Comparison between vertical parallel hole collimator and 30 degrees rotating slant hole collimator for assessing global and regional left ventricular function by radionuclide angiography.

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)

Factors influencing the variations of ejection fraction during exercise in chronic aortic regurgitation.

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)

[Anomalies in left ventricular systolic function disclosed by exercise testing in chronic aortic insufficiency. Study by cavitary scintigraphy]. / Les anomalies de fonction systolique ventriculaire gauche dévoilées par l'effort dans l'insuffisance aortique chronique. Etude par scintigraphie cavitaire.

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)

[Determination of ventricular volumes by a non-geometric method using gamma-cineangiography]. / Détermination des volumes ventriculaires par une méthode non géométrique utilisant la gamma-cinéangiographie.

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)

[Comparative anti-ischemic activity of atenolol and diltiazem. Crossed single-blind randomized study using a computerized exercise test]. / Activité anti-ischémique comparée de l'aténolol et du diltiazem. Etude randomisée simple aveugle croisée par épreuve d'effort informatisée.

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.

[Course of ejection fraction, regurgitation fraction and ventricular volumes during exertion in chronic aortic insufficiency. Study using technetium 99m gamma-cineangiography]. / Evolution au cours de l'effort de la fraction d'éjection, de la fraction de régurgitation et des volumes ventriculaires dans l'insuffisance aortique chronique. Etude par gamma-ciné-angiographie au technetium 99 m.

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)

[Method of isotopic determination of aortic valve regurgitation]. / Méthode de détermination isotopique des régurgitations valvulaires aortiques.

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.

Factors influencing the quantification of valvular regurgitation by gated equilibrium radionuclide angiography.

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.

Temporal Fourier analysis applied to equilibrium radionuclide cineangiography. Importance in the study of global and regional left ventricular wall motion.

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).

[So-called refractory hypoxemia: treatment with acexamic acid]. / Hypoxémies dites réfractaires: traitement par acide acéxamique.

Acexamic acid is currently used to avoid pulmonary fibrosis in patients treated with bleomycim. It seems to be equally effective to prevent pulmonary fibrosis in adult respiratory distress syndrome. The complications of this therapy are hypercalcemia and hypernatremia.