaluation, unaffected by different epidemiologic and clinical characteristics of the population analyzed, can allow early assessment of the effectiveness of fibrinolytic treatment with respect to the main clinical outcomes.

Serum Lp(a) lipoprotein concentration and outcome of thrombolytic treatment for myocardial infarction.

Lp(a) lipoprotein has structural homology with plasminogen and has been shown to inhibit plasminogen activation in vitro. To determine whether the serum concentration of Lp(a) lipoprotein present when streptokinase was given in acute myocardial infarction influenced the outcome as judged by electrocardiographic methods. Serum Lp(a) lipoprotein concentration was measured in 135 consecutive patients admitted with a diagnosis of acute myocardial infarction who received streptokinase treatment. Recovery from myocardial injury was assessed by the reduction in the sum of ST segment elevation measured from the J point (STJ) in the electrocardiogram immediately before streptokinase was given compared with that three hours later. The serum Lp(a) lipoprotein concentrations were measured within 12 hours of the onset of symptoms of myocardial infarction and were higher than in healthy reference populations. Recovery from myocardial infarction could be assessed from the STJ in 116 patients (86% of the series). Those in whom it could not had bundle branch block, left ventricular hypertrophy, did not survive three hours, or had started intravenous nitrate treatment or some other clinical procedure before or at the time the second electrocardiogram was to be recorded. Patients with reductions in STJ after streptokinase that were > 4 mm (the median decrease) had mean (range) serum Lp(a) lipoprotein concentrations of 41.0 (0.8-220) mg/dl and those with a smaller reduction in STJ had concentrations of 29.1 (1.7-151) mg/dl. The difference was not statistically significant. In this study Lp(a) lipoprotein concentration did not significantly influence the outcome of thrombolytic treatment with streptokinase.

Impact of the electrocardiogram on the delivery of thrombolytic therapy for acute myocardial infarction

The initial electrocardiogram is crucial in accurately selecting patients with chest pain for thrombolytic therapy. An electrocardiogram with a large amount of ST-segment elevation and depression is “visually alarming,” and therefore, may influence the efficiency of patient treatment with thrombolytic therapy. It was hypothesized that the amount of ST-segment deviation present on the initial electrocardiogram was an important variable in determining the time to initiation of thrombolysis in the emergency department The time from arrival at the emergency department to thrombolysis was measured in 93 consecutive patients with suspected acute myocardial infarction (AMI) who were treated with intravenous thrombolytic therapy by emergency department physicians. This was correlated with the sum of ST-segment elevation and depression present on the initial electrocardiogram. AMI was proved in 83 patients (89%). In patients with proved AMI, the average time to thrombolysis was 50.8 ± 25.6 minutes. Treatment began within the goal of ≤30 minutes in 18 patients (22%) and was excessively delayed at ≥ 60 minutes in 24 (29%). Regression analysis of multiple clinical variables revealed that ST-segment sum was the only variable that significantly influenced the time to thrombolysis (r = −0.42; p < 0.001). For patients treated in ≤30 minutes, the average ST-segment sum was 21.1 ± 13.5 vs 11.5 ± 11.4 mm for those treated in ≥60 minutes (p = 0.01). In 10 patients mistakenly treated with thrombolytic therapy, the electrocardiographic processes responsible for ST-segment elevation included the early repolarization variant, left ventricular hypertrophy, old anterior AMI with persistent ST-segment elevation, and conduction delay. The amount of ST-segment deviation present on the initial electrocardiogram is a significant factor influencing patient treatment with thrombolytic therapy. Efforts to improve the delivery of thrombolytic therapy in the emergency department should include a focus on electrocardiographic interpretation skills.

ST-segment re-elevation and left ventricular expansion soon after acute anterior myocardial infarction.

The sum of ST-segment elevation (sigma ST on V2-4) was measured to evaluate ST-segment re-elevation during early convalescence in 57 patients with acute myocardial infarction. Following rapid ST-segment elevation resolution during the first 12 h, sigma ST again increased in many patients without signs of reinfarction or pericarditis, reaching a maximum approximately 5 days after onset. The magnitude of this re-elevation (delta sigma ST) was less than 0.3 mV in 30 patients (group A), and 0.3 mV or more in another 27 (group B). Based upon left ventriculography, the global ejection fraction in group B decreased significantly from 51 +/- 10% at the acute phase to 46 +/- 10% at the chronic phase. No such decreases were seen for group A. Regional ejection fraction in the infarcted portion improved significantly from 28 +/- 13% at the acute phase to 35 +/- 14% at the chronic phase in group A, but did not improve in group B. In addition, the non-infarcted portion in group B showed a significantly reduced regional ejection fraction. These results suggest that myocardial expansion of the infarcted portion may contribute to ST-segment re-elevation, an ominous sign of left ventricular dysfunction soon after acute myocardial infarction.

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 < 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.

Prediction of preserved flow to the infarct area based on admission electrocardiogram in anterior wall acute myocardial infarction

To determine whether preserved flow to the infarct area could be predicted from the admission electrocardiogram and to define the effect of preserved flow on the late results after reperfusion, 20 anterior myocardial infarction patients who were successfully reperfused were studied. Patients were divided into 3 groups: (1) no-flow group (8 patients), with an occluded infarct-related artery and no easily visible collaterals; (2) intact collateral group (6 patients); and (3) subtotal obstruction group (6 patients). From the admission electrocardiogram, the sum of ST-segment elevation (ΣST), the sum of R-wave amplitude (ER) in leads V 1 through V 6 and the ratio of these (ΣR/ΣST) were measured. There was no significant difference in ΣR among the 3 groups. The no-flow group had significantly lower ΣR/ΣST and higher ΣST than the intact collateral group or subtotal obstruction group. All patients (6 of 6) with subtotal obstruction and all except 1 patient (5 of 6) with intact collateral showed ΣR/ΣST >2.5 or ΣST <2.0 mV. All patients (8 of 8) with no flow showed ΣR/ΣST ≤2.5 and all except 1 patient with no flow (7 of 8) showed ΣST ≥2.0 mV. The regional wall motion was assessed by the radial method at 4 weeks. The mean percentage systolic shortening in the anterior and apical regions was significantly correlated with ΣR/ΣEST (r = 0.75, p <0.001) and ΣST (r = −0.65, p <0.005). Thus, the admission electrocardiographic finding of ΣR/ΣST >2.5 or ΣST <2.0 mV indicated a preserved flow to the infarct area and relatively good regional wall motion in the convalescent stage after successful reperfusion in patients presenting with their first anterior wall acute myocardial infarction.

Rapid enzyme release from acutely infarcted myocardium after early thrombolyic therapy: Washout or reperfusion damage?

In a randomized study on early intracoronary thrombolytic therapy in patients with acute myocardial infarction (AMI), serial plasma enzyme activities were measured to analyze the rate of enzyme appearance in plasma with reference to treatment allocation, area at risk, and infarct size. Cumulative activities of α-hydroxybutyrate dehydrogenase (HBDH) appearing in plasma in the first 24 hours (Q 24), 48 hours (Q 48), and 72 hours (Q 72) were calculated to obtain infarct size (= Q 72) and rate of HBDH appearance in plasma (= Q 24/Q 72). Analyzed on the bans of “intention to treat” in 448 patients with AMI, the mean Q 24/Q 72 value (± SEM) was 0.653 ± 0.011 in 230 patients receiving thrombolytic therapy; this value was significantly ( p < 0.001) higher than that observed in 218 patients receiving conventional therapy (0.504 ± 0.012). In the thrombolysis group Q 24/Q 72 was independent of infarct size, whereas in the control group Q 24/Q 72 was negatively correlated with Infarct size ( r = −0.26; p < 0.001). Plotted against the sum of ST segment elevations at admission (ΣST) mean Q 24 values were similar in both treatment groups, but mean Q 48 and especially Q 72 values were larger in the control group than in the thrombolysis group. We conclude that: (1) in reperfused infarctions the time course for development of infarct is accelerated in comparison to unreperfused infarcts; (2) this accelerated process of necrosis lasts about 40 to 50 hours, a duration that is hardly influenced by infarct size; and (3) the reperfusion-induced acceleration of enzyme release resembles the reoxygenation-induced enzyme release from anoxic hearts. These conclusions strongly argue against washout as a factor mainly responsible for the reperfusion-induced rapid enzyme appearance in plasma.

Prospective analysis of electrocardiographic variables as markers for extent and location of acute wall motion abnormalities observed during coronary angioplasty in human subjects

To assess the usefulness of different electrocardiographic variables as markers for the presence, extent and location of new wall motion abnormalities seen after sudden controlled coronary occlusion, 23 patients with isolated left anterior descending (n = 12), or right (n = 11) coronary artery disease and a normal baseline left ventriculogram were prospectively studied during transluminal coronary angioplasty. A simultaneous 12 lead electrocardiogram was recorded before passing the balloon catheter and again at 30 seconds into the fourth inflation cycle. Using a second arterial catheter, a left ventriculogram was obtained at 40 seconds into the fourth inflation cycle. The extent of wall motion abnormalities was described as the percent of left ventricular perimeter showing hypocontractility. During balloon inflation, 19 of the 23 patients developed new hypocontractility ranging from 3 to 40%. ST segment elevation in lead V2 was the most sensitive marker for anterior wall hypocontractility and ST segment elevation in lead III was the most sensitive marker for inferior wall hypocontractility. Highly significant correlations were observed between the extent of the hypocontractile perimeter and 1) the sum of ST segment elevation in all 12 leads; 2) the magnitude of ST segment elevation in either lead V2 or lead III; and 3) the total number of leads with ST elevation greater than or equal to 0.5 mV. No significant changes were seen in the sum of R wave amplitudes, but a significant prolongation of the QT interval was seen during ischemia. In conclusion, acute ST segment elevation parallels the development of new asynergy during transluminal coronary angioplasty.(ABSTRACT TRUNCATED AT 250 WORDS)