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Biomedical subjects

M Dellborg

Publications and source records attributed to M Dellborg.

15 recordsLinked to original sources
PubMed1992

[Dynamic continuous vectorcardiography].

Continuous dynamic vectorcardiography is an ideal method for monitoring patients with myocardial ischemia. The monitoring is a non-invasive and real time registration and simultaneously safe and reproducible. The method has proved valuable for describing the evolution in different ischemic heart diseases. The method measures the electric myocardial activity in three orthogonal leads and a computer calculates the different vectorcardiographic parameters for the ST- and QRS-complexes. Vectorcardiographic registration is feasible for computer analysis, because it can summarize all information in a few parameters. Using continuous registration, the different parameters can show dynamic evolution and, in this way, describe the variability during acute myocardial infarction and unstable angina pectoris. The method also made it possible to evaluate anti-ischemic treatment in patients, as for example thrombolytic therapy.

Humans↗
PubMed1992

Dynamic changes of the QRS complex in unstable angina pectoris.

Despite intensive medical treatment to control chest pain, about one-third of patients with unstable angina have an unfavourable outcome within a period of 1 to 2 months. Holter monitoring can identify patients with silent myocardial ischaemia that are at a high risk of sustaining a major cardiovascular event. The present paper describes the use of dynamic, continuous, computerized on-line vectorcardiography for real-time monitoring of QRS-complex and ST-segment changes in patients with unstable coronary disease. In many patients a pattern of frequent repetitive episodes of QRS change was observed, with or without concomitant ST change. Whereas no patient had episodes of ST-vector change without also having episodes of significant QRS change, 15 patients had several episodes of QRS changes without any episode of significant ST change. The number of episodes of significant increase of the QRS vector difference correlated weakly but significantly with the number of episodes of significant ST-vector magnitude change (r = 0.34, p less than 0.05). The present study suggests that myocardial ischaemia will influence the QRS complex as well as the ST segment. The mechanism behind the QRS changes observed is not clear but episodes of QRS change without ST change or chest pain, may reflect sudden depressions of left ventricular function, as has been reported by others to occur in patients with coronary artery disease. Dynamic vectorcardiography offers the opportunity to monitor all parts of the QRST complex in real time.

Adult↗
PubMed1992

The predictive value of CKMB mass concentration in unstable angina pectoris: preliminary report.

Unstable angina pectoris is a common clinical problem, and the diagnosis is based on clinical symptoms. However, these symptoms cannot identify high-risk patients. Holter monitoring can identify patients at high risk, but analysis of a large number of patients is time- and resource-consuming, as is angiographic examination. We determined whether creatine kinase MB isoenzyme mass concentration could predict the prognosis for patients with unstable angina pectoris. A total of 101 consecutive patients were studied, and blood samples were collected three times a day for 48 h after admission. Patients with unstable angina and elevated CKMB (but still within the normal range) had a significantly higher risk of developing acute myocardial infarction or requiring revascularization during 6 months of follow-up than patients without elevated CKMB. We conclude that CKMB analysis is a valuable tool that may be of use in selecting high-risk patients with unstable angina pectoris. This finding needs to be confirmed by more extensive studies.

Aged↗
PubMed1991

Dynamic QRS-complex and ST-segment monitoring in acute myocardial infarction during recombinant tissue-type plasminogen activator therapy. The TEAHAT Study Group.

Changes of the QRS complex are the electrocardiographic expression of irreversible injury of the myocardium. In humans, the process of infarction occurs over several hours. A more rapid development of QRS changes has been reported in patients treated with thrombolytic agents. Patients with strongly suspected acute myocardial infarction (AMI) included in a placebo-controlled trial of 100 mg of recombinant tissue-type plasminogen activator (rt-PA) were monitored for 24 hours with continuous, on-line vectorcardiography. The magnitude of the QRS vector changes correlated with infarct size estimated by the maximal value of lactate dehydrogenase-1 (r = 0.69, p less than 0.001) as well as with left ventricular ejection fraction 30 days after randomization (r = 0.49, p less than 0.001). Treatment with intravenous rt-PA limited total QRS vector change but the QRS vector changes observed occurred more rapidly and reached a plateau 131 minutes earlier in patients treated with rt-PA than in those receiving placebo (p less than 0.01). A certain pattern of highly variable ST vector magnitude was identified and was associated with higher maximal lactate dehydrogenase-1 values (23 +/- 13 vs 14 +/- 10 mu kat/liter, p less than 0.001) and a tendency to higher 1-year mortality (24 vs 9%, p = 0.08) than in patients without this pattern. In patients with this pattern, rt-PA did not affect maximal lactate dehydrogenase-1, time to maximal creatine kinase and final magnitude of QRS vector change.

Double-Blind Method↗
PubMed1991

Buccal versus intravenous nitroglycerin in unstable angina pectoris.

The clinical syndrome of unstable angina includes patients with the first onset of angina, change in a previous stable pattern or the development of chest pain at rest. Administration of intravenous nitroglycerin is established therapy in unstable angina. Buccal nitroglycerin has been introduced as an alternative means of administering nitroglycerin, which provides relief of anginal pain within 2 to 3 min and a sustained effect for 3 to 5 h. Twenty-nine patients admitted to the coronary care unit due to unstable angina were randomized to receive treatment with nitroglycerin i.v. for 24 h or buccal nitroglycerin every 4 h. Therapy was titrated according to haemodynamic effects. The mean dose of buccal nitroglycerin was 4.42 mg versus 0.45 micrograms.kg-1.min-1 in the intravenous group. The efficacy of treatment was similar in the two groups. Buccal nitroglycerin appeared to cause fewer adverse effects, especially less haemodynamic intolerance and headache, although the differences were not significant. Repeated administration of buccal nitroglycerin appears to be a safe and well tolerated alternative to high-dose i.v. nitroglycerin treatment in unstable angina pectoris.

Administration, Buccal↗
PubMed1991

Dynamic QRS complex and ST segment vectorcardiographic monitoring can identify vessel patency in patients with acute myocardial infarction treated with reperfusion therapy.

Reperfusion therapy has lowered the mortality in patients suffering acute myocardial infarction. Failure to reperfuse is associated with significantly higher risk of short- and long-term mortality. Detection of reperfusion is thus important. In a prospective pilot study, we used continuous on-line computerized vectorcardiography to monitor 21 patients with acute myocardial infarction treated with reperfusion therapy to noninvasively detect coronary patency. By using trend analysis of QRS vector difference, we were able to correctly blindly identify 15 of 16 patients with a perfused infarct-related artery and four of six patients with a persistently occluded artery at an early angiogram. The present results are based on a limited number of patients, but suggest that QRS complex and ST segment monitoring with continuous on-line vectorcardiography has substantial potential for monitoring patients with acute myocardial infarction treated with reperfusion therapy.

Coronary Vessels↗
PubMed1991

Effect of early intravenous rt-PA on infarct size estimated from serum enzyme activity: results from the TEAHAT Study.

In 319 patients who participated in a double-blind trial to evaluate the effect of early rt-PA administration compared to placebo in suspected acute myocardial infarction, infarct size was assessed from analyses of serum activity of lactate dehydrogenase isoenzyme 1 (LD 1). Treatment was always started less than 3 h after the onset of symptoms, with one-third of the patients' treatment being initiated outside the hospital. The maximum activity of LD 1 was reduced by 32%, from 13.3 mu kat l-1 in placebo to 9.0 mu kat l-1 in rt-PA treated patients (P = 0.001). A reduction in LD-1 activity after rt-PA treatment was restricted to patients with ST-elevation in the initial electrocardiogram, and was more pronounced in patients with previous ischaemic heart disease, above median age, and in those with a shorter delay in initiation of treatment. We conclude that very early intravenous treatment with rt-PA limits indirect signs of infarct size. The effect appears to be restricted to patients with ST-segment elevation in their initial electrocardiogram.

Ambulatory Care↗
PubMed1991

Effects on chest pain of early thrombolytic treatment in suspected acute myocardial infarction: results from the TEAHAT Study.

In a randomized, double-blind study, in which recombinant tissue plasminogen activator (rt-PA) administered at an early stage was compared with placebo in patients with suspected acute myocardial infarction (AMI), the effects on pain were studied in 312 patients. Inclusion criteria were as follows: (a) chest pain of duration less than 2 h and 45 min; and (b) age less than 75 years. Chest pain was estimated subjectively by the patients, using a 10-point numerical rating scale, at hourly intervals for the first 24 h, and by the requirement for narcotic analgesics. Compared with placebo, rt-PA treatment resulted in a 43% reduction in mean total pain score (P less than 0.0001), a 26% reduction in pain duration (P less than 0.01), and a 33% reduction in morphine requirement (P = 0.01). Fifty-seven per cent of all patients developed a confirmed AMI. In these subjects rt-PA reduced the pain score by 46% (P less than 0.001). Among patients without confirmed AMI, a 37% reduction in pain score was observed (P = 0.05). The effect on pain was most marked in patients with ST-elevation on the initial ECG. We conclude that early treatment with rt-PA in suspected AMI reduces chest pain considerably. The effect is most marked in patients with ST-elevation on the initial ECG.

Aged↗
PubMed1991

Early treatment with thrombolysis and beta-blockade in suspected acute myocardial infarction: results from the TEAHAT Study.

Independent trials of early administration of beta-blockers and thrombolytic agents have shown beneficial effects on both short- and long-term prognoses in acute myocardial infarction (AMI). The effects of a combination of the two strategies have not been thoroughly documented. Three hundred and fifty-two patients, of less than 75 years of age, with chest pain indicative of AMI, and onset less than 2 h and 45 min before first examination, were randomized to treatment with rt-PA or placebo. All patients without contraindication were given intravenous metoprolol 15 mg acutely and then 200 mg orally daily. Treatment was started either at the prehospital stage or in hospital. Thirty-seven per cent of patients had contraindications to beta-blockade, the most frequent of which were heart rate less than 60 beats min-1 and hypotension. The remaining 63% were given intravenous beta-blockade. No side-effects of metoprolol, alone or in combination with rt-PA, were observed during the prehospital phase. Overall, toleration of the treatment was good. Reduction in enzymatically estimated infarct size by rt-PA was more pronounced in patients who were also treated with metoprolol (41%, P less than 0.001) than in those with contraindications to beta-blockade (15%, NS). Patients who were also treated with metoprolol also had a lower incidence of Q-wave infarctions, congestive heart failure and ventricular fibrillation than those who were not given intravenous beta-blockade. In conclusion, toleration of intravenous administration of rt-PA and metoprolol was good, and this was also the case in the prehospital phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Mortality and morbidity 1 year after early thrombolysis in suspected AMI: results from the TEAHAT Study.

We randomized 352 patients with suspected acute myocardial infarction (AMI) to treatment with rt-PA (n = 177) or placebo (n = 175). Patients were eligible if evaluated within 2 h and 45 min from onset of chest pain, and if aged less than 75 years. There were no ECG criteria for inclusion. A mobile coronary-care unit with a cardiologist present was used to initiate treatment at home in 29% of cases. During 1 year of follow-up the mortality in patients treated with rt-PA was 10.2%, as compared with 14.3% in patients the initial ECG, the mortality during the first year was 8% in the rt-PA group vs. 18% in the placebo group (P less than 0.05). Among patients without ST-elevation the mortality was 9% for the rt-PA group vs. 12% for the placebo group (NS). Requirement for rehospitalization, symptoms of angina pectoris and congestive heart failure, time of return to work and requirement for various medications did not differ significantly between the two groups, regardless of the initial ECG pattern.

Aged↗