The prognostic significance of first myocardial infarction type (Q wave versus non-Q wave) and Q wave location. The Multicenter Diltiazem Post-Infarction Research Group

The prognostic significance of the type of first acute myocardial infarction (Q wave versus non-Q wave) and Q wave location (anterior versus inferoposterior) was determined from a multicenter data base involving 777 placebo-treated patients who were participants in the Multicenter Diltiazem Post-Infarction Trial. There were 224 patients (29%) with a non-Q wave infarction, 326 (42%) with an inferoposterior Q wave infarction and 227 (29%) with an anterior Q wave infarction. Mean left ventricular ejection fraction was significantly (p less than 0.001) lower in patients with an anterior Q wave infarction than in the other two groups (anterior Q wave 0.39; inferior Q wave 0.52; non-Q wave 0.53). Nevertheless, the total cardiac mortality rate during the follow-up period (average 25 months per patient) was only marginally higher (p = 0.42) in the anterior Q wave group (8.4%) than in the other two groups (inferoposterior Q wave 7.1%; non-Q wave 6.3%). The total first recurrent cardiac event was somewhat higher (p = 0.08) in the anterior Q wave group (18.1%) than in the other two groups (inferoposterior Q wave 11.7%; non-Q wave 15.6%). Survivorship analyses extending over 3 years revealed that electrocardiographic classification of the type of first infarction and Q wave location did not make significant independent contributions to the risk of postinfarction cardiac death or first recurrent cardiac event, either before or after adjustment for baseline clinical variables.     

Risk stratification of patients with non-Q wave myocardial infarction. The critical role of ST segment depression. The Diltiazem Reinfarction Study Research Group

One-year follow-up data on 515 patients who survived hospitalization with MB-creatine kinase-confirmed, acute non-Q wave myocardial infarction were analyzed for factors related to mortality (n = 57) and late reinfarction (n = 64). Twelve of 24 analyzed variables were significantly associated with mortality. Those factors, which were independently predictive of mortality by Cox regression analysis, were persistent ST depression (p = 0.0009), a history of congestive heart failure (CHF) (p = 0.0069), older age (p = 0.0128), and ST elevation at hospital discharge (p = 0.0173). In-hospital reinfarction achieved borderline significance (p = 0.0512). Mortality during the follow-up period was 5.5% in patients with no ST depression, 10.1% in those with ST depression at baseline or discharge, and 22.2% in patients with ST depression at baseline and discharge (i.e., "persistent" ST depression). The age-adjusted risk of mortality for patients with persistent ST depression, discharge-ST elevation, and CHF was 13.99 times as high as was the risk for patients with no ST depression, no discharge-ST elevation, and no CHF. Of the 483 patients with complete electrocardiographic data at both baseline and discharge, 203 (42%) could be stratified into a high risk population with a risk ratio for 1-year mortality more than sevenfold that of patients with no risk factors. Although persistent ST depression was significantly associated with several measures of structural left ventricular damage, the independent significance of ST depression persisted even after adjusting for these factors. The independent predictors of late reinfarction (persistent ST depression, p = 0.0058; Killip class II or III, p = 0.0106; and left ventricular hypertrophy, p = 0.0470) permitted a similar risk stratification. We conclude that 1) easily identified clinical and electrocardiographic factors permit stratification of patients with non-Q wave infarction into high-risk subsets who may benefit from aggressive therapy; 2) ST depression is a highly significant and independent predictor of poor prognosis; and 3) the powerful predictive value of persistent ST depression suggests that non-Q wave myocardial infarction patients with this depression should be viewed as potentially high-risk patients who may be candidates for additional noninvasive testing or early coronary angiography.     

Prognostic value of symptom limited versus low level exercise stress test before discharge in patients with myocardial infarction treated with thrombolytics

OBJECTIVE: To evaluate the benefits and risks of symptom limited exercise testing versus low level exercise testing soon after a thrombolytic treated acute myocardial infarction. DESIGN AND PATIENTS: 98 patients (71 men, 27 women), mean (SD) age 64 (9) years (range 45-75 years), were investigated 5-8 days after admittance to hospital. An ergometer cycle test was used, starting at 30 W with 10 W increments per minute. Each exercise test was interpreted at the symptom limited end point and a low level end point, which was defined as the point at which the patient rated exhaustion as 13 on the 6-20 point Borg scale for rating perceived exertion. SETTING: A university hospital. RESULTS: 75 of the 98 patients were able to perform a predischarge exercise test. Of the remaining 23 patients who could not perform an early exercise test (because of unstable angina, heart failure, or thrombus detected at echocardiography), five died or had a myocardial infarction and six underwent bypass surgery or percutaneous transluminal coronary angioplasty (PTCA) during a follow up period of one year. There were no complications related to the symptom limited exercise tests. The test results were positive in 15 patients at the low level end point and in 39 patients (p < 0.001) at the symptom limited end point. During a follow up period of one year, six of the 75 patients died or had a myocardial infarction. Two of these six patients had a positive low level exercise test and four had a positive symptom limited exercise test. Twenty three of the 75 patients who performed an exercise test had a cardiac event within one year (death, myocardial infarction, bypass surgery or PTCA); of these, 19 had a positive symptom limited exercise test and nine had a positive low level exercise test (p = 0.025). Four of the 36 patients with a negative symptom limited test suffered cardiac events within a year (two patients had a myocardial infarction and two had bypass surgery). CONCLUSION: Symptom limited exercise testing soon after thrombolytically treated myocardial infarction will identify more patients with exercise induced ST depression or chest pain than a low level test, and seems safe. A negative symptom limited test has a better negative predictive value (11% risk of an event within a year) than a negative low level (25% risk of an event within a year).     

Electrocardiographic subset analysis of diltiazem administration on long-term outcome after acute myocardial infarction. The Multicenter Diltiazem Post-Infarction Trial Research Group

The effect of diltiazem on long-term outcome after acute myocardial infarction (AMI) was assessed in 2,377 patients enrolled in the Multicenter Diltiazem Post-Infarction Trial and subsequently followed for 25 +/- 8 months. The study population included 855 patients (36%) with at least 1 prior AMI before the index infarction and 1,522 patients (64%) with a first AMI, of whom 409 (27%) had a first non-Q-wave AMI, 664 (44%) a first inferior Q-wave AMI, and 449 (30%) a first anterior Q-wave AMI. This post hoc analysis revealed that, among patients with first non-Q-wave and first inferior Q-wave AMI, there were fewer cardiac events during follow-up in the diltiazem than in the placebo group, and that the reverse was true for patients with first anterior Q-wave AMI or prior infarction. The diltiazem:placebo Cox hazard ratio (95% confidence limits) for the trial primary end point (cardiac death or nonfatal reinfarction, whichever occurred first) was: first non-Q-wave AMI-0.48 (0.26, 0.89); first inferior Q-wave AMI-0.66 (0.40, 1.09); first anterior Q-wave AMI-0.82 (0.51, 1.31); and prior AMI-1.11 (0.85, 1.44). Use of cardiac death alone as an end point gave an even more sharply focused treatment difference: first non-Q-wave AMI-0.46 (0.18, 1.21); first inferior Q-wave AMI-0.53 (0.27, 1.06); first anterior Q-wave AMI-1.28 (0.68, 2.40); prior infarction-1.26 (0.90, 1.77). Further analysis revealed that these differences in the effect of diltiazem in large part reflected the different status of the 4 electrocardiographically defined subsets in terms of left ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Risk stratification in patients with non Q wave myocardial infarction: a role for thallium exercise testing

The ability of maximal exercise thallium testing to stratify patients after non Q wave myocardial infarction was prospectively examined in 20 patients. Patients were enrolled in the study if there was no evidence of residual ischemia nor congestive heart failure during initial hospitalization. The thallium exercise test showed four patients to be at high risk, three of whom had successful revascularization. The remaining 16 patients were considered to be at low risk. There were no re-admissions for unstable angina, no myocardial infarctions and no deaths in the follow-up period (average 15 months). Thus patients with no evidence of early ischemia, no signs of left ventricular failure and a negative maximum thallium exercise test are at low risk following non Q wave myocardial infarction.     

Unstable angina and infarction without Q wave treated with verapamil: value of the early exercise test

Twenty patients aged 56.8 +/- 10 years, hospitalised for unstable angina (12 cases) or infarct without Q wave (8 cases) were treated with IV heparin, aspirin and oral verapamil. The clinical syndrome was controlled by verapamil in 16 cases out of 20 (80% of cases) at the dosage of 360 mg/d in 14 patients and of 480 mg/d in two. An exercise ECG, limited by symptoms, was obtained in 18 patients (90%) between the 8th and 12th day. Coronary arteriography was considered to be indicated in three sets of circumstances: recurrence of angina resistant to nitroglycerin, positive exercise ECG with verapamil, persisting despite triple therapy or strongly positive exercise ECG (total duration less than or equal to 6 minutes). An infarct complicated the early course in 4 patients (20%): twice following angioplasty, once following exercise ECG (spastic angina) and once during triple therapy (refractory angina). Hospital and mid-term (18 +/- 6 months) mortality was nil. With verapamil, the absence of recurrence of angina together with a negative exercise ECG enabled the identification of a large group of patients (40%) with a low risk of a subsequent major accident and in whom early and routine coronary arteriography is probably not indispensable.     

Long-term prognosis of patients after a Q wave compared with a non-Q wave first acute myocardial infarction: Data from the SPRINT Registry

OBJECTIVE, DESIGN AND PATIENTS: Between August 1981 and July 1983, 5839 consecutive myocardialinfarction patients were hospitalized in 13 coronary care unitsin Israel. The present study examines 10 year survival among4037 consecutive patients with a first myocardial infarctionwith either Q or non-Q waves. Demographic and medical data werecollected from hospital records, and 1 year clinical follow-upwas complete for 99% of hospital survivors. Mortality follow-upwas extended to June 1992 (mean 10 years of follow-up). RESULTS: Five hundred and eighty patients (14%) had first myocardialinfarctions of the non-Q wave type and 3457 of the Q wave type.Hospital mortality was significantly higher in patients witha Q wave (l0%) than those with a non-Q wave myocardial infarction(7%) (P<0·05). One year post-discharge, non-fatalreinfarction and mortality rates were comparable in patientswith Q wave (4% and 7%) and non-Q wave myocardial infarctions(4% and 7% respectively). Similarly, 5 to 10 year post-dischargemortality rates were equally high in patients with a non-Q wave(26% and 44%) as in those with a first episode of a Q wave myocardialinfarction (22% and 40% respectively). CONCLUSIONS: Patients with a first non-Q wave acute myocordial infarctionexhibited relatively better in-hospital survival than counterpartswith a first Q wave infarction, but the advantage did not persistafter discharge. Patients with a non-Q wave infarction deserveparticular attention as their post-discharge mortality riskis similar to counterparts with a first Q wave myocardial infarction. (Eur Heart J 1996; 17: 1532–1537)     

The prognostic value of electrocardiographic exercise test in patients after acute myocardial infarction

The subject of this trial were 243 patients with uncomplicated acute myocardial infarction, hospitalized in years 1992-1996, who were made an electrocardiographic exercise test in the second or third week of the in-hospital stay and whose further history in the 2-6 period after myocardial infarction (average follow-up time lasted for 4.0 +/- 1.9 years) was known. The aim of this trial was to determine the influence of the positive exercise test on the long-term prognosis after acute myocardial infarction in a group with uncomplicated acute myocardial infarction. The course of infarction and the frequency of cardiac events (cardiac death, reinfarction, revascularisation) occurrence in 78 patients with positive exercise test (group I) were compared with a group of 165 patients with negative exercise test (group II). Both groups were compared in respect to age, gender, history of myocardial infarction, risk factors and the course of the infarction in the in-hospital period. The multivariable logistic regression analyse showed that the positive exercise test did not have a statistically significant influence on the increase of post-hospital morbidity but it correlates with significantly more frequent use of the invasive treatment and reinfarction during the follow-up period in this group. Negative exercise test in patients with uncomplicated acute myocardial was a significant factor of the good long-term prognosis.     

The prognostic value of exercise testing early after myocardial infarction in patients treated with thrombolytics

Exercise testing early post A MI was evaluated as a predictorof re infarction in patients treated with thrombolytics. AMIpatients exercise-tested prior to discharge were included inthe study (n = 178). The patients were followed for 2.9±0.9years (mean±1 SD) for the development of new cardiacevents defined as cardiac death or reinfarction. Cox regressionanalysis of clinical and exercise test variables showed thatthere was significant predictive value of treating heart failurewith drugs from two or more therapeutic groups (P<0.001;hazard ratio 9.4 (3.1–28.2) (estimate and 95% confidenceinterval)), such as those with a previous history of myocardialinfarction (P = 0.001; hazard ratio 4.0 (1.7–9.6)) andof significant ST depression (P = 0.029; hazard ratio 2.5 (1.1–5.7)).Significant ST depression could be substituted by the ST/HRindex (P = 0.042; hazard ratio 2.8 (1.2–6.8)). The exercise test had independent but limited prognostic valuein AMI patients treated with thrombolytics. The ST/HR indexdid not improve the predictive value of the exercise test.     

The prevalence and clinical significance of residual myocardial ischemia 2 weeks after uncomplicated non-Q wave infarction: a prospective natural history study

Despite having smaller infarct size and better left ventricular function, patients with non-Q wave myocardial infarction (NQMI) appear to have an unexpectedly high long-term mortality that is ultimately comparable to that of patients with Q-wave myocardial infarction (QMI). Patients with NQMI may lose their initial prognostic advantage because there is more viable tissue in the perfusion zone of the infarct-related vessel, rendering myocardium more prone to reinfarction. We tested this hypothesis in a prospective study of 241 consecutive patients 65 years of age or younger with acute uncomplicated myocardial infarction confirmed by creatine kinase levels (MB fraction). All patients received customary care and none underwent thrombolytic therapy or emergency angioplasty. Predischarge coronary angiography, radionuclide ventriculography, 24 hr Holter monitoring, and quantitative thallium-201 (201T1) scintigraphy during treadmill exercise were performed 10 +/- 3 days after infarction. Infarcts were designated as QMI (n = 154) or NQMI (n = 87) by accepted criteria applied to serial electrocardiograms obtained on days 1, 2, 3, and 10. The baseline Norris coronary prognostic index, angiographic jeopardy scores, and prevalence of Lown grade ventricular arrhythmias were similar between groups despite evidence for less necrosis with NQMI vs QMI, reflected by lower peak creatine kinase levels (520 vs 1334 IU/liter; p = .0001, 4 hr sampling), higher resting left ventricular ejection fraction (53% vs 46%; p = .0001), fewer akinetic or dyskinetic segments (1.2 vs 2.4; p = .0001), and fewer persistent 201Tl defects in the infarct zone (0.9 vs 1.9; p = .0001). Patients with NQMI also had more patent infarct-related vessels (54% vs 25%; p less than .0001) and a shorter time from onset of infarction to peak creatine kinase level (16.9 vs 22.5 hr; p = .0001). Importantly, the prevalence and extent of quantitatively determined 201Tl redistribution within the infarct zone on exercise scintigraphy was greater in patients with NQMI vs those with QMI (60% vs 36%, p = .007; and 0.98 vs 0.53 myocardial segments, p = .0003); when the two groups were stratified on the basis of the infarct-related vessel, subset analysis revealed the same findings. During 30 months median follow-up, cardiac mortality was low, 8.4% in the QMI group and 9.2% in the NQMI group (p = NS).(ABSTRACT TRUNCATED AT 400 WORDS)     

Response to exercise early after uncomplicated acute myocardial infarction in patients receiving no medication: long-term follow-up

Cardiovascular function and prognosis have not been adequately defined early after an uncomplicated acute myocardial infarction in patients given no medication. Ninety such patients were studied with treadmill testing submaximally at 3 weeks and maximally at 8 weeks after infarction. The exercise heart rate, rate-pressure product and oxygen uptake were, respectively, 120 ± 17 beats/min, 179 ± 43 and 17.4 ± 1.0 ml/kg per min at 3 weeks and 157 ± 20, 271 ± 55 and 24.3 ± 3.7 at 8 weeks. Exercise variables at submaximal equivalent exercise work did not change from 3 to 8 weeks. At maximal exercise 15.6 percent of patients had S-T changes alone, 8.9 percent had angina alone and 12.2 percent had both. Patients were followed up for a mean of 23.7 months for complications—death, reinfarction, bypass grafting and progression to functional class III and IV. Complications occurred in 27 percent of patients with both angina and S-T changes, 29 percent of those with S-T changes alone, 25 percent of those with angina alone, 8 percent of those with ventricular arrhythmia alone, 12 percent of those with a normal 8 week treadmill test and in 17 percent of the group as a whole. Another 18 patients who were given no medication and whose course was uncomplicated could not perform a maximal 8 week treadmill test because of angina pectoris or S-T segment depression, or both, and 56 percent of these had long-term complications.In conclusion, these reference values serve as safe limits in performing treadmill testing early after acute myocardial infarction. S-T changes or angina, or both, and inability to complete a maximal 8 week treadmill test identify patients at risk for later complications even though these patients may have been considered to be in a low risk category clinically.     

Favourable long term prognosis in patients with non-Q wave acute myocardial infarction not associated with specific electrocardiographic changes. Diltiazem Reinfarction Study Research Group.

Electrocardiograms obtained serially from 544 patients with non-Q wave infarction in the Diltiazem Reinfarction Study were analysed to compare the short term (less than or equal to 14 days) and long term (one year) follow up of 105 patients (19%) whose admission electrocardiogram showed no localisable repolarisation abnormalities (group 1) with the outcome in 439 patients (81%) who had ST-T wave abnormalities (group 2) localised to two or more contiguous leads within an anterior, inferior, or lateral lead group. There were no major between group differences in baseline clinical variables, concomitant medications, or treatment allocation (diltiazem v placebo). Group 2 patients, in the first year, had a higher incidence of early recurrent ischaemia (angina greater than or equal to 24 hours after myocardial infarction associated with ischaemic repolarisation changes), reinfarction, and readmission for chest pain than group 1 patients, despite comparable creatine kinase and creatine kinase MB activities in both groups. About 20% of patients with acute non-Q wave myocardial infarction did not have definable ST-T wave abnormalities. These patients had a similar clinical and enzymatic profile as patients with non-Q wave infarction with definable ST-T wave abnormalities and they were more likely to have a favourable short term and long term outcome.     

Favourable long term prognosis in patients with non-Q wave acute myocardial infarction not associated with specific electrocardiographic changes. Diltiazem Reinfarction Study Research Group

Electrocardiograms obtained serially from 544 patients with non-Q wave infarction in the Diltiazem Reinfarction Study were analysed to compare the short term (less than or equal to 14 days) and long term (one year) follow up of 105 patients (19%) whose admission electrocardiogram showed no localisable repolarisation abnormalities (group 1) with the outcome in 439 patients (81%) who had ST-T wave abnormalities (group 2) localised to two or more contiguous leads within an anterior, inferior, or lateral lead group. There were no major between group differences in baseline clinical variables, concomitant medications, or treatment allocation (diltiazem v placebo). Group 2 patients, in the first year, had a higher incidence of early recurrent ischaemia (angina greater than or equal to 24 hours after myocardial infarction associated with ischaemic repolarisation changes), reinfarction, and readmission for chest pain than group 1 patients, despite comparable creatine kinase and creatine kinase MB activities in both groups. About 20% of patients with acute non-Q wave myocardial infarction did not have definable ST-T wave abnormalities. These patients had a similar clinical and enzymatic profile as patients with non-Q wave infarction with definable ST-T wave abnormalities and they were more likely to have a favourable short term and long term outcome.     

Multicenter trial on prognostic value of inducible ischaemia, assessed by dobutamine stress echocardiography and exercise electrocardiography test, in patients with uncomplicated myocardial infarction, treated with thrombolytic therapy

Background. Thrombolysis has reduced early and longterm mortality by about 20%; sometimes, however, there is a re-occlusion of the infarct related artery or an unsuccessful thrombolysis. In these situations, there is a possible increase in detrimental events in the follow-up. Objectives. The aim of the study was to compare the prognostic value of dobutamine echocardiography (DET) and ECG exercise test (EET)in pts submitted to thrombolysis. Methods. One hundred and fifty-one pts, with acute uncomplicated myocardial infarction, were enrolled. The pts were able to perform EET and had a sufficient echocardiographic window; 58 had anterior myocardial infarction (38%), 79 had inferior (52%), 2 had lateral (1%), 12 had non-Q (8%). EET was performed with an initial load of 25 Watt, and thereafter, 25 W every two minutes. DET was performed with step-wise infusion every three minutes (5, 10, 20, 30 and 40 mcg/kg/min.). If the target heart rate was not reached, a further dose of 40 mcg/kg/min. together with atropine 0.25-1 mg was administered, in the absence of signs and symptoms of ischemia. Results. During a mean (± SD) follow-up period of 8 ± 4.5 months (range 1–23), 16 spontaneous events happened (4 deaths, 5 non-fatal re-infarctions, 7 unstable angina). One-hundred and three EET (68%) were negative for ongoing ischaemia, while 48 were positive, 79 DET (52%) were negative for ongoing ischaemia and 72 were positive (48%). Statistical results: DET and EET had a sensitivity of 41% and 54%, a specificity of 57% and 74%, a positive predictive value of 7% and 14%, a negative predictive value of 91% and 95%, an accuracy of 56% and 73%. Kaplan-Maier survival curves demonstrated that patients with Peak Wall motion > 1.8 and EET score > 3, had the higher risk of spontaneous events. Conclusion. A few spontaneous events happened in the follow-up. These data demonstrate that patients treated with thrombolysis are not at high risk of spontaneous events. DET and EET, therefore, have had a high negative predictive value. For this reason, we can conclude that pts with negative tests can be considered at low risk and do not need any further investigations.     

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)     

Early submaximal exercise stress test after myocardial infarction. Comparison with a late test and prognostic value

An early exercise stress test was carried out in 116 patients 8 to 14 days after a myocardial infarction. This test is in good agreement with the late maximal stress test performed 8 weeks after the infarction, both tests being positive together in 86.4% and negative in 84.6% of the cases. Residual coronary insufficiency is present in 41.4% of the patients during the early test, 47.9% after inferior and 30.2% after anterior infarction. With beta blocking therapy, 28.2% of the patients had a positive test, and 48% without this treatment. The sensitivity of the early test is good after inferior infarction but poor after anterior infarction or during beta blocking therapy. A multivessel disease is disclosed by coronary angiography in 78.5% of the patients with a positive early stress test and in 53.3% in cases with a negative test. In the patients with a positive test, mortality at one year is higher (8.7% versus 2.9%). A coronary angiography should be performed relatively precociously in this group of patients.     

Exercise testing after myocardial infarction: relative values of the low level predischarge and the postdischarge exercise test

This study was undertaken to compare the relative values of the low level predischarge exercise test and the postdischarge (6 weeks) symptom-limited test in 518 consecutive patients admitted with an acute myocardial infarction. Of the patients who did not develop significant ST segment depression or angina during the predischarge test, the symptom-limited test also remained negative in 91.5 and 91.9% of the patients, respectively. Similar results were obtained with ST segment elevation and the systolic blood pressure response during the two exercise tests with only 2.1 and 11.4% changing from normal to abnormal, respectively. Discriminant function analysis was done to predict the occurrence of coronary events (unstable angina, reinfarction, cardiac failure, cardiac death) with use of the data from the exercise tests together with other clinical and investigational data. The jackknife method correctly classified 71.9 and 71.4% of the patients with the data from the predischarge exercise test and symptom-limited test, respectively. Combining the data from the two tests improved the overall predictive accuracy to only 75.0%. It is concluded that the routine performance of a symptom-limited test 6 to 8 weeks after infarction does not reveal any significant additional information in those patients who have undergone a predischarge low level exercise test. Thus the 6 to 8 week test should be restricted to selected patients after myocardial infarction.     

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.