The mortality predictive power of discharge electrocardiogram after first acute myocardial infarction

Roles of Morris Index on Poor Outcomes in Patients with Non-ST Segment Elevation Acute Coronary Syndrome

Background

This study aimed to assess the roles of the Morris index in predicting poor outcomes in patients with non-ST segment elevation acute coronary syndrome (NSTE-ACS).

Material/Methods

This study included 905 patients with newly diagnosed NSTE-ACS. The Morris index, also known as P wave terminal force in lead V1 (PTFV1), was recorded at admission and discharge. PTVF1 (+) was defined as an absolute value >0.04 mm·s, while PTFV1 (−) was defined as an absolute value <0.04 mm·s. Based on their PTFV1 values at admission/discharge, patients were divided into 4 groups: PTFV1 (−)/(−), PTFV1 (+)/(−), PTFV1 (−)/(+), and PTFV1 (+)/(+). Univariate and multivariate regression analyses were utilized to identify the variables that could contribute to NSTE-ACS risk.

Results

Compared with the PTFV1 (−)/(−) group, the incidence of poor outcomes was significantly higher in the PTFV1 (−)/(+) (hazard ratio [HR], 3.548; 95% confidence interval [95% CI], 2.024–6.219) and PTFV1 (+)/(+) (HR, 2.133; 95% CI, 1.141–3.986) groups, but not statistically different in the PTFV1 (+)/(−) group (risk ratio, 0.983; 95% CI, 0.424–2.277).

Conclusions

Primary PTFV1 (+) at discharge and PTFV1 (+) during hospitalization were independent risk factors for poor outcomes, which may provide useful prognostic information for patients with NSTE-ACS.

Prognosis following acute myocardial infarction in patients with ST-T abnormalities on electrocardiograms obtained before myocardial infarction

BACKGROUND

Many studies have examined the relationship between prognosis after myocardial infarction (MI) and electrocardiographic (ECG) findings at the time of or after the onset of MI. However, little work has been done concerning the association between ECG findings obtained before the onset of MI (pre-MI) and the prognosis after MI.

HYPOTHESIS

The study was undertaken to determine whether ST-T segment and T-wave morphology on pre-MI ECGs provides useful information for prognosis after acute MI.

METHODS

Pre-MI ECGs of 212 patients recorded within the 6-month period before MI were studied for the presence of high-voltage R waves, ST-segment depression, and negative T waves. The Kaplan-Meier method and multivariate analysis were used to determine the relationship between these ECG findings and in-hospital cardiac death.

RESULTS

In-hospital cardiac death occurred in 32 (15.1%) patients. The in-hospital mortality rate was 38.5% (5/13) for the patients with high-voltage R waves, 54.5% (6/11) for patients with ST-segment depression, and 45.6% (15/33) for patients with negative T waves. The in-hospital mortality rate was 13.6% (27/199) for patients without high-voltage R waves, 12.9% (26/201) for patients without ST-segment depression, and 9.5% (17/179) for those without negative T waves. Multivariate analysis identified age and negative T waves as independent risk factors for cardiac death, with a hazard ratio for negative T waves of 3.1.

CONCLUSION

Negative T waves on pre-MI ECGs represent an independent predictor of in-hospital cardiac death in patients with MI.

Assessment and key targets for therapy in the post-myocardial infarction patient with left ventricular dysfunction

In the post-myocardial infarction (MI) patient with coronary artery disease (CAD) and left ventricular dysfunction (LVD), ischemia and adverse remodeling hinder myocardial performance and increase electrical instability. Collectively, the coronary arteries, myocardium, and conduction system represent the principal pathophysiologic targets in MI complicated by LVD. Consequently, an accurate assessment of disease severity in these targets is essential for the design of an effective therapeutic program. This review describes the current modalities for assessing the key pathophysiologic targets in post-MI patients with LVD and the effects of systemic factors on cardiac disease severity.

Native QRS duration predicts the occurrence of arrhythmic events in ICD recipients

AIMS

Identification of implantable cardioverter/defibrillator (ICD) recipients at higher risk of future therapies may assist in pre-empting future shocks. Native QRS duration is an established predictor of overall mortality, but the role of this parameter as a clinical predictor of arrhythmic events warrants further investigation.

METHODS AND RESULTS

In an analysis of a single-centre, 13-year ICD implantation experience (1990-2002), multiple clinical parameters including QRS duration were analysed using a multiple logistic regression model. Of 562 patients followed for at least 1 year, 98 (17%) did not receive ICD therapies (event-free, group A). Comparisons were made with a randomly selected sample of 123 patients who received ICD therapies (arrhythmic events, group B). There were no significant differences in age, gender, frequency of coronary artery disease, and degree of left ventricular dysfunction. However, QRS duration was a significant determinant of arrhythmic events (> or =100 vs. <100 ms: adjusted OR 2.75, 95% CI 1.37-5.51; > or =120 vs. <120 ms: adjusted OR 1.77, 95% CI 0.97-3.23). QRS duration was also a predictor of overall mortality in the logistic regression models (> or =100 ms: adjusted OR 3.72, 95% CI 1.17-11.9; > or =120 ms: adjusted OR 3.09, 95% CI 1.39-6.85).

CONCLUSION

In this ICD population, consisting largely of secondary prevention ICD recipients, longer QRS duration predicted higher likelihood of arrhythmic events. Extent of QRS prolongation could guide the decision to initiate prophylactic anti-arrhythmic therapy in ICD patients.

Incidence and prognostic significance of atrial fibrillation in acute myocardial infarction: the GISSI-3 data

BACKGROUND

Atrial fibrillation is the most common supraventricular arrhythmia in patients with acute myocardial infarction. Recent advances in pharmacological treatment of myocardial infarction may have changed the impact of this arrhythmia.

OBJECTIVE

To assess the incidence and prognosis of atrial fibrillation complicating myocardial infarction in a large population of patients receiving optimal treatment, including angiotensin converting enzyme (ACE) inhibitors.

METHODS

Data were derived from the GISSI-3 trial, which included 17 944 patients within the first 24 hours after acute myocardial infarction. Atrial fibrillation was recorded during the hospital stay, and follow up visits were planned at six weeks and six months. Survival of the patients at four years was assessed through census offices.

RESULTS

The incidence of in-hospital atrial fibrillation or flutter was 7.8%. Atrial fibrillation was associated with indicators of a worse prognosis (age > 70 years, female sex, higher Killip class, previous myocardial infarction, treated hypertension, high systolic blood pressure at entry, insulin dependent diabetes, signs or symptoms of heart failure) and with some adverse clinical events (reinfarction, sustained ventricular tachycardia, ventricular fibrillation). After adjustment for other prognostic factors, atrial fibrillation remained an independent predictor of increased in-hospital mortality: 12.6% v 5%, adjusted relative risk (RR) 1.98, 95% confidence interval (CI) 1.67 to 2.34. Data on long term mortality (four years after acute myocardial infarction) confirmed the persistent negative influence of atrial fibrillation (RR 1.78, 95% CI 1.60 to 1.99).

CONCLUSIONS

Atrial fibrillation is an indicator of worse prognosis after acute myocardial infarction, both in the short term and in the long term, even in an unselected population.

Prognosis following acute myocardial infarction in patients with ECG evidence of left ventricular hypertrophy prior to infarction

This study was designed to determine the relationship between prognosis after myocardial infarction (MI) and left ventricular hypertrophy (LVH). Left ventricular hypertrophy diagnosed by electrocardiography according to the criteria of Sokolow and Lyon was noted in 57 of 223 patients (25.6%) on the pre-MI electrocardiogram (ECG), in 11.2% on an early post-MI ECG, and in 11.3% on the discharge ECG. In-hospital and 1-year postdischarge mortalities were significantly greater in patients with LVH noted on pre-MI ECG than in patients without prior LVH. There was no relationship between the presence of LVH on early post-MI ECGs and in-hospital or postdischarge 1-year mortality. Multivariate analysis revealed that evidence of LVH on a pre-MI ECG and acute congestive heart failure were independent predictors of cardiac death within 1 year of MI in patients over 70 years old. It is concluded that in patients over 70 years of age, the presence of LVH on a pre-MI ECG is a reliable predictor of post-MI prognosis.

Six year follow up of a consecutive series of patients presenting to the coronary care unit with acute chest pain: prognostic importance of the electrocardiogram

In a retrospective 6 year follow up data were obtained for 536 of 566 (95%) consecutive patients admitted to a coronary care unit with acute chest pain. Their diagnoses were acute myocardial infarction in 290 (54%), myocardial ischaemia in 164 (31%), pericarditis in 16 (3%), and non-cardiac in 66 (12%). Six year mortality was 36%, 24%, 0%, and 16% respectively. In patients with acute myocardial infarction a higher mortality rate during follow up was associated with a higher than average age, a higher than average creatine kinase, previous myocardial infarction, Q wave infarction, and the presence of reciprocal changes. The presence of reciprocal changes was associated with higher than average concentration of serum creatine kinase, indicating more extensive infarction. Infarction complicated by ventricular fibrillation or left bundle branch block was associated with a higher death rate. The electrocardiogram recorded at the time of acute myocardial infarction contains much useful prognostic information.

Prognostic significance of the electrocardiogram after Q wave myocardial infarction. The Framingham Study

The prognostic value of abnormalities on the electrocardiogram (ECG) present 1 year after initial myocardial infarction (MI) is examined in relation to reinfarction and coronary death throughout 32 years (mean, 10.1 years) of follow-up in the Framingham Heart Study. Resting 12-lead ECGs were available in 251 survivors (190 men and 61 women) of clinically recognized Q wave MI. The ECG reverted to normal in 31 (12.4%) cases and was abnormal but without Q waves in 37 (14.7%). Q waves persisted without other significant abnormalities in 108 (43.0%) and with other abnormalities in 75 (29.9%) cases. Electrocardiographic abnormalities at follow-up were more common in women and in those persons whose initial MI was anterior as compared with inferior. Nonspecific T wave, ST segment changes, and electrocardiographic left ventricular hypertrophy on the ECG before or after MI were powerful predictors (p less than 0.01) of coronary death. The relation of these residual post-MI electrocardiographic findings to reinfarction and coronary death was assessed by Cox regression analysis. The follow-up electrocardiographic status was unrelated to the risk of subsequent reinfarction. Subjects who lost Q wave evidence of MI but whose ECG continued to show evidence of repolarization abnormalities, left ventricular hypertrophy, or blocked intraventricular conduction were at a 3.5-fold increased risk (p less than 0.01) of coronary death as compared with those reverting to a normal ECG. Persons with a persistent Q wave MI accompanied by these abnormalities were at a 2.7-fold excess risk (p = 0.01) of coronary death as compared with those with a normalized ECG. These findings remained significant when considering age and standard coronary risk factors. The presence of other electrocardiographic abnormalities without persistent Q waves yields a worse prognosis than a Q wave persisting alone. The prognostic value of a follow-up ECG with abnormalities other than a persistent Q wave MI also remained after considering the effects of left ventricular hypertrophy and cardiac enlargement on x-ray, functional classification, and diuretic usage. Specific electrocardiographic abnormalities present before infarction, however, were potent indicators of long-term prognosis prognosis and diminished the importance of the follow-up ECG. Although survival after initial MI is improved only if the ECG reverts to normal, information on electrocardiographic abnormalities before MI can be especially useful in evaluating long-term risk.

A comparison of serial 49-lead precordial ECG maps and standard 6-lead precordial ECGs in patients with acute anterior Q wave myocardial infarction

A comparison of 265 pairs of standard ECGs and 49-lead precordial maps in 20 patients with ST-segment elevations in anterior ECG leads on admission who eventually were diagnosed as having suffered an anterior Q wave myocardial infarction was carried out to investigate the diagnostic performance provided by the standard ECG in serial studies. Ten patients received intravenous methylprednisolone and 10 were given placebo on admission, and paired map-standard ECG studies were done. ST-segment elevations were taken as an index of ischemic injury and reduction of R wave amplitude or development of Q waves as a marker of developing necrosis. Methods of measurements and derivation of ECG parameters used in the analysis were the same for the standard ECGs and maps. Comparisons of percent change of five ECG-derived variables between 13 time points and admission, as assessed by the six precordial leads of the standard ECGs and the paired 49-lead maps, were made for the entire data base. A separate analysis to assess the performance of the standard ECG was carried out in a comparison of the methylprednisolone and placebo subgroups. In this latter assessment results of comparisons of the standard ECGs from the treatment and placebo cohorts were similar to the conclusions from the comparisons of the corresponding 49-lead maps. Comparisons for the entire 265 pairs of tracings by the two ECG systems demonstrated that the standard ECG is adequate to monitor quantitatively the ischemic injury and necrosis as reflected by the ECG in serial studies throughout the hospitalization and can be effectively employed in lieu of multilead precordial maps in the evaluation of therapeutic modalities for patients with anterior Q wave myocardial infarction.

First myocardial infarction: age and ejection fraction identify a low-risk group

This study examines patients with a first myocardial infarction (MI) (about 70% of the population, n = 2089), and identifies factors associated with 1-year cardiac mortality in patients discharged alive. With the use of multivarate analysis of variables observed at hospital discharge in patients with a first MI, age was the most important predictor, followed by left ventricular ejection fraction (LVEF) (determined in 56%) and other variables. Based on this finding, age subsets (less than or equal to 50, 51 to 70, greater than 70 years) were related to LVEF groups (less than or equal to 0.40, 0.41 to 0.50, greater than 0.50). Patients with a first MI who were less than 50 years of age with LVEF greater than 0.40 and patients between 51 and 70 years of age with LVEF greater than 0.50 had a very low risk for 1-year cardiac death, 1.2 +/- 1.1% (95% confidence interval). Such patients comprised 47% of individuals with a first MI having an LVEF determination. Mortality in the remaining patients less than 70 years was 7.4 +/- 3.5%. Mortality for patients greater than 70 years was high, 22.2 +/- 6.6%. Thus with LVEF as the only predischarge test, a sizable low risk group can be identified among patients with a first MI.

High-risk subgroups of patients with non-Q wave myocardial infarction based on direction and severity of ST segment deviation

To determine the significance of the direction of ST segment deviation on admission of patients who evolved non-Q wave myocardial infarction (MI), 97 patients with initial ST segment depression were compared to 207 patients with initial ST segment elevation. Patients with ST segment depression developed smaller infarcts than those with ST segment elevation (creatine kinase MB isoenzyme 8.2 vs 13.3 gmEq/m2, p less than 0.002), but had a lower left ventricular ejection fraction on admission (44% vs 51%, p less than 0.001), more in-hospital complications, and a higher cumulative 1-year mortality (29% vs 11%, p less than 0.001) that could be accounted for by an excess of adverse baseline characteristics. Although a severity index (combining magnitude and extent of the initial ST segment deviation) was not useful for discriminating prognosis of patients with non-Q wave MI who presented with ST segment depression, it was useful in identifying a subgroup of patients with ST segment elevation with an adverse prognosis. The poor outcome of patients with non-Q wave MI presenting with either ST segment depression or severe ST segment elevation on admission suggests that patients in these subgroups should receive close surveillance and should possibly be considered for aggressive therapy.

Prediction of atrial and ventricular fibrillation complicating myocardial infarction from admission data: a prospective study

This study set out to examine prospectively two logistic formulae based on admission clinical data to predict ventricular or atrial fibrillation complicating acute myocardial infarction. A prospective study of 87 consecutive patients with acute transmural myocardial infarction was conducted. The formula for predicting ventricular fibrillation from the diastolic blood pressure, degree of ST-segment elevation, and QTc had a sensitivity of 93%, specificity of 83%, and a predictive value for an abnormal test of 62% (13 of 14 patients who developed ventricular fibrillation were identified). The formula for predicting atrial fibrillation from the age of the patient, a history of heart failure, systolic blood pressure, and four electrocardiographic parameters had a sensitivity of 78%, specificity of 85%, and a predictive value of 67% (14 of 18 patients identified). Our study shows that patients with myocardial infarction who are liable to develop ventricular or atrial fibrillation can be identified on admission from simple clinical data.

Prognostic value of predischarge 12 lead electrocardiogram after myocardial infarction compared with other routine clinical variables

The prognostic value of QRS score (Selvester), ST depression, ST elevation, extrasystoles, P terminal force in V1, and QTc derived from the predischarge 12 lead electrocardiogram was assessed after myocardial infarction in 474 patients without intraventricular conduction defects, ventricular hypertrophy, or atrial fibrillation. The usefulness of these results in risk assessment was compared with that of other clinical data. During follow up 45 patients died. Logistic regression analysis showed that QRS score, ST depression, and QTc were independently predictive of cardiac mortality. When multivariate analysis was applied to clinical and electrocardiographic data together, however, the 12 lead electrocardiogram did not provide independent information additional to that provided by other routine clinical findings and laboratory tests such as a history of previous myocardial infarction, clinical signs of persistent heart failure, indication for digitalis or antiarrhythmic drugs at discharge, and enlarged heart on chest x ray. In conclusion, the electrocardiogram has important prognostic value; however, it is not powerful enough to further improve the risk assessment of post-infarction patients.