Relation between symptom duration before thrombolytic therapy and final myocardial infarct size

Intracoronary Eptifibatide During Primary Percutaneous Coronary Intervention in Early Versus Late Presenters with ST Segment Elevation Myocardial Infarction: A Randomized Trial

Introduction

The role of intracoronary (IC) eptifibatide in primary percutaneous coronary intervention (PPCI) for ST segment elevation myocardial infarction (STEMI) and whether time of patient presentation affects this role are unclear. We sought to evaluate the benefit of IC eptifibatide use during primary PCI in early STEMI presenters compared to late STEMI presenters.

Methods

We included 70 patients who presented with STEMI and were eligible for PPCI. On the basis of symptom-to-door time, patients were classified into two arms: early (<3 h, n = 34) vs late (≥3 h, n = 36) presenters. They were then randomized to local IC eptifibatide infusion vs standard care (control group). The primary end point was post-PCI myocardial blush grade (MBG) in the culprit vessel. Other end points included corrected TIMI frame count (cTFC), ST segment resolution (STR) ≥70%, and peak CKMB.

Results

In the early presenters arm, no difference was observed in MBG results ≥2 in the IC eptifibatide and control groups (100% vs 82%; p = 0.23). In the late presenters arm, the eptifibatide subgroup was associated with improved MBG ≥2 (100% vs 50%; p = 0.001). IC eptifibatide in both early and late presenters was associated with less cTFC (early presenters 19 vs. 25.6, p = 0.001; late presenters 20 vs. 31.5, p < 0.001) and less peak CKMB (early presenters 210 vs 260 IU/L, p = 0.006; late presenters 228 vs 318 IU/L, p = 0.005) compared with the control group. No difference existed between both groups in STR index in early and late presenters.

Conclusion

IC eptifibatide might improve the reperfusion markers during PPCI for STEMI patients presenting after 3 h from onset of symptoms. A large randomized study is recommended to ascertain the benefits of IC eptifibatide in late presenters on clinical outcomes.

Evaluating the views of paramedics, cardiologists, emergency department physicians and nurses on advanced prehospital management of acute ST elevation myocardial infarction

BACKGROUND

Although advanced prehospital management (PHM) in ST elevation myocardial infarction (STEMI) reduces reperfusion delay and improves patient outcomes, its use in North America remains uncommon. Understanding perceived barriers to and facilitators of PHM implementation may support the expansion of programs, with associated patient benefit.

OBJECTIVE

To explore the attitudes and beliefs of paramedics, cardiologists, emergency physicians and nurses regarding these issues.

METHODS

To maximize the potential to identify unpredictable issues within each of the four groups, focus group sessions were recorded, transcribed and analyzed for themes using the constant comparative method.

RESULTS

All 18 participants believed that PHM of STEMI decreased time to treatment and improved health outcomes. Despite agreeing that most paramedics were capable of providing PHM, regular maintenance of competence and medical overview were emphasized. Significant variations in perceptions were revealed regarding practical aspects of the PHM process and protocol, as well as ownership and responsibility of the patient. Success and failures of technology were also expressed. Varying arguments against a signed 'informed consent' were presented by the majority.

CONCLUSIONS

Focus group discussions provided key insights into potential barriers to and facilitators of PHM in STEMI. Although all groups were supportive of the concept and its benefits, concerns were expressed and potential barriers identified. This novel body of knowledge will help elucidate future educational programs and protocol development, and identify future challenges to ensure successful PHM of STEMI, thereby reducing reperfusion delay and improving patient outcomes.

Abnormal Q waves on the admission electrocardiogram of patients with first acute myocardial infarction: prognostic implications

BACKGROUND

Q waves developed in the subacute and persisting into the chronic phase of myocardial infarction (MI) usually signify myocardial necrosis. However, the mechanism and significance of Q waves that appear very early in the course of acute MI (< 6 h from onset of symptoms), especially if accompanied by ST elevation, are probably different.

HYPOTHESIS

This study assesses the prognostic implications of abnormal Q waves on admission in 2,370 patients with first acute MI treated with thrombolytic therapy < 6 h of onset of symptoms.

RESULTS

Patients with abnormal Q waves in > or = 2 leads with ST-segment elevation (n = 923) were older than patients without early Q waves (n = 1,447) (60.6 +/- 11.9 vs. 58.8 +/- 11.9 years, respectively; p = 0.0003), and had a greater incidence of hypertension (34.3 vs. 30.5%; p = 0.05) and anterior MI (60.6 vs. 41.1%; p < 0.0001). Time from onset of symptoms to therapy was longer in patients with Q waves upon admission (208 +/- 196 vs. 183 +/- 230 min; p = 0.01). Peak serum creatine kinase (2235 +/- 1544 vs. 1622 +/- 1536 IU; p < 0.0001), prevalence of heart failure during hospitalization (13.8 vs. 7.0%, p < 0.0002), hospital mortality (8.0 vs. 4.6%; p = 0.02), and cardiac mortality (6.6 vs. 4.5%, p = 0.11) were higher in patients with anterior MI and with abnormal Q waves than in those without abnormal Q waves upon admission. There was no difference in peak creatine kinase, prevalence of heart failure, in-hospital mortality, and cardiac mortality between patients with and without abnormal Q waves in inferior MI. Multivariate regression analysis confirmed that mortality is independently associated with presence of Q waves on admission (odds ratio 1.61; 95% CI 1.04-2.49; p = 0.04 for all patients; odds ratio 1.65; 95% CI 0.97-2.83; p = 0.09 for anterior wall MI.

CONCLUSION

Abnormal Q waves on the admission electrocardiogram (ECG) are associated with higher peak creatine kinase, higher prevalence of heart failure, and increased mortality in patients with anterior MI. Abnormal Q waves on the admission ECG of patients with inferior MI are not associated with adverse prognosis.

ST resolution 1 hour after fibrinolysis for prediction of myocardial infarct size: insights from ASSENT 3

Acute ST-segment elevation myocardial infarction requires prompt restoration of myocardial perfusion to salvage myocardium at risk of ischemic necrosis and improve clinical outcome. Early resolution of ST-segment elevation during the time after reperfusion has been associated with both these end points. From the ASsessment of the Safety and Efficacy of a New Thrombolytic regimen (ASSENT) 3 trial, 3,425 patients were analyzed to investigate whether the amount of ST-segment resolution, divided into 3 groups (complete, >70%; partial, 30% to 70%; and no resolution, <30%), in the first hour after initiation of therapy was a predictor of final infarct size, estimated by peak creatine kinase and Selvester QRS score on the discharge electrocardiogram. Complete compared with partial and no ST resolution resulted in significantly (p<0.001) smaller infarct sizes of 10.5%, 13.2%, and 15.0% of the left ventricle and significantly (p=0.001) fewer patients with peak creatine >5 times the upper reference level at 50.3%, 71.8%, and 76.3%, respectively. In conclusion, our findings supported previous smaller studies suggesting that early resolution of ST elevation, as a sign of early myocardial reperfusion, resulted in less myocardial damage and preservation of left ventricular function.

Women's descriptions of symptoms and delay reasons in seeking medical care at the time of a first myocardial infarction: A qualitative study

BACKGROUND

Coronary heart disease (CHD) is a major cause of mortality in women. Women have also been identified as late presenters in seeking medical care.

AIM

The aim of this study was to explore and describe women's symptoms and the reasons for delay in seeking medical care at the time of the first myocardial infarction (MI).

METHODS

The study had an explorative and descriptive design based on content analysis approach. Nineteen women were interviewed at the hospital 2 or 3 days after hospitalisation.

RESULTS

The result showed that the women had difficulties interpreting, understanding and linking the symptoms to CHD. They tried to handle the discomfort and even the chest pain, rather then ask for professional help. The women had problems with making the final decision.

CONCLUSION

Women need to be made aware of the clinical symptoms of CHD, in order to understand the consequences of delay in seeking medical care following an MI.

Surgery for myocardial salvage in acute myocardial infarction and acute coronary syndromes

This article addresses the pathophysiology, the treatment options, and their rationale in the setting of life-threatening acute myocardial infarction and acute on chronic ischemia. Although biases may exist between cardiologists and surgeons, with this review, we hope to provide the reader with information that will shed light on the options that best suit the individual patient in a given set of circumstances.

Limitation of infarct size and ventricular remodeling in patients with completely reperfused anterior acute myocardial infarction--the potential role of ischemia time

BACKGROUND

Experimental studies suggest that coronary reperfusion does not result in appreciable myocardial salvage beyond 3 to 4 h.

HYPOTHESIS

The present study was undertaken to examine the potential role of ischemia time as a determinant of infarct size and cardiac function in humans.

METHODS

Ninety patients (69 men, 21 women, aged 61 +/- 1 years) presented within 24 h of onset of a first anterior infarct had ST-segment elevation on electrocardiogram. All patients underwent coronary intervention within 24 h of onset of symptoms and obtained complete reperfusion of the infarct-related artery.

RESULTS

Infarct size expressed as a percentage of the area at risk (IS/RA) and left ventricular end-diastolic volume (LVEDV) were significantly (p < 0.017) smaller and left ventricula rejection fraction (LVEF) assessed by left ventriculography (35 +/- 4 days) was significantly higher in patients treated within 4 h after onset (IS/RA:55 +/- 4%, LVEDV: 127 +/- 7 ml, LVEF: 62 +/- 2%) than in those treated 4 to 12 h (97 +/- 2%, 140 +/- 13 ml, 52 +/- 3%) and 12 to 24 h (93 +/- 2%,163 +/- 14 ml, 49 +/- 5%) after symptom onset. Left ventricular end-diastolic volume was significantly smaller in patients treated 4 to 12 h after onset than in those treated 12 to 24 h after onset.

CONCLUSIONS

Patients with < 4 h of myocardial ischemia exhibited significant myocardial salvage and better left ventricular function and patients with 4 to 12 h of myocardial ischemia exhibited significantly smaller LVEDV than those with more prolonged ischemia, although there was no difference in final infarct size.

Electrocardiographic Markers of Reperfusion in ST-elevation Myocardial Infarction

The outcome of patients who fail to reperfuse with thrombolytic therapy or percutaneous coronary intervention (PCI) for ST-elevation acute myocardial infarction (STEMI) may be improved with additional pharmacologic and mechanical interventions such as rescue PCI or intravenous glycoprotein IIb/IIIa infusion. The standard 12-lead ECG is the most commonly available and suitable tool for routine bedside evaluation of the success of reperfusion therapy for STEMI. This article reviews and discusses the current data on the four ECG markers for prediction of the perfusion status of the ischemic myocardium: ST-segment deviation, T-wave configuration, QRS changes, and reperfusion arrhythmias.

Metabolic treatment with L-carnitine in acute anterior ST segment elevation myocardial infarction. A randomized controlled trial

BACKGROUND

Administration of L-carnitine in patients with anterior acute myocardial infarction (AMI) prevents left ventricular remodeling. Current study was aimed to assess the effect of L-carnitine administration on mortality and heart failure in patients with anterior AMI.

METHODS

CEDIM 2 trial was a randomized, double-blind, multicenter, placebo-controlled trial planned to enroll 4,000 patients with acute anterior AMI. The trial was interrupted after the enrolment of 2,330 patients because of the lower than expected enrolment rate. The primary end point was a composite of death and heart failure at 6 months; 5-day mortality was the secondary end point.

RESULTS

During the 6-month follow-up, the primary end-point was not significantly different between the L-carnitine and placebo group (9.2 vs. 10.5%, p = 0.27). A reduction in mortality was seen in the L-carnitine arm on day 5 (secondary end-point) from randomization (HR = 0.61, 95% CI 0.37-0.98, p = 0.041).

CONCLUSIONS

In CEDIM 2 trial L-carnitine therapy led to a reduction in early mortality (secondary end-point) without affecting the risk of death and heart failure at 6 months in patients with anterior AMI, leading to a non-significant finding with respect to the primary end-point.

Assisting Women to Learn Myocardial Infarction Symptoms

OBJECTIVE

The purpose of this study was to test how teaching format (factual versus storytelling) and restructuring the social norm of caring for others to caring for self affects how women learn to identify and respond to myocardial infarction (MI) symptoms.

DESIGN

The study was a randomized pretest posttest full factorial experiment.

SAMPLE

One hundred and thirteen women participated.

MEASURES

Before and after reading the intervention pamphlet, the women wrote all the MI symptoms that they knew and rated their intention to call 911 if symptoms occurred.

INTERVENTION

The women read one of the four MI pamphlets corresponding to the four conditions.

RESULTS

No significant effects for learning MI symptoms resulted from teaching format or social norms. Women learned three additional MI symptoms. All responded with high intention to call 911 if MI symptoms occurred.

CONCLUSIONS

Women can learn additional MI symptoms from reading a brief pamphlet about MI symptoms. Use of a storytelling format and the social norm of caring for self might not impact how many MI symptoms women learn. Studies using audiovisuals and larger samples are needed to clarify whether storytelling format and the social norm of caring for self-impact learning MI symptoms.

Pre-hospital thrombolysis delivered by paramedics is associated with reduced time delay and mortality in ambulance-transported real-life patients with ST-elevation myocardial infarction

AIMS

There are sparse data on the impact of pre-hospital thrombolysis (PHT) in real-life patients. We therefore evaluated treatment delays and outcome in a large cohort of ambulance-transported real-life patients with ST-elevation myocardial infarction (STEMI) according to PHT delivered by paramedics or in-hospital thrombolysis.

METHODS AND RESULTS

Prospective cohort study used data from the Swedish Register of Cardiac intensive care on patients admitted to the coronary care units of 75 Swedish hospitals in 2001-2004. Ambulance-transported thrombolytic-treated patients younger than age 80 with a diagnosis of acute myocardial infarction were included. Patients with PHT (n=1690) were younger, had a lower prevalence of co-morbid conditions, fewer complications, and a higher ejection fraction (EF) than in-hospital-treated patients (n=3685). Median time from symptom onset to treatment was 113 min for PHT and 165 min for in-hospital thrombolysis. One-year mortality was 7.2 vs. 11.8% for PHT and in-hospital thrombolysis, respectively. In a multivariable analysis, after adjusting for baseline characteristics and rescue angioplasty, PHT was associated with lower 1-year mortality (odds ratio 0.71, 0.55-0.92, P=0.008).

CONCLUSION

When compared with regular in-hospital thrombolysis, pre-hospital diagnosis and thrombolysis with trained paramedics in the ambulances are associated with reduced time to thrombolysis by almost 1 h and reduced adjusted 1-year mortality by 30% in real-life STEMI patients.

A qualitative study of paramedics' attitudes to providing prehospital thrombolysis

OBJECTIVES

To explore paramedics' attitudes to administering prehospital thrombolysis (PHT).

METHOD

In-depth interviews with 20 paramedics were recorded and transcribed and analysed for emergent themes using the constant comparative method.

RESULTS

Although there was a will to provide PHT because of its benefits to patients, its associated risks, aspects of pay and working conditions, and certain organisational factors undermined the willingness of some paramedics to administer thrombolysis. The eight minute response time standard is a competing imperative which can delay thrombolysis.

CONCLUSIONS

A minority of paramedics are likely to be unwilling to deliver PHT unless countervailing imperatives are addressed.

Duration of ischemia is a major determinant of transmurality and severe microvascular obstruction after primary angioplasty: a study performed with contrast-enhanced magnetic resonance

OBJECTIVES

This study sought to assess the relationship between duration of ischemia and both myocardial transmural necrosis (TN) and severe microvascular obstruction (SMO), by contrast-enhanced magnetic resonance (CE-MR), in patients with acute myocardial infarction (AMI) treated with angioplasty (PCI), and to estimate the risk of TN and SMO with the duration of ischemia.

BACKGROUND

The impact of ischemic time on myocardial and microvascular injury is not well characterized in people.

METHODS

We performed CE-MR in 77 patients with first AMI, 5 +/- 3 days after successful PCI. The AMI was labeled as transmural if hyperenhancement at CE-MR was extended to > or =75% of the thickness in two or more ventricular segments. The SMO was identified as areas of late hypoenhancement surrounded by hyperenhanced tissue. The relationship between ischemic time and CE-MR evidence of SMO or TN was evaluated by logistic regression.

RESULTS

Thirteen patients were excluded because of preprocedural Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 of the infarct-related artery. For the remaining 64 patients, the mean time to treatment was 190 +/- 110 min, 45 (65%) patients had TN and 23 (39%) had SMO. Mean pain to balloon time was 90 +/- 40 min, 110 +/- 107 min, and 137 +/- 97 min in patients without TN and SMO, with TN but without SMO, or with both TN and SMO, respectively (p = 0.001). Multivariate analysis showed that time delay was significantly associated both with TN (odds ratio per 30 min, 1.37, p = 0.032), and SMO (odds ratio per 30 min, 1.21; p = 0.021).

CONCLUSIONS

In AMI patients with impaired coronary perfusion undergoing PCI, the risk of TN and SMO increases with the duration of the ischemic time.

Understanding Treatment-Seeking Delay in Women with Acute Myocardial Infarction: Descriptions of Decision-Making Patterns

• Background Women delay seeking treatment for symptoms of acute myocardial infarction longer than men delay. Women’s delay time has not been thoroughly characterized.

• Objectives To qualitatively describe the period between the onset of symptoms of myocardial infarction and enactment of the decision to seek care (decision time) and to identify common patterns of cognitive, affective, and behavioral responses to the symptoms (decision trajectories).

• Methods In this qualitative study, 52 women were asked in semistructured interviews to describe the symptoms and related thoughts, decisions, and actions from the onset of symptoms of myocardial infarction to arrival at the hospital. Narrative analysis was used to examine the stories and to identify patterns of decision-making behavior.

• Results Six common patterns of behavior during the decision time were identified: knowing and going, knowing and letting someone take over, knowing and going on the patient’s own terms, knowing and waiting, managing an alternative hypothesis, and minimizing. The patterns were further grouped as knowing or managing. Women in the 2 groups (knowing and managing) differed primarily in their awareness and interpretations of the symptoms and in their patterns of behavior in seeking treatment.

• Conclusions Women’s delay in seeking treatment for symptoms of myocardial infarction can be categorized into distinct patterns. Clinicians can use knowledge of these patterns to detect responses and situations that can decrease decision time in future cardiac events and to educate women about how to respond to cardiac symptoms.

A dynamic model forecasting myocardial infarct size before, during, and after reperfusion therapy: an ASSENT-2 ECG/VCG substudy

AIMS

Serial forecasts of final myocardial infarct (MI) size during fibrinolytic treatment (Rx) of ST-elevation MI would allow the identification of high-risk patients with a predicted major loss of viable myocardium, at a point when treatment may still be modified. We investigated a model for such forecasting, using time and the ECG.

METHODS AND RESULTS

We collected 234 patients with ST-elevation MI, without signs of previous MI, bundle branch block, or hypertrophy. MI size was determined by the Selvester score and was "forecasted" at: admission with patients stratified by delay time and an ECG acuteness score into three groups (EARLY, DISCORDANT, and LATE); 90 min after Rx by > or =70% ST-recovery or not and occurrence of "reperfusion peaks"; 4 h after Rx by ST re-elevations. EARLY patients had smaller final infarct sizes than LATE (9.4 vs. 20%, P=0.01). EARLY patients with > or =70% ST-recovery without a reperfusion peak had smaller infarct sizes than those with (3.1 vs. 12.5%, P=0.001). EARLY patients without ST re-elevations had smaller infarct sizes (1.5%) than those with some (9%) or many re-elevations (12%), P<0.001.

CONCLUSION

Final infarct size can be forecasted using delay time and serial ECGs. Serially updated forecasts seem especially important when both clock-time and initial ECG- signs indicate earliness.

Comparison between human and automated electrocardiographic waveform measurements for calculating the Anderson-Wilkins acuteness score in patients with acute myocardial infarction

The Anderson-Wilkins (AW) electrocardiographic (ECG) acuteness score complements time from pain onset in prognostic stratification of patients with acute myocardial infarction (AMI). However, for the AW acuteness score to be of practical use in the acute situation, it must be an integral component of a commercial automated ECG analysis program. The objective of this study was to determine the concordance between human and computer measurements and calculation of the AW acuteness score. The mean difference in AW acuteness score was 0.11 +/- 0.66 for anterior and -0.07 +/- 1.24 for inferior AMI. Ninety-nine percent of the differences were found to be 1.0 or less for the anterior AMI group, and 91.7% were 1.0 or less in the inferior AMI group. The differences were primarily caused by minor disagreements in measurements. In conclusion, the AW acuteness score established using manual ECG waveform measurements can be implemented into commercial automated ECG analysis programs to achieve practical use in clinical decision support for patients with AMI.

Treatment-seeking delay among women with acute myocardial infarction: decision trajectories and their predictors

BACKGROUND

Women's delay in seeking treatment for acute myocardial infarction symptoms results in higher rates of mortality and morbidity for women.

OBJECTIVES

To describe decision trajectories used by women when experiencing symptoms of acute myocardial infarction, and to identify predictors of the decision trajectory used by women with acute myocardial infarction.

METHODS

A cross-sectional, descriptive design was used. The nonprobability sample included 52 women hospitalized for acute myocardial infarction. To elicit descriptions of decision making, focused, semistructured interviews were used in this mixed-methods study. Predictors of decision trajectories were measured with standardized instruments among the same women. Narrative analysis was used to examine the stories from the qualitative data and to identify decision trajectory types. Discriminant analysis was used to predict trajectory type membership.

RESULTS

The median delay time was 4.25 hours. Most of the women used one of two trajectory types: knowing (defined as those women who knew almost immediately that they would seek help, n = 25) and managing (those women who managed an alternative hypothesis or minimized their symptoms, n = 23). Discriminant analysis correctly classified 71% (chi [4] = 11.2; n = 48; p =.02) of the cases into trajectory types on the basis of four predictor variables: social support, personal control, heart disease threat, and neuroticism.

DISCUSSION

Women's behaviors during the period between onset of acute myocardial infarction symptoms and treatment seeking can be categorized into a small number of patterns termed decision trajectories. A profile of sociostructural and intrapersonal factors with potential for predicting behavior in relation to future coronary events was developed.

Variations in pre-hospital fibrinolysis process of care: insights from the Assessment of the Safety and Efficacy of a New Thrombolytic 3 Plus international acute myocardial infarction pre-hospital care survey

The Assessment of the Safety and Efficacy of a New Thrombolytic 3 (ASSENT 3 PLUS) Plus trial (n=1639) was an international trial of pre-hospital fibrinolysis with tenecteplase randomly assigned to enoxaparin or unfractionated heparin, involving 106 sites in 12 countries. Given the potential impact of process of care delivery in various healthcare systems, we undertook a comprehensive validated survey of population demographics, geographical factors, emergency medical services, methods of electrocardiogram interpretation and pre-hospital fibrinolysis administration. The potential study population was 42.4 x 10(6) with 70% urban. The land areas of individual emergency medical services sites varied from 6 to 20000/km(2). Three emergency medical services personnel (range 2-5) attended each ambulance with the highest level of training, consisting of a physician (65%), registered nurse (20%) or paramedic. Before the initiation of the study, 72% of sites administered pre-hospital fibrinolysis (range 1-20 years). Electrocardiograms were interpreted on the scene in 60% and transmitted for physician's interpretation in the remainder; 41% of patients (679/1639) were enrolled at sites without a physician at the scene. The ASSENT 3 Plus trial incorporated a wide variation in population density, emergency medical services resources, and physician's interpretation of ECG and administering pre-hospital fibrinolysis. Understanding this diversity will help in evaluating the general applicability and feasibility of pre-hospital fibrinolysis in various health systems, as well as the pre-hospital care of ST elevation myocardial infarction patients regardless of reperfusion strategies.

The electrocardiogram in ST elevation acute myocardial infarction: correlation with coronary anatomy and prognosis

The electrocardiogram is considered an essential part of the diagnosis and initial evaluation of patients with chest pain. This review summarises the information that can be obtained from the admission electrocardiogram in patients with ST elevation acute myocardial infarction, with emphasis on: (1) prediction of infarct size, (2) estimation of prognosis, and (3) the correlations between various electrocardiographic patterns and the localisation of the infarct and the underlying coronary anatomy.

[Impact of a public-directed media campaign on emergency call to a mobile intensive care units center for acute chest pain]

Cardiovascular diseases represent the second highest cause of mortality among the 25-65 age group in the Nord-Pas-de-Calais region. The Monica study clearly showed that in 1996 the average length of time between a casualty showing the first signs of a coronary and the commencement of treatment was 3 h 30 in northern region of France compared with an average of 2 hours for the rest of the country. Many factors play a part: lack of knowledge of the symptoms, ignorance of the benefits of making an early call to the ambulance, lack of awareness of the french emergency services- centre 15 and its role, absence of any structured network for coronary emergencies. Given these observations, an extensive regional informative campaign is being launched for the first time in France, which will involve all relevant health professionals. The 2 aims of this campaign are to encourage people to call centre 15 directly and as quickly as possible after noticing the first coronary symptoms, and to encourage general practitioners (GPs) to "prescribe calling centre 15". The impact of this campaign has been estimated using the descriptive analysis of the relationship between the number of calls made to centre 15 by the general public and doctors and the number of successful prehospital interventions by the mobile emergency unit of Lille in cases of coronaries and thrombosis. The results of 3 telephone surveys of 1200 people carried out by the emergency services and 2 surveys carried out by a private company were also used for this evaluation. The analysis of this data provides a wealth of arguments in favour of the effectiveness of the campaign. On one hand this is due to the quality of its contents, which we compared to a similar campaign and on the other hand it is due to its lengthy duration.

Mass media interventions to reduce help-seeking delay in people with symptoms of acute myocardial infarction: time for a new approach?

Minimizing patient delay in seeking care for acute myocardial infarction (AMI) is important in the reduction of morbidity and mortality. However, mass media interventions to reduce these delays have had limited success. This paper critiques delay reducing intervention studies and draws on other public health campaigns to identify new directions. A Medline search for the years 1985 through 2000 yielded eight intervention studies meeting inclusion criteria. Three of eight studies reported successful interventions although two of three were only marginally successful. Most studies used similar messages. Campaign lengths, type of media, and sample sizes varied. High risk populations and those with confirmed MI responded more quickly. To reduce patient delay, media messages need to do more than create awareness. Future interventions should target high risk audiences, promote dialogue between previous AMI patients and high risk patients, address problems of denial, provide gender specific education, and emphasize symptom evaluation, problem solving, and decision-making skills.

Prehospital thrombolysis in acute myocardial infarction

Efficacy of reperfusion therapy in acute myocardial infarction (AMI) is strictly time-dependent. Most benefit is achieved with initiation of therapy within the first 60-90 min after onset of symptoms. The majority of patients with AMIs are seen within this time window by emergency medical services. Moreover, average time gain of about 60 min is possible by prehospital thrombolysis. Randomized studies yielded a better outcome when a time gain of 90 min and more was achieved. Prehospital diagnosis of AMI is reliable. Moreover, out-of-hospital thrombolysis has no additional specific risks nor is it an obstacle for later percutaneous intervention. Consequently, patients seen within the first 60-90 min after onset of symptoms or for whom a time gain of 90 min or more can be expected should receive immediate prehospital thrombolysis.

The use of the electrocardiogram to identify epicardial coronary and tissue reperfusion in acute myocardial infarction

The standard 12-lead electrocardiogram (ECG) gives us crucial information concerning myocardial perfusion and the success of reperfusion therapy for ST elevation acute myocardial infarction. Continuous monitoring has advantages over repeated snapshot recordings. There are four electrocardiographic markers for prediction of the perfusion status of the ischemic myocardium: (1) ST-segment measurements, (2) T-wave configuration, (3) QRS changes, and (4) reperfusion arrhythmias. Complete and stable (> or = 70%) resolution of ST-segment elevation is associated with better outcome and preservation of left ventricular function than partial (30 to 70%) or no (<30%) ST-segment resolution. Early inversion of the T waves after initiation of reperfusion therapy is another marker of myocardial reperfusion and a good prognostic sign. Using standard 12-lead ECG, dynamic changes in Q-wave number, amplitude, and width; R-wave amplitude; and S-wave appearance are detected during reperfusion therapy. However, the significance of these changes has not been clarified. Reperfusion arrhythmias, especially bradycardia and accelerated idioventricular rhythm, are detected occasionally during reperfusion therapy, but the value of reperfusion arrhythmias as a marker of coronary artery patency is still debatable. Dynamic changes in the QRS complexes, ST segments and T waves occur during reperfusion therapy and the days after. Whereas changes in ST-segment amplitude have been extensively studied, the significance of QRS-complex and T-wave changes is less clear, and especially whether changes in the QRS complex and T wave may be complementary and additive to ST-segment monitoring. It has remained unclear whether electrocardiographic signs of reperfusion and reischemia should be used for therapeutic decision making in the clinical setting.

The symptom experience of angina in women

Angina is the symptom of myocardial ischemia and the most common presentation of women with coronary artery disease. Women have delayed responses to angina and postpone seeking care more than men. Myocardial ischemia is life threatening and timeliness of treatment is critical. Understanding the symptom experience is important to patients and health care providers alike to reduce morbidity and mortality rates. This article reviews current knowledge of the symptom experience to identify gaps in knowledge and provide a basis for future research and interventions. The symptom experience component of the Symptom Management Model is used as an organizing framework. In terms of chest pain perception, biopsychosocially oriented studies are inconsistent. Data suggest that women use different pain descriptors than men and that diabetes, somatic awareness, and hormonal status probably play a role in attenuating or altering anginal pain. In evaluating symptoms, findings suggest that if anginal symptoms were experienced as expected and/or were evaluated as cardiac in origin, response was more appropriate. Even when it is known that the symptoms are related to cardiac disease, women's responses are still delayed because of a need to self-treat to maintain control. If a patient recognizes symptoms to be cardiac in origin, an appropriate evaluation of the urgency of the situation was made more often, and a rapid response was more likely. Therefore, the larger problem may be the accurate perception of the symptom and the recognition that the symptom is cardiac in origin. This article has implications for future research dealing with improved responses.

The impact of time to thrombolytic treatment on outcome in patients with acute myocardial infarction. For the CORE investigators (Collaborative Organisation for RheothRx Evaluation)

OBJECTIVES

To examine the impact of time to thrombolytic treatment on multiple acute outcome variables in a single trial of thrombolysis in acute myocardial infarction.

DESIGN AND PATIENTS

Mortality and reinfarction rate were measured in 2770 patients with acute myocardial infarction who received thrombolysis within 12 hours in CORE, an international, dose ranging trial of poloxamer 188. Tc-99m sestamibi infarct size and radionuclide angiographic ejection fraction substudies included 1099 and 1074 patients, respectively.

RESULTS

Time to thrombolysis, subgrouped by intervals (< 2, 2-4, > or = 4-6, and > or = 6 hours), was significantly associated with infarct size (median 15.0%, 18.5%, 22.0%, 18.5% of left ventricle; p = 0.033), mean (SD) ejection fraction (51.5 (12.0)%, 48. 3 (13.9)%, 48.2 (13.3)%, 48.2 (15.0)%; p = 0.006), 35 day mortality (5.7%, 7.1%, 7.9%, 12.5%; p = 0.0004), six month mortality (7.3%, 8. 6%, 10.4%, 15.5%; p < 0.0001), and 35 day reinfarction rate (6.1%, 3. 2%, 4.0%, 0.9%; p = 0.0001).

CONCLUSIONS

In this single large trial, the beneficial effect of time to thrombolysis on infarct size and ejection fraction was restricted to treatment given within two hours of symptom onset, while the effect on mortality was evident over all time intervals. Reinfarction rate was higher in patients treated with earlier thrombolysis.

The use of the electrocardiogram to identify epicardial coronary and tissue reperfusion in acute myocardial infarction

The standard 12-lead ECG gives us crucial information concerning myocardial perfusion and the success of reperfusion therapy for ST-elevation acute myocardial infarction. Continuous monitoring has advantages over repeated snapshot recordings. There are four electrocardiographic markers for prediction of the perfusion status of the ischemic myocardium: 1) ST-segment measurements; 2) T-wave configuration; 3) QRS changes; and 4) reperfusion arrhythmias. Complete and stable (> or = 70%) resolution of ST-segment elevation is associated with better outcome and preservation of left ventricular function than partial (30% to 70%) or no (< 30%) ST-segment resolution. Early inversion of the T-waves after initiation of reperfusion therapy is another marker of myocardial reperfusion and a good prognostic sign. Using standard 12-lead ECG, dynamic changes in Q-wave number, amplitude and width, R-wave amplitude and S-wave appearance are detected during reperfusion therapy. However, the significance of these changes have not been clarified. Reperfusion arrhythmias, especially bradycardia and accelerated idioventricular rhythm are detected occasionally during reperfusion therapy, but the value of reperfusion arrhythmias as a marker of coronary artery patency is still debatable. Dynamic changes in the QRS complexes, ST-segments and T-waves occur during reperfusion therapy and the days after. While changes in ST-segment amplitude have been extensively studied, the significance of QRS-complex and T-wave changes are less clear, and especially whether changes in the QRS-complex and T-wave may be complementary and additive to ST-segment monitoring. It has remained unclear whether electrocardiographic signs of reperfusion and re-ischemia should be used for therapeutic decision-making in the clinical setting.

Angiographic assessment of prospectively determined non-invasive reperfusion indices in acute myocardial infarction

OBJECTIVE

To investigate the value of non-invasive reperfusion indices in acute myocardial infarction, avoiding the possible need for acute coronary angiography and subsequent angioplasty.

DESIGN

In a prospective angiographic study, seven potential ECG or clinical markers of reperfusion were analysed in 230 patients with acute myocardial infarction. In all patients two 12 lead ECGs were used: the ECG on admission and the ECG immediately before coronary angiography. Non-invasive markers of reperfusion determined just before coronary angiography were prospectively correlated to thrombolysis in myocardial infarction (TIMI) flow. Data analysis correlated these non-invasive indices with coronary flow (analysis A: TIMI 2-3 v TIMI 0-1 flow; analysis B: TIMI 3 v TIMI 0-2 flow).

RESULTS

A sudden decrease in chest pain was the most common sign of reperfusion (36%), followed by reduction in ST segment elevation by >/= 50% (30%), and the development of a terminal negative T wave (20%) in the lead with the highest ST segment elevation. Reduction in ST segment elevation by > or = 50% and the appearance of an accelerated idioventricular rhythm (AIVR) had the highest positive predictive value for reperfusion. For analyses A and B, the positive predictive values were 85% and 66% for resolution of ST segment elevation, and 94% and 59% for AIVR, respectively. The presence of three or more non-invasive markers of reperfusion predicted TIMI 3 flow accurately in 80% of cases.

CONCLUSIONS

The prospective use of non-invasive indices of reperfusion is simple, practical, and can be of value in assessing coronary patency in patients admitted with acute myocardial infarction. Using these indices, discrimination between TIMI 0-1 and TIMI 2-3 flow can be made with good accuracy. However, TIMI 3 flow cannot be determined reliably. The use of such non-invasive indices depends on the goal of reperfusion.

Evidence for the delayed effect in human ischemic preconditioning: prospective multicenter study for preconditioning in acute myocardial infarction

OBJECTIVES

This study aimed to investigate prospectively the protective effect of a first preinfarction angina attack against acute myocardial infarction (AMI) in human hearts without significant collaterals.

BACKGROUND

Several retrospective studies and the prospective studies have demonstrated the existence of the preconditioning (PC) effect in humans. However, collaterals were not examined in the prospective studies. In animal models, the PC effect on myocardial infarct size appears soon after PC reperfusion (classic) but disappears within 1 to 2 h. It then reappears 24 to 48 h after reperfusion (the delayed PC effect). Meanwhile, the PC effect on stunning appears 12 h after PC reperfusion (the delayed PC effect). The concept of the classic and delayed PC effects has not been investigated in human AMI studies. If the above concept is also correct in humans, the infarct size and/or impairment of the left ventricular function should be inversely correlated with the time interval between the first preinfarction angina attack and the onset of AMI when that time interval is limited to between 2 and 48 h.

METHODS

The subjects were 25 patients with first AMI of the proximal left anterior descending artery who underwent successful direct percutaneous transluminal coronary angioplasty (PTCA) 2 to 6 h after the onset and with no (or poor) collateral circulation (grade 0 or 1). They were divided into two groups: preinfarction angina (PA)(+) group: 11 patients with new onset preinfarction angina from 2 to 48 h before the onset, PA(-) group: 14 patients without angina before infarction. Peak creatine kinase (CK) and cumulative CK were examined, and the left ventricular ejection fraction (LVEF) and the regional wall motion (RWM) were determined from the left ventriculograms during the acute (immediately after the coronary reperfusion) and chronic (four weeks after the onset of AMI) phases. The RWM index (RWMI) was then calculated as the mean motion of chords (standard deviation [SD]/chord) lying in the area of chords of RWM < or = -2 SD in the acute phase (ischemic risk area). RESULTS The increase in the RWMI between the acute and chronic phases was significantly larger in the PA(+) group than in the PA(-) group (1.55 +/- 1.32 and 0.69 +/- 0.75, p < 0.05, respectively) although no significant difference in the enzymatic infarct size was seen between the two groups. The increases in the LVEF and the RWMI were significantly correlated with the time interval from the first preinfarction angina attack to the onset of AMI (r = 0.622, p < 0.05 and r = 0.646, p < 0.05, respectively), but the enzymatic infarct size was not.

CONCLUSIONS

The beneficial effect of preinfarction angina on left ventricular wall motion, independently of collateral flows, indicates the existence of the PC effect in humans. The greater protective effect of a longer time interval between angina pectoris and AMI suggests that the protection is due to a delayed PC effect.

Relation of plasma lipoprotein(a) with myocardial viability and left ventricular performance in survivors of myocardial infarction

Previous studies have reported that high serum lipoprotein(a) levels may be responsible for total occlusion of the infarct-related artery via inhibition of intrinsic fibrinolysis during acute myocardial infarction. We evaluated whether this would result in a greater extent of myocardial necrosis and impaired left ventricular function in patients with high lipoprotein(a) levels. Sixty-eight patients with prior myocardial infarction, who were not receiving thrombolytic therapy underwent coronary angiography and stress-redistribution-reinjection Tl-201 scintigraphy. Antegrade TIMI flow in the infarct-related artery was lower (1.54 +/- 1.14 vs 2.15 +/- 1.05; p = 0.03) and the collateral index was higher (1.3 +/- 1.0 vs 0.8 +/- 0.9; p = 0.07) in patients with high lipoprotein(a) levels (> 30 mg/dl) compared to those with low lipoprotein(a) levels (< or = 30 mg/dl). Regional wall motion score index was lower (0.8 +/- 0.8 vs 1.4 +/- 0.5; p = 0.008) and global ejection fraction was higher (46 +/- 10% vs 40 +/- 11%; p = 0.03) in patients with low lipoprotein(a) levels. On SPECT images, the number of non-viable defects was higher in patients with high lipoprotein(a) levels (4.0 +/- 2.5 vs 1.9 +/- 1.3; p = 0.0002), whereas the number of viable defects was higher in those with low lipoprotein(a) levels (2.5 +/- 1.8 vs 1.5 +/- 1.3; p = 0.02). We conclude that high lipoprotein(a) levels may prolong the occlusion of infarct-related artery during acute myocardial infarction and lead to a greater extent of myocardial necrosis and impaired left ventricular function.

Delayed thrombolytic treatment of older patients with acute myocardial infarction

OBJECTIVE

To determine demographic and clinical factors associated with delayed thrombolysis in patients with acute myocardial infarction.

DESIGN

A retrospective cohort.

SETTING

37 Minnesota hospitals during the time periods October 1992-July 1993 and July 1995-April 1996.

PATIENTS

We reviewed the medical records of 776 older patients aged 65 or older hospitalized with an admission diagnosis of acute myocardial infarction, suspected acute myocardial infarction, or rule-out acute myocardial infarction, who were treated with a thrombolytic agent.

MEASUREMENT

We used multivariate logistic regression models to examine the association between selected study characteristics and time between hospital presentation and administration of thrombolytic treatment. Early thrombolysis was defined as less than 60 minutes after hospital presentation and late thrombolysis as 60+ minutes.

RESULTS

Of 776 study patients, 57.5% (n = 446) received early thrombolysis. Of the remaining 330 patients receiving late treatment, 12.1% (n = 94) were thrombolyzed more than 2 hours after hospital presentation. After controlling for other factors, the odds of delayed thrombolysis among patients aged 75 or older were 1.48 compared with younger individuals (95% CI, 1.17-1.88). The odds of delayed thrombolysis among patients with severe comorbidity were 1.46 (95% CI, 1.10-1.94) compared with individuals without severe comorbidity. Predictors of early thrombolytic treatment included hospital arrival via emergency transport (ORdelay = 0.46; 95% CI, 0.34-0.63) and chest discomfort at admission (ORdelay = 0.40; 95% CI, 0.18-0.86).

CONCLUSIONS

The present study indicates that patients of advanced age and with severe comorbidity are more likely to experience delayed thrombolytic treatment after hospital presentation. These are the patients who suffer the highest morbidity from acute myocardial infarction and for whom expeditious treatment may enhance therapeutic benefit.

Rational basis for use of sodium-hydrogen exchange inhibitors in myocardial ischemia

The cardiac sarcolemmal Na+/H+ exchanger extrudes intracellular H+ in exchange for Na+, in an electroneutral process. Of the 6 mammalian exchanger isoforms identified to date, the Na+/H+ exchanger (NHE)-1 is believed to be the molecular homolog of the sarcolemmal Na+/H+ exchanger. The exchanger is activated primarily by a reduction in intracellular pH (intracellular acidosis), although such activation is subject to modulation by a variety of endogenous mediators (e.g., catecholamines, thrombin, endothelin) through receptor-mediated mechanisms. A large body of preclinical evidence now suggests that inhibition of the sarcolemmal Na+/H+ exchanger attenuates many of the unfavorable consequences of acute myocardial ischemia and reperfusion. Much of this evidence has been obtained with recently developed potent, selective inhibitors of the exchanger, such as HOE-642 (cariporide) and its structurally related congener HOE-694, in studies using both in vitro and in vivo models of ischemia and reperfusion in a variety of species. The data from these studies indicate that Na+/H+ exchange inhibition leads to a decreased susceptibility to severe ventricular arrhythmia, attenuates contractile dysfunction, and limits tissue necrosis (i.e., decreases infarct size) during myocardial ischemia and reperfusion. Such protection is likely to arise, at least in part, from attenuation of "Ca2+ overload," which has been linked causally with all of these pothologic phenomena. The consistent and marked cardioprotective benefit that has been observed with cariporide and related compounds in preclinical studies suggests that Na+/H+ exchange inhibition may represent a novel and effective approach to the treatment of acute myocardial ischemia in humans.

Early referral for intentional rescue PTCA after initiation of thrombolytic therapy in patients admitted to a community hospital because of a large acute myocardial infarction

BACKGROUND

If no in-house facilities for percutaneous transluminal coronary angioplasty (PTCA) are present, thrombolytic therapy is the treatment of choice for acute myocardial infarction (AMI). A few studies have shown benefit from rescue PTCA in patients directly admitted to centers with PTCA facilities. The obvious question arises whether patients with AMI initially admitted to a community hospital can benefit from early transfer for intentional rescue PTCA.

METHODS AND RESULTS

One hundred sixty-five patients were transferred early for intentional rescue PTCA from a community hospital at a distance of 20 miles. On arrival at the angioplasty center, bedside markers were used to determine reperfusion. In case of obvious reperfusion, no invasive procedure was done; otherwise, coronary angiography and rescue PTCA, if necessary, was performed. During transfer, 1 (1%) patient died and 15 (9%) patients had arrhythmic or hemodynamic problems. Median time delay between onset of chest pain and arrival at the community hospital and the PTCA center was 61 minutes (range 0 to 413) and 150 minutes (range 28 to 472), respectively. In 66 (40%) patients, reperfusion was diagnosed by noninvasive reperfusion criteria on arrival at the PTCA center (group 1). Ninety-eight (59%) patients without evident noninvasive criteria of reperfusion underwent angiography 187 median minutes after the onset of chest pain. Forty-one (25%) patients had Thrombolysis In Myocardial Infarction grade 3 flow, and no further intervention was performed (group 2). In the remaining 57 (35%) patients, rescue PTCA was performed, which was successful in 96% (group 3). In-hospital mortality rate was lowest in group 1 compared with the other 2 groups (0% vs 7% vs 11%; P <.05). Reinfarction was highest in group 1 compared with the other groups (17% vs 5% vs 2%; P <.01). No significant differences were found in coronary artery bypass grafting, stroke, or bleeding complications. The 1-year follow-up data showed low revascularization rates; 2 (1%) patients died after discharge from the hospital.

CONCLUSIONS

Early transfer of patients with large AMI for intentional rescue PTCA can be done with acceptable safety and is feasible within therapeutically acceptable time limits and results in additional early reperfusion in 33% of patients. A large, randomized, multicenter trial is needed to compare efficacy of intravenous thrombolytic treatment in a community hospital versus early referral for either rescue or primary PTCA.

Combined historical and electrocardiographic timing of acute anterior and inferior myocardial infarcts for prediction of reperfusion achievable size limitation

The historical time of acute symptom onset is not always an accurate indication of the timing of onset of an acute myocardial infarction (AMI). Consideration of electrocardiographic (ECG) timing parameters could supplement historical timing alone as a clinical guide for decisions regarding the use of reperfusion therapy. Three hundred ninety-five patients from 4 trials of thrombolytic therapy conducted in the northwestern United States and western Canada are included in the present study. A total of 316 patients received either streptokinase or tissue plasminogen activator, and 79 received no reperfusion therapy. Historical time of symptom onset was acquired by emergency or cardiology department personnel and recorded on patient report forms. An ECG method for estimating the timing of the AMI, the Anderson-Wilkins (AW) acuteness score, was calculated from the initial standard 12-lead recording by investigators blinded to the knowledge of symptom duration or any other study variables. Tomographic thallium-201 imaging 7 weeks after hospital admission was used to measure final AMI size. The ECG timing method achieved a relation with final AMI size similar to that previously reported for historical timing. The AW acuteness score proved most useful for anterior AMI location when there was a > or = 2 hour delay following symptom onset, but was most useful for the inferior AMI location when there was a < 2 hour delay. Despite a longer delay, patients with high AW acuteness scores had 50% lower final anterior AMI size than those with low scores; and despite a shorter delay, those with low ECG acuteness scores had 50% greater final inferior AMI size than those with high scores. The AW acuteness score combined with the historical estimation of symptom duration should provide a more accurate basis for predicting the potential for limitation of final AMI size than either method alone. These results could potentially provide the basis for developing a new method for noninvasive guidance of clinical decisions regarding administration of reperfusion therapy in the initial evaluation of patients with AMI.

Vectorcardiographic evaluation of myocardial infarct size: departure parameters are superior to conventional spatial parameters

To determine whether the departure parameters derived from a "departure loop" of a vectorcardiogram are more accurate than conventional spatial parameters in evaluating myocardial infarct size, 74 patients with first-onset myocardial infarction (MI) were studied. The correlation between the departure parameters (amplitudes in scalar leads of the departure loop) and the percent defect volume of thallium myocardial scintigrams (%DV) was compared with that of the spatial parameters (magnitude, azimuth, and elevation of the original QRS loop). In anteroseptal MI, the amplitude of a 20-msec vector in the z-axis and the azimuth of a 30-msec vector (H30) were significantly correlated with %DV (r=0.783, p<0.001 and r=0.572, p<0.05). In anteroseptal MI with involvement of the lateral wall, the amplitude of a 30-msec vector in the x-axis and H30 showed significant correlation with %DV (r=0.802, p<0.001 and r=0.772, p<0.01). In inferior and inferoposterior MI, the amplitude of a 30-msec vector in the y-axis and the elevation of a 30-msec vector were significantly correlated with %DV (r=0.920, 0.891, p<0.001 and r=0.871, 0.678, p<0.01, respectively). In conclusion, the departure parameters are more accurate than the spatial parameters for evaluation of myocardial infarct size.

Thrombolytic therapy: a review of its use in acute myocardial infarction

OBJECTIVE

To review the literature on the use of thrombolytic agents in the pharmacotherapeutic management of acute myocardial infarction (AMI).

DATA SOURCE

English-language clinical trials, reviews, and editorials derived from MEDLINE (January 1966-September 1997) and/or cross-referencing of selected articles.

STUDY SELECTION

Articles that were selected best represent the clinical trials researching the role for thrombolytics in the therapy of AMI to improve morbidity and mortality.

DATA SYNTHESIS

AMI is one of the leading causes of mortality in the US. Following supportive data that the most common cause of an AMI is an intracoronary thrombus, clinical investigation has demonstrated that intravenous thrombolytic agents improve survival rates in patients who experience an AMI. Several clinical trials have been conducted to determine whether one thrombolytic agent is superior to others with respect to improving mortality. At present, only the first Global Use of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial has reported any statistically significant difference in mortality rate. In this trial, "front-loaded" alteplase induced a statistically significant (p < 0.001) 1% absolute reduction in 30-day and 1-year mortality compared with streptokinase. This has led to alteplase being the preferred thrombolytic at many US institutions. However, the results of GUSTO-I have been questioned by some on the basis of either study design or clinical significance.

CONCLUSIONS

Thrombolytic agents have secured a place in the treatment of AMI due to their well-proven reduction in mortality rates. In general, comparative trials have demonstrated minimal differences in efficacy among these agents. Probably just as important as choosing which thrombolytic agent to use is ensuring that a patient experiencing an AMI is administered thrombolytic therapy unless a contraindication to receive such therapy exists in the patient and/or the patient is a candidate to receive an emergent intracoronary procedure. Trials also indicate that the sooner thrombolytics can be administered, the greater the benefit to the patient.

Higher T-wave amplitude associated with better prognosis in patients receiving thrombolytic therapy for acute myocardial infarction (a GUSTO-I substudy). Global Utilization of Streptokinase and Tissue plasminogen Activator for Occluded Coronary Arteries

Increased T-wave amplitude is one of the earliest electrocardiographic (ECG) changes following coronary artery occlusion. Therefore, higher T waves in the presenting electrocardiogram should represent earlier time to treatment and thus be associated with lower mortality following thrombolytic therapy. However, T-wave amplitude has never been evaluated as a prognostic marker in this setting. We examined clinical outcomes in 3,317 patients with acute myocardial infarction (AMI) who underwent thrombolysis in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-I) Study. Patients were classified as either those with high T waves or those with low T waves. Higher T waves were defined as those >98th percentile of the upper limit of normal. T-wave amplitude was also evaluated as a continuous variable according to infarct location (maximum T-wave amplitude) and as the amount of excess T-wave amplitude above normal (excess T-wave amplitude). Patients with higher T waves had lower 30-day mortality than those without (5.2% vs 8.6%, p = 0.001) and were less likely to develop congestive heart failure (15% vs 24%, p <0.001) or cardiogenic shock (6.1% vs 8.6%, p = 0.023). Higher maximum T-wave amplitude and excess T-wave amplitude were predictive of lower 30-day mortality (chi-square = 67, p <0.001 and chi-square = 33, p <0.001, respectively). These differences remain significant after controlling for other prognostic baseline ECG variables. In addition, T-wave amplitude added prognostic significance after controlling for time to treatment. T-wave amplitude, an often-overlooked component of the electrocardiogram, can add significant prognostic information in initial evaluation of patients with AMI.

Randomized, controlled trial of RheothRx (poloxamer 188) in patients with suspected acute myocardial infarction. RheothRx in Myocardial Infarction Study Group

BACKGROUND

Patients with acute myocardial infarction (AMI) who are not eligible for thrombolytic therapy or primary coronary angioplasty are distinguished by advanced age, complicated medical histories, relatively frequent use of prior revascularization procedures, and worse outcomes than their counterparts who are eligible for reperfusion therapy.

METHODS AND RESULTS

The purpose of this randomized, controlled trial was to determine whether RheothRx, a hemorheologic agent, reduced myocardial infarct size and improved left ventricular function in patients who had suspected AMI at the time of hospital admission and were not eligible for reperfusion therapy. Patients were randomly assigned to RheothRx (n = 97) or placebo (n = 99). Patients in the two groups were similar with respect to age, sex, medical history, and clinical presentation. Enzyme evidence of AMI was present in 69% of the treatment group and 70% of the placebo group. Infarct size measured before hospital discharge was similar in the two groups (14.1% +/- 18.5% vs 11.7% +/- 14.1%, p = 0.60), although left ventricular ejection fraction was lower in the treatment group (47 +/- 14 vs 52 +/- 11, p = 0.026). Hospital mortality rate was 11.3% and 7.1% in patients receiving RheothRx and patients receiving placebo, respectively (p = 0.30). There was a higher occurrence of acute renal dysfunction in the RheothRx group (12% vs 2%, p = 0.005). Because of changes in drug dosage necessitated by the occurrence of acute renal dysfunction, the trial was stopped.

CONCLUSIONS

In this study of patients who had suspected AMI and were not eligible for thrombolytic therapy, RheothRx did not decrease infarct size or favorably alter outcome. The need for effective treatment for this large patient population remains largely unmet.

[Clinical prediction of the early prognosis in acute myocardial infarct]

Several clinical factors can influence the pathophysiology, clinical course and prognosis of acute myocardial by different means. Some of them may be easily detected through the history, physical examination or ECG in an early phase. The knowledge of these factors may help the therapeutic decision making of patients with myocardial infarction. The influence for the main clinical factors (age, sex, risk factors, cardiologic antecedents and evolutive findings) on the short-term prognosis of acute myocardial infarction is reviewed. An analysis of the likely mechanisms of the influence of these factors on infarct prognosis is also performed.

Clinical value of 12-lead electrocardiogram after successful reperfusion therapy for acute myocardial infarction. Zwolle Myocardial infarction Study Group

BACKGROUND

A simple clinical method to stratify risk for patients who have had successful reperfusion therapy after myocardial infarction is attractive since it facilitates the tailoring of therapy.

METHODS

We investigated the clinical value of the 12-lead electrocardiogram (ECG), in 403 patients after successful reperfusion therapy by primary coronary angioplasty, in relation to infarct size measured by enzyme activity, left-ventricular function, and clinical outcome. ECGs were analysed to find the extent of the ST-segment-elevation resolution 1 h after reperfusion therapy.

FINDINGS

A normalised ST segment was seen in 51% of patients, a partly normalised ST segment in 34%, and 15% had no ST-segment-elevation resolution. Enzymatic infarct size and ejection fraction were related to the extent of the early resolution of the ST segment. The relative risk of death among patients with no resolution compared with patients with a normalised ST segment was 8.7 (95% CI 3.7-20.1), and that among patients with partial resolution compared with patients with a normalised ST segment was 3.6 (1.6-8.3).

INTERPRETATION

Our findings suggest that ECG patterns reflect the effectiveness of myocardial reperfusion. Patients for whom reperfusion therapy by primary angioplasty was successful and who had normalised ST segments had limited damage to the myocardium and an excellent outlook during follow-up. Patients with persistent ST elevation after reperfusion therapy may need additional interventions since they have more extensive myocardial damage and have a higher mortality rate.