Short- and long-term clinical outcome after Q wave and non-Q wave myocardial infarction in a large patient population

Physiological Implications of Myocardial Scar Structure

Once myocardium dies during a heart attack, it is replaced by scar tissue over the course of several weeks. The size, location, composition, structure, and mechanical properties of the healing scar are all critical determinants of the fate of patients who survive the initial infarction. While the central importance of scar structure in determining pump function and remodeling has long been recognized, it has proven remarkably difficult to design therapies that improve heart function or limit remodeling by modifying scar structure. Many exciting new therapies are under development, but predicting their long-term effects requires a detailed understanding of how infarct scar forms, how its properties impact left ventricular function and remodeling, and how changes in scar structure and properties feed back to affect not only heart mechanics but also electrical conduction, reflex hemodynamic compensations, and the ongoing process of scar formation itself. In this article, we outline the scar formation process following a myocardial infarction, discuss interpretation of standard measures of heart function in the setting of a healing infarct, then present implications of infarct scar geometry and structure for both mechanical and electrical function of the heart and summarize experiences to date with therapeutic interventions that aim to modify scar geometry and structure. One important conclusion that emerges from the studies reviewed here is that computational modeling is an essential tool for integrating the wealth of information required to understand this complex system and predict the impact of novel therapies on scar healing, heart function, and remodeling following myocardial infarction.

Immediate effects of upper thoracic spine manipulation on hypertensive individuals

PURPOSE

The aims of this study were to determine if there were any statistically significant immediate effects of upper thoracic spinal manipulative therapy (SMT) on cardiovascular physiology in hypertensive individuals.

INTRODUCTION

Preliminary research suggests that SMT to various regions of the spine may be capable of lowering systolic and diastolic blood pressure in hypertensive individuals. Further studies are warranted to corroborate or refute these findings as well as measure how other attributes of cardiovascular physiology are impacted by SMT.

METHODS

Fifty hypertensive participants (age = 45.5±13.9 years, height = 1.69±0.10 m, body mass = 93.9±21.5 kg: mean±standard deviation (SD)) were equally randomized into a single-blind, controlled trial involving two study groups: supine diversified anterior upper thoracic SMT of T1-4, or a 'no T-spine contact' control. Outcome measures were electrocardiogram, bilateral pulse oximetry, and bilateral blood pressure measurement performed at baseline, post 1-minute intervention, and post 10-minute intervention. An independent samples t-test was used to compare between-group differences at baseline. A repeated measures ANOVA was used to compare within-group changes over time.

RESULTS

Within-group changes in PR interval and QRS duration demonstrated that the atria were transiently less active post-SMT and the ventricles were more active post-SMT, however the changes were clinically minimal.

CONCLUSION

The results of this study, and the limited existing normotensive, thoracic-specific SMT research in this field, suggest that cardiovascular physiology, short-term, is not affected by upper thoracic spine SMT in hypertensive individuals to a clinically relevant level.

Early electrocardiographic findings and MR imaging-verified microvascular injury and myocardial infarct size

OBJECTIVES

This study investigated early electrocardiographic findings in relation to left ventricular (LV) function, extent and size of infarction, and microvascular injury in patients with acute myocardial infarction (MI) treated with percutaneous coronary intervention (PCI).

BACKGROUND

The electrocardiogram (ECG) is the most used and simplest clinical method to evaluate the risk for patients immediately after reperfusion therapy for acute MI. ST-segment resolution and residual ST-segment elevation have been used for prognosis in acute MI, whereas Q waves are related to outcome in chronic MI. We hypothesized that the combination of these electrocardiographic measures early after primary PCI would enhance risk stratification.

METHODS

We prospectively included 180 patients with a first acute ST-segment elevation MI to assess ST-segment resolution, residual ST-segment elevation, and number of Q waves using the 12-lead ECG acquired on admission and 1 h after successful PCI. The ECG findings were related to LV function, infarction size and transmurality, and microvascular injury as assessed with cine and gadolinium-enhanced cardiac magnetic resonance 4 +/- 2 days after reperfusion therapy.

RESULTS

Residual ST-segment elevation (beta = -2.00, p = 0.004) and the number of Q waves (beta = -1.66, p = 0.005) were independent ECG predictors of LV ejection fraction. Although the number of Q waves was the only independent predictor of infarct size (beta = 2.01, p < 0.001) and transmural extent of infarction (beta = 0.60, p < 0.001), residual ST-segment elevation was the only independent predictor of microvascular injury (odds ratio: 19.1, 95% confidence interval: 2.4 to 154, p = 0.005) in multivariable analyses. The ST-segment resolution was neither associated with LV function, infarct size, or transmurality indexes, nor with microvascular injury in multivariable analysis.

CONCLUSIONS

In patients after successful coronary intervention for acute MI, residual ST-segment elevation and the number of Q waves on the post-procedural ECG offer valuable complementary information on prediction of myocardial function and necrosis and its microvascular status.

Prediction of myocardial infarction risk in older patients with acute coronary syndrome

PURPOSES

To identify bedside variables that aid in diagnosis of acute coronary syndrome (ACS) and might facilitate rapid triage of patients aged > or = 65 years.

BASIC PROCEDURES

Prospective, observational study of consecutive patients aged > or = 65 years with suspicion of ACS presenting to our emergency department (ED). Patients' medical characteristics were collected at baseline and during a 1-month follow-up period. We identified variables independently associated with ACS by multivariate analyses and bootstrapping techniques.

MAIN FINDINGS

Among 399 patients, 124 (31.1%) received a diagnosis of ACS (61 acute myocardial infarction, 63 unstable angina). We surveyed multiple clinical and ECG variables to develop a predictive model which included the following variables: male sex, history of coronary artery disease, typical chest pain, dyspnea, epigastric pain, pathological Q-wave, ST-segment elevation (area under the receiver operating characteristic curve (AUC) 0.79, 95% confidence interval 0.71 to 0.82). With the addition of cardiac troponin I to the model the AUC increased to 0.83 (0.79 to 0.88). We used these findings to create the Heart Attack Risk for aged Patient (HARP) scale. Our data suggest that patients with a low HARP score might be safely managed without further testing.

PRINCIPAL CONCLUSIONS

A model based on variables easily available at ED presentation from history, physical examination, and electrocardiography, can help ED physicians to identify seniors at very low risk of ACS.

Incidence, distribution, and prognostic impact of occluded culprit arteries among patients with non-ST-elevation acute coronary syndromes undergoing diagnostic angiography

BACKGROUND

Because acute occlusion of coronary arteries supplying the inferolateral myocardium frequently eludes standard 12-lead electrocardiogram (ECG) diagnosis, these patients may present as non-ST-segment elevation acute coronary syndromes (NSTE-ACS).

METHODS

We examined culprit artery occlusion among 1,957 NSTE-ACS patients in the Platelet IIb/IIIa Antagonism for the Reduction of Acute Coronary Syndrome Events in a Global Organization Network trial who underwent diagnostic coronary angiography. We compared baseline characteristics, electrocardiographic findings, in-hospital treatment, and long-term outcomes between patients with and without occluded culprit arteries.

RESULTS

The culprit artery was occluded in 528 (27%) patients. Culprit lesions were more frequently identified in the inferolateral territory among patients with an occluded culprit artery (63%) compared with those with a nonoccluded artery (45%, P < .0001). Patients with an occluded culprit artery were younger, more often male, and more likely to have had a prior myocardial infarction. Despite similar in-hospital treatment, patients with an occluded culprit artery had larger infarcts (median peak creatine kinase-MB 4.3 vs 2.1 x upper limit of normal, P < .0001) and higher risk-adjusted 6-month mortality (hazard ratio 1.72, 95% CI 1.07-2.79).

CONCLUSIONS

More than 25% of NSTE-ACS patients had an occluded culprit artery on angiography. These patients may represent ST-segment elevation myocardial infarction equivalents; thus, improved early risk stratification techniques would help more rapidly triage these high-risk patients to an early invasive management strategy.

Comparison of outcome in patients with ST-elevation versus non-ST-elevation acute myocardial infarction treated with percutaneous coronary intervention (from the National Heart, Lung, and Blood Institute Dynamic Registry)

Patients with ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) are increasingly being treated with percutaneous coronary intervention (PCI) and we sought to determine risk of adverse outcomes by type of MI. Patients enrolled in the National Heart, Lung, and Blood Institute Dynamic Registry from 1999 to 2004 who presented with an acute MI as an indication for PCI were studied. Baseline data and in-hospital and 1-year outcomes were compared based on ST-segment elevation (STEMI, n = 903; NSTEMI, n = 583) at presentation. Patients with STEMI were younger, had fewer co-morbidities, and had less extensive coronary artery disease than did patients with NSTEMI. Angiographic success and periprocedural complications were similar by MI type. In-hospital coronary artery bypass grafting, stroke, bleeding and recurrent MI were similar but mortality was higher in patients with STEMI (4.0% vs 1.4%, p = 0.004). Cardiogenic shock was associated with the greatest risk of in-hospital death (odds ratio 26.7, 95% confidence interval 11.4 to 62.3, p = 0.0001), but STEMI was also independently predictive of mortality. At 1 year, there was no influence of MI type on outcome. Age, cardiogenic shock, renal disease, peripheral vascular disease, and cancer were predictive of death and MI. Multivessel disease and a larger number of >50% lesions were associated with the need for repeat revascularization. In conclusion, STEMI was associated with a higher likelihood of in-hospital death than was NSTEMI, but long-term outcomes after PCI were independent of MI type. At 1 year, associated co-morbidities were strongly associated with death and MI, whereas only angiographic characteristics predicted the need for repeat revascularization.

Clinical, electrocardiographic, and biochemical data for immediate risk stratification in acute coronary syndromes

The recent evolution in therapeutic options for acute coronary syndromes (ACS) mandates early risk stratification in order to select the appropriate treatment strategy for individual patients. Simple clinical data derived from the patient's medical history and physical examination, a standard twelve-lead electrocardiogram (ECG), and determinations of biochemical markers of myocardial damage can be obtained in the emergency room and serve as a guide for deciding appropriate medical management and optimal use of available resources. Even the most important classification of the ACS is based upon a simple and dichotomous description of the ECG, where the presence of ST-segment elevation mandates an immediate attempt to restore coronary perfusion (either pharmacologically or mechanically), whereas its absence suggests pharmacological stabilization before further evaluation. Across the whole spectrum of ACS, clinical history data (such as older age, previous coronary events, and diabetes) and clinical variables (such as higher heart rate, lower blood pressure, and higher Killip class) are the most powerful prognostic determinants at multivariate analyses derived from large databases. The ECG adds significant and independent prognostic information using the analysis of qualitative (direction of ST-segment shift, associated T-wave inversion, and presence of conduction disturbances) and quantitative (number of leads involved, amount of ST- segment shifts, duration of QRS) characteristics. Biochemical markers of myocardial damage have also been identified as independent predictors of events. In addition, retrospective analyses of clinical trials have suggested that biochemical markers might serve as a guide to select pharmacological therapy. However, how to best combine electrocardiographic and biochemical data for immediate risk stratification remains to be further elucidated.

Application of the Thrombolysis in Myocardial Infarction risk index in non-ST-segment elevation myocardial infarction: evaluation of patients in the National Registry of Myocardial Infarction

OBJECTIVES

The purpose of this research was to evaluate the Thrombolysis In Myocardial Infarction risk index (TRI) to characterize the risk of death among patients with non-ST-segment elevation myocardial infarction (NSTEMI).

BACKGROUND

The TRI, calculated from baseline age, systolic pressure, and heart rate, was established in patients with ST-segment elevation myocardial infarction (STEMI) and is predictive of mortality. Patients presenting with NSTEMI are increasing compared to STEMI and constitute a group with varied risk.

METHODS

The TRI was calculated in 337,192 patients from the National Registry of Myocardial Infarction with NSTEMI. Values and outcomes were compared with 153,486 patients with STEMI classified by reperfusion status. Comparisons of baseline characteristics and clinical outcomes stratified by TRI were made.

RESULTS

There was a graded relationship between the TRI and mortality in patients with NSTEMI with a >30-fold difference in mortality rates between lowest and highest deciles (p < 0.0001). The index showed good discrimination (c = 0.73). Overall mortality in the group with NSTEMI was higher (10.9%) than patients with STEMI treated with (6.6%) but lower than for STEMI patients not receiving reperfusion therapy (18.7%). The higher risk in comparison to patients with STEMI treated with reperfusion therapy was explained largely by the higher-risk profile of the population with NSTEMI.

CONCLUSIONS

There is a graded relationship between TRI and mortality in patients with NSTEMI. This simple risk index provides important information about mortality in patients across the spectrum of myocardial infarction, STEMI and NSTEMI. Early identification of NSTEMI patients who are at high risk of in-hospital mortality may provide clinicians with important information for initial triage and treatment.

Classification of acute coronary syndromes using the 12-lead electrocardiogram as a guide

The management of patients with acute coronary syndromes (ACS) is becoming more complicated. With the advent of new therapies and surgical techniques, the likelihood that patients will make a full recovery improves. Cardiovascular disease remains the leading cause of death for adults in the United States, and with continually increasing trends such as obesity and diabetes, will likely remain so in the future. With the introduction of improved therapies, the numbers of patients dying after their first myocardial infarction continues to decline. Electrocardiogram (ECG) technology has improved, and further research has improved its sensitivity and specificity allowing for earlier, more consistent diagnosis of ACS. As a result, guidelines have been developed to assist nurses and clinicians in the management of patients with ACS. Nurses are in a unique position to provide primary triage, recognize ACS based on the patient's presentation and initial 12-lead ECG, and initiate an appropriate response. Key elements of 12-lead ECG interpretation and their application to established guidelines are essential skills for nurses working in clinical arenas frequented by patients with ACS.

MR imaging in ischemic heart disease

This article reviews the current MR imaging literature with respect to ischemic heart disease and focuses on the clinical practicalities of cardiac MR imaging today.

Relationship of contractile function to transmural extent of infarction in patients with chronic coronary artery disease

OBJECTIVES

We sought to determine the relationship of contractile function to the transmural extent of infarction (TEI) in patients with chronic coronary artery disease.

BACKGROUND

In the setting of reperfused, chronic myocardial infarction (MI), the relationship of contractile function to the TEI has not been established.

METHODS

We studied function by cine magnetic resonance imaging (MRI) and the TEI by contrast-enhanced MRI in 31 patients with single-vessel disease 162 +/- 62 days after reperfused first MI.

RESULTS

Of all 516 segments with MI, blinded observers were unable to detect abnormal thickening in 193 (37%), and wall thickening measured quantitatively in these segments was 66 +/- 28%. Of the 193 segments, 163 (84%) were infarcts limited to the subendocardium. The average TEI reached 53% before half of the patients had abnormal contractile function. When patients with small MI (< or =5% of total left ventricular [LV] mass) were excluded, the average TEI reached 43% before half the patients had abnormal function. In subjects with small MI (< or =5% of total LV mass [n = 13]), even segments with TEI >75% had normal function (14 of 14) because they were surrounded by normally moving neighbor segments.

CONCLUSIONS

In the setting of reperfused chronic MI, the TEI approaches 50% before contractile dysfunction can be systematically identified. Contractile function cannot be used to rule out chronic MI.

Angiographic and clinical characteristics associated with the development of Q-wave and non-Q-wave myocardial infarction in the thrombolysis in myocardial infarction (TIMI) 14 trial

BACKGROUND

In the absence of thrombolytic therapy, patients with non-Q-wave myocardial infarction (MI) have previously been shown to have lower long-term mortality rates than patients with Q-wave MI. The goal of our study was to examine the angiographic and clinical differences between non-Q-wave MI and Q-wave MI in patients with ST elevation MI (STEMI) in the era of thrombolytic and combination therapy of thrombolytics plus glycoprotein IIb/IIIa inhibitors.

METHODS

Angiography was performed 90 minutes after thrombolytic administration in the Thrombolysis in Myocardial Infarction (TIMI) 14 trial. The development of a non-Q-wave MI was assessed on electrocardiogram performed at the time of hospital discharge. Angiographic findings were assessed at an angiographic core laboratory by blinded investigators.

RESULTS

The qualifying episode of ST elevation developed into a non-Q-wave MI in 36% of patients (315/878) and into a Q-wave MI in 64% of patients (563/878). In patients in whom non-Q-wave MI developed, the rate of TIMI grade 3 flow was higher, peak creatine kinase level was lower, mean left ventricular ejection fraction was greater, corrected TIMI frame counts (CTFCs) were lower (ie, faster blood flow), and chest pain duration after thrombolytic administration was shorter. Patients in whom non-Q-wave MI developed less frequently underwent a percutaneous coronary intervention (PCI), and when they did, they had faster post-PCI CTFCs and higher rates of post-PCI TIMI grade 3 flow. Patients in whom a non-Q-wave MI developed had lower rates of severe recurrent ischemia. There were no differences in 30-day or in-hospital mortality rates or recurrent MI between patients with Q-wave MI and patients with non-Q-wave MI.

CONCLUSION

After thrombolytic therapy in STEMI with or without abciximab, ejection fractions were higher, the duration of ischemia was shorter, and coronary blood flow at both 90 minutes and after PCI was faster in patients who sustained non-Q-wave MI than in patients who sustained Q-wave MI. No differences in mortality or recurrent MI rates were detected in patients who sustained a Q-wave MI and patients in whom a Q-wave MI did not evolve in the modern thrombolytic era.

Potentially avoidable rehospitalizations following acute myocardial infarction by insurance status

Few studies have explored the impact of health insurance on patients with severe, chronic diseases. This retrospective study examined the association between health insurance and the risk of potentially avoidable rehospitalization in the 3 years following validated acute myocardial infarction (AMI) for a community-based probability sample of 683 patients admitted to 30 California hospitals in 1990-1991. In a multivariate analysis adjusted for measures of comorbidity burden, severity of illness, and AMI-related inpatient care, the risk of readmission was not significantly different among patients with no insurance, Medicare insurance, and non-Medicaid, non-Medicare ("private or other") insurance. However, compared to the latter group, patients with Medicaid were 2.6 times more likely to be readmitted for an AMI-related process (risk ratio. 2.61; 95% confidence interval, 1.33 to 5.11). Additional studies are needed to define the role of health insurance on clinical outcomes and health care access across a broader range of conditions and communities.

Changing the diagnostic criteria for myocardial infarction in patients with a suspected heart attack affects the measurement of 30 day mortality but not long term survival

OBJECTIVES

To explore the effects of alternative methods of defining myocardial infarction on the numbers and survival patterns of patients identified as having sustained a confirmed myocardial infarct.

DESIGN

An inclusive historical cohort of patients admitted with a suspected heart attack. Patients were recoded from raw clinical data (collected at the index admission) to the epidemiological definitions of myocardial infarction used by the Nottingham heart attack register (NHAR), the World Health Organization (MONICA), and the UK heart attack study.

SETTING

Single health district.

PATIENTS

The NHAR identified all patients admitted in 1992 with suspected myocardial infarction.

OUTCOME MEASURES

Survival at 30 days and four year postdischarge.

RESULTS

2739 patients were identified, of whom 90% survived to discharge. Recoding increased the numbers of patients defined as having confirmed myocardial infarction from 26% under the original NHAR classification to 69%, depending on the classification system used. In confirmed myocardial infarction, subsequent 30 day survival from admission varied from 77-86% depending on the classification system; four year survival after discharge was not affected. The distribution of important prognostic variables differed significantly between groups of patients with confirmed myocardial infarction defined by different systems. Patients with suspected but unconfirmed myocardial infarction under all classification systems had a worse postdischarge mortality.

CONCLUSIONS

The classification system used had a substantial effect on the numbers of patients identified as having had a myocardial infarct, and on the 30 day survival. There were significant numbers of patients with more atypical presentations, not labelled as myocardial infarction, who did badly following discharge. More research is needed on these patients.

Ten year mortality in subsets of patients with an acute coronary syndrome

OBJECTIVE

To describe the mortality during the subsequent 10 years for subsets of patients hospitalised for suspected acute coronary syndrome.

PATIENTS AND METHODS

All patients who were admitted to the emergency department in one hospital during 21 months for chest pain or other symptoms raising suspicion of an acute coronary syndrome were registered. From this baseline population three subgroups were defined among those being hospitalised: patients who developed a Q wave acute myocardial infarction (AMI) (n = 306); patients who developed a non-Q wave AMI (n = 527); and patients who developed confirmed or possible myocardial ischaemia (unstable angina pectoris) (n = 1274). These three groups were compared in terms of 10 year mortality.

RESULTS

Patients who developed a non-Q wave AMI had the highest 10 year mortality (70.3%), significantly higher than those who developed a Q wave AMI (60.1%; p = 0.004) and those who had confirmed or possible myocardial ischaemia (50.1%; p < 0.0001). There was no difference between patients with confirmed and those with possible myocardial ischaemia (50.0% and 50.1%, respectively). After correction for dissimilarities in age, sex, and history the adjusted risk ratio for death in patients with a non-Q wave AMI compared with Q wave AMI was 1.01 (95% confidence interval (CI) 0.82 to 1.25). The corresponding risk ratio for death in patients with a non-Q wave AMI compared with confirmed or possible myocardial ischaemia was 1.91 (95% CI 1.64 to 2.23). There was also an imbalance in drug regimens among groups.

CONCLUSION

This study shows that in a non-selected population of patients hospitalised with a suspected acute coronary syndrome, the highest risk of death is found in those with a non-Q wave AMI and the lowest in those with confirmed or possible myocardial ischaemia. Thus, patients with a Q wave AMI have a long term mortality risk intermediate between the two fractions defined as having unstable coronary artery disease. However, adjusting these results for age and history of cardiovascular disease eliminated the observed difference in mortality between non-Q wave and Q wave AMI. Furthermore, an imbalance in drug regimens might have affected the outcome.

Pathophysiology of early coronary angioplasty with stenting on non-Q-wave vs Q-wave myocardial infarction

This study was undertaken to evaluate the pathophysiologic and clinical effects of the early application of percutaneous transluminal coronary angioplasty (PTCA) supported by stenting on non-Q-wave myocardial infarction (MI). Ninety-four patients with non-Q-wave MI and 316 patients with Q-wave MI were studied. Early PTCA with provisional stenting (40%) was performed in all of them. A history of MI (22% vs 12%, p=0.018), preinfarction angina < or = 24 hours before the onset of MI (60% vs 33%, p<0.001), and patent infarct-related vessels (83% vs 21%, p<0.001) were significantly more common in non-Q-wave MI than in Q-wave MI. As predictors of the occurrence of non-Q-wave MI, preinfarction angina (p=0.001) and previous MI (p=0.021) were significant variables. Clinical outcomes showed more improvement in in-hospital death (0.0% vs 5.0%, p=0.036) and long-term event-free curves for death and/or MI (p=0.035) in non-Q-wave MI than Q-wave MI when patients with previous MI were excluded. There was no significant difference in clinical outcome between the two groups when patients with previous MI were included. The high incidence of patent infarct-related vessels and preinfarction angina as well as the improved outcome obtained by early PTCA/stenting suggest instability of coronary occlusion and culprit coronary lesions in non-Q-wave MI. In conclusion, non-Q-wave MI constitutes a characteristic feature of MI induced by unstable coronary lesions, and early interventional therapies are presumed to result in improved outcomes by stabilizing the unstable culprit lesions.

Dynamic changes of QT interval and QT dispersion in non-Q-wave and Q-wave myocardial infarction

QT interval and QT dispersion both prolong early postinfarction. Non-Q wave (NQMI) and Q-wave myocardial infarction (QMI) differ in the extent of transmural necrosis, which may influence these measures of myocardial repolarization. This study compared dynamic changes in QT interval and QT dispersion early postinfarction between NQMI and QMI. In 40 patients with NQMI and 69 patients with QMI, maximum QTc (QTc(max)) and QT dispersion (QTD) were measured during the first 4 days postinfarction. Infarct size was assessed daily by using the Selvester QRS score. In both infarct types, QTc(max) and QTD were prolonged on day 1 of infarction, peaking over the next 2 days before returning toward baseline by day 4. NQMI patients had significantly longer QTc(max) and QTD by days 2 to 3 when compared with QMI patients. Multivariable linear regression identified "infarct type x QRS score" as the only independent predictor of QTc(max) (R(2) =.32, P <.0001) and QTD (R(2) =.19, P <.0001) on day 2. In conclusion, dynamic changes of QTc(max) and QTD occur in both infarct types. Large NQMI is associated with greater prolongation of QTc(max) and QTD, which may be due to greater M cell uncoupling and exposure when compared with QMI.

Visualisation of presence, location, and transmural extent of healed Q-wave and non-Q-wave myocardial infarction

BACKGROUND

A technical advance in contrast-enhanced magnetic resonance imaging (MRI) has significantly improved image quality. We investigated whether healed myocardial infarction can be visualised as hyperenhanced regions with this new technique, and whether assessment of the transmural extent of infarction yields new physiological data.

METHODS

82 MRI examinations were carried out in three groups: patients with healed myocardial infarction; patients with non-ischaemic cardiomyopathy; and healthy volunteers. Patients with healed myocardial infarction were prospectively enrolled after enyzmatically proven necrosis and imaged 3 months (SD 1) or 14 months (7) later. The MRI procedure used a segmented inversion-recovery gradient-echo sequence after gadolinium administration. Findings were compared with those of coronary angiography, electrocardiography, cine MRI, and creatine kinase measurements.

FINDINGS

29 (91%) of 32 patients with infarcts imaged at 3 months (13 non-Q-wave) and all of 19 imaged at 14 months (eight non-Q-wave) showed hyperenhancement. In patients in whom the infarct-related-artery was identified by angiography, 24 of 25 imaged at 3 months and all of 14 imaged at 14 months had hyperenhancement in the appropriate territory. None of the 20 patients with non-ischaemic cardiomyopathy or the 11 healthy volunteers showed hyperenhancement. Irrespective of the presence or absence of Q waves, the majority of patients with hyperenhancement had only non-transmural involvement. Normal left-ventricular contraction was shown in seven patients examined at 3 months and three examined at 14 months, but in these cases hyperenhancement was limited to the subendocardium.

INTERPRETATION

The presence, location, and transmural extent of healed Q-wave and non-Q-wave myocardial infarction can be accurately determined by contrast-enhanced MRI.

Patient preference-based treatment thresholds and recommendations: a comparison of decision-analytic modeling with the probability-tradeoff technique

BACKGROUND

Decision analysis (DA) and the probability-tradeoff technique (PTOT) are patient preference-based methods of determining optimal therapy for individuals. Using aspirin therapy for the primary prevention of stroke and myocardial infarction (MI) in elderly persons as an example, the objective of this study was to determine whether group-level treatment thresholds and individual-level treatment recommendations derived using PTOT are identical to those of DA incorporating the patients' own values.

METHODS

Persons in a pilot study of the efficacy of aspirin in the prevention of stroke and MI were asked to participate. Participant values and utilities for pertinent health states (e.g., minor and major stroke, MI, major bleeding episode) were determined. Then, in three hypothetical clinical situations in which the chance of stroke or MI was varied, PTOT was used to directly determine treatment thresholds for aspirin therapy (i.e., the smallest reduction in MI or stroke risk for which participants would be willing to take aspirin). Using DA modeling, with the same probabilities of events as in the PTOT exercise and incorporating participants' own values, treatment thresholds for the three clinical situations were determined. The thresholds determined by the two approaches were compared. Finally, based on these treatment thresholds, using the best estimates of the efficacy of aspirin to prevent first-time stroke and MI, PTOT and DA treatment recommendations for individual participants were compared.

RESULTS

The 42 participants reported that a major stroke was the least desirable health state, followed by MI, minor stroke, and major bleeding. The minimum risk reduction required to take aspirin was greater for MI prevention compared with stroke prevention. For the two clinical situations in which the hypothetical efficacy of aspirin to prevent stroke was varied, treatment thresholds for the PTOT versus DA approaches differed (p < 0.04), but this difference was not significant (p = 0.19) for the MI-based clinical situation. Using the best estimate of the efficacy of aspirin to prevent first-time stroke and MI, PTOT and DA treatment recommendations whether or not to take aspirin were discordant for 38% of participants (16 of 42) (p < 0.001).

CONCLUSIONS

Patient preference-based group-level treatment thresholds and individual-level treatment recommendations can differ significantly depending on whether PTOT or DA is used, apparently because the two emphasize different aspects of the decision-making process. DA theory assumes that effective therapeutic decision making should maximize both quality and quantity of life; with PTOT, the emphasis for effective clinical decision making allows patients to be fully engaged in the process, thus hopefully leading to fully informed decisions that may result in satisfaction and compliance.

Early Prognostic Assessment and Treatment of Acute Myocardial Infarction in the Elderly

The progressive aging of the population is associated with an increase in the proportion of very old patients (greater than 75 years) hospitalized with acute myocardial infarction. The lack of evidence regarding the efficacy of most therapeutic interventions for acute myocardial infarction in these patients is leading to a significant degree of uncertainty in the cardiology community with respect to their optimal management. When aggressive treatment (defined as a therapeutic strategy designed to obtain and maintain a patent infarct-related coronary artery at an early moment) of acute myocardial infarction is considered in very old patients, three main questions should be addressed: why should we treat? Whom should we treat? And how should we treat? To answer these questions, the authors reviewed the data available in the literature as well as new data from the PPRIMM75 (Pronóstico del PRimer Infarto de Miocardio en Mayores de 75 aÃ+/-os) Registry, a large, prospective database of patients aged 75 years or older, admitted to a single coronary care unit in Madrid, Spain, for their first acute myocardial infarction during the last decade. (c) 2000 by CVRR, Inc.

The prognosis of a first Q-wave versus non-Q-wave myocardial infarction in the reperfusion era

PURPOSE

To compare the prognosis of patients with a first Q-wave versus non-Q-wave myocardial infarction (MI) in the reperfusion era.

METHODS

Patients with a first MI were compared according to type of infarct-Q-wave (n = 1,786) versus non-Q-wave (n = 722)-and by treatment with thrombolysis.

RESULTS

Patients with non-Q-wave MI were more likely to be female and to have undergone previous coronary revascularization. Their 30-day mortality rate was 7%, as compared with a rate of 9% among patients with Q-wave infarction (adjusted odds ratio [OR] = 0.6, 95% confidence interval [CI]: 0.4 to 0.9). However, the subsequent 30-day to 1-year mortality rates were similar in patients with Q-wave or non-Q-wave MI. Patients who were not treated with thrombolysis and who had a non-Q-wave MI had a lower 30-day mortality rate (OR = 0.6, 95% CI: 0.3 to 0.9) but a similar 30-day to 1-year mortality rate (hazard ratio [HR] = 1.5, 95% CI: 0.9 to 2.5) as compared with their counterparts who developed Q-wave infarction. Among thrombolysis-treated patients, 30-day (OR = 0.8, 95% CI: 0.4 to 1.5) as well as 30-day to 1-year (HR = 1.2, 95% CI: 0.5 to 3.0) mortality rates were similar between patients who developed either Q-wave or non-Q-wave MI.

CONCLUSIONS

Patients who received thrombolysis had similar early and late mortality rates after the index infarction regardless of whether they had a Q-wave or non-Q-wave MI. Conversely, among patients who were not treated with thrombolysis, patients with a non-Q-wave MI had lower early mortality rates but similar long-term mortality rates as those with Q-wave MI.

Non-Q-Wave Myocardial Infarction

The treatment of non-Q-wave infarction involves the use of antithrombotic therapy (aspirin and heparin) along with appropriate antianginal medication to reduce myocardial oxygen demands and prevent coronary spasm. In certain high-risk patient subgroups (ie, those with recurrent ischemia, persistent or significant ST segment change, congestive heart failure, or hypotension with chest pain), the use of newer agents such as the platelet glycoprotein IIb/IIIa antagonists is indicated. The role of angiography appears to be changing. In the past, at least in the United States, angiography was performed on nearly all patients with non-Q-wave infarction. Now, risk stratification into high- and low-risk subgroups can be performed based on clinical criteria. In low-risk individuals, we recommend that noninvasive testing be performed before a decision is made about an invasive evaluation. In high-risk patients, it is appropriate to perform angiography and, based on the angiographic findings, to provide appropriate therapy. Although the results of the Veterans Affairs Non-Q-Wave Infarction Strategies in Hospital (VANQWISH) study suggest that if bypass surgery is required, it should not be performed acutely, we do not believe that this is necessarily correct. Therapy must be individualized based on the risk-benefit profile of acute revascularization. Furthermore, the use of percutaneous coronary intervention, particularly with the glycoprotein IIb/IIIa antagonists and stents, is expanding to include multivessel disease, even in the presence of left ventricular dysfunction. Again, we believe therapy must be individualized to include an estimate of short- and long-term risk versus benefit. In the future, however, more data from appropriately designed clinical trials will be required to establish evidence-based therapy.

Non-Q wave myocardial infarction. Assessment and management of a unique and diverse subset

Acute cardiac events involving coronary symptoms, elevated enzyme levels, and electrocardiographic changes without the development of Q waves often result in higher rates of reinfarction and unstable angina than do more severe myocardial infarctions. The incidence of these non-Q wave events is on the rise, possibly because of earlier detection and treatment of heart disease. Familiarity with the characteristics and management of the condition, therefore, is more important than ever.

Significance of resting wall motion abnormalities in 2-dimensional echocardiography in patients without previous myocardial infarction referred for pharmacologic stress testing

BACKGROUND

Resting wall motion abnormalities (WMA) in 2-dimensional echocardiography may be encountered in patients without previous myocardial infarction or known coronary artery disease (CAD) who are referred for stress testing. However, the functional significance of these abnormalities has not been evaluated by an independent technique. The goals of this study were to assess the value of resting WMA in the prediction of an ischemic response during dobutamine stress testing independent of other clinical characteristics in patients without known CAD, and to evaluate whether the presence of resting WMA is related to the presence or extent of myocardial perfusion abnormalities during dobutamine stress testing.

METHODS

We studied 116 patients (mean age 57 +/- 13 years, 50 men) without known CAD or a history of myocardial infarction by dobutamine-atropine (dobutamine: </=40 microg/kg/min; atropine: </=1 mg) stress echocardiography and simultaneous stress and rest technetium sestamibi single-photon emission computed tomography imaging. Ischemia was defined as new or worsening wall motion abnormalities and reversible perfusion defects, respectively.

RESULTS

Resting WMA were detected in 24 patients (21%). Patients with resting WMA had a higher prevalence of abnormal perfusion (75% vs 25%, P <.001) and a higher prevalence of ischemia by single-photon emission computed tomography (50% vs 24%, P <.05) and by echocardiography (42% vs 9%, P <.001) compared with patients without resting WMA, respectively. Stress and rest perfusion defect scores were significantly higher in patients with than in those without rest WMA (3.25 +/- 2.67 vs 0.88 +/- 1.77, P <.0001; and 1.46 +/- 1.69 vs 0.21 +/- 0.70, P <.0001; respectively). Independent predictors of the occurrence of ischemia by echocardiography were the presence of resting WMA (P <.01, chi(2) = 6.7), ST-segment depression (P <.005, chi(2) = 11.3), and angina during the test (P <. 05, chi(2) = 5.3) by using multivariate analysis of clinical and stress test variables. The presence of resting WMA was the only independent predictor of an abnormal perfusion (P <.0001, chi(2) = 20).

CONCLUSION

The presence of resting WMA in patients without known CAD or a previous myocardial infarction who were referred for pharmacologic stress testing is highly predictive of abnormal myocardial perfusion. Resting WMA are powerful independent predictors of an ischemic response during dobutamine stress testing and identify a population with a higher prevalence and extent of myocardial perfusion abnormalities.

Clinical utility of lipid and lipoprotein levels during hospitalization for acute myocardial infarction

The management of dyslipidemia after myocardial infarction (MI) is an important aspect of post-myocardial infarction care. However, acute changes in the lipid profile immediately following myocardial infarction have resulted in uncertainty regarding the clinical utility of lipid levels assessed during hospitalization for MI. We studied the effect of the timing of plasma lipid assessment among 294 patients who presented with MI to determine whether the differences between the serum lipid values in-hospital when compared with post-discharge values (generally 2-3 months after MI) would have a substantial impact on the decision to initiate lipid-lowering therapy. We found that the mean total and LDL cholesterol levels were significantly lower in-hospital when compared with generally 2-3 months later. However, patients whose lipids were measured within 48 h of presentation did not have significantly different values compared with generally 2-3 months post-discharge. Moreover, despite slightly lower in-hospital levels, 83.7% of patients were above the National Cholesterol Education Program target LDL for secondary prevention and 57.6% met the criteria for drug therapy based on in-hospital assessment. Total and LDL cholesterol levels fall modestly after an acute MI; however, from a clinical perspective, in-hospital levels can be used to guide decisions regarding lipid-lowering therapy which can begin in the immediate post-MI setting. In-hospital levels approximate post-MI levels, particularly if drawn within 48 h of presentation. All patients with acute myocardial infarction should have complete lipid profiles measured prior to discharge.

Prognostic Importance of Previous Myocardial Infarction in Patients Receiving Thrombolytic Therapy for Acute Infarction

This study evaluated the prognostic significance of reinfarction location by considering the previous site or type of myocardial infarction (MI) among 1601 patients with a history of previous MI who took part in the International (non-Italian) tPA/STK trial and/or the Israeli GUSTO study population. These patients were accordingly divided and hospital mortality was compared by six location groups as follows: acute inferior with previous inferior (8.1% hospital mortality), acute inferior with previous anterior (12.8%), acute anterior with previous inferior (13.3%), acute anterior with previous anterior (11.1%), acute inferior with previous non-Q-wave MI (7.6%), and acute anterior with previous non-Q-wave MI (11.2%) (p = 0.17 for comparison between the six groups). Hospital mortality tended to increase among patients with an anterior reinfarction compared with those with an inferior one (12.1% vs. 9.5%, p = 0.12). Among patients with a reinfarction at a different ECG location from the previous event, mortality tended to be higher compared with patients with two MIs at the same location (13.1% vs. 9.7%, p = 0.07). Recurrent MI following a previous Q-wave MI did not cause a higher mortality compared with a previous non-Q-wave type of MI (11.5% vs. 9.5%, p = 0.24). Among patients sustaining reinfarction, overall mortality did not differ between STK- and tPA-treated patients (11.0% vs. 11.4%, p = NS). In conclusion, the current study identified trends for higher mortality rates in patients with anterior compared with inferior reinfarction, with remote compared with the same ECG location of the two infarctions but not following a previous non-Q-wave compared with Q-wave MI. However, no particular combination of successive MIs location was significantly associated with a higher risk for hospital mortality.

Automated electrocardiographic scores to estimate myocardial injury size during the course of acute myocardial infarction

The automated ST-elevation score at admission and maximal QRS score during hospitalization provide good estimates of biochemical injury size during the course of first myocardial infarction. Being easily computerized, such scores could be used routinely to monitor the effect of injury-limiting therapy.

Prognostic value of dipyridamole thallium imaging after acute myocardial infarction in older patients

OBJECTIVE

To assess the utility of intravenous dipyridamole thallium testing for predicting major cardiac events following acute myocardial infarction in older patients.

DESIGN

Prospective cohort study with a median follow-up of 18 months.

SETTING

A university teaching hospital.

PARTICIPANTS

73 patients aged 65 years and older with enzymatically confirmed acute myocardial infarction (mean age 75 years, 56% male, 71% white).

MEASUREMENTS

All patients underwent a detailed clinical assessment, an echocardiogram, and an intravenous dipyridamole thallium stress test before hospital discharge. The study endpoint was death or nonfatal reinfarction during the follow-up period.

RESULTS

Overall, 24 patients (33%) died or developed recurrent myocardial infarction during follow-up. Among 44 patients with a reversible thallium defect, 19 (43%) reached the study endpoint, compared with only five of 29 patients (17%) without reversible ischemia (P = .04). On multivariate analysis, independent prognostic variables included non-use of aspirin at hospital discharge (P = .002), decreased left ventricular systolic function (P = .009), non-use of a beta-blocker at hospital discharge (P = .013), and reversible ischemia on thallium scintigraphy (P = .025). The relative risks for death or reinfarction associated with non-use of aspirin, non-use of a beta-blocker, left ventricular dysfunction, and reversible ischemia were 2.65, 2.39, 2.01, and 2.51, respectively. Patients with three or four of these risk factors had an 83% probability of death or reinfarction, compared with 41% in patients with two risk factors and 6% in patients with one or no risk factor (P < .001).

CONCLUSION

Intravenous dipyridamole thallium imaging provides independent prognostic information in older patients with acute myocardial infarction. Moreover, the combination of clinical, echocardiographic, and dipyridamole thallium variables effectively stratifies older postinfarction patients into high-, intermediate-, and low-risk categories for death or recurrent myocardial infarction.

Clinical outcomes after detection of elevated cardiac enzymes in patients undergoing percutaneous intervention. IMPACT-II Investigators. Integrilin (eptifibatide) to Minimize Platelet Aggregation and Coronary Thrombosis-II

OBJECTIVES

We examined the relations of elevated creatine kinase (CK) and its myocardial band isoenzyme (CK-MB) to clinical outcomes after percutaneous coronary intervention (PCI) in patients enrolled in Integrilin (eptifibatide) to Minimize Platelet Aggregation and Coronary Thrombosis-II (trial) (IMPACT-II), a trial of the platelet glycoprotein IIb/IIIa inhibitor eptifibatide.

BACKGROUND

Elevation of cardiac enzymes often occurs after PCI, but its clinical implications are uncertain.

METHODS

Patients undergoing elective, scheduled PCI for any indication were analyzed. Parallel analyses investigated CK (n=3,535) and CK-MB (n=2,341) levels after PCI (within 4 to 20 h). Clinical outcomes at 30 days and 6 months were stratified by postprocedure CK and CK-MB (multiple of the site's upper normal limit).

RESULTS

Overall, 1,779 patients (76%) had no CK-MB elevation; CK-MB levels were elevated to 1 to 3 times the upper normal limit in 323 patients (13.8%), to 3 to 5 times normal in 84 (3.6%), to 5 to 10 times normal in 86 (3.7%), and to >10 times normal in 69 patients (2.9%). Elevated CK-MB was associated with an increased risk of death, reinfarction, or emergency revascularization at 30 days, and of death, reinfarction, or surgical revascularization at 6 months. Elevated total CK to above three times normal was less frequent, but its prognostic significance paralleled that seen for CK-MB. The degree of risk correlated with the rise in CK or CK-MB, even for patients with successful procedures not complicated by abrupt closure.

CONCLUSIONS

Elevations in cardiac enzymes, including small increases (between one and three times normal) often not considered an infarction, are associated with an increased risk for short-term adverse clinical outcomes after successful or unsuccessful PCI.

Long-term prognosis of painless exercise-induced ischemia in stable patients with previous myocardial infarction

OBJECTIVES

This study was designed to better understand the functional correlates and the prognostic relevance of exercise-induced painless ischemia relative to painful ischemia in patients with stable coronary artery disease and previous myocardial infarction (MI).

BACKGROUND

The usefulness of exercise testing (ET) for predicting cardiac events, years after MI, although suggested and widely applied, is questionable. In particular, previous studies have reached conflicting conclusions as to whether exercise-induced painless ischemia is related to a less severe myocardial ischemia or to a different prognosis than painful ischemia.

METHODS AND RESULTS

Seven hundred sixty-six consecutive stable patients (mean age 57+/-8.6 years, 89% men) with previous MI (mean time from MI 2.8+/-0.75 years) who underwent a Bruce treadmill test and whose data were prospectively entered into our institutional database were enrolled. Patients were followed up for an average of 7+/-0.6 years. End points were (1) cardiac death, (2) cardiac death or nonfatal reinfarction (primary), (3) cardiac death, nonfatal reinfarction, or unstable angina (secondary), and (4) cardiac death, nonfatal reinfarction, unstable angina, or revascularization procedures (secondary, restricted). These patients were retrospectively classified into 4 groups according to exercise test results: (1) painless ischemia, 156 patients; (2) painful ischemia, 75 patients; (3) negative ET, 99 patients; and (4) nondiagnostic ET, the remaining 436 patients. Patients with painless ischemia had less functional impairment and less exercise ischemia than the symptomatic patients (longer exercise duration [P < .001], higher double product [P < .001], higher ischemic threshold [P < .001], and shorter time to ST normalization [P < .001]). Patients with painful ischemia had significantly (P < .0005) increased 6-year risk rates of secondary and restricted end points (49% and 64%, respectively) versus those with painless ischemia (28% and 35%), no inducible ischemia (25% and 27%), or nondiagnostic ET (32% and 37%). Adverse outcomes were mainly the result of higher incidence of unstable angina or revascularization procedures. At multivariate analysis, neither painless nor painful exercise-induced ischemia were independent predictors of end points.

CONCLUSIONS

Stable patients with previous MI represent a very low-risk population. In this subset, painless exercise-induced ischemia signifies less severe ischemia than the symptomatic one and has a limited prognostic power. Thus painless exercise-induced ischemia in stable patients with previous MI does not identify patients at increased risk.

Poor long-term survival after acute myocardial infarction among patients on long-term dialysis

BACKGROUND

Cardiovascular disease is common in patients on long-term dialysis, and it accounts for 44 percent of overall mortality in this group. We undertook a study to assess long-term survival after acute myocardial infarction among patients in the United States who were receiving long-term dialysis.

METHODS

Patients on dialysis who were hospitalized during the period from 1977 to 1995 for a first myocardial infarction after the initiation of renal-replacement therapy were retrospectively identified from the U.S. Renal Data System data base. Overall mortality and mortality from cardiac causes (including all in-hospital deaths) were estimated by the life-table method. The effect of independent predictors on survival was examined in a Cox regression model with adjustment for existing illnesses.

RESULTS

The overall mortality (+/-SE) after acute myocardial infarction among 34,189 patients on long-term dialysis was 59.3+/-0.3 percent at one year, 73.0+/-0.3 percent at two years, and 89.9+/-0.2 percent at five years. The mortality from cardiac causes was 40.8+/-0.3 percent at one year, 51.8+/-0.3 percent at two years, and 70.2+/-0.4 percent at five years. Patients who were older or had diabetes had higher mortality than patients without these characteristics. Adverse outcomes occurred even in patients who had acute myocardial infarction in 1990 through 1995. Also, the mortality rate after myocardial infarction was considerably higher for patients on long-term dialysis than for renal-transplant recipients.

CONCLUSIONS

Patients on dialysis who have acute myocardial infarction have high mortality from cardiac causes and poor long-term survival.

Prognostic value of dobutamine echocardiography in patients after Q-wave or non-Q-wave acute myocardial infarction

We investigated the role of dobutamine echocardiography in predicting future spontaneous events in patients with Q-wave or non-Q-wave first acute myocardial infarction (AMI). DE was performed in 168 patients with a Q-wave AMI and 105 patients with a non-Q-wave AMI. Patients were observed for hard events (cardiac death and nonfatal reinfarction) and all spontaneous events (hard events and unstable angina). When compared to patients with a Q-wave AMI, patients with non-Q-wave AMI had a higher rate of positive dobutamine echocardiographic results (51.8% vs 80.0%, p <0.0001), greater changes in wall motion score index (WMSI) (0.31+/-0.17 vs 0.42+/-0.23, p = 0.001), and more remote zone ischemia (27.9% vs 43.8%, p = 0.0072). Patients with non-Q-wave infarct had a higher all-event rate, but a similar hard-event rate. In patients with a positive dobutamine echocardiogram (DE), the rate of hard or all events was similar, regardless of different infarct patterns. Patients with a negative DE had a higher event-free survival rate for all events in both Q-wave (85.2% vs 60.9%, p <0.0001) and non-Q-wave (76.2% vs 52.4%, p = 0.0083) groups. By stepwise analysis in the Q-wave group, the most important predictors were peak stress WMSI and diabetes for hard events, and a positive DE and baseline WMSI for all events. However, in the non-Q-wave group, the strongest predictors were dobutamine time for hard events and positive DE for all events. We conclude that a positive DE is a powerful predictor of future spontaneous events in patients after either a Q-wave or non-Q-wave AMI. However, for hard events, high-risk patients with different infarct patterns were recognized with variable efficiency by different dobutamine echocardiographic variables.

Outcomes in patients with acute non-Q-wave myocardial infarction randomly assigned to an invasive as compared with a conservative management strategy. Veterans Affairs Non-Q-Wave Infarction Strategies in Hospital (VANQWISH) Trial Investigators

BACKGROUND

Non-Q-wave myocardial infarction is usually managed according to an "invasive" strategy (i.e., one of routine coronary angiography followed by myocardial revascularization).

METHODS

We randomly assigned 920 patients to either "invasive" management (462 patients) or "conservative" management, defined as medical therapy and noninvasive testing, with subsequent invasive management if indicated by the development of spontaneous or inducible ischemia (458 patients), within 72 hours of the onset of a non-Q-wave infarction. Death or nonfatal infarction made up the combined primary end point.

RESULTS

During an average follow-up of 23 months, 152 events (80 deaths and 72 nonfatal infarctions) occurred in 138 patients who had been randomly assigned to the invasive strategy, and 139 events (59 deaths and 80 nonfatal infarctions) in 123 patients assigned to the conservative strategy (P=0.35). Patients assigned to the invasive strategy had worse clinical outcomes during the first year of follow-up. The number of patients with one of the components of the primary end point (death or nonfatal myocardial infarction) and the number who died were significantly higher in the invasive-strategy group at hospital discharge (36 vs. 15 patients, P=0.004, for the primary end point; 21 vs. 6, P=0.007, for death), at one month (48 vs. 26, P=0.012; 23 vs. 9, P=0.021), and at one year (111 vs. 85, P=0.05; 58 vs. 36, P= 0.025). Overall mortality during follow-up did not differ significantly between patients assigned to the conservative-strategy group and those assigned to the invasive-strategy group (hazard ratio, 0.72; 95 percent confidence interval, 0.51 to 1.01).

CONCLUSIONS

Most patients with non-Q-wave myocardial infarction do not benefit from routine, early invasive management consisting of coronary angiography and revascularization. A conservative, ischemia-guided initial approach is both safe and effective.

[Prognostic implications of early discharge from the coronary unit in patients with acute myocardial infarction]

INTRODUCTION AND OBJECTIVES

The high demand for health care has obliged Coronary Units to hasten the discharge of patients in less serious condition and this might be an influence on their prognosis. Our objective have been: a) to analyse the characteristics and the evolution (death or readmission) during the first month of patients with myocardial infarction and very early discharge from the Coronary Unit (stay of 2 days or less), and b) to assess the profile of very low risk group patients for complications who could be discharged early from the Coronary Unit.

PATIENTS AND METHODS

A study of 978 consecutive patients who had been admitted for acute myocardial, in faration were divided into two groups according to their length of stay in the Coronary Unit (A < or = 2 and B > 2 days). Their baseline characteristics, course of stay and vital status at month, were compared. A subgroup of patients at low risk was studied and complications that might have arisen from their early discharge from the Coronary Unit were assessed.

RESULTS

Seventy-three patients (7.5%) died within the first two days. Of the remaining 905, the stay was 2 days or less for 336 patients (group A); and longer than 2 days for 569 (group B). Group A had a higher frequency of dyslipemia, Killip class I on admission, uncomplicated myocardial infarction in the Coronary Unit and the use of beta-blockers and had less frequency of diabetes, Q wave myocardial infarction, anterior infarction or the use of fibrinolytics. In the first month after discharge from the Coronary Unit, 10 patients from group A and 18 patients from group B died, the rate of death or readmission into the Coronary Unit within 30 days was similar between both groups (group A = 13% and group B = 13%). A multiple regression showed that Killip class on admission (p < 0.001) and an uncomplicated course (p < 0.001) were independently related with the length of stay in the coronary unit. A subset of 378 low risk patients (Killip I on admission, uncomplicated course in the ICU and age < 71 years) had no mortality at 30 days and their readmission rate in the first month was 4%. In this subgroup, those patients whose stay was equal to or less than two days were more frequently readmitted in the first week. (group A = 9/197 [5%] and group B = 1/181 ([0.5%]; p = 0.034).

CONCLUSION

Selected patients with myocardial infarction can be discharged very early from the Coronary Unit with a low risk of death. A readmission rate following discharge of some 5% must be allowed for these patients.

Preoperative cardiac evaluation of women for noncardiac surgery

Cardiac risk assessment is a crucial aspect of perioperative evaluation because it is estimated that 1 million people, regardless of gender, will have perioperative cardiac complications at a cost of 20 billion dollars. Unfortunately, establishment of optimal guidelines for selected patient subgroups, particularly women, are lacking. More prospective studies are needed to help evaluate the most cost-effective, yet accurate way to noninvasively assess the presence of coronary artery disease in women.

Design and baseline characteristics of the Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) trial. VANQWISH Trial Research Investigators

OBJECTIVES

The Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) trial was designed to compare outcomes of patients with a non-Q wave myocardial infarction (NQMI) who were randomized prospectively to an early "invasive" strategy versus an early "conservative" strategy. The primary objective was to compare early and late outcomes between the two strategies using a combined trial end point (all-cause mortality or nonfatal infarction) during at least 1 year of follow-up.

BACKGROUND

Because of the widely held view that survivors of NQMI are at high risk for subsequent cardiac events, management of these patients has become more aggressive during the last decade. There is a paucity of data from controlled trials to support such an approach, however.

METHODS

Appropriate patients with a new NQMI were randomized to an early "invasive" strategy (routine coronary angiography followed by myocardial revascularization, if feasible) versus an early "conservative" strategy (noninvasive, predischarge stress testing with planar thallium scintigraphy and radionuclide ventriculography), where the use of coronary angiography and myocardial revascularization was guided by the development of ischemia (clinical course or results of noninvasive tests, or both).

RESULTS

A total of 920 patients were randomized (mean follow-up 23 months, range 12 to 44). The mean patient age was 61 +/- 10 years; 97% were male; 38% had ST segment depression at study entry; 30% had an anterior NQMI; 54% were hypertensive; 26% had diabetes requiring insulin; 43% were current smokers; 43% had a previous acute myocardial infarction; and 45% had antecedent angina within 3 weeks of the index NQMI.

CONCLUSIONS

Baseline characteristics were compatible with a moderate to high risk group of patients with an NQMI.

Evaluation of left ventricular diastolic function in patients with non-Q-wave myocardial infarction and its correlation with underlying coronary artery disease

Left ventricular diastolic function was studied by Doppler echocardiography in 35 patients with non-Q-wave myocardial infarction, on the third and tenth day of hospitalization and six weeks after hospitalization and was correlated with electrocardiogram, serum enzyme values, and angiographic data. Normal diastolic function on the first echocardiographic study predicted (p = 0.0001) the existence of no or single-vessel disease, and excluded (p = 0.005) the presence of 3-vessel or left main disease, whereas an abnormal study on either the second or third echocardiographic discriminated (p = 0.0001), with higher sensitivity (80.97%, 92.31%, respectively), patients with 3-vessel or left main vessel disease.

Significance of prolonged left ventricular wall motion abnormalities after exercise echocardiography following non-Q-wave acute myocardial infarction

Exercise echocardiography was used to assess myocardial ischemia after non-Q-wave acute myocardial infarction in 40 consecutive patients. Resting parasternal long- and short-axis views and apical 4- and 2-chamber views were recorded, digitized, and stored. A maximal symptom-limited exercise test was performed within 21 days (mean 17.7 +/- 3) using a cycle ergometer with continuous monitoring and the echocardiogram was repeated in the same views. Resting and exercise echocardiograms were then compared. Coronary angiography was performed in all patients within 21 days of exercise echocardiography. Stenosis in > or =50% of the lumen diameter was considered significant. Of the 40 patients studied, 29 (72%) had continuing angina and 11 (28%) had no angina. Eighteen patients (62%) with angina developed angina during exercise testing and 19 (65%) developed ST-segment depression. In patients without angina, 1 (9%) developed postexercise angina and 2 (18%) developed ST-segment depression. The mean wall motion score index after exercise increased from 1.2 +/- 0.3 to 1.8 +/- 0.4 in patients with continuing angina (p <0.001) and from 1.2 +/- 0.3 to 1.4 +/- 0.3 in patients without angina (p = NS). Prolonged wall motion abnormalities lasting >20 minutes persisted in > or =1 segment in 27 of 29 patients (93%) with angina or in 2 of 1 1 patients (18%) without angina (p <0.001). Patients with continued angina had predominantly 3-vessel coronary artery disease (22 of 29 [76%]) or 2-vessel disease (7 of 29 [24%]), and those without angina had 1-vessel disease (6 of 11 [55%]) or 2-vessel disease (4 of 11 [36%]). One patient had 3-vessel disease. The duration of wall motion abnormality demonstrated a significant relation to 2- and 3-vessel coronary artery disease (p <0.001). Thus, patients with non-Q-wave acute myocardial infarction had a high incidence of multivessel coronary disease not necessarily detected on routine exercise testing. There was also a significant incidence of prolonged wall motion abnormality.

[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.

Comparison of short- and long-term prognosis in patients with anterior wall versus inferior or lateral wall non-Q-wave acute myocardial infarction. Secondary Prevention Reinfarction Israeli Nifedipine Trial (SPRINT) Study Group

We evaluated the early and long-term prognosis of patients with a first non-Q-wave acute myocardial infarction (AMI) in relation to infarct site. Among 4,314 patients with a first AMI, 610 (14%) had a non-Q-wave AMI. Of them, 248 patients with anterior wall AMI were compared with 327 patients with inferior/lateral AMI. Baseline clinical characteristics were similar in both groups except for higher mean age in the anterior wall group. In-hospital complications were more common among patients with anterior wall AMI than in the inferior/lateral group. Patients with anterior wall AMI also had higher rates of in-hospital (15%), 1-year (12%), and 5-year (36%) postdischarge mortality compared with the inferior/lateral infarction group (10%, 6%, and 22%, respectively). The 1-year cardiac event rate (recurrent AMI and cardiac death) was significantly higher among the anterior wall AMI group than the inferior/lateral AMI group (14.2% and 4.8% respectively, p = 0.001). After adjustment for age, gender, systemic hypertension, diabetes mellitus, prior angina, and treatment with various medications, an increased risk for 1-year (odds ratio 1.31, 95% confidence interval [CI] 0.62 to 2.78) and 5-year mortality (relative risk 1.29, 95% CI 0.90 to 1.85) was observed, but it did not reach statistical significance. Anterior wall AMI location emerged as a predictor for higher 1-year cardiac event rate (odds ratio 3.15, 95% CI 1.59 to 6.78). These findings suggest that AMI location is an important prognostic variable for risk stratification of patients with a first non-Q-wave AMI.

Digoxin therapy and survival in heart failure in sinus rhythm

The effect of digoxin therapy on the survival of heart failure patients in sinus rhythm was assessed using a retrospective case control study. Patients with an acute exacerbation of chronic heart failure secondary to ischemic heart disease were selected. All were in sinus rhythm and all were treated with digoxin. Case-matched controls were identified for all digoxin-treated patients. Long-term survival was ascertained for all 18 digoxin-treated patients and 18 controls who formed the study population. The relative risk of death was 6.4 for digoxin-treated patients (95% confidence interval 0-36) during the period of hospitalization. Te increased risk of death among digoxin-treated patients persisted up to 1 year following discharge from hospital. The results raise further concern regarding the safety of digoxin therapy in managing heart failure exacerbation, when the patients are in sinus rhythm.

Prognostic significance of ST-T segment alterations in patients with non-Q wave myocardial infarction

OBJECTIVE

To determine whether, among patients with non-Q wave myocardial infarction, the characteristics of the segment ST-T shifts at presentation in the diagnostic electrocardiogram can identify those with more severe coronary artery disease and predict a poor clinical outcome.

DESIGN

Prospective controlled clinical trial.

SETTING

Primary referral medical centre.

PATIENTS

93 patients (mean (SD) 62.0 (7.5) years) were studied: 41 with non-Q wave myocardial infarction and T wave inversion and 52 with ST segment depression. Cardiac events and mortality rates were assessed over 42 months. Age, sex, risk factors, creatinine kinase MB isoenzyme peak, and left ventricular function were comparable.

RESULTS

31 patients with T wave inversion myocardial infarction (94.6%) had total occlusion of the infarct related artery, compared with 12 patients with ST segment depression myocardial infarction (26.7%) (P < 0.05). When compared with patients with T wave inversion, patients with ST segment depression had a higher incidence of cardiac events during the first month and in the 41 subsequent months: 9.6% and 30.8% v 0% (P < 0.01) and 9.8% (P < 0.02), respectively. For the same observation periods, the mortality rates in patients with T wave inversion were 4.9% and 7.3%, and in patients with ST segment depression they were 5.8% and 9.6%, respectively.

CONCLUSION

These data suggest that during a non-Q wave myocardial infarction the presence of ST segment depression is related to higher rates of short and long term cardiac events when compared with T wave inversion--possibly because of a higher incidence of residual stenosis of the infarct related artery.

Late assessment of thrombolytic efficacy (LATE) study: prognosis in patients with non-Q wave myocardial infarction. (LATE Study Investigators)

OBJECTIVES

We examined the impact of thrombolytic therapy and the prognosis of patients with non-Q wave myocardial infarction in a randomized placebo-controlled trial known as the Late Assessment of Thrombolytic Efficacy (LATE) study.

BACKGROUND

Patients with non-Q wave as compared with Q wave myocardial infarction in the era before thrombolytic therapy were traditionally thought to have a higher rate of reinfarction and death between hospital discharge and 1 year such that the overall prognosis for outcome at 1 year was similar in the two groups.

METHODS

The study patients began treatment with either recombinant tissue-type plasminogen activator (rt-PA) or matching placebo, 6 to 24 h after the onset of chest pain. Post hoc analysis of mortality and reinfarction was carried out by comparing rt-PA and placebo in various subsets of patients based on the presenting electrocardiogram (ECG) and the evolution of the ECG with respect to the development of Q waves.

RESULTS

Among 5,711 participants, 4,759 had a confirmed myocardial infarction, including 1,309 classified as having a non-Q wave infarction at hospital discharge. Irrespective of treatment assignment, all patients with non-Q wave versus Q wave infarction had a lower 1-year mortality rate (13.3% vs. 17.1%, p = 0.001) and a similar 1-year reinfarction rate (8.6% vs. 7.9%, p = 0.7). Of the 4,759 patients with confirmed myocardial infarction, 2,973 presented with ST segment elevation or bundle branch block, 528 with ST depression and 1,258 with neither ST elevation nor depression. No overall benefit from rt-PA versus placebo with respect to mortality rate at 1 year was seen among patients presenting with ST elevation (21.2% vs. 22.4%, p = 0.5 [90% power to detect 20% relative difference]). Patients with ST elevation who were treated with rt-PA versus placebo <3 h after hospital admission had a lower mortality rate at 1 year (15.8% vs. 19.6%, p = 0.028) than did those treated after 3 h (17.6% vs. 13.0%, p = 0.055). Patients presenting initially with ST depression >2 mm had significant benefit from treatment with rt-PA with respect to 1 year mortality rate (20.1% vs. 31.9%, p = 0.006).

CONCLUSIONS

Patients with non-Q wave myocardial infarction constitute a heterogeneous group of patients. Although the observations presented here are limited by post hoc analysis, it is apparent that patients classified as having a non-Q wave infarction after thrombolytic therapy have a better prognosis than do those given placebo. Late admission of thrombolytic therapy (after 6 h) may also be beneficial in patients presenting with ST depression >2 mm and confirmed myocardial infarction. These hypotheses require prospective testing in a larger number of patients.