Importance of timing of treadmill predictors for risk stratification after myocardial infarction: a five year follow-up study

The prognostic value of information derived from clinical characteristics and exercise treadmill tests performed before discharge and repeated at three months was evaluated in 205 consecutive patients followed for five years. Recurrent myocardial infarction, unstable angina and mortality were tabulated. Survival was analyzed by the Kaplan-Meier life-table method and the Cox regression model. The major difference between the predischarge and three month intervals was the failure of exercise-induced ST depression to predict mortality from the predischarge test. However, it was predictive of mortality at three months when 76% survived five years with a positive ischemic response compared to 94% with a negative response (P less than 0.0005). In contrast, resting ST depression of at least 1 mm was associated with a very poor five year survival rate of 58.3% and 50% when assessed at both predischarge and three months (P less than 0.0005 and P less than 0.004, respectively). Selected univariately at the predischarge interval, the following characteristics were ranked in descending order of predictive power for five year mortality by discriminant analysis: history of previous infarction; exercise capacity; and ST depression on resting ECG greater than 1 mm. At three months, the same characteristics were selected. However, recurrent infarction and unstable angina were not predictable at either interval by any clinical or treadmill variable. Characteristics tending to reflect poor exercise capacity are stronger predictors of five year outcome than exercise-induced ischemia. While predischarge exercise testing for ST segment response failed to predict survival, this variable showed improved predictive power with repeat testing at three months.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prediction of 1-year outcome after complicated and uncomplicated myocardial infarction: Bayesian analysis of predischarge exercise test results in 300 patients

After myocardial infarction (MI), the additive prognostic value of exercise variables to clinical variables has been questioned. The merits of a symptom-limited predischarge exercise test were therefore evaluated in clinically defined subgroups of patients. Exercise tests were consecutively performed by 208 survivors of uncomplicated MI (no heart failure, postinfarction angina, recurrent infarction, or late arrhythmias) and by 92 survivors of complicated MI. After uncomplicated MI (1-year mortality rate 4%), an achieved workload greater than 70% of age-predicted maximum identified 145 patients at very low risk (predictive value for survival 98%). After complicated MI (1-year mortality rate 13%), an exaggerated heart rate response was the best predictor of outcome, but had low (92%) predictive value of survival at 155 bpm. It is concluded that stress testing has only limited value after complicated MI. After uncomplicated MI, exercise variables are extremely helpful in identifying patients at very low risk in whom further investigations are not warranted.     

A metaanalysis of predischarge risk stratification after acute myocardial infarction with stress electrocardiographic, myocardial perfusion, and ventricular function imaging

We assessed the relation of abnormal predischarge noninvasive test results to outcomes in postmyocardial infarction patients. We included series published from 1980 to 1995 containing only myocardial infarction patients, enrolling most patients after 1980, testing within 6 weeks of infarction, having follow-up rates > 80%, and having 2 × 2 frequency outcome rates for test results, that were the latest of multiple reports. Sensitivity, specificity, and predictive values were calculated for test results for 1-year outcomes (cardiac death, cardiac death or reinfarction). Univariable and summary odds were calculated for test results. Reports (n = 54) included a total of 19,874 patients and were primarily retrospective (76%) and small series (35% of reports included < 5 deaths). One-year mortality ranged from 2.5% for pharmacologic stress echocardiography to 9.3% for exercise radionuclide angiography. Positive predictive values for most noninvasive risk markers were < 0.10 for cardiac death and 0.20 for death or reinfarction. Electrocardiographic, symptomatic, and scintigraphic risk markers of ischemia (ST-segment depression, angina, a reversible defect) were less sensitive (≤44%) for identifying morbid and fatal outcomes than markers of left ventricular dysfunction or heart failure (exercise duration, impaired systolic blood pressure response, and peak left ventricular ejection fraction). The positive predictive value of predischarge noninvasive testing is low. Markers of left ventricular dysfunction appear to be better predictors than markers of ischemia. Limitations of the literature—small samples and widely varying event rates—impede our ability to discern the accuracy of predischarge noninvasive testing. More rigorous, controlled trials are required to elucidate the relative value of these tests for risk stratification.     

Preinfarction angina as a major predictor of left ventricular function and long-term prognosis after a first Q wave myocardial infarction

Objectives. The purpose of this study was to assess the prognostic significance of preinfarction angina after a first Q wave myocardial infarction. Patients with anterior or inferior myocardial infarction were compared.Background. The effect of preinfarction angina on prognosis after anterior and inferior myocardial infarction remains unclear.Methods. A total of 291 patients with a first Q wave anterior (n = 171) or inferior (n = 120) myocardial infarction were examined to assess the effect of preinfarction angina on short- and long-term prognosis. The relation between predischarge left ventriculographic findings and preinfarction angina was also examined.Results. The presence of preinfarction angina was associated with lower peak creatine kinase activity, a lower in-hospital incidence of sustained ventricular tachycardia and fibrillation and a lower incidence of pump failure and cardiac mortality in patients with either anterior or inferior infarction. Among patients with anterior infarction, preinfarction angina was associated with a lower incidence of cardiac rupture and less need for readmission for heart failure within 1 year after the onset of infarction. In this subgroup it was also associated with a higher ejection fraction, a smaller end-diastolic volume and a lower incidence of aneurysm formation noted on ventriculography during convalescence. In patients with inferior infarction, these variables did not differ significantly in the presence or absence of preinfarction angina. Multivariate analysis confirmed that the presence of preinfarction angina was an independent predictor of development of ventricular aneurysm, late phase heart failure and 1-year cardiac mortality.Conclusions. The presence of preinfarction angina has a favorable effect on infarct expansion and late phase left ventricular function, especially in patients with anterior myocardial infarction. The mechanisms responsible for this phenomenon are not known but may be secondary to limitations of infarct size through unidentified mechanisms other than collateralization (e.g., ischemic preconditioning).     

Left ventricular dysfunction after acute myocardial infarction: results of a prospective multicenter study

In a multicenter prospective study of 866 patients who survived the coronary care unit phase of an acute myocardial infarction, variables reflecting left ventricular function were examined to assess their impact on 2 year survival. Single variables that reflected left ventricular dysfunction before infarction and in the acute and recovery phases were, respectively, history of prior myocardial infarction, rales in the coronary care unit dichotomized at greater than bibasilar and predischarge radionuclide ejection fraction dichotomized at less than 0.40. When combined in a stepwise fashion, patients lacking these three risk characteristics had a 2 year 4.2% mortality rate, whereas patients possessing all three characteristics had a 45% mortality rate. Rales in the coronary care unit and predischarge ejection fraction act independently, and each contributes to mortality. Fifty-two patients with advanced rales but an ejection fraction of 0.40 or greater had a 21% mortality rate. Similarly, 208 patients with few rales but an ejection fraction of less than 0.40 had a 15% mortality rate. These data suggest that the mortality risk imposed by those factors that assess permanent left ventricular damage is independent of and additive to the mortality risk contributed by dynamic, acute phase dysfunction. These data fit the hypothesis that acute phase dysfunction is, in part, due to transient ischemia that, on reversal, can restore function toward normal. The results suggest 1) that assessment of left ventricular function during the acute and recovery phases of myocardial infarction is necessary to define prognostic characteristics of an individual patient, and 2) that of particular importance is the identification of patients whose postinfarction course is consistent with reversible ischemia.     

Comparison of clinical and treadmill variables for the prediction of outcome after myocardial infarction

To assess the relative prognostic merits of 15 clinical and 10 predischarge exercise test variables, 226 patients who had sustained an acute myocardial infarction were studied. A submaximal treadmill test was performed on 205 patients to a mean work load of 5.7 +/- 2.9 METS. Testing was performed an average of 11.7 (range 6 to 33) days after myocardial infarction. During the first year of observation, major cardiac events were noted in 33 patients (16%), unstable angina in 7 (3.4%), recurrent myocardial infarction in 14 (6.8%) and death in 12 patients (5.9%). Cardiac mortality correlated with mean peak serum creatine kinase (CK) (p less than 0.05), history of previous myocardial infarction (p less than 0.01) and ST segment depression at rest (p less than 0.01). The only exercise variable that correlated with cardiac mortality was poor exercise endurance (p less than 0.05). Multivariate risk stratification of clinical and treadmill variables from these 205 patients using linear discriminant analysis produced a function that correctly classified 95% of those who were event-free and 80% of those who died. The first four discriminant variables that contributed independent information for the prediction of cardiac mortality were: 1) ST segment depression at rest; 2) CK greater than 1,280 IU/liter; 3) exercise duration less than 3 minutes; and 4) a history of previous myocardial infarction. ST segment depression on the predischarge treadmill test did not predict any event, nor did it improve the predictive accuracy of the clinical variables. It is concluded that a history of previous myocardial infarction and ST segment depression on the rest electrocardiogram indicate a poor prognosis after acute myocardial infarction. Poor endurance is the only exercise variable that suggests a future cardiac event. Prognosis after acute myocardial infarction is more accurately predicted by these clinical data than by variables derived from the predischarge treadmill test.     

Holter-detected myocardial ischemia. Impact for prognosis and decision making after acute myocardial infarction

BACKGROUND: Aim of the study was to evaluate the prognostic and decision making value of Holter detected myocardial ischemia after acute myocardial infarction in comparison with clinically detected postinfarction angina and exercise test. METHODS: To this aim the patients consecutively admitted to our coronary care unit with acute myocardial infarction during one year were retrospectively evaluated. One hundred and eighty-nine patients (age 70+/-11 years, 137 male and 51 female) had a 24 hour Holter monitoring. One-year follow up of these patients was obtained. RESULTS: Myocardial ischemia was detected by Holter monitoring in 21 patients (11%), 4 with and 17 without angina. Symptom limited exercise test was obtained before discharge in 116 patients (62%): 45% were positive, 42% non-diagnostic and 13 negative for myocardial ischemia. Post infarction angina was present in 15 patients (9%). Patients with Holter detected myocardial ischemia were older (73+/-10 vs 66+/-11 years, p<0.05) and had higher prevalence of both angina and positive exercise test (p<0.01). One-year follow up was obtained in 186 patients. Holter detected myocardial ischemia positive predictive value for death or reinfarction was 15%, negative predictive value was 90%, similar to the absence of angina (90%) and the absence of positive exercise test (93%). Angina and exercise test identified 62% of patients with Holter detected myocardial ischemia. Residual myocardial ischemia was exclusively observed by Holter monitoring in 4% of the population, particularly in 1 patients with and 7 without exercise test. CONCLUSIONS: The additive contribution of Holter detected myocardial ischemia in the prognosis and decision making of post infarction patients is rather scanty.     

Exercise testing for patients after myocardial infarction and coronary bypass surgery: emphasis on predischarge phase

Data from the preceding low-level exercise test studies have been compiled and are presented in Table II. The table is arranged according to groups of prognostic indicators for future coronary events or indicators for those patients with multivessel coronary artery disease. In summary, current studies demonstrate safety and predictive value in predischarge low-level exercise testing in patients after myocardial infarction. If the test reveals a positive S-T segment change or angina or both, the predictive value for future cardiac events is significant. In addition, a limited duration on the exercise test, a flat or falling blood pressure response, and the presence or absence of premature ventricular depolarizations add to this predictive value. A more sophisticated technique that employs radionuclide ventriculography may add to the sensitivity and specificity of these various tests but should be used selectively. Post-myocardial infarction patients who perform low-level exercise testing prior to discharge and demonstrate no exercise-induced abnormality from baseline may also harbor multivessel coronary disease, and this group of patients needs to be carefully followed. Testing at 3 weeks and 6 weeks after infarction may be beneficial in revealing additional clinical data. Less data are currently available on predischarge low-level exercise testing in patients with myocardial revascularization. However, these limited data support both feasibility and safety of low-level exercise testing in myocardial revascularization patients before discharge. Prognostic data with regard to low-level exercise testing for this group of patients should be forthcoming. Data from low-level exercise testing need to be incorporated during the in-hospital phase to eliminate unnecessary testing as the patient proceeds home and/or to medically supervised exercise programs. Proper therapeutic modalities based on these data should be included. In accord with this, it is imperative that the cardiac rehabilitation team or exercise testing laboratory correspond directly with the private physician regarding all clinical data and recommendations for discharge activity. Follow-up exercise testing for patients after myocardial infarction and coronary bypass surgery utilizes end points similar to those of predischarge low-level testing and therefore will not be discussed in detail. In general the patient should be able to achieve a higher heart rate or MET level in follow-up testing.(ABSTRACT TRUNCATED AT 400 WORDS)     

Impact of prodromal angina pectoris and white blood cell count on outcome of patients with acute myocardial infarction

BACKGROUND: Elevation of white blood cell (WBC) count at admission is associated with adverse outcome after acute myocardial infarction (AMI). Prodromal angina, by the mechanism of ischemic preconditioning, improves left ventricular (LV) function and survival after reperfusion therapy in patients with AMI. Recent experimental studies have reported that preconditioning has anti-inflammatory effect. METHODS: This study consisted of 598 patients with first anterior wall AMI who underwent coronary angiography within 12 h after symptom onset. WBC count was measured at the time of hospital admission. Prodromal angina was defined as angina occurring within 24 h before the onset of AMI. Serial measurements of LV ejection fraction (EF) were obtained before reperfusion therapy and before discharge in 421 patients (71%). RESULTS: High WBC count (>10.2 x 103/mm3, n=297) was associated with higher 30-day mortality (8% vs. 4%, p=0.02) and lower predischarge LVEF (51+/-15% vs. 57+/-14%, p<0.001), although there was no significant difference in acute LVEF (47+/-10% vs. 49+/-11%, p=0.07). High WBC count was an independent predictor of 30-day mortality (p=0.009) and predischarge LVEF (p=0.002). Prodromal angina was associated with lower 30-day mortality (3% vs. 7%, p=0.02) and preserved predischarge LVEF (57+/-15% vs. 53+/-14%, p=0.006). Patients with prodromal angina had lower WBC count (10.0+/-3.3 x 10(3)/mm3 vs. 11.0+/-3.9 x 10(3)/mm3, p=0.001) and prodromal angina was an independent predictor of WBC count (p<0.001). CONCLUSIONS: Elevation of WBC count and lack of prodromal angina were associated with impaired LV function and mortality after reperfusion in patients with AMI. Prodromal angina might have contributed to favorable outcome after AMI through its anti-inflammatory effect.     

Prediction of mortality after myocardial infarction by simple clinical variables recorded during hospitalization

Simple clinical variables obtainable in any coronary care unit and in any patient were recorded in 769 consecutive patients who were admitted with acute myocardial infarction (AMI) and who were discharged from the hospital and followed for up to 3 years. To identify the patients at highest and lowest risk of posthospital mortality, a prognostic index was established from a stepwise logistic discriminant analysis of variables obtained in a consecutive series of 418 patients discharged alive from one of two coronary care units admitting new patients on alternate days. This prognostic index was validated by applying it to a comparison group of 351 consecutive control patients discharged from the other coronary care unit. In the training group, 59 of the 418 patients (14%) died during the first year after hospital discharge and 34 (8%) died during the second or third year. The stepwise logistic discriminant analysis made it possible to distinguish between 1-year survivors and nonsurvivors, but not between the patients who died during the second and third years and the 3-year survivors. Four variables were selected for obtaining a 1-year prognostic index: the maximum grade of left ventricular function during hospitalization (0 to 4), history of previous AMI (1 or 0), predischarge cardiothoracic ratio (0 to 0.99), and complete bundle branch block (1 or 0). Prognostic index = 7.0196-0.6515 function - 1.6623 previous AMI - 0.0729 cardiothoracic ratio - 1.0813 bundle branch block. This index was validated in the comparison group.(ABSTRACT TRUNCATED AT 250 WORDS)     

The diagnostic and prognostic importance of ambulatory ST recording compared to a predischarge exercise test after an episode of unstable angina or non-Q wave myocardial infarction

The diagnostic and prognostic value of ambulatory ST recordingsafter admission to the CCU and before discharge was comparedto a symptom-limited predischarge exercise test in 170 men withunstable angina pectoris or non-Q wave myocardial infarction.ST depression in recordings before discharge identified a smallgroup of patients (18%) out of whom 23% had a myocardial infarctionwithin 3 months compared to 7% in those without this finding.The exercise test gave more diagnostic information, with STdepression found in 52% including 70% of those with ST depressionat Holier monitoring. After 3 months, 13% of patients with STdepression at exercise test had a myocardial infarction comparedto 5% in the other patients. ST depression at exercise alsoindicated an increased risk of myocardial and future severeangina over a longer time period. Thus ST recordings are recommendedbefore discharge in all patients after an episode of unstablecoronary artery disease as it identifies the patients with themost severe prognosis who might benefit from early revascularization.In those without ST depression at Holter a predischarge exercisetest will give further information regarding the long-term riskfor angina and coronary events.     

Use of survival analysis to determine the clinical significance of new Q waves after coronary bypass surgery

There are few data on the long-term effects of new Q waves on survival and morbidity after coronary bypass graft surgery (CABG). We followed 1340 patients who underwent CABG in 1978 at 10 hospitals participating in the Coronary Artery Surgery Study (CASS). The incidence of perioperative Q-wave infarction was 4.76% (range 0.0-10.3% by hospital). The rate of infarction was higher in patients who had an increased left ventricular end-diastolic pressure or cardiomegaly on the preoperative chest radiograph. Patients who received more grafts or who had longer cardiopulmonary bypass time were also at higher risk of infarction. In a stepwise discriminant analysis of 44 clinical, angiographic and surgical variables, cardiopulmonary bypass time, topical cardiac hypothermia and cardiomegaly entered the stepwise selection of variables. Long-term survival was adversely affected by the appearance of new postoperative Q waves. The hospital mortality was 9.7% in the 62 patients who had new postoperative Q waves and 1.0% in the 1278 patients who did not (p less than 0.001); the 3-year cumulative survival rates were 85% and 95%, respectively (p less than 0.001). In patients who survived to hospital discharge, the presence of new postoperative Q waves did not adversely affect 3-year survival (94% and 96%, respectively). The survival rates were worse in patients who had a history of infarction or who had impaired left ventricular function preoperatively. The number of readmissions to hospital after CABG among the patients who had a transmural perioperative infarction was similar to to that among patients who did not. We conclude that the appearance of new Q waves after CABG adversely affects survival. The major impact on mortality occurs before hospital discharge. Patients who are destined to have a perioperative infarct cannot be predicted from commonly measured preoperative and angiographic variables.     

Prediction of mortality during the first year after acute myocardial infarction from clinical variables and stress test at hospital discharge

The predictive value of a predischarge symptom-limited stress test was studied in 405 consecutive survivors of acute myocardial infarction (AMI). Three hundred patients performed bicycle ergometry; 105 could not perform it. Among these latter 105 patients, the stress test was contraindicated in 43 because of angina or heart failure and in 62 because of noncardiac limitations. One-year survival was 44% in the "cardiac-limited" group (19 of 43) and 92% in the "non-cardiac-limited" group (57 of 62). One-year survival among the patients who performed an exercise test at discharge was 93% (280 out of 300). The best stress test predictor of mortality by univariate analysis was the extent of blood pressure (BP) increase: 42 +/- 24 mm Hg in 280 survivors vs 21 +/- 14 mm Hg in 20 nonsurvivors (p less than 0.001). Among the 212 patients in whom BP increased 30 mm Hg or more, mortality was 3% (n = 6), while it was 16% (n = 14) among the 88 patients in whom BP increased less than 30 mm Hg. Angina, ST changes and arrhythmias were not as predictive. Stepwise discriminant function analysis showed inadequate BP increase to be an independent predictor of mortality. A high-risk group can be identified at discharge on clinical grounds in patients unable to perform a stress test, whereas intermediate- and low-risk groups can be identified by the extent of BP increase during exercise.     

Stress testing predischarge and six weeks after myocardial infarction to compare submaximal and maximal exercise predischarge and to assess the reproducibility of induced abnormalities

Submaximal and maximal treadmill exercise tests were performed predischarge in 64 patients after acute myocardial infarction to assess the relative yield of residual ischaemic abnormalities. The reproducibility of individual abnormalities resulting from maximal stress tests performed predischarge and 6 weeks after infarction was also assessed in 55 of these patients. Compared with predischarge submaximal exercise testing, a maximal exercise test identified a significantly greater number of patients with residual myocardial ischaemia (26 vs. 15, P less than 0.05) and this was associated with a significantly longer average maximal exercise duration (P less than 0.001), and a higher rate-pressure product (P less than 0.001). Among the 55 patients who had maximal stress tests both predischarge and 6 weeks after infarction, there was a significant lack of reproducibility in the occurrence of exercise induced angina (P less than 0.01) and an abnormal blood pressure response (P less than 0.02). In contrast, exercise induced ST segment depression and elevation and ventricular arrhythmias were relatively reproducible. More patients had an ischaemic test result (ST depression or angina) at the later test compared to the predischarge test (33 vs. 25 patients) but this increase was not statistically significant. There were, however, significant increases at the later test in mean maximal exercise duration (P less than 0.001). mean maximal heart rate (P less than 0.001) and heart rate-systolic blood pressure double product (P less than 0.001). The majority of patients who had a cardiac event in the period between the two tests had a predischarge test abnormality. We conclude that a significantly greater number of patients with residual reversible myocardial ischaemia after infarction will be identified by symptom limited exercise testing compared with a submaximal predischarge test. Because ST depression and elevation appear reproducible, patients who develop these abnormalities during a predischarge test do not, for prognostic reasons, need retesting 6 weeks after infarction. Exercise induced angina pectoris and an abnormal blood pressure response, however, are highly variable and in these patients a repeat test may be useful.     

Reduced prostacyclin production in patients with different manifestations of ischemic heart disease

Prostacyclin, a substance produced by vessel wall, has a sustained vasodilating and platelet antiaggregating activity and therefore the variations in its production in patients with ischemic heart disease are of interest. Prostacyclin production was assessed in 59 patients with ischemic heart disease and 59 control subjects matched for age, sex, body weight, smoking habits, blood pressure and serum cholesterol levels. Of the 59 patients examined, 23 had had a myocardial infarction 3 to 12 months earlier; 21 had had spontaneous angina and 15 effort angina for at least 3 months. Patients with myocardial infarction and spontaneous angina were also classified in subgroups with and without acute coronary insufficiency, according to the occurrence of ischemic attacks in the week preceding the study.Both circulating prostacyclin levels and prostacyclin produced after 3 minutes of ischemia were measured by bioassay. Circulating prostacyclin was significantly less in patients with ischemic heart disease than in matched control subjects independent of the clinical type of ischemic heart disease. Circulating prostacyclin was particularly reduced in patients with acute coronary insufficiency in comparison to patients without, both in the group with myocardial infarction (1.11 ± 0.22 ng/ml and 2.09 ± 1.32, respectively) and in the group with spontaneous angina (1.24 ± 0.42 and 2.17 ± 1.16, respectively). No differences could be found for prostacyclin produced after 3 minutes of ischemia in relation to the presence of acute coronary insufficiency. The lower level of prostacyclin production in patients with ischemic heart disease and especially in those with acute coronary insufficiency may be an important factor in the occurrence of coronary occlusion or spasm.     

5-year mortality rate in patients with suspected acute myocardial infarction in relation to early diagnosis

In 1,395 patients admitted to hospital between 1976 and 1981 due to suspected acute myocardial infarction, the 5-year mortality rate was related to whether they developed infarction or not during the first 3 days. In all, patients with definite myocardial infarction had a 5-year mortality rate of 33.4% as compared with 13.3% in patients not fulfilling the criteria for this diagnosis (p less than 0.001). When separately analyzing patients with no previous myocardial infarction before admission and discharged from hospital, the corresponding mortality rate was 24.1% for myocardial infarction patients versus 8.1% in nonmyocardial infarction patients (p less than 0.001). Among all patients with nonconfirmed myocardial infarction, those who partly fulfilled the criteria (possible myocardial infarction) had a 5-year mortality rate of 16.7% as compared with 12.0% in those in whom myocardial infarction was completely ruled out (p = 0.18). Independent risk factors for death among patients not developing early infarction were high age and a clinical history of previous myocardial infarction and smoking. We conclude that in this study the long-term prognosis among patients admitted to hospital due to suspected acute myocardial infarction was clearly related to whether they developed an infarction or not during the first 3 days in hospital.     

The predictive value of silent ischemia at an exercise test before discharge after an episode of unstable coronary artery disease. RISC Study Group.

The prognostic value of silent ischemia during a symptom-limited predischarge exercise test (ET) was evaluated in 740 men after an episode of unstable angina or non-Q wave myocardial infarction. The 51% of patients with ST depression at the ET had a higher rate of myocardial infarction or death after 1 year (18%) compared with those without ST depression (9%; p less than 0.01). This increased risk was not influenced by the presence or absence of pain at the ET: 18.3% in patients with painful ischemia compared with 18.1% in patients with silent ischemia. However, ST depression combined with pain at the ET predicted a higher incidence of class III or IV angina at follow-up (43.9% compared with 16.7% in the group with asymptomatic ST depression; p less than 0.001). Because revascularization in addition to alleviating symptoms also enhances the prognosis in certain groups of patients, selections for coronary angiography and possible revascularization should not be made only on the basis of symptoms but also on the presence of myocardial ischemia, whether symptomatic or not.     

Prognostic importance of predischarge exercise capacity for long-term mortality and non-fatal myocardial infarction in patients admitted for suspected acute myocardial infarction and treated with metoprolol.

To evaluate the influence of acute beta-blockade on the ability of predischarge exercise test data to predict long-term prognosis in patients admitted for suspected acute myocardial infarction, patients randomized at hospital admission to intravenous metoprolol or placebo were studied. Among 190 patients discharged alive, total 4-year mortality was 20.5% (n = 39); (33 cardiac deaths, 6 non-cardiac deaths). Non-fatal infarction rate was 6.8% (n = 13). Multiple logistic regression analysis revealed that total mortality and non-fatal infarctions were independently predicted by (a) inability to perform predischarge stress testing (event-free survival for patients exercise tested 79.5% vs 56.9% for patients not eligible for testing; relative risk (RR) 1.40, 95% confidence interval (CI) 1.10-1.78; P = 0.01), and (b) low predischarge exercise capacity (RR 1.44, CI 1.08-1.93; P = 0.034). ST segment shift > or = 1 mm did not predict mortality or reinfarction. Administration of metoprolol in the acute phase did not influence the predictive value of these parametres. It is concluded that assessment of exercise capacity at early exercise testing yields independent information for later death and myocardial infarctions, and that beta-blockade with metoprolol does not influence the predictive value of early exercise testing.     

Prognostic evaluation of silent ischemia during exercise in patient with recent infarction. Italian multicenter study. SMISS Group

AIM: The aim of the Multicenter Silent Ischemia Study (SMISS), co-ordinated by the Italian Working Group on Cardiac Rehabilitation, was to evaluate prospectively, the prognostic significance of silent myocardial ischemia during exercise testing in patients with proven ischemic cardiac disease. METHODS: Over a period of six months 4389 consecutive patients performing a maximal symptom-limited exercise testing, after drug withdrawal, were enrolled in the 73 ergometric laboratories. All patients were followed up after 12 months, at which time electrocardiogram, examination and clinical history were reassessed. Here we report the results of 1111 patients group with the recent myocardial infarction (inferior 3 months). The follow-up was completed in 1031 (93%) patients. RESULTS: The results of exercise testing were normal in 666 (64.6%) patients; angina alone in 33 (3.2%) patients; silent ischemia in 234 (22.7%) patients; symptomatic ischemia in 98 (9.5%) patients. In 270 patients (26.1%) new events occurred: angina (19.7%); myocardial infarction (3.1%; PTCA (4%); CABG (6%); cardiac death (1.4%). The total events were more common in the patients with exercise induced angina (48.5%) and in those who had exercise induced-symptomatic ischemia (48%), in respect of patients with silent ischemia (29.5%) and of those who had normal testing (20.7%) (p = 0.0001). Myocardial infarction rate was higher in patients with symptomatic ischemia (7.1%) that for those of all other groups (silent ischemia: 1.3%, angina: 3%, normal 3.2%) (p = 0.05). Moreover, the patients with symptomatic ischemia had higher incidence of CABG (p = 0.0001). The mortality rate was low among all patients and did not show differences among the groups. Only among the 31 patients (3%) with blood pressure fall was mortality higher that in patients with a normal blood pressure increase. By multivariate logistic analysis the angina induced by exercise maintained its prognostic significance for all the events, but also other variables were significant: poor exercise tolerance and, between clinical variables angina before myocardial infarction. CONCLUSION: The results showed, in patients who underwent to exercise testing after drug withdrawal, a low incidence of cardiac death and of myocardial infarction on 12 month follow-up; the patients with induced-exercise symptomatic schema had a greater risk for all cardiac events, except for death.     

Natural history of left ventricular thrombi: their appearance and resolution in the posthospitalization period of acute myocardial infarction

A series of 198 consecutive patients with acute myocardial infarction were prospectively studied before hospital discharge and during 24.0 +/- 8.6 months of follow-up. A predischarge thrombus was found in 38 (31%) of 124 patients with anterior infarction but in none of 74 patients with inferior infarction (p less than 0.001). Early thrombolytic therapy in 34 patients did not decrease the rate of thrombus occurrence. Acute anterior infarction, ejection fraction less than or equal to 35% and apical dyskinesia or aneurysm (but not akinesia) were significantly related to the appearance of thrombus during hospitalization by stepwise logistic regression analysis. Echocardiographic follow-up of 159 patients for at least 6 months (mean 26.6 +/- 8.4) revealed that thrombus disappeared in 14 (48%) of 29. Disappearance of thrombus was related to predischarge apical akinesia (but not dyskinesia) and to warfarin therapy during the follow-up period. A new thrombus first appeared after hospital discharge in 13 of 130 patients, and in 7 of the 13 it resolved during further follow-up. Thus, 30% (13 of 42) of thrombi in these patients appeared after discharge from the hospital. Three factors were related to occurrence of new thrombi during the follow-up period: deterioration in left ventricular ejection fraction, predischarge ejection fraction less than or equal to 35% and ventricular aneurysm or dyskinesia. Systemic embolism occurred in six patients, all with a predischarge thrombus (p less than 0.001). Mobility of the thrombus was the only variable significantly related to subsequent embolic events (p = 0.001) by logistic regression analysis. Thus, the predischarge echocardiogram identifies patients with thrombus and those at highest risk of embolic events. It can indicate patients who are likely to have thrombus resolution and those at risk of developing a new thrombus after hospital discharge. Follow-up echocardiograms may help in guiding the length of long-term anticoagulant therapy. Four additional patients with a predischarge apical mobile thrombus (not part of the consecutive series) received thrombolytic therapy. In two of the four, lysis of thrombus was achieved without complications, but systemic embolism occurred in the other two, and proved fatal in one.