Cardiac event rate after non-Q-wave acute myocardial infarction and the significance of its anterior location

The Prognostic Values of the Admission Electrocardiography, Myocardial Injury Markers and Physical Examination in Patients with Acute Myocardial Infarction

Introduction

Acute coronary syndromes (ACS) are leading life threatening causes of chest pain, which is one of the most common complaints in the emergency department (ED). The aim of the study was to demonstrate the usefulness of physical examination, ECG and cardiac markers to predict short term outcome of ACS patients.

Methods

A total of 1728 patients with chest pain were evaluated between 1st January 2003 and 31st December 2003 in the ED and 236 of the patients matched our study criteria.

Results

In the study group 184 patients were (78%) male and the mean age was 59.8±12.2 (range=4-92) years old. Age, Killip score, cardiac marker values, the time interval between the beginning of the chest pain and ED entry and the ECG changes were the studied variables. With the logistic regression analysis, Killip score and any rhythm other than normal sinus rhythm on the first ECG were found to be the only independent variables to predict early mortality (p=0.036 and p=0.033).

Conclusion

Simple measures in the ED such as ECG and serum markers of myocardial injury along with the thorough physical evaluation of the physician may predict early negative outcome.

B-type natriuretic peptide as a predictor of anterior wall location in patients with non-ST-elevation myocardial infarction

OBJECTIVE

Involvement of the left ventricular anterior wall in ST-elevation myocardial infarction has a worse prognosis compared with other regions. In non-ST-elevation myocardial infarction, noninvasive methods of locating the ischemic myocardial territory have been limited. The objective of this report is therefore to determine what factors are predictive of the anterior location of the ischemic myocardial territory.

METHODS

This study included 170 patients with non-ST-elevation myocardial infarction. Clinical, echocardiographic, and laboratory characteristics, including B-type natriuretic peptide measured within 24 hours of hospitalization, and coronary angiographic features were analyzed.

RESULTS

The mean age was 64.5 ± 12.3 years, and 112 of the patients were male (66%). The median follow-up was 23 months. The territory involved, as determined from the angiogram, was divided into anterior [n = 80 (47%)] regions and inferior and lateral [n = 90 (53%)] regions. Multivariate analysis showed that B-type natriuretic peptide was the only independent predictor of an anterior wall infarct [OR = 3.70 (95% CI: 1.61 - 8.53); P = 0.002] in non-STelevation myocardial infarction patients. Multivariate analysis also showed that B-type natriuretic peptide was an independent predictor of in-hospital cardiac events during index admission [OR = 5.05 (95% CI: 1.49 - 17.12); P = 0.009] and of cardiac events occurring during follow-up [HR = 1.79 (95% CI: 1.05 - 3.04); P = 0.032].

CONCLUSIONS

B-type natriuretic peptide was the only factor independently associated with anterior wall involvement in non-ST-elevation myocardial infarction, and the peptide levels upon admission predicted in-hospital and subsequent cardiac events.

Prognostic significance of ST segment depression in lateral leads I, aVL, V5 and V6 on the admission electrocardiogram in patients with a first acute myocardial infarction without ST segment elevation

OBJECTIVES

We sought to investigate the short-term prognostic value of the admission electrocardiogram (ECG) in patients with a first acute myocardial infarction (MI) without ST segment elevation.

BACKGROUND

ST segment depression on hospital admission predicts a worse outcome in patients with a first acute MI, but the prognostic information provided by the location of ST segment depression remains unclear.

METHODS

In 432 patients with a first acute MI without Q waves or > or = 0.1 mV of ST segment elevation, we evaluated the ability of the initial ECG to predict in-hospital death.

RESULTS

The presence, magnitude and extent of ST segment depression were associated with an increased mortality, but the only electrocardiographic variable that was significant in predicting death after adjusting for baseline predictors was ST segment depression in two or more lateral (I, aVL, V5, or V6) leads (odds ratio 3.5, 95% confidence interval 1.2 to 10.6). Patients with lateral ST segment depression (n = 91, 21%) had higher rates of death (14.3% vs. 2.6%, p < 0.001), severe heart failure (14.3% vs. 4.1%, p < 0.001) and angina with electrocardiographic changes (20.0% vs. 11.6%, p = 0.04) than did the remaining patients, even though they had similar peak creatine kinase, MB fraction levels (129 +/- 96 vs. 122 +/- 92 IU/liter, p = NS). In contrast, ST segment depression not involving the lateral leads did not predict a poor outcome. Among patients who were catheterized, those with lateral ST segment depression had a lower left ventricular ejection fraction (57 +/- 12% vs. 66 +/- 13%, p = 0.001) and more frequent left main coronary artery or three-vessel disease than did the remaining patients (60% vs. 22%, p < 0.001).

CONCLUSIONS

In patients with a first non-ST segment elevation acute MI, ST segment depression in the lateral leads on hospital admission predicts a poor in-hospital outcome.

Management of high-risk subsets in unstable angina

This article focuses on the optimal treatment of postinfarction, refractory, or recurrent angina based on the results of recent clinical trials. Many of our recommendations hold true for the general management of unstable angina, but special considerations for the high-risk subsets are emphasized. Specifically, we discuss acute medical management and suggest that an early aggressive strategy that leads to early coronary angiography with the goal of revascularization when feasible best serves this subset. A special emphasis on the emerging role of glycoprotein IIb-IIIa antagonists is made because the important role of platelets in coronary thrombosis has dominated recent views on the pathophysiology of unstable angina.

[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.

Comparison of early invasive and conservative treatments in patients with anterior wall non-Q-wave acute myocardial infarction

To compare the long-term prognosis of a group of patients treated by an early invasive approach after a non-Q-wave anterior wall acute myocardial infarction (AMI) with a similar group treated conservatively, data from 110 consecutive patients with non-Q-wave AMI were retrospectively obtained from 3 different hospitals: (1) a hospital with coronary angioplasty and coronary bypass facilities favoring on early invasive approach, (2) a hospital with a catheterization laboratory and no coronary angioplasty or coronary bypass facilities, and (3) a community hospital without a catheterization laboratory. Patients were divided according to the presence or absence of an early invasive approach: those who had undergone in-hospital catheterization and revascularization (n = 55) and those with a conservative approach (n = 55). The early invasive approach resulted in a significant decrease in major events. The rate of recurrent myocardial infarction was 29% in the conservative group versus 7.2% in the invasive group (p = 0.025). Survival rate curves at 3-year follow-up showed significant differences in mortality (p = 0.001), recurrent myocardial infarction (p = 0.002), recurrent angina pectoris (p = 0.001), and development of congestive heart failure (p = 0.05). Multivariate analysis disclosed the early invasive approach to be an independent predictor for decreasing the likelihood of recurrent infarction by 86% (odds ratio 0.14, confidence intervals 0.04 to 0.48, p = 0.0006), and for decreasing the likelihood of recurrent angina by 66% (odds ratio 0.34, confidence intervals 0.18 to 0.63, p < 0.005). The early invasive strategy may result in an improved outcome in the treatment of patients with non-Q-wave anterior wall AMI compared with patients treated conservatively.

Immediate and long-term prognostic significance of a first anterior versus first inferior wall Q-wave acute myocardial infarction. Secondary Prevention Reinfarction Israeli Nifedipine Trial (SPRINT) Study Group

Of 3,981 patients with a first Q-wave acute myocardial infarction (AMI), 1,929 (48%) had an anterior and 1,724 (43%) an inferior wall AMI. These 2 groups were well-matched with respect to age, gender and relevant history. The in-hospital mortality rate was 18%, and the 1- and 5-year post-discharge mortality rates were 9 and 25%, respectively, in patients with anterior wall AMI compared with the corresponding rates of 11, 6 and 19% in those with inferior wall AMI (p < 0.0001 for each category). The frequency of recurrent nonfatal AMI in the year after the index AMI was 8% in the patients with anterior wall AMI compared with 4% in those with inferior wall AMI (p < 0.0001). By multiple logistic regression analysis of events, anterior wall AMI was an independent predictor of in-hospital mortality only. The findings indicate that the anatomic location of a Q-wave AMI influences immediate and short-term survival of patients with a first Q-wave AMI.

Very early risk stratification by electrocardiogram at rest in men with suspected unstable coronary heart disease. The RISC Study Group

OBJECTIVES

To determine the possibility of very early prognostic stratification based on electrocardiograms (ECGs) at rest and/or cardiac enzyme levels after an episode of suspected unstable coronary heart disease.

DESIGN AND SETTING

Men with suspected unstable angina or non-Q-wave myocardial infarction were studied in the coronary care units of eight hospitals. The ECGs at rest and creatinine kinase were followed.

SUBJECTS

In total 911 men were followed for 12 months. Of 8136 consecutively admitted, 3365 fulfilled the inclusion criteria. Excluded were 2454 patients, mainly because of a larger myocardial damage, signs of myocardial dysfunction, other serious cardiac or non-cardiac disease or an ECG not possible to interpret regarding ST-T-segment changes in the precordial leads.

MAIN OUTCOME MEASURES

End-points at follow-up were cardiac death, myocardial infarction and severe (class III or IV) angina.

RESULTS

Compared to patients with normal a ECG who had an 8% 1-year risk of myocardial infarction or death, the risk with isolated negative T waves was 14% (P < 0.05), ST elevation 16% (P < 0.05), ST depression 18% (P < 0.01) and the combination of ST elevation and ST depression 26% (P < 0.001). The only finding related to future severe angina was ST depression. The risk of cardiac events was comparably elevated in patients with anterior or inferior site of ECG changes. Cardiac enzyme levels had no predictive value regarding future events.

CONCLUSIONS

Electrocardiograms at rest obtained during the initial days of hospitalization provide very early and valuable prognostic information in men admitted with suspected unstable coronary heart disease.

Prognostic significance of early ischemia after acute myocardial infarction in low-risk patients. IRES (Ischemia Residua) Study Group

Early postinfarction angina is generally believed to imply an unfavorable prognosis. However, most of the published information devices from data collected in the prethrombolytic era, with widely differing populations and definitions of early angina, and very little data pertinent to low-risk patients are available. This collaborative study prospectively assessed the incidence of early recurrent ischemia after thrombolysis, as well as its prognostic significance, in 453 consecutive patients aged < or = 70 years with an uncomplicated course in the first 24 hours of a first myocardial infarction participating in the second Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-2) trial. Early recurrent ischemia (spontaneous, transient ST depression or elevation of > 1 mm and/or T-wave inversion), assessed in the coronary care unit with continuous clinical and electrocardiographic monitoring, was documented in 35 of 453 patients (8%) and was unrelated to sex, age, electrocardiographic location, Q-wave or non-Q-wave infarction, thrombolytic agent and time to its administration. In-hospital cardiac events (7 deaths, 19 nonfatal reinfarctions and 8 urgent revascularizations) occurred in 15 of 35 patients (43%) with versus 19 of 418 without (4.5%) recurrent ischemia (p < 0.001). At the 6-month follow-up of 352 medically treated patients who did not have in-hospital events, the incidence of death, reinfarction and recurrent angina was comparable between patients with (2 of 18, 11%) and without (62 of 334, 19%) early ischemia (p = NS). With use of stepwise multivariate analysis, early ischemia was the only significant predictor of in-hospital cardiac events (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Infarct site-related mortality in patients with recurrent myocardial infarction. SPRINT Study Group

PURPOSE

The purpose of this study was to determine the effect of acute and old myocardial infarction (MI) sites on early (15 days) mortality in patients with a second MI.

PATIENTS AND METHODS

Data are derived from the SPRINT 2 study population that included 1,161 consecutive patients with acute MI, aged 50 to 79 years, recruited from 14 coronary care units in Israel between November 1985 and July 1986. Two hundred twenty-six of these patients (19.5%) had a previous MI prior to the index acute MI. Sixty-two patients were excluded from the analysis either because the MI site was not of anterior or inferior location, or because of incomplete data. In the 164 (73%) remaining patients, acute and old MI locations were determined to be either anterior or inferior and were accordingly divided into 4 groups: acute anterior-old anterior (Group 1-23 patients); acute anterior-old inferior (Group 2-86 patients); acute inferior-old anterior (Group 3-34 patients); acute inferior-old inferior (Group 4-21 patients).

RESULTS

Significant differences in clinical parameters among the four groups included a higher proportion of Q-wave MI (p = 0.04), severe congestive heart failure during admission (p = 0.04), and markedly elevated serum lactate dehydrogenase levels (p = 0.05) in Group 3. High-degree atrioventricular block (p = 0.001) and cardiogenic shock (p = 0.05) also developed more often in this group during hospitalization. Twenty-three patients (14%) died within 15 days. Death rates in the acute anterior (Group 1 plus Group 2) and the acute inferior (Group 3 plus Group 4) groups were 11% versus 20%, respectively (NS). However, death rate variability across the four groups was statistically significant (p = 0.018), with the highest mortality observed in Group 3 (old anterior-acute inferior MI-29%). Multivariate analysis identified acute inferior MI following old anterior MI as a strong independent predictor of early death (relative odds vis-à-vis other combinations 5.0, 95% confidence interval 1.5 to 16.6).

CONCLUSION

This study identifies a subgroup of patients with acute inferior MI at high risk for early mortality. It is possible that such patients would benefit from early reperfusion therapy.

The relationship between 1-year mortality and infarct location in patients with non-Q wave myocardial infarction

The association between 1-year mortality and infarct location was evaluated in 544 patients with acute non-Q wave myocardial infarction. Infarcts were anterior (alone or including other locations) in 51.1% (n = 278) of cases, localizable but not anterior 29.6% (n = 161) of the time, and nonlocalizable in 19.3% (n = 105) of patients. One-year actuarial mortality (73 deaths) was 16.9% in the anterior group, 13.3% in the nonanterior group, and 6.8% in nonlocalizable patients (p = 0.037). Anterior and localizable nonanterior mortality were similar (p = 0.367). However, there were differences when mixed location infarcts were excluded. Mortality in the inferior infarction only group (2.8%, n = 36) was less than in the lateral infarction only group (16.8%, n = 79, p = 0.041) and almost significantly less than in the anterior only group (15.1%, n = 62, p = 0.064). The positive prognosis in the inferior infarction only group may be associated with the low rate of ST depression among these patients compared with those with other infarct locations (p less than 0.0001). Mortality among localizable infarcts (15.5%) was greater than among those that were nonlocalizable (6.8%, p = 0.021). Despite the low overall risk of the nonlocalizable infarcts, 41.9% (n = 44) of these patients developed at least one important risk factor while in hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk stratification in survivors of acute myocardial infarction: routine cardiac catheterization and angiography is a reasonable approach in most patients

Noninvasive risk assessment in survivors of AMI can effectively subdivide patients into groups with differing risk profiles after hospital discharge, but some patients at risk for late death or recurrent AMI may be incorrectly identified; data from cardiac catheterization and angiography provide complementary and generally more powerful prognostic information. Many patients may derive particular benefit from early cardiac catheterization and angiography, including: (1) patients with AMI complicated by recurrent myocardial ischemia, congestive heart failure, and/or complex ventricular arrhythmias; (2) patients with abnormal or inconclusive results of noninvasive testing or those patients unable to perform an exercise test; (3) patients with abnormal left ventricular global systolic function and those with increased left ventricular end-systolic volume; (4) "young" patients (younger than 50 years of age?); (5) older patients (older than 65 to 70 years of age?); (6) patients with non-Q wave AMI; and (7) patients who are receiving thrombolytic therapy. Performance of early cardiac catheterization and angiography in virtually all survivors of AMI, with selective use of appropriate noninvasive tests, may provide a more efficacious means of risk assessment after AMI; if all tests are performed judiciously, the cost of such an approach need not be excessive. A combination of invasive and selected noninvasive tests probably provides optimal information. The risks to the routine performance of diagnostic cardiac catheterization and angiography in all survivors of AMI are: (1) adequate care and attention may not be paid to proper performance of the procedure(s) and to detailed and proper analyses of the data; (2) the need for additional noninvasive testing in selected patients may be ignored; and most importantly, (3) premature or unnecessary revascularization procedures may be performed subsequently. For optimal patient care, the clinician must obtain all necessary data, avoid unnecessary and repetitive tests, know the accuracy of individual tests at his or her own facility, interpret all data in proper context, and then counsel patients objectively about available management strategies. With this approach, all patients who might appropriately benefit from coronary artery revascularization will be correctly identified, and patients who are truly at very low risk (minimal residual coronary artery disease and preserved left ventricular function particularly if associated with a patent infarct-related artery) may be similarly identified and managed appropriately with elimination of unnecessary additional testing and pharmacologic therapy. Finally, whatever approach to risk stratification one chooses for an individual patient, the importance of and the need to correct and/or ameliorate risk factors for coronary artery disease must be recognized and undertaken.