Search

Non-Uniform Rational B-splines (NURBS) surfaces can be used for a computer simulation of shapes. Some anatomical models of human or animal structures have been recently developed on that basis. We used positron-emission tomography (PET) and computed tomography (CT) data for NURBS modeling of anatomical structures and isotope uptake in the rat brain. Our simplified model of the rat cerebral blood flow is the first step in a larger project aiming a simulation of PET scans in small animals followed by its validation in vivo.

Theory and previous studies showed that KLT (an application of principal component transform for imaging) can be use for analysis of cardiac function. This paper presents the results of our studies concerning the applications of KLT for images smoothing, quantification of myocardial contraction, and improvement of inter-observer reproducibility in cardiac imaging. The paper also describes the use of 4D cardiac phantom to quantify Karhunen-Loeve images.

Purpose of the Study: Fractures of the scaphoid must be diagnosed quickly to avoid persistent nonunion and the risk of osteoarthritis. Despite meticulous physical examination and adequate x-ray detection, numerous occult fractures still go unrecognized. The aim of this prospective study was to analyze the pertinence of quantitative radio-scintigraphy (QRS) presently used for the diagnosis of occult wrist fractures., Material and Methods: Quantitative radio-scintigraphy (QRS) is a new imaging technique associating quantitative bone scan and numerical fusion between bone scan images and x-ray images. We conducted a prospective study between November 1994 and March 1999 to evaluate the pertinence of this examination technique for the diagnosis of occult wrist fractures in patients presenting clinical symptoms suggestive of wrist fracture but whose plain x-rays were initially considered normal. Further some patients had several series of plain x-rays performed at several week intervals in order to search for fractures becoming progressively visible on plain x-rays. After the QRS data was acquired, these patients' x-rays were reviewed again. We also compared the cost of QRS, repeated x-rays, bone scan and MRI at the Besançon University Hospital., Results: QRS was performed in all 154 patients and revealed 61 fractures (56 single-line and 5 multiple-line fractures). Thus 43.5% of these patients had occult wrist fractures (41% of which involved the carpal scaphoid)., Discussion: Occult fracture of the wrist, particularly the carpal scaphoid, is frequent. Repeated x-ray examination does not increase the rate of detection of these fractures. Bone scans may also fail to reveal occult fractures. MRI is a key examination in the assessment of wrist fracture symptoms, but is presently not available in all institutions. Bone scan is classically insufficiently precise. QRS is a rapidly available low-cost examination which we have found to be indispensable for the diagnosis of occult wrist fractures. With early QRS diagnosis, the risk of neglected carpal scaphoid fracture and subsequent nonunion and osteoarthritis together with the personal, social, and medicolegal consequences can be avoided.

Unlabelled: When performing (201)Tl myocardial SPECT using a dual-head gamma camera on patients after exercise stress, we have observed in some a sudden increase in the counting rate between the 16th and 17th images. This increase provoked motionlike artifacts, which increased the number of false-positive findings. The aim of our study was to determine possible causes for this leap in activity., Methods: We performed myocardial SPECT using a dual-head gamma camera on 110 patients after exercise stress: in 38 patients approximately 5 min after injection (group 1), in 43 patients approximately 14 min after injection (group 2), and in 29 patients twice, at approximately 5 and 20 min after injection (group 3). We also performed dynamic data acquisition for 10 min on 18 patients after exercise stress. We compared activity in the heart region in image series obtained after exercise stress and at rest., Results: Daily quality control tests eliminated the possibility of any malfunctions of the gamma camera. Careful image analysis showed no visible patient motion. Our results showed that upward creep of the heart could not be a cause of the described phenomenon. After exercise stress, a > or = 5% activity leap in the heart region on the 16th and 17th frames was more frequent in group 1 than in group 2. Two consecutive acquisitions after exercise stress showed that the leap was >5% in 24 patients (83%) and 12 patients (41%) at the first and second acquisitions, respectively (group 3). In all patients, the leap was <5% at rest. Dynamic studies showed that the activity in the heart region steadily decreased in all patients after exercise stress. We suggest that decreasing (201)Tl concentrations in myocardium or blood could be a major reason for the described artifacts., Conclusion: We proposed that the pharmacokinetics of (201)Tl-chloride be evaluated within a short time after injection in humans after exercise stress. Now, in our department, we have begun acquisition approximately 12 min after (201)Tl administration, and the above-mentioned phenomenon has not appeared. However, to avoid the artifacts caused by early redistribution of (201)Tl, acquisition must not begin too late.

A hundred and eighty three patients with a primary myocardial infarction less than 4 hours old were included in a double blind trial versus placebo comparing an isolated plasminogen streptokinase activator complex (APSAC: 30 mu in 5 mn) and tissue type plasminogen activator (rt PA: 10 mg bolus followed by 90 mg in 130 mn). Clinical evolution, side effects, patency of the artery responsible for infarction, left ventricular contractile function (contrast angiography on the 7th day and angioscintigraphy on the 21st day) and infarct size were studied. The two groups were comparable in age (54 +/- 11 years), delay in randomisation (170 +/- 50 mn), infarct site and severity of cardiac failure. There was no significant difference in hospital mortality (7 in the rt PA group and 5 in the APSAC group) or in adverse effects (haemorrhage: rt PA: 9 patients, APSAC: 11 patients). The patency was 72% in the APSAC and 76% in the rt PA group. Left ventricular function and infarct size were comparable in the two groups: angiographic EF (0.50 +/- 0.1 in the APSAC and 0.52 +/- 0.1 in the rt PA group: NS); asynergic score (11.3 +/- 1.7 in the APSAC and 10.5 +/- 1.8 in the rt PA group: NS); infarct size (10.9 +/- 8.0 in the APSAC and 9.4 +/- 7.2 in the rt PA group: NS). This trial shows that these two thrombolytic agents have the same efficacy. The authors recommend adaptation of the dosage of rt PA to body weight.

Anomalous origin of the left coronary artery from the main pulmonary trunk results in myocardial ischemia or infarction, and may be a cause of death in the first months of life. Some patients, however, develop satisfactory coronary collateral circulation and remain asymptomatic into adulthood. In these patients, myocardial perfusion and left ventricular function are not well understood. We report the case of a 17-yr-old female patient, suffering from anomalous origin of the left coronary artery from the main pulmonary trunk, who underwent reimplantation of the left coronary artery to the aorta. The preoperative permanent 201Tl defect of the left antero-lateral ventricular wall and the abnormal regional wall motion induced by stress exercise testing were fully reversed after the operation.

Resting and stress radionuclide angiography was performed before and, on average, one year after surgery for adult aortic stenosis in 26 patients. The left ventricular ejection fraction, ventricular volumes, left ventricular stroke volume and peak velocity of ventricular filling were studied under basal conditions and at the peak of exercise. Right and left heart catheterisation and coronary angiography were performed before surgery with determination of the conventional indices of left ventricular function. Investigations were completed by pre and postoperative echocardiography. The same procedures were carried out in a control population of the same age. Before surgery, hemodynamic adaptation to exercise, judged by the change in left ventricular stroke volume, solicits the passive properties of the left ventricle: the left ventricular stroke volume increases by an increase in the end diastolic volume. In the control group, the increase in stroke volume is obtained by a decrease in end systolic volume, that is to say by increasing systolic shortening. The peak velocity of ventricular filling increases on exercise but to a lesser degree than in the control population. After surgery the hemodynamic adaptation to exercise results from an improved systolic shortening of the left ventricle but also from an increase in end diastolic volume. The peak velocity of left ventricular filling increases with respect to the preoperative values but remains less than that observed in the control population. No relationship was observed between the hemodynamic adaptation to exercise, the peak velocity of ventricular filling and myocardial mass whichever method was used for calculating the latter parameter.(ABSTRACT TRUNCATED AT 250 WORDS)

An automated process for the detection of the left ventricular end diastolic contour is defined. The extraction of a pure left ventricular behavior, obtained by the application of the Gram-Schmidt orthogonalization process on a set of vectors representing the three main typical behaviors present in the scintigraphic sequence, yields the synthesis of a new factorial image particularly matched for the extraction of the left ventricular region of interest (ROI). An edge following technique with conditional dilation applied simultaneously on the two binary images resulting from processing the new left ventricular factorial and the average images with a Laplacian operator gives a robust method for the detection of the left ventricular ROI.

We have excised six cases of osteoid osteoma in children, by using intra-operative accurate radioactive localization. The value of this technique is considerable and allows a better localization of the lesion. Exact detection and elective excision are the two advantages of this technique. We are reporting these case and describing the equipment being used.

The venous outflow curve obtained using strain gauge plethysmography (Periflow JSI) frequently displays a slope change which modifies the classic exponential pattern: The semi-continuous arterial blood flow measurement together with an ECG-triggered plethysmography let the authors show the arterial origin of this slope change they called "the rebound phenomenon". Venous occlusion induces an ischemia which creates a reactive hyperemia when the venous blood current is let free. All the venous outflow curves stem from both a venous and arterial phenomenon. This latter may sometimes be of importance and has to be considered in plethysmography studies.

Regional and global left ventricular wall motion was assessed in 120 patients using radionuclide cineangiography (RCA) and contrast angiography. Functional imaging procedures based on a temporal Fourier analysis of dynamic image sequences were applied to the study of cardiac contractility. Two images were constructed by taking the phase and amplitude values of the first harmonic in the Fourier transform for each pixel. These two images aided in determining the perimeter of the left ventricle to calculate the global ejection fraction. Regional left ventricular wall motion was studied by analyzing the phase value and by examining the distribution histogram of these values. The accuracy of global ejection fraction calculation was improved by the Fourier technique. This technique increased the sensitivity of RCA for determining segmental abnormalities especially in the left anterior oblique view (LAO).

Peeling method and a non linear regressions method (Newton's method) have been tested on experimental and simulated data. Newton's method is the most accurate and precise when running on simulated data. Experimental curves artefacts make Newton's algorithm automatically running less efficient than classical peeling algorithm working in interactive mode.

Previous studies have shown that variations of the ejection fraction (EF) during exercise were representative of the contractile state of the left ventricle: an increased EF on effort is considered to be physiological, whilst a decrease would indicate latent LV dysfunction unmasked during exercise. This hypothesis was tested by performing Technetium 99 gamma cineangiography at equilibrium under basal conditions and at maximal effort in 8 healthy subjects and 44 patients with pure, severe aortic regurgitation to measure the ejection and regurgitant fractions and the variations in end systolic and end diastolic LV volume. In the control group the EF increased and end systolic volume decreased significantly on effort whilst the regurgitant fraction and end diastolic volume were unchanged. In the 44 patients with aortic regurgitation no significant variations in EF, end systolic and end diastolic volumes were observed because the individual values were very dispersed. Variations of the EF and end systolic volume were inversely correlated. The regurgitant fraction decreased significantly on effort. Based on the variations of the EF and end systolic volume three different types of response to effort could be identified: in 7 patients, the EF increased on effort and end systolic volume decreased without any significant variation in the end diastolic volume, as in the group of normal control subjects; in 22 patients, a reduction in EF was observed on effort, associated with an increased end systolic volume. These changes indicated latent IV dysfunction inapparent at rest and unmasked by exercise; in a third group of 15 patients, the EF decreased on effort despite a physiological decrease in end systolic volume due to a greater decrease in end diastolic volume.(ABSTRACT TRUNCATED AT 250 WORDS)

To test the clinical validity of the stroke volume ratio (SVR) and the factors influencing its value we determined it in a population of 41 patients free of valvular regurgitation. The SVR was estimated from multigated blood pool scans in left anterior oblique position by two methods. The first method followed the classical formula of the left to right ventricular stroke count ratio. The second method used the same formula except that the right atrial activity emanating from the area of right atrioventricular overlap as traced at right ventricular end-systole, was subtracted from the right ventricular stroke count. The SVR averaged 1.25 +/- 0.18 (range 0.97-1.80) by the first technique and 1.05 +/- 0.12 (range 0.82-1.36) by the second (P less than 0.001). In our results the SVR is not correlated to either ejection fraction or angiographically determined left ventricular volumes. Conversely the SVR is correlated with the left to right end-diastolic volume ratio evaluated from radionuclide counts measured at right and left ventricular end-diastole (r = 0.48, P less than 0.01). This may be due to variations in the area of right atrioventricular overlap, depending on the size of the ventricular chamber. It is postulated that the accuracy of SVR determination could be enhanced by subtraction of the right atrial activity from the right ventricular activity at end-systole. In patients free of valvular regurgitation the LV/RV stroke volume ratio approaches unity and the variability of the results is smaller. Interobserver and intraobserver variability is reduced using the Fourier phase approach.

Photoplethysmography, cutaneous blood flow measurement by Xenon 133 were carried out before and after resolution by Puva therapy on a lesion and on the symmetrical healthy skin area of 29 psoriatic subjects. The increase of the blood pulsatility and cutaneous blood flows found before treatment, disappears after resolution. The correlation between the two methods is studied.

The authors suggest a new way of determining ventricular volume by a non-geometric method using gamma-cineangiography. The results obtained by this method were compared with those obtained by a geometric methods and contrast ventriculography in 94 patients. The new non-geometric method supposes that the radioactive tracer is evenly distributed in the cardiovascular system so that blood radioactivity levels can be measured. The ventricular volume is then equal to the ratio of radioactivity in the LV zone to that of 1 ml of blood. Comparison of the radionuclide and angiographic data in the first 60 patients showed systematic values--despite a satisfactory statistical correlation (r = 0.87, y = 0.30 X + 6.3). This underestimation is due to the phenomenon of attenuation related to the depth of the heart in the thoracic cage and to autoabsorption at source, the degree of which depends on the ventricular volume. An empirical method of calculation allows correction for these factors by taking into account absorption in the tissues by relating to body surface area and autoabsorption at source by correcting for the surface of isotopic ventricular projection expressed in pixels. Using the data of this empirical method, the correction formula for radionuclide ventricular volume is obtained by a multiple linear regression: corrected radionuclide volume = K X measured radionuclide volume (Formula: see text). This formula was applied in the following 34 patients. The correlation between the uncorrected and corrected radionuclide volumes and the angiographic volumes was improved (r = 0.65 vs r = 0.94) and the values were more accurate (y = 0.18 X + 26 vs y = 0.96 X + 1.5).(ABSTRACT TRUNCATED AT 250 WORDS)

One hundred seven patients who recently had acute myocardial infarction were randomly assigned either to standard heparin therapy or to intravenous streptokinase within 5 hours after the onset of symptoms in 7 hospitals without catheterization facilities. In the third week, the patients were referred to a university hospital, where the patency rate of the infarct-related artery was studied by selective coronary arteriography and left ventricular function by radionuclide angiography. Fifty-five patients received heparin and 52 streptokinase within a mean period of 190 minutes after the onset of symptoms. Seven patients in the heparin group and 4 in the streptokinase group died in hospital. The patency rate of the infarct-related artery was identical in both groups (69% in the heparin group vs 68% in the streptokinase group). Left ventricular ejection fraction was not statistically different (0.44 +/- 0.13 in the heparin group vs 0.45 +/- 0.12 in the streptokinase group). Left ventricular ejection fraction was significantly higher in patients with a patent infarct-related artery than in patients with an obstructed infarct-related artery (0.49 +/- 0.12 vs 0.41 +/- 0.15, p less than 0.01). In patients with inferior wall infarction, left ventricular ejection fraction was identical (0.50 +/- 0.10 in the heparin group vs 0.52 +/- 0.09, in the streptokinase group). In patients with anterior wall infarction, left ventricular ejection fraction was significantly higher in the streptokinase group than in heparin group (0.40 +/- 0.10 vs 0.33 +/- 0.09, p less than 0.05). Analysis of regional wall motion revealed that improvement occurred in the lateral wall of the left ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)

The cutaneous and subcutaneous blood flow measurement by a diffusible inert gas concerns theorically capillary nutritional flow. In clinical routine, where pathological openning of arteriovenous anastomosis is suspected, the blood flows measured by Xenon technic are often increased. The function of the shunts are displayed on the epuration curve obtained on a region where there are numerous: rabbit's ear.

A multicentre randomised therapeutic trial was undertaken in 8 hospitals in the Franche-Comté department of France (Belfort, Besançon, Dole, Lons-le-Saunier, Luxeuil, Montbéliard, Vesoul, Pontarlier) in which 101 patients with acute primary myocardial infarction were treated within 5 hours of onset of symptoms with either intravenous streptokinase (1,500,000 U in 30 mn) or conventional heparin therapy. The results were assessed on the clinical outcome, arterial patency in the necrosed territory and global and regional ejection fractions (EF) at the 3rd week. After randomisation, 51 patients were given heparin and 50 received streptokinase. Seven patients died in the heparin group and 4 in the streptokinase group (NS). At the third week, the artery in the necrosed zone was patent in 69% of the heparin group and in 68% of the streptokinase group (NS). The EF was significantly higher in the patients with patent arteries in the necrosed zone than in those with occluded arteries (0.49 +/- 0.12 vs 0.41 +/- 0.15, p less than 0.01). There was no significant difference in EF between the heparin and streptokinase groups. The EF was significantly higher in patients with anterior infarction who received streptokinase than in those who received heparin (0.40 +/- 0.10 vs 0.33 +/- 0.09 p less than 0.05). Segmental wall motion was significantly better at the apex and free wall. There was no significant difference between the two groups in posterior infarction. These results show that reestablishment or maintenance of arterial patency in the necrosed zone improves left ventricular function and that patients with anterior wall infarction are the ones most likely to benefit from streptokinase therapy.

Left ventricular ejection fraction (LVEF) and regional wall motion abnormalities were determined in 40 patients (30 with coronary artery disease and 10 with valvular heart disease) using equilibrium radionuclide angiography. Scintigraphic acquisitions were collected in random order with 2 different collimators as follows: in anterior face (AF), left anterior oblique (25 degrees-45 degrees LAO) and 70 degrees LAO, with a vertical parallel hole collimator (VTC), and in 25 degrees-45 degrees LAO and 65 degrees-80 degrees LAO with a 30 degrees rotating slant hole collimator (RSHC), with the slant of the collimator directed towards the cardiac apex in both projections. Results were compared to contrast ventriculography (CV) performed in the 30 degrees right anterior view (3 segments: anterior, apical, inferior) and in a 60 degrees left anterior oblique view (3 segments: septal, apical and lateral). Radionuclide LVEF in both series was closely correlated with contrast ventriculographic LVEF (r = 0.89, VTC vs CV and r = 0.87, RSHC vs CV, respectively). Regional wall motion analysis was only performed among the 30 patients suffering from coronary heart disease. Eight contrast angiographic studies were normal and 22 abnormal. Global sensitivity and specificity were 100% and 63% with the VTC (3 false positives) and 91% and 87% with the 30 degrees RSHC (2 false negatives and 1 false positive, P = ns). Agreement for the localisation of the regional wall motion abnormalities between CV and radionuclide angiography was 70.6% with the VTC and 71.2% with the RSHC (P = ns).(ABSTRACT TRUNCATED AT 250 WORDS)

The diffusion of radioactive inert gas xenon 133 through the epidermis in man was studied by compartimental model with a constant speed injection. From this we deduce the cutaneous and subcutaneous flow.

In a multicenter randomized double-blind trial comparing heparin and a new fibrinolytic agent, anisoylated plasminogen streptokinase activator complex (APSAC), 231 patients presenting with a less than 5 hr acute myocardial infarction underwent a contrast angiography (CA) before the end of the first week of admission, and radionuclide cardiac blood-pool imaging and a 201Tl single photon emission computed tomography (SPECT) study before the end of the third week. Left ventricular ejection fraction (LVEF) and a wall motion score (WM) were calculated from CA. LVEF was also obtained from cardiac blood-pool imaging, and defect size (DS) from 201Tl SPECT. Results demonstrated that all parameters were significantly improved in patients treated with APSAC versus heparin (contrast LVEF 53 +/- 13 vs. 47 +/- 14 p less than 0.01, WM 9.8 +/- 6.5 vs. 13.3 +/- 7.9 p less than 0.001, radionuclide LVEF 43 +/- 12 vs. 40 +/- 13 p less than 0.05, DS 14 +/- 12 vs. 18 +/- 14 p less than 0.05). When the patients were divided according to infarct site and infarct-related coronary artery patency, it was demonstrated with all four parameters that the beneficial effect of APSAC can be largely explained by the lower incidence of vessel obstruction in this group (37% vs. 77% in the heparin group, p less than 0.001). It is concluded that (a) when compared with heparin and in the conditions of the trial, APSAC significantly improves the cardiac function and decreases the DS and (b) DS measured by 201Tl SPECT is as valuable a quantitative parameter of therapeutic evaluation as are LVEF and WM.

This article develops two contrast-modification techniques for the display of scintigraphic images. Based on histogram-modification techniques, histogram equalization, where each level of gray is used to the same extent, gives maximum entropy. The first technique uses the application of histogram equalization in the whole image. To eliminate contrast attenuation small but important portion of the gray scale histogram, local area histogram equalization has been applied to images with differences in intensity. Both techniques were tested using a phantom with known characteristics. The global equalization technique is more suitable to bone scintigraphies, and some well-chosen boundaries improved the difference between two comparable areas. For liver scintigraphies, where intensity is quite equal in every pixel, a local area equalization was chosen that allowed detection of heterogeneous structures. The images resulting from histogram-equalization techniques improve the readability of data, but are often far from usual images and necessitate an apprenticeship for the physician.

We have excised four osteoid osteomas in four children, aided by intraoperative radioactive localization. Here we report these cases and describe the equipment used. Exact detection and elective excision are the two advantages of this technique.

Fifty-two patients with a symptomatic chronic aortic insufficiency underwent radionuclide angiography. The following parameters were measured at rest and at peak exercise: ejection fraction, regurgitant fraction, ventricular volumes, stroke volume, cardiac output and an index of systemic arterial resistance. The ventricular dimensions, the thickness of the septal and posterior walls, left ventricular myocardial mass and endsystolic stress were determined by 2D echocardiography. The patients were divided into 3 groups based on left ventricular changes on exercise: the first group (18 patients) had physiological left ventricular adaptation to exercise (increased ejection fraction, reduced endsystolic volume); a second group of 18 patients had moderate left ventricular dysfunction (absence of increase in ejection fraction and a reduction of less than 20% of endsystolic volume with respect to basal values); a third group of 17 patients had what was considered to be severe left ventricular dysfunction (decreased ejection fraction of over 5% and increased endsystolic volume of over 20% with respect to basal values). There was no significant difference between the three groups with respect to basal values of ejection fraction, ventricular volumes and systemic arterial resistance. On exercise, the heart rate, blood pressure and systemic arterial resistances varied in a comparable manner in each of the three groups. The left ventricular dimensions and myocardial mass were identical in the three groups. Only left ventricular endsystolic strain tended to be higher in the third group of patients compared with the other two, but the difference was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

The index of valvular regurgitation was measured by two techniques after technetium 99 m gamma-cineangiography: the classical technique of comparing left and right ventricular stroke volumes, and the same technique after subtracting the radioactivity arising from the right atrium from the zone of right atrioventricular superposition. The index of valvular regurgitation was calculated in 41 patients with chronic coronary artery disease without valvular regurgitation and also undergoing coronary angiography with 30 degrees right anterior oblique ventriculography, in 8 healthy volunteer subjects, at rest and on exercise; and in 15 patients with chronic aortic regurgitation also undergoing cardiac catheterization and 30 degrees right anterior oblique left ventriculography and aortography. The regurgitant index by the classical technique was 1,25 +/- 0,18; when the index was calculated again after subtracting right atrial radioactivity, a value of 1,05 +/- 0,12 (p less than 0,01) was obtained. The regurgitant index is not affected by left ventricular contractility or by the degree of left ventricular dilatation. On the other hand, this index is affected by the degree of right ventricular dilatation. The valvular regurgitant index did not vary significantly on exercise (1,01 +/- 0,11 to 1,17 +/- 0,16 NS). The isotopic regurgitant fraction deduced from the valvular regurgitant index correlated well with the angiographic regurgitant fraction (R = 0,74; p less than 0,001). The index of valvular regurgitation gives an exact, reliable and reproducible quantification of left sided regurgitant lesions. It is only valid when there is no intracardiac shunt or regurgitant right heart lesion.

The influence of left ventricular volume variations and regurgitant fraction variations upon left ventricular ejection fraction during exercise was examined using equilibrium radionuclide angiography in patients suffering from aortic regurgitation. Ejection fraction (EF), regurgitant fraction (RF), end diastolic volume (EDV) and end systolic volume (ESV) variations from rest to peak exercise were determined in 44 patients suffering from chronic aortic regurgitation (AR) and in 8 healthy volunteers (C). In C, EF increased (+0.10 +/- 0.03, P less than 0.01) and ESV decreased significantly (-23% +/- 12%, P less than 0.01), RF and EDV did not vary significantly. In AR patients, EF, EDV and ESV did not vary significantly because of important scattering of individual values. Changes in EF and ESV were inversely correlated (r = -0.79, P less than 0.01) and RF decreased significantly (-0.12 +/- 0.10, P less than 0.01). Volumes and EF changes during exercise occurred in three different ways. In a 1st subgroup of 7 patients, EF increased (+0.09 +/- 0.03, P less than 0.05) in conjunction with a reduction of ESV (-24% +/- 12%, P less than 0.05) without a significant change in EDV. In a 2nd group of 22 patients, EF decreased (-0.04 +/- 0.07, P less than 0.01) in association with an increase in ESV (+17% +/- 16%, P less than 0.01) and no change in EDV. In a 2nd group of 22 patients, EF decreased (-0.04 +/- 0.07, P less than 0.01) in association with an increase in ESV (+17% +/- 16%, P less than 0.01) and no change in EDV. In a 3rd subgroup of 15 patients, EF decreased (-0.02 +/- 0.06, P less than 0.01) despite a reduction in ESV (-7% +/- 6%, P less than 0.01) because of a dramatic EDV decrease (-10% +/- 6%, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The left ventricular volumes, the left ventricular ejection fraction, the stroke volume index and the cardiac index were non-invasively determined in 47 patients suffering from moderate to severe pure aortic stenosis using radionuclide angiography at rest and at peak supine exercise. Each patient was previously submitted to right and left heart catheterization and to selective coronary angiography. The left ventricular ejection fraction decreased significantly during exercise (0.62 +/- 0.09 to 0.59 +/- 0.09, P less than 0.01). End-systolic volume, end-diastolic volume, stroke volume index and cardiac index increased significantly. The stroke volume variations were linked to the end-diastolic volume variations by a strong relationship (r = 0.84, P less than 0.001) and to left ventricular mass by a weak, but significant, inverse relationship (r = -0.42, P less than 0.05). No relation existed between stroke volume index variations and any other variables, particularly systolic gradient, aortic valve area and resting left ventricular ejection fraction. The results suggest that, in aortic stenosis, the adaptation of the left ventricular pump function during exercise is mostly dependent upon the diastolic properties of the left ventricular wall and is limited by the progression of left ventricular hypertrophy, i.e. diastolic stiffness. By contrast, the role of the basal systolic pump function and of the severity of the valvular obstruction seems of limited importance.

Exercise-induced changes in haemodynamic values were studied by radionuclide ventriculography in 21 patients with permanent systolic dysfunction (15 with non-obstructive cardiomyopathy and 6 with ischaemic heart disease). The results were compared with those obtained in 8 control subjects with normal heart. In healthy subjects, during exercise the ejection fraction increased due to constant diminution of the end-systolic volume; the end-diastolic volume and the systolic ejection volume did not significantly vary; the cardiac output augmented only because of the accelerated heart rate. In patients with permanent left ventricular dysfunction, the ejection fraction remained unchanged during exercise, whereas the end-systolic volume increased significantly. Yet the systolic ejection volume increased due to a rise in end-diastolic volume. Heart rate and cardiac index increased, but not as much as in normal subjects. There was a close correlation between changes in end-diastolic and end-systolic volumes. It was the relative importance of changes in these two ventricular volumes that determined the direction and amplitude of variations in ejection fraction. It is concluded that in patients with permanent left ventricular dysfunction: (1) the end-systolic volume increases during exercise, thus betraying a worsening of the systolic dysfunction; (2) however, the systolic ejection volume is maintained or increases due to an increase in end-diastolic volume; (3) the changes in ejection fraction observed during exercise are of little value to characterize the modifications that occur in left ventricular work performance.

The anti-ischaemic activities of atenolol (200 mg) and diltiazem (240 mg) were compared in 23 patients undergoing retraining 4 weeks after a limited postero-inferior or anterior primary myocardial infarction. The patients, who had signs of residual ischaemia during stress with or without angina, were subjected to 3 exercise tests on a bicycle ergometer; a computer was used to analyze the results (Case-Marquette). The first test was performed under placebo, the second after randomized treatment with one of the two drugs and the third test after taking the other drug. The parameters evaluated were: total duration of the test, time of occurrence of a 1 mm ST-segment depression, maximal work load and total work performed, heart rate, systolic arterial pressure, heart rate X systolic arterial pressure product at rest and at submaximal and maximal stress, and ST depression at submaximal and maximal stress. The results showed that exertion was improved to the same degree by the two drugs, but atenolol had greater anti-ischaemic activity than diltiazem.