PubMed Health⌕ Search

Biomedical subjects

H Ihlen

Publications and source records attributed to H Ihlen.

At least 55 records · Page 3Linked to original sources
PubMed1987

Reproducibility of cardiac stroke volume estimated by Doppler echocardiography.

Doppler echocardiography was used to measure cardiac stroke volume in 10 patients with coronary artery disease who were treated with cardioactive drugs. Stroke volume estimates were determined at the aortic orifice by multiplying area by systolic velocity integral measured both from the suprasternal and the apical approach. Recordings were done independently by 2 experienced observers on the same day and repeated once after 1 to 21 days. Analysis of variance showed that no systematic differences were introduced by the 2 observers and Doppler approaches or by measuring on different days. The coefficient of variation between any pair of measurements in each patient was 9%. This variability is probably a result of the method or spontaneous fluctuations of the stroke volume and not of the varying recording conditions. The ultrasonic method detects day-to-day changes of cardiac stroke volume larger than 20% with a probability greater than 0.95.

Adult↗
PubMed1987

Quantification of mitral regurgitation by Doppler echocardiography.

The present study was undertaken to evaluate a new non-invasive approach to the quantification of mitral regurgitation. Doppler echocardiography and left ventriculography were performed in 20 patients without valvular heart disease (group A), and in 30 patients with pure mitral regurgitation (group B). Volumetric flows through the aortic and mitral valve orifices were determined by Doppler technique. The aortic flow (AF) was calculated as the product of the aortic orifice area by the systolic velocity integral. The mitral flow (MF) was computed as the product of the corrected mitral orifice area by the diastolic velocity integral. The mitral regurgitant fraction (RF) was calculated as: RF = 1 - AF/MF. In group A, there was a close agreement between aortic and mitral flows (r = 0.94, P less than 0.001), and there was no significant difference between the two measurements. In group B, the mitral flow was significantly higher than the aortic flow. The regurgitant fraction assessed by Doppler echocardiography correlated well with the grades of severity of regurgitation obtained at left ventriculography. We conclude that combined measurement of both aortic and mitral flows by Doppler echocardiography provides a new and promising approach to the noninvasive quantification of mitral regurgitation.

Adult↗
PubMed1987

Cardiac stroke volume during exercise measured by Doppler echocardiography: comparison with the thermodilution technique and evaluation of reproducibility.

Cardiac stroke volume was measured simultaneously by Doppler echocardiography and thermodilution in patients with severe coronary artery disease. One group (20 patients) was examined during supine exercise at 25 W and a second group (20 patients) during sitting exercise at 25 W and 50 W. In a third group (10 patients) the reproducibility of the non-invasive stroke volume estimate was determined during upright exercise. There was a considerable variation between results obtained with the invasive and non-invasive technique at rest and during exercise, but no systematic differences were found. Analysis of variance showed that no systematic differences between ultrasonic results were introduced by two observers or by measurements on different days. The coefficient of variation between any pairs of Doppler measurements in each patient was 6%. These findings demonstrate that the ultrasonic technique is suitable for detecting changes in stroke volume induced by low load exercise in patients with severe angina pectoris.

Adult↗
PubMed1986

Estimation of the peak-to-peak pressure gradient in aortic stenosis by Doppler echocardiography.

The present study was designed to develop a new Doppler method to estimate noninvasively the peak-to-peak pressure gradient in patients with aortic stenosis. It was carried out in two steps. In the first study, left heart catheterization data were analysed in 58 patients with aortic stenosis. The peak pressure gradient correlated highly with (r = 0.98) but overestimated significantly the peak-to-peak pressure gradient. The averaged pressure gradient (average of the peak gradient and the gradient at the peak aortic pressure) was found to approximate closely the peak-to-peak pressure gradient (r = 0.99) with a good separation between significant and insignificant aortic stenosis. The ratio of the left ventricular ejection time over the aortic pressure descending time was studied and the beginning of the late one-third systole was chosen as the point for determining the late systolic gradient by the Doppler technique. In the second study, Doppler echocardiography and cardiac catheterization were performed in 35 patients with aortic stenosis. The Doppler-determined peak pressure gradient correlated highly with catheterization-measured peak pressure gradient (r = 0.95) but overestimated significantly the peak-to-peak pressure gradient. The Doppler-determined averaged pressure gradient (average of the peak and the late systolic gradients) estimated accurately the peak-to-peak gradient (r = 0.97) with a good separation between significant and insignificant aortic stenosis. These results demonstrate the limitations of the peak pressure gradient measurement and the reliability of the Doppler-determined averaged pressure gradient for estimation of the peak-to-peak pressure gradient.

Adolescent↗
PubMed1986

Optimal atrioventricular delay in physiological pacing determined by Doppler echocardiography.

Our study included eight patients with physiological pacemakers programmed to the VDD mode. The blood velocity in the aortic root was determined by Doppler echocardiography. Changes in the integral of maximum velocity reflect stroke volume changes. The Doppler probe was placed and held in the suprasternal position while programming the pacemakers from the VVI to all available AV delays in the VDD mode; the heart rates were nearly constant. Stroke volumes were highly dependent on changes of the AV delay; the optimum AV delay varied considerably from patient to patient. These changes were more pronounced in the patients with left ventricular strain due to aortic valve disease than in the patients with isolated conduction defects.

Adult↗
PubMed1986

Measurement of aortic regurgitation by Doppler echocardiography.

In an attempt to develop a new approach to the non-invasive measurement of aortic regurgitation, transmitral volumetric flow (MF) and left ventricular total stroke volume (SV) were measured by Doppler and cross sectional echocardiography in 23 patients without aortic valve disease (group A) and in 26 patients with aortic regurgitation (group B). The transmitral volumetric flow was obtained by multiplying the corrected mitral orifice area by the diastolic velocity integral, and the left ventricular total stroke volume was derived by subtracting the left ventricular end systolic volume from the end diastolic volume. The aortic regurgitant fraction (RF) was calculated as: RF = 1 - MF/SV. In group A there was a close agreement between the transmitral volumetric flow and the left ventricular total stroke volume, and the difference between the two measurements did not differ significantly from zero. In group B the left ventricular total stroke volume was significantly larger than the transmitral volumetric flow, and there was good agreement between the regurgitant fractions determined by Doppler echocardiography and radionuclide ventriculography. Discrepancies between the two techniques were found in patients with combined aortic and mitral regurgitation or a low angiographic left ventricular ejection fraction (less than 35%). The effective cardiac output measured by Doppler echocardiography accorded well with that measured by the Fick method. Doppler echocardiography provides a new and promising approach to the non-invasive measurement of aortic regurgitation.

Adolescent↗
PubMed1986

Analysis of methodology for quantifying mitral regurgitation by Doppler echocardiography.

It is generally agreed that Doppler echocardiography is highly sensitive and specific for the detection of mitral regurgitation. There is more confusion about its ability to quantitate the degree of mitral regurgitation. Studies of the intensity of the Doppler signals, as well as cross sectional Doppler studies apparently can provide a straightforward, but rough estimate of the degree of regurgitation in term of atrial extent of the disturbed flow. The methods are also sensitive to methodological errors as beam direction, movement of the heart, signal/noise relationship and the size of the left atrium. Another approach to the non-invasive measurement of mitral regurgitation includes the use of Doppler echocardiography for the determination of both aortic and mitral volumetric flow. In a study of patients with mitral regurgitation, we found a close correlation between the regurgitant fraction determined by Doppler echocardiography, and the regurgitant severity determined by left ventriculography. This technique can only be used in pure mitral regurgitation, while associated atrial fibrillation, mitral stenosis, and combined aortic and mitral regurgitation make correct measurements difficult.

Cardiac Output↗
PubMed1985

Significance of a positive exercise ECG in middle-aged and old athletes as judged by echocardiographic, radionuclide and follow-up findings.

To study the pathologic and prognostic significance of--and possible underlying mechanisms for--a pathological exercise ECG in athletes, two age-matched groups were selected from a total population of 117 middle-aged and old endurance athletes: Group A: 21 with a pathological exercise-ECG, and group B: 21 with normal exercise-ECGs. Data from 201-thallium perfusion scintigraphy, 99 m-technetium multiple gated acquisition ventriculography (MUGA), resting echocardiography and 3 years follow-up are as follows: None had thallium findings indicating reversible myocardial ischaemia, but one from group A had a probable old myocardial infarction. All had normal resting MUGA, but group A men slightly more often presented a subnormal increase in ejection fraction according to exercise MUGA than group B men (9/20 vs 4/21). The former also more often had ventricular hypertrophy (LVH) (19/21 vs 14/21). However, apart from slightly longer ventricular filling time among group A men the echocardiograms revealed no group differences e.g. in cardiac dimensions or in indices of systolic or diastolic function. Regardless of exercise-ECG response, 18/42 athletes had one or more value of left ventricular dimensions or diameter exceeding the 95th percentile of the normal range. Since one patient from group A had asymmetric septal hypertrophy, one developed cardiomyopathy during the 3 years follow-up and one had a previous myocardial infarction, only 3/21 had cardiac disease which might explain the pathological exercise-ECG. Thus, pathological exercise-ECG rarely signifies heart disease in athletes, and very rarely coronary heart disease. Rather, the pathological exercise-ECG may be related to LVH and various subtle alterations in cardiac physiology following long-term endurance training.

Adult↗
PubMed1985

Aortic regurgitation associated with ventricular septal defects in adults. Clinical course, haemodynamic, angiographic and echocardiographic findings.

In 125 consecutive patients, aged greater than or equal to 10 years (mean 27, range 10-64), evaluated for isolated ventricular septal defects (VSD) the initial prevalence of aortic regurgitation (AR) was 12/125. Forty-one patients were operated on, and post-operative mortality was 3/6 in patients operated on for VSD and AR and 1/35 in those operated on for VSD alone. All but one of the patients have been followed until death or beyond the age of 30 years (mean 42, range 31-73) and a prospective restudy has been performed after a mean observation time of 15 years (range 4-21). The incidence of new cases of AR arising during this period was 10/111. AR was severe in 5 cases (one died from heart failure), moderate in 1 and mild in 4. Surgical repair of AR and VSD was performed in 3 cases. Common characteristics of patients who developed AR were advanced age, male sex, history of bacterial endocarditis, small subaortic VSDs and tricuspid aortic valves without prolapse. Echocardiography revealed larger aortic root diameter (p less than 0.001), increased eccentricity factor (p less than 0.001) and increased left ventricular dimensions (p less than 0.02) in those with complicating AR. AR in adults with VSD may have an unpredictable clinical course; it may be difficult to assess clinically and the need for close clinical control is emphasized. Echocardiography remains of considerable value in selected cases.

Adolescent↗
PubMed1985

Doppler echocardiographic measurement of cardiac output using the mitral orifice method.

Cardiac output was determined in 20 patients with various cardiac conditions by measuring the cross sectional area of the mitral orifice by echocardiography and the transmitral flow by the Doppler technique. Cardiac output was calculated by multiplying the corrected mitral orifice area by the maximum diastolic velocity integral recorded by the pulsed mode. The results were compared with that obtained by the Fick method. The correlation for cardiac output by the two techniques was high in the whole group, particularly in patients without mitral regurgitation. There was also a good correlation for stroke volume determined by the two methods. Cardiac output was significantly overestimated by the continuous mode and in patients with mitral regurgitation. These results show that the mitral orifice method provides a new and reliable approach to the non-invasive measurement of cardiac output.

Adolescent↗
PubMed1985

Changes in left ventricular stroke volume measured by Doppler echocardiography.

Cardiac stroke volume was measured simultaneously by Doppler echocardiography and thermodilution in 20 patients with coronary artery disease. Stroke volume as determined by ultrasound was calculated from the area of the aortic orifice and the flow velocity just distal to the aortic cusps. The recordings were made twice at rest. Ten patients were given dobutamine (2.5 and 5.0 micrograms/kg/min) by infusion to induce rapid changes in stroke volume from the resting state. The individual Doppler data before, during, and after dobutamine infusion correlated closely with the thermodilution data (r = 0.92). These results suggest that Doppler echocardiography reliably detects changes in stroke volume.

Adult↗
PubMed1985

Measurement of mitral regurgitation by Doppler echocardiography.

In an attempt to develop a new approach to the non-invasive measurement of mitral regurgitation, Doppler echocardiography and left ventriculography were performed in 20 patients without valvar heart disease (group A) and in 30 patients with pure mitral regurgitation (group B). Volumetric flows through the aortic and the mitral orifices were determined by Doppler echocardiography. Aortic flow (AF) was calculated as the product of the aortic orifice area and the systolic velocity integral. The mitral flow (MF) was calculated as the product of the corrected mitral orifice area and the diastolic velocity integral. The mitral regurgitant fraction (RF) was calculated as RF = 1 - AF/MF. In group A aortic and mitral flow were very similar and the difference between the two did not differ significantly from zero. In group B the mitral flow was significantly larger than the aortic flow. There was a good correlation (r = 0.82) between the regurgitant fraction determined by Doppler echocardiography and the regurgitant grades determined by left ventriculography. The regurgitant fraction increased significantly with each grade of severity. These results show that Doppler echocardiography can be used to give a reliable measure of both aortic and mitral flow. This technique is a new and promising approach to the non-invasive measurement of mitral regurgitation.

Adult↗
PubMed1984

Evaluation of potential adverse effects of sodium nitroprusside during pacing-induced myocardial ischaemia in man.

To elucidate the potential harmful effects of sodium nitroprusside (NP) on myocardial ischaemia, eleven patients with coronary artery disease were studied before and during two doses NP infusion. The infusion rates were adjusted to reduce systolic aortic pressure by 10-20 mmHg and to between 100 and 110 mmHg. Myocardial haemodynamic and metabolic measurements were undertaken in sinus rhythm and during pacing-induced angina pectoris. The procedure was repeated at the low and high dose NP using the same pacing rate. One patient did not develop ischaemia and was excluded. Low dose NP reduced ischaemia slightly, whereas the higher dose had no effect despite falling indices of cardiac work. The oxygen uptake was maintained except at high dose treatment during pacing due to an increased catecholamine stimulation. The transmural perfusion gradient was unchanged at low dose NP, but fell at the higher dose suggesting reduced perfusion of ischaemic tissue. High dose NP also decreased coronary arteriolar resistance considerably which may have induced a coronary 'steal' effect. Thus, NP may induce adverse haemodynamic and metabolic changes which counteract the beneficial actions of the drug on ischaemia when used in high doses and in patients without heart failure.

Acute Disease↗
PubMed1984

Determination of cardiac output by Doppler echocardiography.

Cardiac output determined by Doppler echocardiography was compared with that determined by thermodilution at rest and during dobutamine infusion in 10 patients (group A) and by the Fick method at rest in 11 patients (group B). All patients had angina pectoris without valvular heart disease. Maximum spatial blood velocity and cross sectional aortic area were estimated by the Doppler technique and echocardiography. Cardiac output was calculated by multiplying blood velocity by aortic area at various levels in the ascending aorta. The best correlation of cardiac output between the invasive and non-invasive methods was obtained when maximum velocity in the aortic root and the aortic orifice area were used in the calculations. Cardiac output was considerably overestimated when area measurements in the aortic root were used.

Adult↗
PubMed1984

Potential deleterious haemodynamic effects of glyceryl trinitrate on myocardial ischaemia in man.

The potential adverse effects of glyceryl trinitrate on myocardial ischaemia were studied using low and high dose infusions in 10 patients with coronary heart disease. Cardiac venous flow was measured by the thermodilution technique and blood was sampled for metabolic studies. Angina pectoris was provoked by atrial pacing before drug infusion and the same heart rate was regained with low and high doses of glyceryl trinitrate. Both doses reduced myocardial ischaemia equally. The low dose of glyceryl trinitrate reduced mean systolic aortic pressure from 145(23) to 128(23) mm Hg and the high dose further to 103(9) mm Hg. Myocardial oxygen uptake decreased owing to a combined reduction in preload and afterload with the low dose and was substantially more reduced with the high dose owing to a further afterload reduction. Transmural perfusion gradient did not change with the low dose of glyceryl trinitrate but fell significantly with the high dose. This fall in myocardial perfusion probably accounts for the lack of further reduction in ischaemia with the high dose. Thus the adverse effects of glyceryl trinitrate infusion are small and do not increase myocardial ischaemia.

Adult↗
PubMed1984

Effect of adrenaline on myocardial oxygen consumption during selective and non-selective beta-adrenoceptor blockade comparison of atenolol and pindolol.

The effect of adrenaline on myocardial oxygen consumption (MVO2) during selective and non-selective beta-adrenoceptor blockade was examined in 26 patients with angina pectoris. Cardiac venous flow was measured by thermodilution and blood was sampled for metabolic studies. Thirteen patients were given atenolol 62.5 micrograms/kg i.v. and the other 13 patients pindolol 7.5 micrograms/kg i.v. Measurements were repeated before and during infusion of adrenaline 0.1 microgram/kg/min. Compared to the control situation, adrenaline increased MVO2 more in atenolol-treated (39%) than in pindolol-treated patients (11%). This was partly due to augmented external cardiac work. Arterial FFA was considerably increased in the atenolol group (105%), but was unchanged in the pindolol group, suggesting an additional metabolic mechanism. Thus, adrenaline stimulation, which is comparable to that found in acute myocardial infarction, increases MVO2 more during selective than non-selective beta-blockade.

Adult↗