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Biomedical subjects

S Simonsen

Publications and source records attributed to S Simonsen.

At least 55 records · Page 3Linked to original sources
PubMed1979

Determination of pressure gradient in mitral stenosis with Doppler echocardiography.

The accuracy of a non-invasive ultrasound Doppler technique for the determination of the pressure gradient in mitral stenosis was evaluated in a study of 8 adult patients. Transseptal left atrial catheterisation and retrograde left ventricular catheterisation were performed. The same diastoles were used to compare the gradient constructed from the ultrasound data (delta PU) with that constructed from the manometric data (delta PM). In the 8 patients the difference betweent he mean diastolic values of delta PU and delta PM was - 0.54 +/- 1.0 (SD) mmHg. The corresponding figure for mid-diastole was 0.01 +/- 0.9 (SD) mmHg. The results indicate that the ultrasound technique is sufficiently accurate for diagnostic purposes.

Adult↗
PubMed1979

An ultrasound Doppler technique for the noninvasive determination of the pressure gradient in the Björk-Shiley mitral valve.

The accuracy in determining the pressure gradient in the Björk-Shiley mitral implant from noninvasive ultrasound Doppler data was explored in nine adult patients. Manometric and ultrasound data were collectd simultaneously, and identical diastolic periods were used to compare the manometric gradient (delta Pm) with the gradient obtained from ultrasound data (delta Pu). In the nine patients the mean diastolic value of delta Pm ranged from 2-12.5 mm Hg and the difference between the mean diastolic values of delta Pm and delta Pu was 0.3 +/- 1.0 mm Hg(SD). The results of the investigation indicated that the method is accurate and reliable in the nonivasive determination of the mean diastolic gradient in the Björk-Shiley mitral implant.

Blood Pressure↗
PubMed1978

Effect of carbocromen induced coronary vasodilatation on myocardial metabolism in coronary artery disease.

Myocardial metabolism was studied during coronary vasodilatation by carbocromen during atrial pacing in patients with coronary arteriosclerotic disease. Coronary sinus flow was measured by the continuous infusion thermodilution technique. Carbocromen increased myocardial flow by the same amount at rest and during pacing-induced tachycardia. The administration of carbocromen did not interfere with myocardial oxygen consumption, free fatty acid (FFA) uptake, pulmonary or systemic hemodynamics. Atrial pacing above the anginal threshold increased lactate and hypoxanthine excretion to the coronary sinus, but to a greater extent during carbocromen treatment. Thus, carbocromen is a specific coronary vasodilator acting independently of pacing induced vasodilatation. Metabolic data indicate a small but unfavourable effect on ischemic metabolism which might be due to a "coronary steal".

Cardiac Pacing, Artificial↗
PubMed1978

Determination of renal blood flow by thermodilution method.

The single bolus thermodilution method for measurement of renal vein blood flow was tested. In model experiments the thermodilution method was compared with graduated cylinder measurements over a flow range from 50 to 1050 ml/min. There was a good correlation between the two methods (r = 0.98) with a mean of differences of 5.2%. In eighteen patients measurements were performed in duplicate in thirty-one renal veins. Comparison was made between the first (x) and second (u) measurement--performed within 3 min. The correlation between the two was very good (r = 0.99; y = 1.03x - 11.48). In twelve patients bilateral renal vein blood flow measurements were performed simultaneous to blood flow measurement by PAH clearance. The correlation between total flow measured by thermodilution (y) and by the clearance method (x) was good (r = 0.98; y = 0.79x + 221). It is concluded that the thermodilution method requires catheterization of the renal veins, but is otherwise simple to perform, is inexpensive and gives reliable results. It is particularly advantageous when repeated measurements in the study of acute changes in renal haemodynamics is desirable.

Humans↗
PubMed1978

Effect of nifedipine (Adalat) on coronary haemodynamics in patients with coronary arteriosclerotic disease.

Effects of the new Ca++ antagonist nifedipine (Adalat) on coronary haemodynamics were studied in 8 patients with documented ischaemic heart disease. The continuous infusion thermodilution technique was used to measure cardiac venous blood flow. Sublingual application of 10 mg nifedipine caused a significant increase (16%) in myocardial blood flow and a decrease (18%) in coronary arteriolar resistance at rest, but not during a submaximal atrial pacing test. There was no change in coronary arteriovenous oxygen difference, myocardial oxygen consumption, oxygen consumption per unit of heart rate blood pressure index or left ventricular efficiency index. The effects on the coronary haemodynamics are discussed in relation to the simultaneous changes in general haemodynamics. Systolic aortic pressure was slightly reduced, significantly only at rest, while peripheral vascular resistance decreased and cardiac output increased also during atrial pacing. No change in free fatty acid metabolism was observed. It is concluded that nifedipine is a mild coronary vasodilator. No effect was observed on myocardial oxygen demand. The oxygen cost of left ventricular work was unchanged by the drug both at rest and during the submaximal stress test.

Adult↗
PubMed1978

Dialysis fistulas and cardiac failure.

A haemodialysis fistula may be a factor in the development of cardiac failure, and surgical reduction of fistula blood flow can improve the condition. We have investigated 6 patients with dialysis fistulas and closed the fistula in one of them, with marked improvement of cardiac failure. It is unlikely that a peripheral dialysis fistula can cause cardiac failure by itself, but it may be a contributing factor when the cardiac reserve is reduced due to other causes.

Adult↗
PubMed1978

Verapamil and pulmonary hypertension.

We report on the effect of verapamil in 12 patients suffering from pulmonary hypertension. The drug caused a slight, but statistically significant decrease in mean pulmonary artery pressure and in the work performance by the right ventricle. The mean pressure of the right atrium, the end-diastolic pressure of the right ventricle, the pulmonary arteriolar resistance, the cardiac index and the stroke volume were not significantly changed, however, and there was a wide spread of the values observed. In some patients the drug exerted a marked negative inotropic effect, with a concomitant increase in the pulmonary arteriolar resistance.

Adult↗
PubMed1978

Myocardial biopsy in diagnosis of endomyocardiopathy in patient with electro- and vectorcardiographic signs of myocardial infarction.

A 52-year-old woman is described with the clinical picture of congestive heart failure, electro- and vectorcardiographic evidence of myocardial infarction, combined with angiographically hypokinetic left ventricle, but with patent coronary arteries. Endomyocardial biopsy disclosed changes consistent with 'congestive cardiomyopathy'. Thus, the study shows that the Q wave pattern on the electrocardiogram provides insufficient evidence for the diagnosis of myocardial infarction, and may be misleading in patients with cardiomyopathy. In such circumstances, endomyocardial biopsy from the left or right ventricle appears to be a helpful diagnostic method, and further use of this technique may permit a more precise diagnosis in patients with a history of myocardial infarction, but with normal coronary arteries.

Biopsy↗
PubMed1978

The effect of free fatty acids on myocardial oxygen consumption during atrial pacing and catecholamine infusion in man.

The effect of myocardial uptake of free fatty acids (FFAu) on myocardial oxygen consumption (MVO2) in relation to increased heart rate and inotropic stimulation was determined in patients with coronary artery disease. Submaximal atrial pacing and isoproterenol stimulation increased MVO2 by 66% and 142%, respectively, at similar heart rates. Inhibition of lipolysis with beta-pyridyl carbinol almost abolished FFAu and reduced MVO2 significantly. Increased heart rate contributed 47% and FFAu 50% of the raised MVO2 attributed to inotropic stimulation was 30%. Augmentation of FFAu by triglyceride/heparin infusion increased MVO2 significantly above control levels, both during pacing and isoproterenol infusion. We conclude that MVO2 is closely correlated to FFAu, catecholamines sensitize the heart to FFA, and increased FFAu account for a major part of the increased MVO2 during catecholamine stimulation. The importance of reducing heart rate and lipolysis to reduce myocardial oxygen requirements is emphasized.

Blood Pressure↗
PubMed1978

Effect of verapamil on coronary hemodynamics in patients with coronary heart disease.

The effect of verapamil (Isoptin) on coronary hemodynamics was studied in 18 patients with coronary heart disease. The continuous infusion thermodilution technique was used to measure cardiac venous blood flow. At rest, verapamil produced a 13% decrease in coronary arteriolar resistance, a 5% decrease in coronary arteriovenous oxygen difference and a 19% increase in left ventricular efficiency index. No significant effect was noted on myocardial blood flow, oxygen consumption or oxygen consumption per unit of left ventricular pressure work. No change occurred in any of the measured parameters during a submaximal stress test after drug administration. The findings are discussed in relation to the general hemodynamic effects of the drug. It is concluded that verapamil is a mild coronary vasodilator and that myocardial oxygen consumption, in relation to performed left ventricular work, is unaltered by the drug up to a near-maximal work-load.

Blood Pressure↗
PubMed1977

Determination of effective orifice area in mitral stenosis from non-invasive ultrasound Doppler data and mitral flow rate.

Ten patients with mitral stenosis, but without mitral insufficiency, have been studied during cardiac catheterization. The mitral orifice blood velocities, the mitral pressure gradient, and the mitral flow rate were determined with ultrasound, manometry, and the direct Fick method, respectively. The effective orifice area was calculated from the ultrasound data and the mitral flow rate. The geometric orifice area was calculated from the pressure gradient and the mitral flow rate, using a revised Gorlin formula. A comparison of the two methods showed a correlation coefficient of 0.975. The investigation demonstrated that the ultrasound method represents an alternative to the conventional catheterization methods used for the quantification of mitral flow obstruction.

Blood Flow Velocity↗
PubMed1977

Relation between left ventricular filling pressure and angiographic findings in coronary heart disease. Ventriculography used as a stress test.

In 80 male patients with coronary heart disease maximum diastolic pressure in the left ventricle (LVMDP) (usually the top of the a wave), and 'post a' end-diastolic pressure (LVEDP) before and 2 and 3 minutes after ventriculography were correlated to angiographic estimates of left ventricular function (aneurysm, ejection fraction (EF), and to lesions shown by selective coronary arteriography using a score system (coronary artery lesions index, CALI). A significant correlation between CALI and LVEDP (or LVMDP) could not be shown either before or after ventriculography. Before ventriculography, however, LVEDP and LVMDP were good predictors of left ventricular dyskinesia (aneurysm and/or EF less than 50%). A positive and significant correlation between CALI and the LVEDP (and LVMDP) increments following ventriculography (delta LVEDP, delta LVMDP) was found in patients with LVEDP (or LVMDP) below 12 mmHg before ventriculography. Using delta LVEDP the correlation coefficient was 0-51 (n = 41, P less than 0-001, 95 per cent confidence interval 0-24 to 0-88). Using delta LVMDP r = 0-47 (n = 41, 0-001 less than P less than 0-01). Delta LVEDP greater than 12 mmHg was found only in patients with triple vessel disease.

Adult↗
PubMed1977

Studies of correlation between progression of coronary artery disease, as assessed by coronary arteriography, left ventricular end-diastolic pressure, ejection fraction, and employability.

The occupational status of a group of 100 male patients, 35 to 68 years of age, with chronic ischaemic heart disease was studied, and related to the severity and distribution of coronary artery stenosis seen on the arteriograms and to left ventricular function. In this series of patients 31 per cent were working, 31 per cent were recorded as temporarily sick, and 38 per cent as permanently disabled. It appears that while the type of previous occupation and physical activity associated with the job were of importance, there was no correlation between employability on the one hand and severity and distribution of coronary artery disease on the other. 'Blue-collar' workers had a higher rate of unemployment than those in 'white collar' occupations, but this could not be explained by differences in severity of coronary artery disease.

Adult↗
PubMed1977

Aspects of cardiac venous flow measured by the continuous infusion thermodilution technique.

The continuous infusion thermodilution method for the measurement of cardiac venous blood flow was investigated in 26 patients with angina pectoris. In 10 patients, the correlation coefficients for duplicate flow measurements within 1 min were 0.98 for the coronary sinus (CS) and 0.99 for the great cardiac vein (GCV), with a variation in relation to mean flow of 3.3 and 3.5%, respectively. The average CS drainage in 16 patients amounted to 126 ml/min with the GCV contributing 57% of the total and all other veins (OV) draining into the sinus 43%. Submaximal atrial pacing led to a significant increase in flow in all veins. The mean increase in flow per heart beat was 1.41 ml in the CS, 0.93 ml in the GCV, and 0.58 ml in the OV. The increase in flow per unit (1 X 10(-3) mm Hg - beats) heart rate times blood pressure product was 9.18, 6.97 and 4.71 ml, respectively. The method is suitable for the measurement of rapid changes in total and regional left ventricular blood flow under different conditions. For longer studies spontaneous changes in parameters governing myocardial oxygen demand must be taken into consideration.

Angina Pectoris↗