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Biomedical subjects

J Ohayon

Publications and source records attributed to J Ohayon.

At least 37 records · Page 2Linked to original sources
PubMed1986

[Correlations between vectorcardiographic data and effect of myocardial infarction on global and regional left ventricular function].

The object of this study was to identify vector-cardiographic parameters (VCG) dependant on the size of myocardial infarction and its consequences on segmental left ventricular wall motion. Forty-five patients were selected for study after a complete haemodynamic investigation including quantitative analysis of LV wall motion. They were divided into three groups: Group I, comprising 15 normal control subjects; Group II, comprising 16 patients with abnormal LV wall motion related to anterior wall infarction due to a solitary lesion of the left anterior descending artery; Group III, comprising 14 patients with abnormal LV wall motion related either to posterior wall infarction or inferior wall infarction due to a solitary lesion of the right coronary or left circumflex arteries. Segmental wall motion was analysed by a semi-automatic programme derived from the Standford method. This programme detects the number of pathological segments in a ventricle and their shortening, and also determines a coefficient of severity of the abnormal zone. The VCG was performed according to Frank's principle and exploited using the computerised Arnaud RUBEL system. The characteristics of the instantaneous vectors were determined every 10 ms up to 60 ms: X, Y and 2 coordinates, amplitude, azimuth and elevation. These coordinates were compared with the segmental wall motion in every patient. There was a close correlation between LV regional wall motion abnormalities and the deflection of the initial vectors (during the first 40 ms) in the horizontal and frontal planes. A ROC statistical analysis showed that VCG was an excellent method of detecting abnormal LV wall motion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Hemodynamic course during fibrinolysis in severe pulmonary embolism].

Seventy seven cases of severe pulmonary embolism (Miller index greater than 13 points) including 61 acute (under 5 days) and 16 subacute episodes, underwent continuous haemodynamic monitoring during treatment with either urokinase 2 000 U/kg/h for 24 hours with heparin (Group I: 18 patients), or urokinase 4 500 U/kg/h for 12 hours without heparin (Group II: 47 patients), or with streptokinase 2 00 000 U over 10 hours (Group III: 12 patients). Efficacy was defined as greater than 20% improvement of Miller index at control angiography after 48 hours (Group I: 10 patients, Group II: 31 patients, Group III: 8 patients). In the 49 patients (63%) with good results, the Miller index fell by about 50% with a significant increase in cardiac index (20%) from the 12th hour. There was a concomitant fall in pulmonary systolic arterial pressure (35%). In the 28 patients (37%) with partial improvement a 20% increase in cardiac index and an 18% fall in pulmonary systolic arterial pressure were observed only in the high dose urokinase group, despite incomplete pulmonary revascularisation demonstrating the vasodilator effect of this protocol. Fibrinolysis was repeated in the patients with incomplete results or a Miller index of over 13 points, leading to improvement in 78% of patients. Accelerated lysis of pulmonary embolism leads to rapid normalisation of haemodynamic parameters and improves the prognosis of massive pulmonary embolism by reducing the number of recurrences and the mortality rate (4%).

Acute Disease↗
PubMed1986

[Isolated stenosis of the left anterior descending coronary artery and regional function of the left ventricle].

This study compared regional and global left ventricular function of a population of patients with a stenosis of the left anterior descending (LAD) artery and a control population in a prospective 18 months protocol. The 25 patients in the LAD group, 21 men and 4 women (55 +/- 9 years), had a pure and isolated stenosis of the LAD artery (70 +/- 8%) without infarction with normal global systolic function. The 12 patients in the control group strictly no cardiovascular disease after extensive investigation. Cardiac catheterisation was carried out in the conventional manner under the same conditions in both groups, after withdrawal of all medication. Regional wall motion was studied on 30 degrees right anterior oblique selective left ventriculography by a technique derived from Ingel's method using every frame of a cycle in terms of amplitude, velocity and time of segmental shortening and lengthening. The patients in the LAD group had normal cardiac function and no hypo or akinesia. The principal characteristic was the finding of anterior wall asynergy which was significantly different from the uneven contraction common in control subjects. This asynergy is observed from the end of systole to early diastole and features: early termination of anterior wall contraction (normalised contraction time: 86 +/- 13% vs 97 +/- 4% in the control group; p less than 0.02; and 90% in the inferior zone, NS, compared with the control group and p less than 0.05 compared with the anterior wall); dephased velocities of segmental shortening at the end of ejection (positive velocities in the inferior zones 0.17 +/- 1.7 circ/sec and negative velocities in the anterior zones, -0.34 +/- 2.2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Hemodynamic study of the elderly subject. Indications, risks and value].

The authors record all the hemodynamic evaluations realised on aged population above severity years during two years (549 patients) representing ten per cent of the whole investigations in an hemodynamic department. The greater part of the indications were severe coronaritis resistant to medical treatment (54 percent) with unstable angina or steady state angina, and valvulopathy (37 percent) with prevalence of symptomatic aortic stenosis. The catheterization incidents and accidents do not appear more owing to the high risk pathology and to the taken precautions. The lethal accident frequency is three point five per thousand little above the frequency in a general catheterized population (two per thousand). Seldinger difficulties are easily got over by using axillary passage in case of need. The surgical interest is underlined by the fact that sixty six percent of the investigated patients will be operated. The hemodynamic evaluation in aged population between 70 and 80 years is realizable in good conditions with little risk increase when it's necessary.

Aged↗
PubMed1985

[Effects of injectable calcium blockers on cardiac function and relaxation in left ventricular hypertrophy].

Nineteen patients with left ventricular hypertrophy were given intravenous calcium antagonists: 9 patients received intravenous verapamil (VPM IV) and 10 patients diltiazem (DTZ) by intracoronary and then intravenous injection. Systemic and pulmonary resistances, cardiac output, left ventricular and aortic pressures, isometric contractility, isometric relaxation and left ventricular compliance were studied in sinus rhythm, during atrial and then ventricular pacing at 120/min and finally after tachycardia before and after administration of calcium antagonists. Left ventriculography in the 30 degrees RAO projection in sinus rhythm was performed before and after injection of the calcium antagonists to study the variations in the end diastolic volume, mass and mass-volume ratio. Finally, frame by frame numerisation of the ventriculographies during systole and diastole helped evaluate variations in amplitude, time and velocity of fibre shortening or lengthening. The administration of the calcium antagonists did not have any significant effect on heart rate (-2.8 +/- 10 p. 100, NS) or indices of isometric contractility (delta Vmax + 4 +/- 43 p. 100, NS). Significant falls in systemic and pulmonary resistances (-15 +/- 23 p. 100, p less than 0.05 and - 26 +/- 32 p. 100, p less than 0.05, respectively) and an increase in systolic index (+ 15.5 p. 100 +/- 12 p. 100, p less than 0.01) were observed. The improvement in left ventricular ejection was independent of the variation in resistances but was closely related to variations of parameters of relaxation. The effects on volumic compliance and filling velocities were also closely related to variations in relaxation (p less than 0.05 and p less than 0.01). Calcium antagonists protected left ventricular ejection during supraventricular tachycardia and prevented the changes in left ventricular relaxation observed during arrhythmias and after tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Comparative effects of intracoronary fibrinolysis and conventional treatment of myocardial infarction].

57 patients with a complete coronary thrombosis were treated by intracoronary fibrinolysis during the first 6 hours of inaugural myocardial infarction. The artery was revascularised in 37 cases (65 p. 100). Eleven patients had isolated stenosis of the left anterior descending artery and 16 patients isolated stenosis of the right coronary artery. These patients were compared with 27 other patients admitted between the 6th and 18th hours of primary myocardial infarction treated conventionally, in whom coronary angiography performed between the 14th and 21st day after infarction showed isolated left anterior descending disease in 14 cases (9 thromboses and 5 stenoses) and isolated right coronary disease in 13 cases (7 thromboses and 6 stenoses). The haemodynamic data and heart rates were identical in both groups during control coronary angiography between the 14th and the 21st days. Global left ventricular function and regional wall motion were studied by 30 degrees right anterior oblique ventriculography using the Stanford method before fibrinolysis in the first group and at the end of the 3rd week in both groups. In LAD, repermeabilisation by fibrinolysis, significant improvements were observed in ejection fraction (EF p. 100 = 42 +/- 9 vs 50.6 +/- 14 p. 100, p less than 0.05); fractional shortening of the hypokinetic segment (FS p. 100 = 4.5 +/- 4.6 vs 12.4 +/- 8.8 p. 100, p less than 0.001), and in the number of hypokinetic or akinetic segments (6.0 +/- 1.1 vs 4.2 +/- 2.1, p less than 0.05). Segmental and global left ventricular function was much poorer in the group treated conventionally at the 21st day (EF p. 100 = 44 +/- 11 p. 100, p less than 0.05; FS p.t100 = 5.8 +/- 9.7 p.t100, p less than 0.05; number of diseased segments: 6.0 +/- 1.4, p less than 0.01). On the other hand, the improvement was less marked in patients with inferior wall infarction; the results in the two groups were comparable.

Adult↗
PubMed1985

[Normalization of the dimensions of the left ventricle as measured by echocardiography].

An M mode echocardiographic study was performed, of left ventricular dimensions and wall thickness in two series of normal (N1, N2) and pathological (P1, P2) subjects. In the more recent series (N2 = 40, P2 = 17) data acquisition was facilitated by tests deduced from the technique of ultrasound transit time. The parameters compared were based on: 1) the proportionality between fractional shortening and fractional thickening (N1: not significant; N2: p less than 0.001), 2) the relationship between systolic radius and wall thickness (linear correlation, r = 0.95, between N2 and P2). The slope seemed to be related to the initial condition of contraction, the ratio of end diastolic wall thickness/radius (N1: p less than 0.01). There are several ways of normalising myocardial surface of section in adults and children; the normal surface is related to body surface area (r = 0.87; p less than 0.001 between calculated and predicted values for a N2 mean of 9.3 +/- 0.06 cm2/m2). The end diastolic diameters and wall thicknesses correlated with body surface area but the coefficients were not as statistically significant due to physiological variations in chamber filling. The indexed myocardial surface was increased (p less than 0.001) in the pathological series. The introduction of these tests improves the reliability of echocardiographic data. The use of several measurements simultaneously allows normalisation of body surface area and increases the diagnostic efficacy.

Echocardiography↗
PubMed1984

Global left ventricular function and regional wall motion in pure mitral stenosis.

Global left ventricular function (LVF) and segmental wall motion of the left ventricle are registered in 113 patients presenting a pure mitral stenosis (MS) and in a control group of 50 individuals. The segmental wall motion is measured on the end-diastolic-end-systolic frames of the left ventricle, obtained from right anterior oblique (RAO) monoplane cineangiography. Measurement of the segmental wall shortening is performed using the Stanford method. Group 1 includes 68 patients (60% of the total number of patients studied). These patients show no pathological contraction abnormality. In this group, the global LVF is not different from the control group. Group 2 includes 45 patients (40% of the total) for whom contraction abnormalities are present: anterior hypokinesis in 20% of the cases (anterior area mean shortening (AAS) = 18 +/- 8%; p less than 0.001 vs. group 1 and control group), and posterior hypokinesis in 20% of the cases (posterior area mean shortening (PAS) = 9.8 +/- 5.8%, p less than 0.001 vs. group 1 and control group). In this group, global LVF is impaired; ejection fraction (EF) = 0.57 +/- 0.1% (p less than 0.001 vs. group 1); velocity of circumferential fiber shortening (VCF) = 1 +/- 0.3 circ/s (p less than 0.001 vs. group 1); enddiastolic pressure (EDP) = 11 +/- 5 mmHg (p less than 0.01 vs. group 1). Segmental contraction abnormalities appear to be the main factor involved in the global LVF impairment. Segmental wall motion abnormalities could be related to subvalvular fibrosis, or LV filling difficulties, or principally, to a possible interplay between the right and the left ventricles.

Adult↗
PubMed1984

Effects of contrast media used in angiocardiography on the mechanical performance and the relaxation of normal and ischaemic myocardium.

The aim of this study was to investigate the mechanisms of the cardiodepressive action of ionic and non-ionic contrast media currently used in coronary arteriography. Experiments carried out on isolated preparations of cat papillary muscle, treated with increasing concentrations of Telebrix 39, Radioselectan, Hexabrix and Iopamidol 370 and 300, on the one hand and, on the other hand, a pre-determined dose of Telebrix and Iopamidol 300 during hypoxia and subsequent reoxygenation, showed that, at constant Ca2+ concentrations: (1) The cardiodepressive effects of contrast media are correlated with the hyperosmolality that they induce. When osmolality was higher than 400 mOsm, all the products caused a reduction of the peak force (PF: 40.49 +/- 5.15%), the maximum velocity of contraction (Vmax: 39.85 +/- 3.66%) and of the peak velocity of relaxation (Vrelax: 23.30 +/- 2.20%) (P less than 0.01). The time to peak force (TPF), on the other hand, remained constant, whereas the half-relaxation time (THR) was increased. No significant differences were observed between these effects and those induced by control iso-osmolar solutions when the same osmolality was induced. In practice, however, the critical hyperosmolality value of 400 mOsm is never reached when using non-ionic contrast media such as Hexabrix and Iopamidol 300. This could explain the excellent tolerance to these substances. (2) During hypoxia and reoxygenation, the effect of hyperosmolality is more marked. Thus, the non-ionic contrast medium, Iopamidol 300 (340 mOsm), reduces the hypoxic contractility depression (PF: 53.10 +/- 2.60% compared to the control values of 47.60 +/- 5.00%, P less than 0.01), whereas, at the same dose, the ionic medium Telebrix is hyperosmolar (440 mOsm) and induces a more pronounced hypoxic depression of contractility (P less than 0.01). The critical hyperosmolality is never reached during ventriculography (320 mOsm), whatever the medium used, but it can be observed during coronary arteriography. It is, therefore, important to use non-ionic contrast media in the investigation of unstable angina and of acute myocardium infarction.

Angiocardiography↗
PubMed1984

Theoretical models in mechanics of the left ventricle.

Different rheological concepts and theoretical studies have been recently presented using models of myocardial mechanics. Complex analysis of the mechanical behavior of the left ventricular wall have been developed in order to estimate the local stresses and deformations that occur during the heart cycle as well as the ventricular stroke volume and pressure. Theoretical models have taken into account non-linear and viscoelastic passive properties of the myocardium tissue, when subjected to large deformations, through given strain energy functions or stress-strain relations. Different prolate spheroid geometries have been considered for such thick shell cardiac structure. During the active state of the contraction, the rheological behavior of the fibers has been described using different muscle models and relationships between fiber tension and strain, and activation degree. A forthcoming approach for bridging the gap between the knowledge of the muscle fiber microrheological properties and the study of the mechanical behavior of the entire ventricle, consists in including anisotropic and inhomogeneous effects through fiber direction field.

Animals↗
PubMed1984

Quantitative analysis of left-ventricular function using gated single photon emission tomography.

We describe a quantitative method that measures segmental motion of the left ventricle, using tomographic slices obtained by gated single photon emission tomography (GSPECT). These slices contain the major axis of the left ventricle and are presumed to show wall motion directed towards a center of contraction. Values of parameters describing segmental wall motion in GSPECT were obtained from 61 patients, who received a left cardiac catheterization 1 hr later. These values were compared with results of similar calculations applied to data from contrast ventriculography. We conclude that GSPECT allows a detailed and quantitative, noninvasive study of wall motion of all left ventricular segments, with high inter- and intraobserver reproducibility.

Angiocardiography↗
PubMed1984

[Left ventricular global and segmental function in pure mitral valve prolapse with poor tolerance for exertion].

Poor effort tolerance is observed in a small percentage of cases of idiopathic mitral valve prolapse (IMVP). The aim of this study was to assess the possible left ventricular dysfunction in such cases, responsible for poor effort tolerance. Left ventricular function and segmental wall motion were studied retrospectively in a group of 17 patients with IMVP. The patients, average age 53 +/- 12 years, had poor effort tolerance (ST segment depression of 2 to 4 mm in 15 cases, drop in blood pressure in 6 cases) justifying catheter and angiographic studies. All patients had IMVP confirmed on RAO left ventriculography. There was no associated mitral regurgitation or coronary artery disease. Left ventricular function was studied by parameters of global function (systolic and diastolic parameters, volume measurements) and by a quantitative study of segmental wall contraction. The method used for studying regional wall motion was an application of the Stanford method in which segmental shortening is studied over all the endocavitary contour of the LV during an angiographic cycle filmed at 50 frames/second in the RAO projection. The time and velocity amplitudes of wall motion were measured during systole and diastole. The same methodology was applied to 21 normal control subjects. The results showed abnormal volumic compliance and wall motion in the IMVP group. Asynergy was mainly confined to the antero-lateral wall of the LV. The amplitude of contraction was generally normal but the contraction was slower and finished earlier. In the same zone, relaxation was abnormally early and lasted longer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Hemodynamic effects of a new positive inotropic agent (AR-L 115 BS) in ischemic and nonischemic myocardiopathies].

AR-L 115 BS is an imidazo-pyridine derivative with a positive inotropic action associated with peripheral and coronary vasodilatory properties. The effects of intravenous administration (a bolus of 0,45 mg/kg/min) were studied in 19 patients in functional class III of the NYHA classification in the absence of any previous drug therapy. Twelve patients had a primary myocardiopathy and the other 7 had coronary artery disease with akinetic anterior walls. A Swan-Ganz thermodilution catheter and a Millar microtransducer were used to measure pressures (pulmonary artery, left ventricular, aorta) and cardiac output under basal conditions and then every 2 minutes during intravenous administration of AR-L 115 BS. Left ventriculography in the 30 degrees RAO plane was performed under basal conditions and at the end of the investigation to measure volumes, ejection fraction, volumic compliance and segmental wall motion by the Stanford method. A stable concentration of circulating AR-L 115 BS was obtained (1 500 ng/ml). The positive inotropic action of the drug was responsible for a significant increase of all ejectional indices (cardiac and systolic index X 24 p. 100, p less than 0.01; ejection fraction +14 p. 100, p less than 0.01), of all indices of isometric contractility (dP/dt max +25 p. 100, velocity of contractile elements +35 p. 100, V max +30 p. 100 (p less than 0.01) and of the velocity of circumferential fibre shortening (+65 p. 100, p less than 0.001). All segmental shortening was improved.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

[Left ventricular aneurysms. Prognostic study. Operative results].

Eighty three patients with symptomatic post-myocardial infarction left ventricular aneurysms (cardiac failure: 62 cases; angina; 41 cases; ventricular arrhythmias: 37 cases; systemic embolism: 8 cases) underwent surgery between 1975 and March 1981. Preoperative investigations comprised clinical examination, left heart catheterisation and ventriculography. End systolic and end diastolic volumes, ejection fraction velocity of circumferential fibre shortening, and the akinetic surface area were calculated firstly for the whole of the left ventricle and then for the contractile zones after hypothetical resection of the aneurysm. Selective coronary angiography was carried out in 75 patients. The results were as follows: 16 perioperative fatalities (19.2 p. 100): Group IA; 14 late deaths or not improvement after surgery (17 p. 100): Group IB; 53 patients had little or no symptoms after surgery (63 p. 100), Group II. The 5 year survival rats is 69.7 p. 100. Severe cardiac failure (Stages III or IV of the NYHA Classification) is associated with a poor prognosis (33 p. 100 mortality). The hemodynamic parameters of the whole ventricle (end diastolic volume, global ejection fraction) had little or no correlation with the outcome. The ejection fraction of the contractile zones was significantly lower in Groups IA and IB (0.39 +/- 0.08, and 0.41 +/- 0.05) than in Group II (0.51 +/- 0.05), p less than 0.001). When the ejection fraction of the contractile zone exceeded 0.45, good results were obtained in 90 p. 100 of cases. The velocity of circumferential fibre shortening was also a good prognostic index (0.63 +/- 0.18 in Group IA compared to 1.10 +/- 0.09 in Group II, p less than 0.001). On the other hand, the diastolic volume of the contractile zone was very variable in all three groups. Extensive coronary artery disease not treated surgically worsened the prognosis (50 p. 100 mortality in triple vessel disease.) Seven of the 8 patients operated during the acute phase of myocardial infarction (less than I month) died, but they all had very poor hemodynamic parameters.

Adult↗