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L Wallentin

Publications and source records attributed to L Wallentin.

At least 91 records · Page 5Linked to original sources
PubMed1997

Early assessment of patients with suspected acute myocardial infarction by biochemical monitoring and neural network analysis.

Neural network analysis was applied for early diagnosis/exclusion of acute myocardial infarction (AMI), prediction of infarct size, and estimation of "time from onset of infarction." Eighty-eight patients admitted within 8 h after onset of chest pain were included. Blood samples for measurement of myoglobin, creatine kinase isoform MB, and troponin T were obtained every 30 min during the first 3 h and then after successively longer intervals. Data from 50 patients were used to train a set of neural network components of a decision support system. The performance of the system was evaluated and compared with experienced clinicians for the remaining 38 patients. The computer system detected myocardial infarction and predicted infarct size earlier than the clinicians, but did not differ significantly in terms of diagnostic sensitivity, specificity, and predictive values when disregarding time for diagnosis. With a cross-validation procedure the cumulated sensitivities of the computer system for the first five measurements were estimated to be (mean +/- 2SEM, n = 100): 0.77 +/- 0.03, 0.89 +/- 0.02, 0.94 +/- 0.02, 0.97 +/- 0.01, and 0.99 +/- 0.01, respectively, with corresponding cumulated specificities between 0.93 +/- 0.01 and 0.91 +/- 0.01. We concluded that neural network analysis of serial measurements of biochemical markers might provide useful support for the early assessment of patients with suspected AMI.

Aged↗
PubMed1996

Relation between troponin T and the risk of subsequent cardiac events in unstable coronary artery disease. The FRISC study group.

BACKGROUND: Early risk assessment is important in patients with unstable coronary artery disease, ie, unstable angina or non-Q-wave myocardial infarction. Some previous small studies have indicated that patients with unstable angina and elevation of troponin T (tn-T) have worse short-term and long-term prognoses. In this study, the prognostic value of tn-T was evaluated and compared with other early available risk indicators. METHODS AND RESULTS: Nine hundred seventy-six patients participating in a randomized study of low-molecular-weight heparin in unstable coronary artery disease were followed for 5 months after the index episode. The risk of cardiac events increased with increasing maximal levels of tn-T obtained in the initial 24 hours. The lowest quintile (<0.06 microgram/L) constituted a low-risk group, the second quintile (0.06 to 0.18 microgram/L) an intermediate-risk group, and the three highest quintiles (> or =0.18 microgram/L) a high-risk group, with 4.3%, 10.5%, and 16.1% risk of either myocardial infarction or cardiac death, respectively. Troponin T level was identified together with age, hypertension, number of antianginal drugs, and ECG changes at rest as independent prognostic variables for myocardial infarction or cardiac death in a multivariate analysis. The prognostic value of tn-T was independent of the classification of index event into unstable angina or myocardial infarction. CONCLUSIONS: Troponin T determination is an inexpensive and widely applicable method for early risk assessment in patients with unstable coronary artery disease. The maximum tn-T value obtained during the first 24 hours provides independent and important prognostic information.

Aged↗
PubMed1996

Low molecular weight heparins: a valuable tool in the treatment of acute coronary syndromes.

Standard heparin, low molecular weight heparin and aspirin are at present the only antithrombotic agents of proven value in the initial treatment of patients with an acute coronary syndrome. The combined use of aspirin and one of the heparins for at least 6 days should be considered for all such patients. With their high bio-availability after subcutaneous injection and prolonged half-life, low molecular weight heparins simplify short-term treatment in the acute phase and enable long-term therapy to be maintained on an outpatient basis without the need for repeated laboratory monitoring of anticoagulant effects. Such long-term therapy would appear to be beneficial, at least in high-risk patients, in the light of increasing evidence that the underlying lesion in acute coronary syndromes resolves over a period of weeks or months.

Angina, Unstable↗
PubMed1996

Dynamic vectorcardiography for early diagnosis of acute myocardial infarction compared with 12-lead electrocardiogram. BIOMACS Study Group.

BACKGROUND: The aim of the study was to assess the diagnostic accuracy of multilead continuous vectorcardiography (VCG) for early diagnosis of acute myocardial infarction (AMI) in patients admitted to hospital because of suspicion of AMI. VCG was compared with resting 12-lead electrocardiogram (ECG) on admission. METHODS: In a multicentre study, 107 patients with chest pain (< or = 12 h) were included. The diagnosis of AMI was on the basis of World Health Organization criteria. Continuous VCG was recorded for 12-24 h and the data were evaluated blindly at 2 and 6 h of recording and after the completion of recording (12-24 h). RESULTS: AMI was diagnosed in 74 patients. The VCG recording had a diagnostic accuracy of 71% after 2 h and 86% after both the 6 h and the completed VCG recording. Compared with ECG on admission, the VCG recording after 6 h showed a significantly greater sensitivity: 86% compared with 62% (P < 0.01). In patients with non-diagnostic ECG on arrival (n = 55), VCG after 6 h had a diagnostic accuracy of 85%, a sensitivity of 82% and a specificity of 89%. CONCLUSIONS: VCG might be useful for early diagnosis of AMI, especially in patients with non-diagnostic ECG.

Electrocardiography↗
PubMed1995

Additional value of thallium-201 SPECT to a conventional exercise test for the identification of severe coronary lesions after an episode of unstable coronary artery disease.

The additional value of thallium-201 SPECT to a conventional exercise test for the identification of patients with severe coronary lesions was evaluated in 170 men, one month after an episode of unstable coronary artery disease. Severe coronary lesions at coronary angiography--defined as three vessel disease, left main stenosis or proximal left anterior descending artery stenosis as part of two vessel disease--were observed in 45.9%. In the SPECT image, the left ventricular myocardium was divided into nine segments and each segment was classified as either normal (= 0), reduced uptake (= 1) or uptake defect (= 2). The sum of gradings in all segments post-exercise was denoted "SPECT score". The patients were divided into nine different groups regarding ST-depression during exercise (no ST-depression, ST-depression in 1-2 leads or > or = 3 leads) and "SPECT score" (no SPECT score, 1-3 scores or > or = 4 scores). Severe coronary lesions were, in 68% identified by SPECT score > or = 4 and in 65% by ST-depression in > or = 1 lead at exercise test. The specificity for identification of severe coronary lesions was, for both tests, 65%. SPECT score > or = 4 and/or ST-depression in > or = 3 leads identified 82% of the patients with severe coronary lesions with a specificity of 63%. Furthermore, SPECT score > or = 3 identified more patients with isolated proximal left anterior descending artery stenosis than ST-depression alone at exercise test.

Adult↗
PubMed1995

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 recordings after admission to the CCU and before discharge was compared to a symptom-limited predischarge exercise test in 170 men with unstable angina pectoris or non-Q wave myocardial infarction. ST depression in recordings before discharge identified a small group of patients (18%) out of whom 23% had a myocardial infarction within 3 months compared to 7% in those without this finding. The exercise test gave more diagnostic information, with ST depression found in 52% including 70% of those with ST depression at Holter monitoring. After 3 months, 13% of patients with ST depression at exercise test had a myocardial infarction compared to 5% in the other patients. ST depression at exercise also indicated an increased risk of myocardial and future severe angina over a longer time period. Thus ST recordings are recommended before discharge in all patients after an episode of unstable coronary artery disease as it identifies the patients with the most severe prognosis who might benefit from early revascularization. In those without ST depression at Holter a predischarge exercise test will give further information regarding the long-term risk for angina and coronary events.

Administration, Oral↗
PubMed1995

Early diagnosis and exclusion of acute myocardial infarction using biochemical monitoring. The BIOMACS Study Group. Biochemicals Markers of Acute Coronary Syndromes.

BACKGROUND: The aim was to evaluate whether frequent analysis of creatine kinase MB (CK-MB), myoglobin and troponin T alone or in combination could either confirm or exclude acute myocardial infraction (AMI) within the first few hours after patients were admitted to hospital with chest pain and a non-diagnostic ECG. METHODS: One hundred and forty-two patients with chest pain (< or = 12 h) and a non-diagnostic ECG were included in the study. Blood samples were obtained every 30 min during the first 3 h and thereafter at longer intervals. Different discriminatory levels and combinations of markers were tested for their ability to detect (n = 59) or exclude (n = 83) AMI during the first 6 h after admission. RESULTS: No single marker adequately combined high early sensitivity and specificity. However, a combination of myoglobin and CK-MB analyses had a sensitivity at entry of 59%, which increased by 5-10% every 30 min and reached 92% after 2 h and 98% after 6 h with a specificity of 93%. A combination of myoglobin and troponin T analyses showed identical sensitivity but a slightly inferior specificity. In the patients with no AMI it was possible to exclude AMI in 64% within 3 h by using myoglobin and within 6 h in approximately 70% by using CK-MB or troponin T. CONCLUSIONS: Monitoring of a combination of myoglobin and CK-MB or troponin T will allow confirmation or exclusion of AMI within 3-6 h in almost all patients. This method will have a large impact on the handling of patients with suspected AMI without a diagnostic ECG.

Aged↗
PubMed1994

Insulin treatment improves microalbuminuria and other cardiovascular risk factors in patients with type 2 diabetes mellitus.

OBJECTIVES: Insulin treatment of patients with type 2 diabetes causes hyperinsulinaemia and improves glycaemic control. We have studied how this affects risk factors for cardiovascular disease. DESIGN: Patients with secondary failure to oral hypoglycaemic agents were studied whilst still taking oral agents and after insulin treatment for 8 weeks in an open study. SETTING: Department of Internal Medicine, University Hospital, Linköping. SUBJECTS: Ten consecutive patients with type 2 diabetes and secondary failure to oral hypoglycaemic agents. INTERVENTIONS: Switching oral treatment to insulin treatment. MAIN OUTCOME MEASURES: Effect on several cardiovascular risk factors. RESULTS: Fasting and postprandial plasma insulin concentrations were increased by insulin treatment whereas C-peptide concentrations were lowered. HbA1c was reduced from 8.9 +/- 0.3% (mean +/- SEM) to 6.3 +/- 0.2% after 8 weeks. There was a weight gain of 2.8 +/- 0.7 kg. Plasma concentrations of total- and very-low-density-lipoprotein (VLDL) cholesterol, VLDL-, low density lipoprotein and high-density-lipoprotein triglycerides were all reduced. The plasma concentration of apolipoprotein B was also lowered. Tissue plasminogen activator antigen measured after venous occlusion showed a significant reduction whilst plasminogen activator inhibitor 1 activity was 26.0 +/- 9.8 IU ml-1 on oral treatment and 18.2 +/- 4.7 IU ml-1 on insulin treatment (NS). Albumin excretion in the urine was reduced and the percentage reduction correlated with the percentage lowering of the tissue plasminogen activator antigen concentration after venous occlusion but not with the percentage change of basal tissue plasminogen activator antigen concentration. CONCLUSIONS: Insulin treatment of patients with type 2 diabetes and secondary failure to oral hypoglycaemic agents causes hyperinsulinaemia and improves or has no unfavourable effect on several cardiovascular risk factors.

Adult↗
PubMed1994

Exercise echocardiography and thallium 201 single-photon emission computed tomography in male patients after an episode of unstable coronary artery disease.

To compare modern, digital exercise echocardiography and thallium 201 single-photon emission computed tomography (SPECT) in patients with unstable coronary artery disease, 65 men unselected with regard to echocardiography were prospectively investigated 1 month after an episode of unstable angina or non-Q-wave myocardial infarction. Exercise echocardiography and 201Tl SPECT were performed on consecutive days in connection with a standard symptom-limited upright bicycle test and analyzed in a 9-segment model. Coronary angiography was performed in all but 1 patient and 60 patients had significant coronary lesions. Wall motion abnormalities were seen in 53 patients (81%) at rest and perfusion defects in 57 patients (88%) at the redistribution images. New or worsening of wall motion abnormalities were seen in 55 patients, either seated at peak exercise or recumbent after exercise, and 43 patients had reversible or partially reversible 201Tl scintigraphic defects (P = .02). The segmental agreement between wall motion abnormalities and scintigraphic defects was low (58%). The additional value of exercise echocardiography and 201Tl SPECT to exercise test was greatest in patients with one-vessel disease. Thus, 1 month after an episode of unstable coronary artery disease in men, there is a high incidence of significant coronary stenoses as well as signs of ischemia shown both by wall motion abnormalities during exercise echocardiography and by postexercise studies with 201Tl SPECT. Exercise echocardiography gives a higher diagnostic yield regarding occurrence of reversible ischemia.

Adult↗
PubMed1993

Ambulatory ST-recording has no additional value to exercise test for identification of severe coronary lesions after an episode of unstable coronary artery disease in men.

One month after an episode of unstable coronary artery disease, 95 male patients performed coronary angiography, 48 hours ambulatory ST-recording and also an exercise test. ST-depression occurred in 29.5% during the ST-recording and in 44.2% during the exercise test (p < 0.05). In patients with ST-depression at ambulatory monitoring, 79% demonstrated the same finding at the exercise test. A high risk response at the exercise test--defined as either ST-depression in > or = 3 leads, ST-depression in 1-2 leads with a maximal work load below the 60th percentile or a maximal work load below the 30th percentile regardless of the ECG reaction--occurred in 56.8%. Severe coronary lesions--defined as three vessel disease, left main stenosis or proximal left anterior descending artery stenosis as part of two vessel disease--was observed in 46.3%. Patients with a high risk exercise test response and patients with ST-depression during ST-recording had severe coronary lesions in 67% and 64% respectively. However, a high risk exercise test response occurred in 82%, while ST-depression at ambulatory monitoring was observed only in 41% of the patients with severe coronary lesions (p < 0.001). Thus, ambulatory ST-recording one month after an episode of unstable coronary artery disease in men adds no further information to a symptom limited exercise test in order to identify patients with severe coronary lesions.

Adult↗
PubMed1993

Risk stratification by early exercise testing after an episode of unstable coronary artery disease. The RISC Study Group.

After stabilization of symptoms by medication a predischarge exercise test was performed in 855 men admitted with suspected unstable angina (54%) or non-Q-wave myocardial infarction (46%). Multiple logistic regression analysis demonstrated that the number of leads with ST-depression at exercise, low maximal work load, increasing age and ST-elevation in electrocardiogram at rest had independent prognostic value concerning the risk of myocardial infarction or death during the following year. Therefore a combination of extension of ST-depression and peak work load was used to define 'high and low risk response' at the exercise test. After 1 year the mortality in patients with 'high risk' compared to 'low risk' exercise response was 3.6% and 0% (P < 0.001) and the risk of either myocardial infarction or death was 15.4% and 3.9% (P < 0.0001), respectively. ST-depression, occurrence of angina and low peak load at exercise were independent predictors of future severe angina. After 1 year 29.5% of patients with any of these indicators at exercise had incapacitating symptoms that necessitated referral for coronary angiography compared to 4.8% in the group without these findings (P < 0.0001). The predictive value of the exercise test remained high in subgroups based on inclusion diagnosis, age or findings in electrocardiogram at rest and independently of treatment with beta-blockade, other antianginal medication or aspirin at the time of the exercise test.

Aged↗
PubMed1993

ST-changes in ECG at rest or during exercise indicate a high risk of severe coronary lesions after an episode of unstable coronary artery disease.

After an episode of unstable coronary artery disease, 190 patients performed a predischarge exercise test. A postdischarge exercise test and coronary angiography was performed by 172 patients after 1 month. A subgroup of 104 men performed both exercise tests with a computer-aided system. More sophisticated methods of evaluating the ECG reaction during exercise were not diagnostically superior to the simple identification of ST-depression of > or = 0.1 mV. ST-depression in ECG at rest indicated a 70% risk of severe coronary lesions and in such patients, the ECG reaction at exercise carried no additional diagnostic information. Stepwise multiple regression analysis showed that ST-depression and low maximal work load were the most important exercise variables for identification of severe coronary lesions. Using a combination of these parameters, the sensitivity and specificity for identification of severe coronary lesions were, respectively, 77% and 61% predischarge and 77% and 70% after 1 month.

Adult↗
PubMed1993

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.

Adult↗