Sudden increase of the ST segment elevation at time of reperfusion predicts extensive infarcts in patients with intravenous thrombolysis

Characteristics, Management, and Outcome of Transient ST-elevation Versus Persistent ST-elevation and Non-ST-elevation Myocardial Infarction

Patients with acute myocardial infarctions (AMIs) present as persistent ST-elevation myocardial infarction (STEMI) or as non-ST-segment elevation myocardial infarction (NSTEMI). In some patients with STEMI, ST elevations are transient and resolve before coronary intervention (transient ST-elevation myocardial infarction [TSTEMI]). We analyzed our registry comprising all consecutive patients with AMI admitted during 2009 to 2014, and compared the characteristics, management, and outcome of patients with TSTEMI with those of patients with STEMI and NSTEMI. Of 1,847 patients with AMI included in the registry, 1,073 patients sustained a STEMI (58%), 649 had a NSTEMI (35%), and 126 presented with TSTEMI (6.9%). Patients with TSTEMI were younger than patients with NSTEMI and STEMI (56.5 vs 62.8, p <0.001, and 59.5 years, p <0.02, respectively), smoked more (77.8 vs 54.0, p <0.001, and 62.1%, p <0.0005), and fewer were hypertensive (52.4 vs 74.2% and 58.8%, both p <0.001) and diabetic (26.2% vs 47.7%, p <0.0001, and 36.9%, p <0.02). The extent of coronary artery disease in patients with TSTEMI was similar to that of patients with STEMI except for less involvement of the left anterior descending artery (p <0.001), but less extensive than in NSTEMI patients. TSTEMI involved less myocardial damage by troponin-T level (p <0.005) with better cardiac function (LVEF 61% vs 55% and 49%, both p <0.0001). Mortality was lower among TSTEMI both in-hospital (0 vs 2.3% [p = NS] and 4.2% [p <0.01]) and long-term (4.8% vs 14.7% and 14.2%, both p <0.003) at a median of 36 months. In conclusion, TSTEMI is an acute coronary syndrome distinct from NSTEMI and STEMI, characterized by fewer risk factors, a similar extent of coronary artery disease to STEMI, but is associated with less myocardial damage and portends a better outcome.

Significance of additional ST segment elevation in patients with no reflow after angioplasty for acute myocardial infarction

OBJECTIVES

We sought to evaluate the incidence, timing, and clinical significance of additional increase in ST segment elevation (ST-SE) in patients showing no reflow after angioplasty for acute myocardial infarction.

METHODS

We studied 26 patients with acute myocardial infarction showing myocardial contrast echocardiography no reflow after successful angioplasty. Baseline and 6-month 2-dimensional echocardiograms were obtained in 21 surviving patients.

RESULTS

After angioplasty, 13 patients showed greater than 30% additional increase in ST-SE (group 1), whereas 13 did not (group 2). Baseline clinical, echographic, and angiographic characteristics, and 6-month patency and restenosis rate, were similar between the two groups. From baseline to 6 months, a similar global and regional systolic function was found between the two groups, whereas a higher increase in left ventricular end-diastolic volume occurred in group 1 (135 +/- 45 vs 168 +/- 42 mL, P = .033). The additional increase in ST-SE was not associated with more severe microvascular damage (myocardial contrast echocardiography score index: 0.14 +/- 0.26 vs 0.22 +/- 0.27), higher peak creatine kinase value (4888 +/- 2533 vs 3109 +/- 2055 U/L, P = .061), higher incidence of left ventricular remodeling (73% vs 60%, P = .537), or worse outcome (26 +/- 24 months) such as death (15% vs 23%, P = .619), hospitalization for heart failure (8% vs 23%, P = .277), or reinfarction (8% vs 0%, P = .308).

CONCLUSIONS

Our data show that in patients showing no reflow after angioplasty a transient additional increase in ST-SE occurs in half of patients. The prognostic value of additional increase in ST-SE remains uncertain in the era of primary angioplasty.

Reperfusion phenomenon is a strong predictor of left ventricular remodeling after acute myocardial infarction

BACKGROUND

Many clinicians have seen the reperfusion phenomenon, a paradoxical response that includes a transient increase of chest pain, additional ST-segment elevation or ventricular arrhythmias immediately after coronary reperfusion, in patients with acute myocardial infarction (AMI). The aim of the present study was to investigate the impact of this phenomenon during coronary reperfusion on left ventricular (LV) remodeling in patients with AMI.

METHODS AND RESULTS

One hundred and thirty-eight consecutive patients with a first anterior-wall AMI, undergoing coronary reperfusion treatment within 24 h of onset were prospectively evaluated for reperfusion phenomenon and followed up with scheduled evaluations of LV function and morphology with left ventriculography for 1 year. Of the 138 enrolled patients, 77 underwent serial left ventriculography at the acute, subacute and 1-year phases. Of these 77 patients, 39 demonstrated the reperfusion phenomenon. The LV end-diastolic volume index significantly increased from the acute to subacute phase and to the 1-year phase, but was unchanged in the 38 patients without reperfusion phenomenon. In multivariate analysis, reperfusion phenomenon was the only determinant of LV dilatation after AMI.

CONCLUSIONS

Reperfusion phenomenon was a strong predictor of LV remodeling after reperfusion therapy for AMI.

Significance of Neutrophil Counts After Reperfusion Therapy in Patients With a First Anterior Wall Acute Myocardial Infarction

BACKGROUND

Previous studies have demonstrated that an elevated neutrophil count on admission is associated with a higher risk of adverse events after acute myocardial infarction (AMI). However, the significance of the neutrophil count after reperfusion therapy has not been elucidated.

METHODS AND RESULTS

The association of the neutrophil count on admission and days 2 and 3 with peak creatine kinase (CK) concentration, ST-segment resolution (a marker of myocardial tissue-level reperfusion), and left ventricular (LV) function at predischarge were examined in 122 patients (102 men, 20 women, mean age 61+/-11 years) with a first anterior wall AMI. Neutrophil counts were increased on day 2 and decreased on day 3 compared with admission (8,768+/-3,005 mm3, 6,617+/-2,424 mm3, and 7,725+/-3,388 mm3, respectively). Patients with ST-segment resolution (n=52) had lower neutrophil counts on days 2 and 3 than those without it (n=70), but neutrophil counts on admission did not differ significantly between patients with and without ST-segment resolution. Neutrophil counts on admission and days 2 and 3 were weakly but significantly correlated with peak CK concentration (r=0.31, p=0.0004; r=0.43, p<0.0001; r=0.32, p=0.003, respectively) and with LV ejection fraction at predischarge (r=-0.18, p=0.04; r=-0.26, p=0.003; r=-0.27, p=0.003; respectively).

CONCLUSION

The neutrophil count after reperfusion is weakly but significantly correlated with infarct size, myocardial tissue-level reperfusion, and LV function at predischarge in a first anterior wall AMI. These correlations were slightly stronger than the correlations with the neutrophil count on admission.

Pharmacological prevention of reperfusion injury in acute myocardial infarction. A potential role for adenosine as a therapeutic agent

The concept of reperfusion injury, although first recognized from animal studies, is now recognized as a clinical phenomenon that may result in microvascular damage, no-reflow phenomenon, myocardial stunning, myocardial hibernation and ischemic preconditioning. The final consequence of this event is left ventricular (LV) systolic dysfunction leading to increased morbidity and mortality. The typical clinical case of reperfusion injury occurs in acute myocardial infarction (MI) with ST segment elevation in which an occlusion of a major epicardial coronary artery is followed by recanalization of the artery. This may occur either spontaneously or by means of thrombolysis and/or by primary percutaneous coronary intervention (PCI) with efficient platelet inhibition by aspirin (acetylsalicylic acid), clopidogrel and glycoprotein IIb/IIIa inhibitors. Although the pathophysiology of reperfusion injury is complex, the major role that neutrophils play in this process is well known. Neutrophils generate free radicals, degranulation products, arachidonic acid metabolites and platelet-activating factors that interact with endothelial cells, inducing endothelial injury and neutralization of nitrous oxide vasodilator capacity. Adenosine, through its multi-targeted pharmacological actions, is able to inhibit some of the above-mentioned detrimental effects. The net protective of adenosine in in vivo models of reperfusion injury is the reduction of the infarct size, the improvement of the regional myocardial blood flow and of the regional function of the ischemic area. Additionally, adenosine preserves the post-ischemic coronary flow reserve, coronary blood flow and the post-ischemic regional contractility. In small-scale studies in patients with acute MI, treatment with adenosine has been associated with smaller infarcts, less no-reflow phenomenon and improved LV function. During elective PCI adenosine reduced ST segment shifts, lactate production and ischemic symptoms. During the last years, three relatively large placebo-controlled clinical trials have been conducted: Acute Myocardial Infarction Study of Adenosine Trial (AMISTAD) I and II and Attenuation by Adenosine of Cardiac Complications (ATTACC). In the AMISTAD trials, the final infarct size was reduced and the LV systolic function was improved by adenosine treatment, mainly in patients with anterior MI localization. However, morbidity and mortality were not affected. In the ATTACC study, the LV systolic function was not affected by adenosine, however, trends towards improved survival were observed in patients with anterior MI localization. The possibility of obtaining a Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow in the infarct-related artery in up to 95% of patients with acute MI (increasing the occurrence of reperfusion injury) has turned back the interest towards the protection of myocardial cells from the impending ischemic and reperfusion injury in which adenosine alone or together with other cardio-protective agents may exert important clinical effects.

ST segment resolution as a tool for assessing the efficacy of reperfusion therapy

Rapid, simple and inexpensive measures are needed to assess the efficacy of reperfusion therapy both in clinical practice and in clinical trials testing novel reperfusion regimens. In the last decade, several observations have led to a favorable reappraisal of the utility of ST segment monitoring as a simple means of assessing reperfusion in patients receiving fibrinolytic therapy for acute ST elevation myocardial infarction, and ST resolution is being used increasingly in clinical practice and in clinical research. This review focuses on four interrelated roles for ST segment monitoring: the assessment of epicardial reperfusion and the identification of candidates for rescue percutaneous coronary intervention; the evaluation of microvascular and tissue-level reperfusion; the determination of prognosis early after fibrinolytic therapy; and the use of ST segment resolution to compare different reperfusion regimens.

Comparison of a 60- versus 90-minute determination of ST-segment resolution after thrombolytic therapy for acute myocardial infarction. In TIME-II Investigators. Intravenous nPA for Treatment of Infarcting Myocardium Early-II

Determination of ST-segment resolution 60 minutes after the administration of thrombolytic therapy allows accurate risk stratification for mortality and congestive heart failure. Patients with complete ST resolution at 60 minutes tended to be at lower risk for 30-day mortality than patients with complete ST resolution at 90 minutes.

Failure of thrombolysis by streptokinase: detection with a simple electrocardiographic method

OBJECTIVE

To determine whether simple, readily applicable ECG criteria will allow early prediction of inadequate (< TIMI 3) flow in the infarct related vessel in patients receiving thrombolytic treatment for acute myocardial infarction; and to determine the success of streptokinase in achieving adequate antegrade flow in the infarct related vessel two hours after starting treatment.

DESIGN

Cohort study.

SETTING

Regional cardiothoracic unit.

PATIENTS

100 sequential patients with acute myocardial infarction.

INTERVENTIONS

Coronary angiography two hours after the initiation of thrombolytic treatment, proceeding to rescue angioplasty for inadequate flow in the infarct related vessel where appropriate.

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of six ECG criteria for the detection of inadequate antegrade flow in the infarct related vessel.

RESULTS

The ECG test that performed best as a positive test for < TIMI 3 flow in the infarct related vessel was < 50% resolution of the ST segment elevation in the worst lead and no accelerated idioventricular rhythm. This had a sensitivity of 81%, specificity of 88%, positive predictive value of 87%, negative predictive value of 83%, and overall accuracy of 85%.

CONCLUSIONS

Sensitive, specific, and simple ECG criteria are defined for diagnosing failure of thrombolytic treatment with streptokinase. These allow the early detection of patients at high risk of further adverse events from a persistently occluded vessel. They may be used without recourse to sophisticated equipment or complex analyses. Such patients can then be considered for alternative treatments or enrollment into appropriate research protocols.

Reperfusion syndrome: relationship of coronary blood flow reserve to left ventricular function and infarct size

OBJECTIVES

We tested the hypothesis that the reperfusion syndrome (RS), defined as an additional elevation of the ST segment upon reperfusion, may be a marker of microcirculatory reperfusion injury during acute myocardial infarction (AMI).

BACKGROUND

The pathophysiology of the RS is unknown, and its prognostic implications are controversial.

METHODS

Twenty-one patients with an anterior AMI treated < or =12 h after onset by primary coronary angioplasty (PTCA) were studied. Coronary velocity reserve (CVR), an index of microcirculatory function, was measured using a Doppler guidewire. Left ventricular (LV) ejection fraction, infarct size (percent defect) and LV end-systolic volume index (LVESVi) were evaluated by radionuclide ventriculography, 201T1 single-photon emission computed tomography and contrast ventriculography, respectively.

RESULTS

Baseline ST elevation and pain-to-TIMI 3 time were similar in patients with and without RS. Patients with RS (10/21) had a lower post-PTCA CVR than patients without RS (median [95% confidence interval]: 1.2 [1-1.3] vs. 1.6 [1.5-1.7], p < 0.005). Even though predischarge CVR was similar in the two groups, infarct size at six weeks (26 [21 to 37] vs. 14 [10-17]% 201T1 defect, p = 0.001) and predischarge LVESVi (45% [40 to 52] vs. 30% [29 to 38] mL/m2, p = 0.001) were larger, and LV ejection fraction at six weeks (40% [37 to 46] vs. 55% [50 to 60], p = 0.004) was lower in patients with RS than in patients without RS.

CONCLUSIONS

Patients with RS during primary PTCA for an anterior AMI have a transiently lower CVR than patients without RS, but sustained LV dysfunction and larger infarct size, suggesting that RS is a marker of microcirculatory reperfusion injury.

Coronary microembolization--its role in acute coronary syndromes and interventions

The diagnosis coronary artery disease is classically based on patient's symptoms and morphology, as analyzed by angiography. The importance of risk factors for the development of coronary atherosclerosis and disturbance of coronary vasomotion is clearly established. However, microembolization of the coronary circulation has also to be taken into account. Microembolization may occur as a single or as multiple, repetitive events, and it may induce inflammatory responses. Spontaneous microembolization may occur, when the fibrous cap of an atheroma or fibroatheroma (Stary i.v. and Va) ruptures and the lipid pool with or without additional thrombus formation is washed out of the atheroma into the microcirculation. Such events with progressive thrombus formation are known as cyclic flow variations. Plaque rupture occurs more frequently than previously assumed, i.e. in 9% of patients without known heart disease suffering a traffic accident and in 22% of patients with hypertension and diabetes. Also, in patients dying from sudden death microembolization is frequently found. Patients with stable and unstable angina show not only signs of coronary plaque rupture and thrombus formation, but also microemboli and microinfarcts, the only difference between those with stable and unstable angina being the number of events. Appreciation of microembolization may help to better understand the pathogenesis of ischemic cardiomyopathy, diabetic cardiomyopathy and acute coronary syndromes, in particular in patients with normal coronary angiograms, but plaque rupture detected by intravascular ultrasound. Also, the benefit from glycoprotein IIb/IIIa receptor antagonist is better understood, when not only the prevention of thrombus formation in the epicardial atherosclerotic plaque, but also that of microemboli is taken into account. Microembolization also occurs during PTCA, inducing elevations of troponin T and I and elevations of the ST segment in the EKG. Elevated baseline coronary blood flow velocity, as a potential consequence of reactive hyperemia in myocardium surrounding areas of microembolization, is more frequent in patients with high frequency rotablation than in patients with stenting and in patients with PTCA. The hypothesis of iafrogenic microembolization during coronary interventions is now supported by the use of aspiration and filtration devices, where particles with a size of up to 700 microns have been retrieved. In the experiment, microembolization is characterized by perfusion-contraction mismatch, as the proportionate reduction of flow and function seen with an epicardial stenosis is lost and replaced by contractile dysfunction in the absence of reduced flow. The analysis of the coronary microcirculation, in addition to that of the morphology and function of epicardial coronary arteries, and in particular appreciation of the concept of microembolization will further improve the understanding of the pathophysiology and clinical symptoms of coronary artery disease.

Relation between ST-segment changes and myocardial perfusion evaluated by myocardial contrast echocardiography in patients with acute myocardial infarction treated with direct angioplasty

The aim of this study was to evaluate the relation between myocardial perfusion and ST-segment changes in patients with acute myocardial infarction treated with successful direct angioplasty. Thirty-seven patients, successfully treated with direct angioplasty, underwent myocardial contrast echocardiography before and after angioplasty. The sum of ST-segment elevation divided by the number of the leads involved (ST-segment elevation index) was calculated at 1, 5, 10, 20, and 30 minutes after restoration of a Thrombolysis In Myocardial Infarction trial grade 3 flow. After recanalization, myocardial reperfusion within the risk area was observed in 26 patients, whereas a no-reflow phenomenon occurred in 11. In patients with myocardial reperfusion, the ST-segment elevation index progressively declined, whereas in patients with no reflow, no significant change was observed. Reduction of > or = 50% in the ST-segment elevation index occurred in 20 of the 26 patients with reflow and in 1 of the 11 with no reflow (p = 0.0002). An additional increase of > or = 30% in the ST-segment elevation index occurred in 3 patients with reflow and in 7 with no reflow (p = 0.003). Sensitivity, specificity, positive and negative predictive values, and accuracy of the reduction in the ST-segment elevation index for predicting microvascular reflow were 77%, 91%, 95%, 62%, and 81%, respectively. The corresponding values of the increase in ST-segment elevation index for predicting no reflow were 64%, 88%, 70%, 85%, and 81%, respectively. In conclusion, after successful angioplasty, different patterns of myocardial perfusion are associated with different ST-segment changes. Analysis of ST-segment changes predicts the degree of myocardial reperfusion.

Relation of absence of ST reelevation immediately after reperfusion and success of reperfusion with myocardial salvage

To examine whether resolution in ST elevation without ST reelevation immediately after reperfusion indicates successful reperfusion with myocardial salvage, we studied 40 patients who had an extensive acute myocardial infarction with early reperfusion: 24 patients had ST reelevation and 16 patients had no ST reelevation. Results indicate that (1) in the group with ST reelevation, rapid progression of myocardial damage occurs by reperfusion itself (i.e., reperfusion injury) and (2) in the group without ST reelevation, myocardial damage had already been extensive and irreversible at the time of reperfusion; thus, the absence of ST reelevation is not always a sign of reperfusion with myocardial salvage.

Changes in R wave amplitude: ECG differentiation between episodes of reocclusion and reperfusion associated with ST-segment elevation

This study assesses the electrocardiographic (ECG) differences between episodes of increased ST-segment amplitude induced by coronary artery occlusion and by reperfusion in the open-chest rabbit model. Nine anesthetized open-chest male New Zealand White rabbits were subjected to four episodes of 5 minutes of coronary artery occlusion followed by 5 minutes of reperfusion. The ST-segment and R wave amplitudes were measured from an ECG lead attached to the pericardium overlying the ischemic myocardium. In 10 out of 35 (29%) of the episodes, reperfusion resulted in a transient increase in ST-segment amplitude. While episodes of coronary artery occlusion were associated with increase in R wave amplitude (69% and 97% of the episodes after 1 and 5 minutes, respectively), all reperfusion episodes were associated with prompt decrease in R wave amplitude. There was no difference between the repeated episodes in the occurrence of ST-segment elevation during reperfusion. However, ST-segment elevation during reperfusion could be distinguished from the ischemic episodes by the prompt decline in the R wave amplitude in the former compared with no change or increase in the latter.

Relation of duration of ST reelevation at reperfusion and improvement of left ventricular function after successful primary angioplasty of the left anterior descending coronary artery in anterior wall acute myocardial infarction

We conducted a prospective study to investigate the relation between ST reelevation during primary angioplasty and improvement in left ventricular function. The duration, not the occurrence, of ST reelevation at reperfusion was associated with improvement in left ventricular function in patients with anterior wall acute myocardial infarction successfully recanalized by primary angioplasty.

Further ST elevation at reperfusion by direct percutaneous transluminal coronary angioplasty predicts poor recovery of left ventricular systolic function in anterior wall AMI

Some patients with acute myocardial infarction (AMI) develop further ST elevation at reperfusion by percutaneous transluminal coronary angioplasty (PTCA). This study reports the ST deviation at reperfusion by direct PTCA in relation to the clinical factors and the recovery of left ventricular (LV) systolic function. Fifty-two patients with anterior wall AMI were treated with direct PTCA. They were classified into the following 3 groups according to the change in ST elevation at reperfusion: increase of > or = 20% (ST reelevation); reduction of > or = 20% (ST resolution); and the other (ST no change). Angina pectoris preceding AMI occurred less often in the ST reelevation group (ST reelevation group, 38%; ST no change group, 81%; ST resolution group, 70%; p < 0.05). Recovery of LV ejection fraction during the first month after direct PTCA was significantly poor in the ST reelevation group in contrast to the ST resolution group (ST reelevation group, -6.3 +/- 13%; ST no change group, 18 +/- 20%; ST resolution group, 45 +/- 29%; p < 0.0001). The change in ST elevation at reperfusion was an index predicting the recovery of LV systolic function in the reperfusion by direct PTCA.

Extent of early ST segment elevation resolution: a strong predictor of outcome in patients with acute myocardial infarction and a sensitive measure to compare thrombolytic regimens. A substudy of the International Joint Efficacy Comparison of Thrombolytics (INJECT) trial

OBJECTIVES

This study was undertaken to assess prospectively the prognostic power of early ST segment elevation resolution in a large cohort of patients with myocardial infarction and to test the value of differences in ST segment resolution as a surrogate end point.

BACKGROUND

Previous studies revealed that the use of two cutoff points for three groups of ST segment resolution within 3 h after the start of thrombolysis is most effective in predicting outcome.

METHODS

The International Joint Efficacy Comparison of Thrombolytics (INJECT) trial compared mortality in 6,010 patients randomized to receive either reteplase or streptokinase. The 1,909 German patients form the basis of this substudy. The three groups of ST segment resolution were defined as complete (> or = 70%), partial (70% to 30%) and no resolution (< 30% to > or = 0%).

RESULTS

In 1,398 patients presenting < or = 6 h from onset of acute myocardial infarction, the 35-day mortality rate for complete, partial and no ST segment resolution was 2.5%, 4.3% and 17.5%, respectively (p < 0.0001). Peak creatine kinase levels (fraction of normal) were 9.8, 13.4 and 14.0, respectively (p < 0.0001). When baseline characteristics were included, ST segment resolution was the most powerful independent predictor of 35-day mortality. The proportion of patients with complete ST segment resolution was larger, and that with no ST segment resolution smaller, with reteplase than with streptokinase (p = 0.006).

CONCLUSIONS

No ST segment resolution, indicating failed thrombolysis, predicts very high early mortality, whereas complete resolution is associated with a small infarct area and low mortality. Partial ST segment resolution also predicts larger infarct areas, but early mortality is relatively low. Different extents of ST segment resolution may serve as a sensitive surrogate end point in clinical trials.

Streptokinase-induced transient aggravation of myocardial injury

We examined the relationship between streptokinase infusion, intensity of myocardial injury and systemic hypotension in patients receiving streptokinase for treatment of evolving acute myocardial infarction. Twenty consecutive patients treated with streptokinase for evolving acute myocardial infarction received continuous blood pressure and S-T segment monitoring of the 12 lead electrocardiogram (ECG) for at least 5 h, commencing prior to commencement of the streptokinase infusion. Aggravation of injury, manifested both by episodic increases in S-T segment elevation on the electrocardiogram (ECG) (P < 0.001), and in mean S-T segment elevation (P < 0.05) occurred within the first 20 min after initiation of streptokinase infusion. Hypotension also occurred transiently in most patients, with a mean minimum systolic blood pressure of 92 +/- 22 (S.D.) mmHg occurring 16 +/- 5 min after commencement of streptokinase. There was no correlation between the extent of aggravation of injury and that of hypotension. All patients showed ECG evidence of reperfusion, with a reduction of S-T elevation in the reference lead to 50% of maximal value, after a median of 62 min (range 9-174 min). It is concluded that streptokinase aggravates injury prior to reperfusion, although probably not via the induction of hypotension: It is possible that this effect contributes to the 'early hazard' of thrombolytic therapy.

Myocardial damage after successful thrombolysis is associated with the duration of ST re-elevation at reperfusion

The purpose of this study was to investigate the significance of ST re-elevation at reperfusion using strict criteria for patient inclusion and exclusion. Twenty-nine patients who had a first anterior infarction with single-vessel disease, successful recanalization by intracoronary thrombolysis (ICT) with urokinase, and an angiographically confirmed patent infarct-related artery after 4 weeks, were divided into three groups according to the deviation of the ST segment at reperfusion: Group A, 10 patients with sustained ST re-elevation; Group B, 10 patients with transient ST re-elevation; and Group C, 9 patients with ST reduction. Left ventricular (LV) function was evaluated from cineventriculograms performed in the 30 degrees right anterior projection 4 weeks after ICT. LV ejection fraction and regional wall motion of the infarct area, evaluated by the centerline method (SD/chords), were significantly lower in Group A (44 +/- 10%, -3.2 +/- 0.4) than in Group B (61 +/- 9%, -1.9 +/- 0.7) and Group C (60 +/- 5%, -2.0 +/- 0.4) (p < 0.01). Peak creatine kinase (CK) activity was significantly higher in Group A (5848 +/- 2112 IU) than in Group B (2485 +/- 1254 IU) and Group C (1889 +/- 1525 IU) (p < 0.05). These data suggest that a sustained ST re-elevation at reperfusion was strongly associated with marked LV dysfunction and higher peak CK activity. It was concluded that sustained, not transient, ST re-elevation associated with successful reperfusion indicates extensive myocardial damage.

ST segment reelevation after acute myocardial infarction: marked differences in the electrocardiographic pattern between early and late episodes

This study assesses the electrocardiographic (ECG) morphologic differences between early (< 24 h) and late (> 24 h) episodes of ST segment reelevation after acute myocardial infarction. We studied the records of 101 consecutive patients with acute myocardial infarction whose admission ECG demonstrated ST segment elevation with positive T waves, without pathological Q waves in the relevant leads, and without signs of bundle branch block or left ventricular hypertrophy. Thirty-five patients had 44 episodes of early ST segment reelevation, while 22 patients experienced 26 late episodes of ST segment reelevation. Seven patients experienced both early and late episodes. Early episodes of ST segment reelevation was seen more often after thrombolytic therapy: 43% (32 of 74 patients) versus 11% (3 of 27 patients) (P < 0.006). No differences were found in the incidence of late episodes between those who underwent (23%) or did not undergo (19%) thrombolytic therapy. Two patterns of ST segment elevation were distinguished. Pattern A with positive T waves, ST segment elevation (> or = 0.1 mV), but without distortion of the terminal portion of the QRS complex. Pattern B characterized by positive T waves, ST segment elevation (> or = 0.1 mV) with distortion of the terminal portion of the QRS complex. Each ECG was categorized according to these two patterns. The admission ECG pattern was A in 75 patients, and B in 26. No significant differences were found between patients with early, late, or no episodes of ST segment reelevation in the appearance of pattern A or B on admission.(ABSTRACT TRUNCATED AT 250 WORDS)

Early assessment of outcome by ST-segment analysis after thrombolytic therapy in acute myocardial infarction

As an early marker of outcome, the sum of ST-segment elevation resolution between the electrocardiogram before and 3 hours after initiation of thrombolysis was investigated in 77 patients with acute myocardial infarction. Prospectively, three groups were defined according to complete (> or = 70%, n = 34), partial (< 70% to > or = 30%, n = 26), or no (< 30%, n = 17) ST resolution. There were considerable differences in the enzyme-determined infarct size (alpha-hydroxybutyrate dehydrogenase release for complete, partial, and no ST resolution: 529 +/- 397 IU/L, 689 +/- 484 IU/L, and 1293 +/- 742 IU/L, respectively; p = 0.0001) and the angiographic left ventricular function 1 week later (ejection fraction 58% +/- 10%, 53% +/- 13%, and 43% +/- 12%, respectively, p < 0.01; regional dyssynergic area 24 +/- 19, 39 +/- 23, and 50 +/- 21 U2, respectively, p < 0.01). Early reperfusion as assessed by creatine kinase release measured in 15-minute intervals was 90%, 65%, and 18%, respectively (p = 0.0001). Differences in degrees of ST-elevation resolution at 3 hours may help facilitate timely screening of patients for appropriate therapeutic intervention. Patients with complete ST resolution may be considered for early discharge, and patients with no ST resolution may be candidates for an early invasive approach or additional thrombolytic therapy.

Extent of early ST segment elevation resolution: a simple but strong predictor of outcome in patients with acute myocardial infarction

OBJECTIVES

This study proposed to verify the prognostic power of early ST segment elevation resolution in patients with acute myocardial infarction from the Intravenous Streptokinase in Acute Myocardial Infarction study data base.

BACKGROUND

Data from a small prospective study suggested that use of two cutoff points for three different levels of ST segment resolution 3 h after the start of thrombolysis may be an efficient way to predict outcome in an individual patient.

METHODS

The three groups of ST segment resolution were defined as 1) complete resolution (> or = 70% [552 patients]) or only slight ST segment elevation (127 patients); 2) partial resolution (< 70% to 30% [475 patients]); 3) no resolution (< 30% to > 0% [362 patients]). Infarct size was measured from creatine kinase isoenzyme, MB fraction, release and from the number of Q waves. Left ventricular function was assessed in 818 patients 1 month after infarction.

RESULTS

For complete, partial and no ST segment resolution 3 h after the start of streptokinase or placebo infusion, enzyme release was 1.2, 1.8 and 2.1 IU/ml x h; number of Q waves 1.7, 2.5 and 3.0; and ejection fraction 60%, 53% and 49%, respectively (all adjusted p = 0.0000). Mortality rate at 21 days was 2.2%, 3.4% and 8.6%, respectively. No ST segment resolution was the most powerful independent predictor of early mortality (p = 0.0001). Survival rate curves at 6-year follow-up showed significant mortality differences with increasing divergence (p = 0.0003 anterior infarction; p = 0.005 inferior infarction). In subgroups with an overall higher risk of dying, mortality was strongly determined by the extent of early ST segment resolution.

CONCLUSIONS

The extent of ST segment elevation resolution conveys useful early information about outcome in an individual patient after acute myocardial infarction.