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Biomedical subjects

B Wennerblom

Publications and source records attributed to B Wennerblom.

52 records · Page 3Linked to original sources

Effects of cold on ST amplitudes and blood pressure during exercise in angina pectoris.

To investigate the mechanisms of cold susceptibility in angina pectoris nine male angina patients were studied. All were cold susceptible by history and had developed ischaemic ST changes during a previous exercise test. The patients underwent two additional bicycle exercise tests, one in a cold chamber with an average temperature of -8 degrees C, and the other at room temperature. The ECG was computer analysed and the intra-arterial blood pressure was measured. No significant decrease in work capacity was found during exercise in the cold chamber. In the cold, systolic blood pressure was consistently higher throughout the test and in seven of nine subjects ST depression was more pronounced at corresponding workloads. ST depression was also analysed versus heart work which was assessed as rate pressure product. In the cold, 1 mm ST depression appeared at a somewhat higher rate pressure product when compared to room temperature. It was concluded, therefore, that an augmented heart work, secondary to substantial increases in blood pressure, appears to account for the cold-induced increase in ST depression found in the angina patients in this study.

Adult↗

Mortality and morbidity in suspected acute myocardial infarction in relation to ambulance transport.

In 681 patients admitted to the coronary care unit (CCU) at Sahlgrenska hospital between 1 May 1983 and 31 May 1984, due to suspected acute myocardial infarction (MI), the hospital mortality and morbidity were related to whether the patients were transferred to hospital by ambulance or not. In the ambulance group acute MI developed in 48% (during the first 3 days in hospital) compared with 41% in the non-ambulance group (P = 0.10). The overall mortality rate was 10.4% in the ambulance group versus 3.8% in the non-ambulance group (P = 0.001). Corresponding figures for MI patients were 19.3% versus 9.1% (P = 0.02). In all, patients referred by ambulance had larger infarcts according to maximum serum enzyme activity and a higher incidence of congestive heart failure. Similar findings were observed when MI patients were analysed separately. On the other hand, the incidence of ventricular fibrillation, requirement for lidocaine, and the course of pain was fairly similar in the two groups. In a multivariate analysis, infarct size was the major independent predictor for early mortality rate. We conclude that patients who call for an ambulance due to suspected acute MI appear to have a different early mortality and morbidity pattern compared to those who do not. The most obvious observation was a higher early mortality. These patients therefore might be the most suitable candidates for early intervention studies.

Adult↗

Göteborg Metoprolol Trial: effects on chest pain.

The effect of metoprolol on chest pain was compared with that of placebo in all randomized patients. The pain score before and 15 minutes after the injection of trial medication was registered and a reduction in chest pain was observed in the metoprolol group. Increasing chest pain after blind injection was observed in only 16 and 9 patients from the placebo and metoprolol groups, respectively. Comparison with the placebo as well as detailed analysis of clinical data revealed that in these patients the increasing pain could not be explained by coronary spasm evoked by beta-blockade. Similarly, metoprolol did not exhibit any unfavorable effect on the 14 patients who were withdrawn (together with the 28 patients given placebo) from blind treatment due to angina pectoris. Either metoprolol does not induce coronary vasospasm or spasm does not play a role in these patients with definite and suspected acute myocardial infarction as well as unstable angina pectoris. Metoprolol reduced the need for analgesics during the first 4 days and shortened the duration of pain. The effects were similar in patients with early and late treatment, but may depend on initial heart rate, blood pressure and site of infarction.

Administration, Oral↗

Resuscitation of patients in cardiac arrest outside hospital. Comparison of two different organizations of mobile coronary care in one community.

We have compared the effectiveness of two different mobile coronary care systems with regard to mortality from cardiac arrest (CA) outside hospital in Gothenburg, Sweden. In period 1, the mobile coronary care unit (MCCU) was part of a randomized study of the effect of an MCCU versus standard ambulances on early mortality from ischaemic heart disease. The MCCU was single, hospital based and manned by two CCU nurses and two ambulance drivers. The organization ran on workdays 08.00 a.m. to 17.00 p.m. from October, 1973 to May, 1978, corresponding to twelve months of effective time. One-year data for the MCCU have been calculated by extrapolating to a 100% allocation to the MCCU. In period 2, from November, 1980, through December, 1981, also corresponding to twelve months of effective time, the system was reorganized to a mobile intensive care unit (MICU) manned by paramedics 24 h all days of the week, and part of the time by CCU nurses. The MICU was dispatched to all suspected emergencies and the treatment capacity was defibrillation, endotracheal intubation and, part of the time, drugs. Simultaneously with the MICU, the nearest standard ambulance was dispatched and the first crew to arrive started cardiopulmonary resuscitation (CPR). Comparing the extrapolated data from period 1 with the exact data from period 2, there was an increase in period 2 of dispatches to subjects in CA due to heart disease from 59 to 181. The retrieval of subjects in ventricular fibrillation (VF) increased from 20 to 87 as a result of reduced delay times from the collapse to alarm, start of CPR and defibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Care Units↗

Death outside hospital with special reference to heart disease.

For one year (1 September 1975-31 August 1976) an analysis was made of all deaths occurring outside hospital in the Gothenburg area (population 480 000). The total number of deaths was 1309. It was found that 675 (52%) of these deaths were caused by ischaemic heart disease (IHD), while 54 (4%) were caused by other heart diseases. The circumstances preceding death were analyzed in 363 cases representing all autopsied subjects under 75 years of age who died from IHD (autopsy rate 95%). Of these, 68% died at home, 4% during transport to hospital, and 4% at work. 214 (59%) of the deaths were witnessed, and in 189 (52%) cases, an ambulance had been called. 111 (52% died within 1 min of the onset of symptoms. 23 subject were in ventricular fibrillation on arrival at hospital. 11 of them were resuscitated, but only 3 were discharged alive. Additionally 12 of the non-autopsied subjects who died from IHD and 11 who died from other heart diseases had been witnessed and an ambulance had been called. In summary, 212 subjects who died outside hospital from heart disease in one year in Gothenburg died witnessed, and an ambulance was called. This should be the maximum annual number of cases of cardiac arrest outside hospital which it is possible to reach with a mobile coronary care organization within the time limit for effective resuscitation attempts.

Adult↗

Electrophysiological methods in assessing cardiac effects of the tricyclic antidepressant imipramine.

The tricyclic antidepressant agent imipramine was tested intravenously in 8 healthy individuals with respect to its effect on sinus recovery time, intervals in His bundle electrograms and the duration of the repolarization in the right atrium and ventricle judged from the refractoriness and monophasic action potential duration. Sinus recovery time was unchanged after the drug. The interval between the His bundle deflection and the start of the QRS complex in the standard lead showed no consistent changes but increased to pathological values in two individuals. The duration of the repolarization decreased in the atrium--an effect which could be arrhythmia-provoking or arrhythmia-protecting. The duration increased at the ventricular level. This effect could explain the antiarrhythmic effect on ventricular ectopics observed in other investigations.

Action Potentials↗

The effect of intravenous digoxin on the occurrence of ventricular tachyarrhythmias in acute myocardial infarction in man.

Patients with acute myocardial infarction were allocated to two groups according to a double blind-system of radomization. The patients (n = 18) in one of the groups received digoxin intravenously as an injection of 0.01 mg. per kilogram of body weight during 10 minutes. The patients in the other group (n = 15) received saline and served as controls. A continuous ECG record was obtained from each patient during 1 hour preceding the administration of digoxin or saline and was continued for 3 hours following the injection. No antiarrhythmic treatment was given during the time of the study. Based on the continuous ECG, calculations were made of the relative incidence of patients with different types of ventricular tachyarrhythmias during the period of observation as well as the percentage of arrhythmia-containing 1 minute intervals observed during this period. There was no statistical difference between the incidence of ventricular tachyarrhythmias in the two groups in the 1 hour period preceding drug injection. The administration of digoxin and saline did not change the incidence of ventricular tachyarrhythmias and there was also no statistically significant difference between the two groups as regards the incidence of patients showing different types of ventricular tachyarrhythmias during the 3 hour period following drug administration, Considering the 1-minute intervals, those without any ventricular premature contractions were less in the digoxin group (92 per cent) than in the saline group (88 per cent; p less than 0.001). Serum levels of digoxin at the end of the observation period were well above what is considered the minimum therapeutic level and in three patients the level approached or reached the toxic range. In these three patients there was still no increased incidence of ventricular tachyarrhythmias. It is concluded that patients with acute myocardial infarction complicated by incipient left ventricular failure do not show an increased sensitivity to an ordinary dose of digoxin as measured by the occurrence of ventricular tachyarrhythmia.

Acute Disease↗

Effect of the tetracyclic antidepressant drug maprotiline on cardiac electrophysiology in human volunteers.

The tetracyclic antidepressant drug maprotiline was given intravenously to seven healthy volunteers in order to evaluate its effect on sinus node automaticity, on the atrioventricular conduction system judged from Hisbundle electrograms, and on the repolarization of the right atrium and ventricle judged from the refractoriness and monophasic action potential duration. Sinus recovery time decreased after the drug, probably as a result of the anticholinergic action of maprotiline. No other significant changes were obtained. The electrophysiological effects of maprotiline on the atrium, AV-nodal conduction, and the ventricle seem less pronounced than those of tricyclic antidepressant drugs and this may explain the less pronounced arrhythmogenic effect of maprotiline.

Action Potentials↗