[A case of "resistant" ventricular fibrillation with favorable outcome].
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Adult↗
Biomedical subjects
L G Ekelund
Publications and source records attributed to L G Ekelund.
Antianginal efficiency of nifedipine with and without a beta-blocker, studied with exercise test. A double-blind, randomized subacute study.
Twenty-one patients, mean age 60.3 years, with stable angina pectoris earlier treated with beta-blockers, were investigated with standardized exercise tests to evaluate the action of nifedipine alone and in combination with a beta-blocker. The first exercise test was performed 3 weeks after treatment with the patient's usual beta-blocker. Following this, the patients were tested twice after a double-blind cross-over 3-week trial with nifedipine and placebo. The patients were subsequently treated for 3 weeks with nifedipine 10 mg 3 times daily or placebo and then performed an exercise test. During the 4th period of 3 weeks the patients took a combination of nifedipine, 10 mg 3 times daily, and their usual beta-blocker and then performed the final exercise test. Nifedipine alone raised the heart rate by 5 beats/min at rest and diminished the systolic blood pressure at rest by 17 mm Hg. During exercise at comparable load the heart rate did not change significantly, but the systolic blood pressure decreased with 22 mm Hg. The exercise tolerance expressed as total work increased on a average by 20%, range-14 - + 194%. Nifedipine in combination with a beta-blocker gave a further decrease in the systolic blood pressure, totally 37 mm Hg at comparable load. The exercise tolerance increased more, totally by an average of 41%. There was a significant correlation between basal values for systolic blood pressure registered during the placebo period at rest and the percentage change in total work. The atrioventricular conduction time did not change significantly compared to placebo during treatment with nifedipine or the combination nifedipine + beta-blocker. No serious side-effects were observed during the study.
Aged↗
Ca-blockers and peripheral circulation--physiological viewpoints.
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Blood Circulation↗
The significance of AV block I in asymptomatic young men. Variability, some anthropometric data, orthostatic test reaction and physical work capacity.
Twenty-nine young men with AV block I (P-R interval greater than 0.22 sec), without any history of heart disease, have been compared with 112 randomly selected healthy men of the same age. In 24 subjects who were free from concomitant ECG changes the P-R interval was normalized during orthostatic test and/or physical exercise. This group did not differ from the controls regarding anthropometric data and physical work capacity except for a higher heart rate at rest, thus suggesting that in these subjects an occurrence of AV block I has no pathological significance. However, it cannot be excluded that the block is a sequela, for instance, to myocarditis. Three subjects with AV block I and inverted T waves in the precordial leads and two subjects with unchanged P-R intervals to increased sympathetic tone had on average a smaller body size, a higher HR and systolic BP in recumbent position and smaller blood volumes.
Adolescent↗
[Health examination of diagnosis hyperlipidemia--clinical and clinical physiological findings].
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Adult↗
Effects of cedilanid-D in combination with metoprolol on exercise tolerance and systolic time intervals in angina pectoris.
The interaction between cedilanid-D and metoprolol, a selective beta receptor blocking agent, on exercise tolerance and systolic intervals was studied in 15 patients with angina pectoris. The patients had been treated with metoprolol for several months in a dose of 50 mg, three times daily (one patient received 25 mg three times daily). Each patient participated in two studies separated by at least 1 week. After arriving at the laboratory each received 50 mg of metoprolol orally; thereafter, either cedilanid-D or placebo was infused intravenously in a double-blind study performed in randomized order. When the effect of the drugs was maximal, the systolic intervals and the heart volume were recorded at rest, and the exercise tolerance was tested with a bicycle ergometer. The mean maximal value of plasma concentrations of metoprolol assessed during the study was about 50 ng/ml but the variation among subjects was great (20 to 187 ng/ml). After administration of cedilanid-D there was a shortening of the pre-ejection period and left ventricular ejection time compared with results after placebo; the reduction was similar to that found after administration of cedilanid-D without beta blocking drugs. The total heart volume decreased by an average of 55 ml, but the individual variation was great. The patients' average work capacity, expressed as total work, was not altered by cedilanid-D when compared with results after placebo. No relation was found between initial heart size and the effect of cedilanid-D on capacity for physical work. It therefore appears that there is no indication for the routine use of digitalis during beta blocking therapy in patients with angina pectoris who do not have cardiac failure.
Adrenergic beta-Antagonists↗
Enzyme activities in hepatic venous blood under strenuous physical exercise.
In order to study the influence of physical exercise on liver function, experiments were performed in healthy volunteers subjected to controlled major physical effort. Blood samples obtained by catheterization of hepatic vein during exercise were analyzed for activities of LD (thermostabile and thermolabile isoenzymes), AlAT, SDH, ICD, AP and CPK, and these activities were compared with corresponding values in arterial blood samples taken simultaneously. Hepatic blood flow and oxygen saturation of hepatic venous blood were measured. Physical exercise resulted both in diminished hepatic blood flow and a fall in hepatic venous oxygen saturation. These changes were accompanied by release of liver specific enzymes, indicating that exhausting exercise may induce an "increased hepatocyte membrane permeability" in man.
Adult↗
On-line computer processing of pressure data from cardiac catheterizations.
A flexible program system for on-line analysis of pressure data from cardiac catheterizations is described. The programs are implemented on an IBM 1800 computer, equipped with remote oscilloscope/keyboard terminals. The current computer system can handle any combination of up to 4 pressure signals. During catheterization, measurement specifications (i.e. calibration levels or sites of pressure recordings) are entered via the keyboard immediately before each recording. As an option the whole expected measurement sequence may be stored on disk before the catheterization starts. This method will minimize the necessary interaction with the computer when the same catheterization procedure is used on several occasions. Changes from the predetermined scheme may, however, be undertaken before each recording to meet with unexpected events that may arise during the catheterization. After computer detection of calibration levels, the recorded signals are digitized during 20 seconds and analysed beat-by-beat. Calculated values are averaged and presented on the terminal oscilloscope in tabular and/or graphic form. The waveform analysis performed by the program system is validated in a statistical comparison between manually and automatically computed values.
Cardiac Catheterization↗
Measurement of cardiac output by impedance cardiography in patients with myocardial infarction. Comparative evaluation of impedance and dye dilution methods.
The cardiac output was measured simultaneously by the impedance cardiography and dye dilution methods in 10 patients with acute myocardial infarction 2-3 weeks after admission to the Coronary Care Unit. The impedance cardiac output was on the average 9.7% higher than the dye dilution cardiac output. The reproducibility of impedance cardiac output 4.1%, compared with 5.1% for the dye dilution method. The study showed a satisfactory reliability of impedance in predicting the relative changed of cardiac output in response to tilting from the supine to the 30 degrees head-up position, to a 10 degrees head-down position, and to the intravenous administration of propranolol.
Acute Disease↗
Effects of the cardioselective beta-adrenergic receptor blocking agent metoprolol in angina pectoris. Subacute study with exercise tests.
The effect of a cardioselective beta-adrenergic blocking agent, metoprolol, on symptoms and exercise tolerance was studied in 16 patients with angina pectoris. Metroprolol was compared with placebo at two dose levels (20 mg t.d.s. and 50 mg t.d.s.) in a double-blind trial in 14 patients. Compared with placebo, metroprolol caused a significant reduction of heart rate and systolic blood pressure during exercise, and consequently a reduction of the rate-pressure product. The reduction was greater with 50 mg t.d.s. than with 20 mg t.d.s. The exercise tolerance measured as total work increased significantly by 21 per cent during treatment with metroprolol 20 mg t.d.s., and by 17 per cent during treatment with 50 mg t.d.s. There was a reduction in the number of anginal attacks and in nitroglycerin consumption, and subjective improvement of angina pectoris at both dose levels of metroprolol. No signs of cardiac failure appeared during any of the four treatment periods. Heart volume showed no significant change. Unwanted effects were of the same frequency and severity during treatment with metroprolol at both dose levels as with placebo.
Adrenergic beta-Antagonists↗
Frequency of ischaemic exercise E.C.G. Changes in symptom-free men with various forms of primary hyperlipaemia.
Serum cholesterol and triglycerides were measured in approximately 12,000 men attending a screening centre. 130 symptom-free men (aged thirty-five to sixty-five) were selected from the top 2% with the highest lipid values. They, and 59 normolipaemic controls, were studied by recording electrocardiograms (E.C.G.) before and during exercise. The frequency of so-called ischaemic E.C.G. changes (ST-segment depressions Minnesota code 4.1-4.4) increased with age both in controls and in the hyperlipaemic group. Ischaemic E.C.G. changes were significantly more common in all types of hyperlipaemia (types IIA, IIB, III, and IV) than in controls. The high frequency of the exercise E.C.G. changes in symptom-free hyperlipaemic men reinforces the argument for early treatment of hyperlipaemia to prevent ischaemic heart-disease.
Adult↗
Exercise tolerance in patients with angina pectoris after pentaerythritol trinitrate and alprenolol studied by two different methods.
Exercise tolerance has been studied by two different methods, heart-rate-controlled exercise and stepwise increased load, in 12 patients with angina pectoris. The response to a beta-adrenergic blocking agent, alprenolol, and an alkyl nitrate derivative, pentaerythritol trinitrate (PETRIN) was studied by the two methods after double-blind administration of the drugs. Rating scales were used to quantitate the degree of dyspnoea, angina pectoris and tiredness in the legs. After PETRIN both methods showed significant increases in exercise tolerance (19 and 21 per cent). The heart-rate-controlled test showed a significant increase (33%) after alprenolol, but the change was not significant by the other method. In the patients studied, heart-rate-controlled exercise discriminated between active drug and placebo better than the stepwise increased load test, what might have been due to more optimal matching of the loads obtained in the heart-rate-controlled test. Indications are given about how to design an exercise study in patients with angina pectoris.
Aged↗
Haemodynamic effects of intravenous verapamil at rest and during exercise in subjectively healthy middle-aged men.
Verapamil, 0.1 mg/kg body wt, was injected i.v. over 2 minutes in 8 subjectively healthy middle-aged men, followed by a continuous infusion of 0.007 mg/kg body wt per minute. Prior to the injection several of the subjects had raised pulmonary or systemic arterial pressures. At rest, the central pressures increased slightly, which was taken as a sign of a moderate negative inotropic effect, but there was no change in pre-ejection period or maximal dp/dt of the aortic pressure. The heart rate increased and there was a small decrease in systemic arterial pressure, probably due to a fall of systemic vascular resistance. The PQ time was prolonged. During exercise, with its positive inotropic stimulation, the moderate negative inotropic effect of verapamil disappeared, whereas the increase in heart rate and decrease in aortic pressures persisted. Some variables that reflected the oxygen demand of the heart decreased. The slight negative inotropic effect does not appear to be a particular contraindication to the use of verapamil, but it should be employed cautiously in conditions with a compensatory rise in systemic vascular resistance, or if atrioventricular conduction is impaired.
Adult↗
[The hemodynamic effect of verapamil by intravenous administration in middle-aged, subjectively healthy subjects at rest and during exercise].
After an intravenous injection of 0.1 mg Verapamil per kg body weight and during an infusion of 0.007 mg Verapamil per kg body weight and minute the heart rate increased, P,Q,-time increased, pulmonary vascular pressures increased. Aortic pressures decreased. No change in maximum dp/dt of the aortic pressure. The word maximum is still missing. Pre-ejection period decreased. During an exercise on a load of 650 kpm/min on average heart rate after Verapamil was increased, aortic pressures decreased, stroke work decreased and there were no signs of any negative inotropic effect.
Adult↗
Effect of nifedipine on exercise tolerance in patients with angina pectoris.
To test if nifedipine, 10 mg sublingually, could increase exercise tolerance, ten patients with angina pectoris each performed two types of bicycle exercise test, one with a stepwise increase in load and the other with a continuously increasing load. The drug was given in a double-blind cross-over trial. Nifedipine raised the heart rate and diminished the systemic blood pressure at rest, on standing and during exercise at comparable loads. Work time was prolonged and higher work loads were achieved. The total work performed rose by 50 per cent in one of the tests and by 23 per cent in the other, about 50 minutes after taking the drug. The mechanism of the greater work capacity in angina pectoris after nifedipine was assumed to be diminished heart work due to a fall in systemic vascular resistance.
Adult↗
Studies in asymptomatic primary hyperlipidaemia, III. Physical working capacity.
One-hundred-and-sixty male and 123 female subjects with asymptomatic primary hyperlipidaemia (HLP) selected from a health control centre have been studied with a heart rate (HR) controlled exercise test. Ther serum cholesterol and/or TG at screening were above 350 mg/100 ml and 3.5 mmol/l, respectively. As a reference group 49 male and 60 female age-matched subjects from the same centre with serum cholesterol below 300 mg/100 ml and TG below 2.00 mmol/l were investigated using the same technique. Quantitative lipoprotein (LP) analyses and typing were performed on all HLP and control subjects. The subjects were divided into two age groups, 36-50 and above 50 years of age. Men with all types of HLP had lower working capacity, expressed in W170 or W150, than controls, most pronounced in the younger age group. Younger women with type II A had lower working capacity than their controls. After correction for variation in body weight and age there remained a significantly lower W150, in male types II A (11%) and IV (21%) and female type II A (11%). There was no difference in systolic BP during exercise between controls and HLP. The total exercise time and final HR did not differ in control and HLP subjects. Dynamic spirometry was performed im 102 of the male subjects and a significantly lower vital capacity was found in HLP subjects compared with controls after correction for variation in age, weight and height. No differences were found in the maximal flow values. The observed differences in working capacity between controls and HLP subjects are explained by a difference in stroke volume. The lower stroke volumes in male types II A and IV and female type II A could be explained by a lower degree of physical fitness, by a common genetic factor resulting in HLP and decreased stroke volume or by a less effective myocardial function in HLP subjects.
Adult↗
Studies in asymptomatic primary hyperlipidaemia. IV. ECG at rest and during exercise and its relation to various lipoprotein classes.
Among approximately 20,000 apparently healthy subjects whose serum cholesterol and triglyceride (TG) values were screened at a health examination, those with the most pronounced hyperlipidaemia have been selected for further studies. Thus, 188 males and 126 females, aged 30-65 years, with asymptomatic primary hyperlipoproteinaemia (HLP) and 59 male and 69 female controls with non-elevated serum lipids were studied with regard to frequency of ST segment depressions during exercise to near maximal heart rate. Furthermore, the concentrations of cholesterol and TG were determined in the lipoprotein (LP) classes very low (VLDL), low (LDL) and high (HDL) density LP, separated by preparative ultracentrifugation. From the LP analysis each subject's HLP was classified according to the typing system of HLP recommended by the WHO. The frequency of ST depressions (Minnesota code 4.1-4.3 as well as 4.1-4.4) increased with age, was higher in females than in males and was increased in all types of HLP in males. The percentage frequencies of ST depressions 4.1-4.4 in the various types of HLP were (male/female, p against controls): controls 16/36, type IIA 50 (p less than 0.01)/56, type IIB 64 (p less than 0.01)/75 (p less than 0.01)/75 (p less than 0.05), type III 67 (p less than 0.01)/33 and type IV HLP 40 (p less than 0.01/53. There was no significant difference in the frequencies of ST depressions in subjects with "high" and "low" BP (hypertensives were excluded from the study) or in subjects with "high" and "low" k-value for the i.v. glucose tolerance. Non-smokers had a tendency to higher frequencies of ST depressions than smokers. The association between different LPs and other "risk factors" and the occurrence of ST depressions in HLP were studied further with multiple regression analysis. Invariably age was the best predictor of ST depressions. The LP fraction giving the highest correlation coefficient was LDL cholesterol in both sexes. VLDL TG and LDL TG were also positively and significantly associated with ST depressions. HDL cholesterol was negatively but insignificantly correlated to ST depressions. When age and LDL cholesterol had been entered into the multiple regression, the only factor giving further significance was VLDL TG in males. Probability tables for the occurrence of ST depressions considering age and different levels of LDL cholesterol and VLDL TG were given. The importance of simultaneous consideration of both VLDL TG and LDL cholesterol in ST segment depression was evident from the tables. Of other "risk factors" (BP, glucose tollerance, smoking, ESR) entered into the regression together with only age and the LPs, only ESR contributed with borderline significance to ST depressions.
Adult↗