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Biomedical subjects

E Karlsson

Publications and source records attributed to E Karlsson.

At least 127 records · Page 7Linked to original sources

Established beta-adrenergic receptor blocking therapy and acute myocardial infarction. A clinical study of risks and benefits.

In order to evaluate the risks and benefits of continuing established therapy with beta-adrenergic receptor blocking drugs during acute myocardial infarction (AMI), 183 consecutive patients, 63 with (beta-blocker group) and 120 without (control group) this therapy, were studied. Detailed information on previous diseases, present symptoms, established medication, clinical and laboratory findings on admission and during the first 12 hours in the CCU was collected. The incidences of congestive heart failure, hypotension, AV blocks and ventricular arrhythmias were not significantly more common in the control group (8 vs. 28%, p less than 0.01). Thus, continuation of established therapy with beta-adrenergic receptor blocking drugs does not seem to increase the risk of complications after hospital admission for AMI. The reason for the low incidence of inferior wall infarction in the beta-blocker group is not clear but it cannot be excluded that when patients on beta-adrenergic receptor blocking therapy develop an inferior AMI, they may run a greater risk of sudden death.

Adrenergic beta-Antagonists↗

Comparative antiarrhythmic efficacy of intravenous N-acetylprocainamide and procainamide.

Ten patients with persistent ventricular arrhythmia were studied in a comparison of the antiarrhythmic efficacy of N-acetylprocainamide (NAPA) and procainamide (PA). Each patient performed three exercise tests for 40 min., on different days, with submaximal and fixed work loads. During the first exercise test no drug was administered. During the following two tests PA and NAPA, respectively, were administered by intravenous infusion. The electrocardiogram was continously recorded and was analyzed minute by minute. Blood samples for determination of plasma drug concentration were frequently collected. Exercise alone did not significantly change the incidence of arrhythmia. Both PA and NAPA showed a similar and significant antiarrhythmic effect. A blood pressure fall was seen in two patients after administration of each drug. No other adverse reaction was observed.

Adult↗

Procainamide-induced lupus erythematosus-like syndrome in relation to acetylator phenotype and plasma levels of procainamide.

To investigate the relationship between acetylator phenotype and the development of procainamide (PA)-induced systemic lupus erythematosus (SLE-like syndrome, 28 patients with chronic ventricular arrhythmias treated with PA were followed for one year. The therapy was guided by plasma monitoring in all patients in order to obtain the proposed therapeutic plasma level of PA. Nine patients (30%), both slow and rapid acetylators, developed the SLE-like syndrome within one year. PA plasma levels were similar in both slow and rapid acetylators and there was no difference in total dose or duration of therapy before development of the syndrome. Thus, the acetylator phenotype is probably of no or minor predictive importance when PA therapy is guided by plasma monitoring. On the other hand, the antinuclear antibodies appeared significantly more rapidly in patients developing the syndrome and could possible be used as an indicator of the risk. The results support the hypothesis that the primary amino group structure of PA may be of importance in the induction of the SLE-like syndrome.

Acecainide↗

Lidocaine and the quarternary ammonium compound QX-572 in acute myocardial infarction. A comparative study.

Patients with suspected or proven acute myocardial infarction complicated by ventricular arrhythmias not corrected by lidocaine therapy (bolus dose 100 mg followed by infusion 2 mg/min) were treated either with an increased dose of lidocaine (bolus dose 50 mg followed by infusion 3 mg/min) or with 600 mg N,N-bis dimethylammonium chloride (QX-572, Astra, Sweden) as an i.v. infusion during 30 min (3 patients) or 60 min (13 patients). In the lidocaine group the arrhythmias were controlled in 6 out of 15 patients, in the QZ-572 group in 12 out of 16, a difference that is not statistically significant. However, the frequency of side-effects was significantly higher (p less than 0.001) in the QX-572 group (15 out of 16 patients). They were also more severe, including pronounced tachycardia and hypertension. It is concluded that despite the high antiarrhythmic effect of QX-572, an increase of the lidocaine dose would be safer and preferable in the clinical situation studied.

Acute Disease↗

Role of cardiac output in the pressor responses to graded muscle ischemia in man.

Ten men repeatedly performed leg exercise (100-150 W) for 7 min with 30-min recovery periods interspersed. Both legs were made ischemic by total occlusion (OCCL), first for 3 min immediately after exercise and second for 30 s before exercise ended and 3 min into recovery. In addition legs were occluded for 3 min at rest (seated). OCCL at rest increased mean arterial pressure (MAP) by 9 Torr but did not affect cardiac output (CO) or heart rate (HR). OCCL at the end of exercise significantly raised MAP and HR above control values during 3-min recovery but CO was unaffected. OCCL 30 s before the end of exercise further increased MAP and HR significantly during recovery; MAP, CO, and HR were significantly increased above control values (CO by 2.1 1-min-1) during the 3rd min of recovery. We conclude that a strong reflex from ischemic legs maintains normal or elevated CO during leg OCCL. Thus CO was too high relative to total vascular conductance so that MAP was elevated.

Blood Pressure↗

Comparisoin between mass spectrometry and Haldane technique in analysing O2 and CO2 concentrations in air gas mixtures.

We have evaluated a mass spectrometer for use as a gas analyser in air gas mixtures. Simultaneous determinations of O2 and CO2 concentrations with both the mass spectrometer and the Haldane technique were done in ninety-nine different samples of expired air from ordinary laboratory experiments. The mean differences (+/- SD) between the two techniques for O2 and CO2 concentrations were 0.003% (+/- 0.049%), and 0.001% (+/- 0.045%) absolute values, respectively, (P greater than 0.05 for both), r values being 0.996 for O2 and 0.994 for CO2. There was a drift in the apparatus, which decreased with operating time. Proper calibration is necessary for accurate readings. A cost-benefit balance is made.

Carbon Dioxide↗

Comparative evaluation of intravenous phenytoin, procainamide and practolol in the acute treatment of ventricular arrhythmias.

Ten patients with a persistent ventricular arrhythmia, but no other sign of heart disease, were studied by means of an exercise test performed 4 times with a fixed work load, over 30--40 min. No drug was given in the first exercise test and in the others phenytoin, procainamide or practolol were chosen at random for i.v. administration. Blood samples for determination of plasma concentration were frequently collected. The ECG was recorded continuously during the exercise test and was analysed minute by minute. Despite plasma levels within the suggested therapeutic range, only procainamide showed a statistically significant antiarrhythmic effect in this group of patients.

Adult↗

Evaluation of the sulphapyridine acetylator phenotyping test in healthy subjects and in patients with cardiac and renal diseases.

The acetylator phenotype of 35 healthy, drug-free volunteers and 21 patients with cardiac and/or renal disease has been assessed using oral sulphapyridine. Comparative evaluation of a simplified and a more selective method of sulphapyridine analysis was performed. Thirteen of the patients were also phenotyped by determination of plasma isoniazid half-life. 81% of the patients were slow acetylators, compared with only 51% of the volunteers. When phenotyping healthy, drug-free subjects the analytical procedure, involving a direct estimation of sulphapyridine in urine with the Bratton-Marshall procedure, was satisfactory. On the other hand, in patients receiving concomitant drug therapy the more selective analytical procedure was necessary in order to diminish the risk of methodological interference.

Acetylation↗

Spontaneous systemic lupus erythematosus and acelylator phenotype.

Fifteen patients with spontaneous systemic lupus erythematosus (SLE) have been phenotyped by determination of plasma isoniazid (INH) half-life. Seven patients had signs of renal insufficiency. Of the 15 patients, 13 were slow and only 2 rapid acetylators. No correlation was found between the plasma INH half-lives and the renal function. Thus, there is the same marked predominance of slow acetylators in patients with spontaneous SLE as in patients with the drug-induced SLE-like syndrome.

Acetylation↗

Cardiovascular function during early recovery from acute myocardial infarction.

Fifty patients with acute myocardial infarction were studied serially to evaluate the extent and nature of functional cardiovascular impairment and the time course of recovery. Reinfarction or death occurred in six patients. Peak workload during bicycle exercise in a subgroup of 25 patients with maximal initial test and complete follow-up increased from 334 to 409 kpm/min (P less than 0.01) bwtween three and six weeks. There was further significant (P less than 0.01) improvement between three and six months from 438 to 488 kpm/min. The incidence of ischemia at a constant workload decreased between three and six weeks without any significant changes in heart rate or blood pressure. Mean cardiac output during exercise at three months was 6.5 and at six months 7.8 L/min (P less than 0.05). Corresponding values for stroke volume were 61 and 72 ml (P less than 0.05). The data suggest that in clinically stable patients there is an early improvement of the relation between myocardial oxygen supply and demand and a late improvement of functional capacity associated with increased stroke volume and cardiac output.

Acute Disease↗

Ventricular arrhythmias in acute myocardial infarction. A comparative study on some tests for ventricular arrhythmias.

A continuous ECG recording has been made in 31 myocardial infarction patients during the first 24 hours after admission to hospital. The number and severity of ventricular arrhythmias were recorded in great detail. Before discharge from hospital the patients were submitted to 20 hours of ECG tape recording, an exercise test on a bicycle ergometer and a static work test (handgrip). Another exercise test was performed one month after discharge. During the first day in the Coronary Care Unit (CCU) all 31 patients had ventricular arrhythmias and in 27 of them the arrhythmia was classified as major (calling for treatment according to Lown's criteria). At the exercise tests 23 patients showed ventricular arrhythmias, 12 of them considered as major. No antiarrhythmic therapy was given during the investigation. No correlation was found between the degree of arrhythmia during the first day in the CCU and during the exercise tests. Tape-recorded ECG's appeared to be inferior to dynamic exercise tests in the ability to disclose a latent tendency to ventricular arrhythmia. Static work did not provoke any ventricular arrhythmias. At a 2-year follow-up 5 patients had died, 4 of them suddenly. Examination of additional material on 11 patients with ventricular tachycardia or ventricular fibrillation during the CCU stay, showed that 2 had died, but only one suddenly. Frequency and severity of arrhythmias during the first day after the infarction seemed to correlate poorly to a persistent tendency to arrhythmias during the first day after the infarction seemed to correlate poorly to a persistent tendency to arrhythmias or to the risk of sudden death during the following 2 years. A dynamic exercise test performed before discharge would appear to be more effective in selecting patients in need of long-term prophylaxis. However, very few patients seem to need such a specific antiarrhythmic prophylaxis.

Acute Disease↗

Haemodynamic effects of procainamide and phenytoin at apparent therapeutic plasma levels.

The haemodynamic effects of procainamide and phenytoin after intravenous administration to 19 patients with suspected congenital heart lesions were studied. The drugs were injected into the pulmonary artery in a dose of 5 mg per kg bodyweight, at an infusion rate of 50 mg per minute, thus giving plasma concentrations within the suggested therapeutic ranges. The diastolic pressures in the pulmonary artery and the right ventricle were reduced by procainamide and the converse effect was noted after phenytoin. The heart rate was significantly increased by both drugs but with phenytoin this effect was only transitory. The latter drug also caused a small and transient fall in cardiac output and mean arterial pressure. It was concluded that of the two drugs phenytoin seemed to have the most marked myocardial depressant effect.

Adolescent↗