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Biomedical subjects

H Lafont

Publications and source records attributed to H Lafont.

At least 163 records · Page 9Linked to original sources

[Indications for prosthetic replacement of the aortic valve].

There is no controversy about the prosthetic replacement of the aortic valve in cases in which there is a disorder of function or cardiac failure, or in cases with a tight aortic stenosis, even if it appears to be well-tolerated clinically. It is especially critical in cases of aortic incompetence with marked cardiac enlargement, but the problems are not overwhelming. The indications for operation in very advanced cases with cardiac failure which is refractory, or in aged patients, are discussed.

Age Factors↗

[Selective coronary scintigraphy using labelled microspheres].

Selective intracoronary injection of microspheres labelled with radioactive substances which emit gamma rays with different energy levels (Indium 113 m and Technetium 99 m) allows us to explore by scintigraphic methods the areas of distribution of the two coronary arteries. Having been carefully calibrated, the particles are injected in limited numbers, and block the precapillary arterioles, where they gradually diminish in number. Scintigraphic examination is carried out in various projections (anteroposterior, left anterior oblique and right anterior oblique) immediately after coronary arteriography. Coronary scintigraphy allows us to establish the integrity of the distribution network of a coronary trunk which appears normal on coronary arteriography, to visualise the diminution of flow caused by a stenosed but patent trunk, and to visualise the extent of the collateral circulation and the quality of revascularisation achieved by an aorto-coronary bypass operation.

Angina Pectoris↗

[Aortopulmonary fistula with interventricular defect and pulmonary valve stenosis in a 15-year-old girl. Surgical correction].

A young girl of 15 with an aorto-pulmonary fistula was treated surgically, with a successful outcome. The clinical diagnosis could only be established at right-sided catheterisation, and especially at retrograde per-arterial aortography. The small size of the fistula explains the low level of the pulmonary arterial hypertension, and the way in which the condition was well-tolerated for some time. The association of this lesion with ventricular septal defect and pulmonary stenosis is extremely rare.

Adolescent↗

[Diastolic compliance and indices of contractibility in aortic insufficiency].

A cine-angiographic study was carried out in eleven patients with major aortic incompetence, in two of whom there was an associated aortic stenosis. The ventricular end-diastolic volume is always greatly increased, disproportionately to the modest increase in end-diastolic pressure. The pressure-volume relationship during filling is therefore altered, and makes it possible for a normal end-diastolic compliance (dV/dP) TD to be preserved. The indices of contractility are markedly altered, despite the recent appearance of signs of poor tolerance. These findings argue in favour of a full haemodynamic investigation and of early corrective surgery.

Adult↗

[Radioisotope measurement of left ventricular ejection fraction. Comparison with results of cineangiocardiography].

The combination of radiocardiography with scintigraphy of the cavities of the heart allows us to calculate the effective systemic ejection fraction. The systolic volume effectively ejected into the systemic circulation is obtained from radiocardiography using Stewart-Hamilton's principle. It is correlated with the left ventricular end-diastolic volume as calculated by planimetry on the scintigraphic record of the cavities of the heart, making due allowance for the geometrical axis of the heart. The ejection fraction measured by this isotope method has been compared with the ejection fraction measured by selective left ventricular cineangiography, both measurements being carried out at an interval of less than 48 hours in 100 patients without valvular disease. The results show an excellent correlation between the two methods (r = 0.94). In the 15 cases where the haemodynamic status of the ventricule appeared to be normal, the ejection fraction meastured by the two techniques was 0.65 +/- 0.04 and 0.66 +/- 0.04 respectively. In those patients with valve disorders with incompetence, the effective systemic ejection fraction is always lower than the total ejection fraction given by cineangiography. The difference corresponds with the fraction of the blood volume which is regurgitated.

Angiocardiography↗

[Contractility and diastolic complicance of the left ventricle in patients with coronary insufficiency without myocardial necrosis].

The 19 coronary patients studied were found to have a "normalised" rigidity k = dp/(dVP) identical to that of normal subjects, and a lowered instantaneous end-diast-lic compliance (dV/dP)TD. The increase in end-diastolic pressure is due to a small increase in end-diastolic volume, and brings about Starling's phenomenon to compensate for a diminution in contractility. The maximimum speed of shortening of the myocardium (VCFmax) shows up the baseline contractility, and appears to be more sensitive than the mean speed of myocardial shortening (VCF) and the ejection fraction.

Adult↗

[Supravalvular ring type aortic stenosis with hypoplasia of the ascending aorta and stenosis of the origin of the innominate artery. Surgical correction].

The authors report the case of a 19 year old woman with supravalvar aortic stenosis and hypoplasia of the ascending aorta with stenosis at the origin of the innominate artery. This was a sporadic form, without mental deficiency nor facial dysmorphia. No similar case was found in the family. The patient had three attacks of bacterial endocarditis over a period of 3 years and became cured without any cardiac sequelae. In view of the onset of left ventricular failure and sequelae. In view of the onset of left ventricular failure and syncope, operation was decided. A lozange-shaped patch was placed on the aorta from the narrowed supravalvar part to the origin of the innominate artery and prolonged on the latter vessel after relief of the stenosis. This gave an excellent result.

Adult↗

[Unruptured aneurysms of Valsalva sinus of septal origin].

Aneurysms of Valvsalva sinus unruptured into a cavity, but developing into the membranous and even muscular interventricular septum are exceptional. Two cases illustrating this fact are reported. In one of them, a massive mitral incompetence by elongated chordae tendinae related to the presence of a voluminous intra-septal pouch. Atrio-ventricular and intraventricular conduction disturbances were present in both patients. The interest of supra-valvar angiography which makes it possible to advise operation before the eventual rupture is underlined.

Adult↗