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Biomedical subjects

F Guérin

Publications and source records attributed to F Guérin.

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

Left ventricular ultrastructure in pulmonary stenosis and in tetralogy of Fallot.

Twelve patients underwent haemodynamic studies and myocardial biopsies: 7 with pulmonary stenosis (PS) and 5 with tetralogy of Fallot (TOF). Their ages ranged between 2 and 43 years. Right ventricular pressure was 128 +/- 43 mmHg in PS and 98 +/- 8 mmHg in TOF. Aortic blood oxygen saturation was 97.0% +/- 1.4% in PS, and 88.4% +/- 6.3% in TOF. Left ventricular (LV) weight was normal in TOF while it was increased in PS: 140.7 +/- 74.3 vs 74.0 +/- 8.7 g/m2 (P less than 0.001). Contractility was altered in both PS and TOF: ejection fractions were 56% +/- 7% vs 65% +/- 6% (P less than 0.001). Light microscopy showed abnormal transverse diameter of left ventricular myocytes in both PS and TOF: 18.6 micron +/- 4.0 micron vs 19.4 micron +/- 4.9 micron. The percentage of interstitium was normal: 29.6% +/- 3.9% vs 26.2 +/- 5.1%. Transmission electron microscopic examination revealed hypertrophic changes in all patients and degeneration in 7 of them. Hyperfunctional alterations of the myocytes were characterized by the increased number and reduced size of mitochondria, the enlarged Golgi complex, the increased number of ribosomes, the marked folding and convolutions of the nuclear membrane, the dilatation and tortuosity of T tubules. Myofibrillar lysis was the major degenerative change, which was also observed in the right ventricle (RV) of the same patients. No correlation was observed between these alterations and the patient ages, RV pressures, aortic blood oxygen saturations and ejection fractions. These findings led us to conclude that: (1) suprasystemic pressure overload of the RV induces macroscopic LV hypertrophy; (2) mild and suprasystemic pressure overload of the RV induces hyperfunctional changes in the LV; (3) myocardial degeneration is not related to hypertrophy nor to hypoxia, but is part of a more widespread cardiovascular fetopathy.

Adolescent↗
PubMed1987

Nicardipine in the treatment of Raynaud's phenomenon: a randomized double-blind trial.

The efficacy of the calcium-channel blocker nicardipine in the treatment of Raynaud's phenomenon was assessed in a prospective, double-blind, randomized, crossover trial in 20 patients. Each patient received nicardipine 20 mg or placebo three times a day for two weeks and then was crossed over for two weeks. Nicardipine significantly decreased the frequency and severity of Raynaud's phenomenon as compared with placebo. The authors conclude that nicardipine is effective in the treatment of Raynaud's phenomenon.

Adolescent↗
PubMed1987

[The value of NMR spectroscopy in the study of myocardial ischemia and in cardiovascular pharmacology].

Nuclear magnetic resonance spectroscopy is a non-destructive method used to investigate the intracellular repercussions of experimental myocardial ischaemia. The effectiveness of drugs or cardioplegic agents in preserving myocardial metabolism during and immediately after ischaemia can be tested on various models. The results obtained in different experiments and the metabolic studies conducted in patients treated with cardiotropic drugs illustrate the value of this method in cardiovascular pharmacology.

Adrenergic beta-Antagonists↗
PubMed1987

[Demonstration of reversible myocardial ischemia in necrotic akinetic areas using endocoronary ECG during angioplasty].

The presence of ischaemic myocardial tissues in necrotic territories and the usefulness of revascularizing these territories are controversial matters. We have determined the existence of this phenomenon by the per-angioplastic intracoronary ECG method, and we have compared the sensitivities of intracoronary ECG and surface ECG. Intracoronary EVG is achieved by using the mobile teflon-coated guide wire of coronary angioplasty as a unipolar epicardial electrode. Being epicardial and localized, the electrode explores a limited area of the myocardium, distal to the artery being dilated and momentarily occluded by the balloon during inflations. The study involved 12 patients (mean age 53.7 years) who presented with the following criteria of admission: transmural myocardial infarction, presence of a Q wave on two leads, akinetic segment at ventriculography and coronary stenosis or occlusion amenable to angioplasty. Patients with collateral circulation between the larger epicardial vessels were excluded. Intracoronary ECG recordings were taken before, during and after inflations. In 9 out of 12 patients the ST segments was elevated by 1.3 mV on average between inflations (S.D. 3.14 mV) and by 4.8 mV (S.D. 3.99 mV) during inflations. These high standard deviations were due to major inter- and intra-individual variations of ST. The difference was significant (p less than 0.05) at variance analysis. No variation of ST was observed in 3 patients. Only one of the 12 patients had elevated ST on both surface ECG and intracoronary ECG tracings. Thus, intracoronary ECG is a sensitive method to evaluate myocardial ischaemia during coronary angioplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Study of myocardial metabolism of NADH by laser fluorimetry during cardiac catheterization].

Laser fluorimetry of reduced nicotinamide-adenine-dinucleotide (NADH) p6 a new technique used for in situ and real-time study of myocardial metabolism. We have evaluated its applicability to clinical situations in 5 patients undergoing haemodynamic exploration. An optic fibre was inserted in a catheter the end of which was positioned in the postero-diaphragmatic part of the left ventricle. The optic fibre was connected to a Cilas-Alcatel fluorimeter. Variations in fluorescence were studied during variations in left ventricular end-diastolic pressure (LVEDP) and during coronary arteriography. An increase in LVEDP resulted in a slight increase in NADH, but when the LVEDP was reduced by a nitroglycerin infusion, NADH fell significantly below baseline values in patients with coronary disease. This effect was most probably due to redistribution of the coronary blood flow from healthy territories to ischaemic territories. In patients without significant coronary stenosis, NADH was not modified by an injection of 10 ml of contrast medium into the right coronary artery. In contrast, in patients with severe stenosis NADH fluorescence significantly increased during the injection, reflecting the ischaemia or myocardial anoxia induced by the contrast medium. NADH laser fluorimetry therefore seems to be promising as a means of exploring myocardial metabolism during cardiac catheterization.

Cardiac Catheterization↗
PubMed1987

[Incomplete spontaneous rupture of the supravalvular aorta complicated by pericarditis and aortic insufficiency].

The natural history of an incomplete spontaneous rupture of the ascending aorta over a 4-year period is reported. The initial presentation was subacute pericarditis which regressed spontaneously. Aortic regurgitation developed on the 100th day of the disease and was perfectly well tolerated haemodynamically for 4 years. This favourable course was interrupted by type I aortic dissection. The post-mortem examination provided an explanation for the peculiar development and course of the aortic regurgitation: it was due not to the usual prolapse of the cups but to displacement of the left posterior commissure by the retractile fibrosis arising from the lower lip of the spontaneous rupture.

Aged↗
PubMed1986

Nifedipine and thallium-201 myocardial perfusion in progressive systemic sclerosis.

Heart disease in patients with progressive systemic sclerosis may be due in part to myocardial ischemia caused by a disturbance of the coronary microcirculation. To determine whether abnormalities of myocardial perfusion in this disorder are potentially reversible, we evaluated the effect of the coronary vasodilator nifedipine on myocardial perfusion assessed by thallium-201 scanning in 20 patients. Thallium-201 single-photon-emission computerized tomography was performed under control conditions and 90 minutes after 20 mg of oral nifedipine. The mean (+/- SD) number of left ventricular segments with perfusion defects decreased from 5.3 +/- 2.0 to 3.3 +/- 2.2 after nifedipine (P = 0.0003). Perfusion abnormalities were quantified by a perfusion score (0 to 2.0) assigned to each left ventricular segment and by a global perfusion score (0 to 18) for the entire left ventricle. The mean perfusion score in segments with resting defects increased from 0.97 +/- 0.24 to 1.26 +/- 0.44 after nifedipine (P less than 0.00001). The mean global perfusion score increased from 11.2 +/- 1.7 to 12.8 +/- 2.4 after nifedipine (P = 0.003). The global perfusion score increased by at least 2.0 in 10 patients and decreased by at least 2.0 in only 1. These observations reveal short-term improvement in thallium-201 myocardial perfusion with nifedipine in patients with progressive systemic sclerosis. The results are consistent with a potentially reversible abnormality of coronary vasomotion in this disorder, but the long-term therapeutic effects of nifedipine remain to be determined.

Adult↗
PubMed1985

Prevention with molsidomine of coronary artery spasm caused by alkalosis.

A provocative test of coronary artery spasm caused by alkalosis was used to evaluate a possible anti-coronary artery spasm effect of molsidomine. The rapid infusion of an alkaline buffer followed by maximal voluntary hyperventilation in 10 patients with angina at rest led to the appearance of anginal pain and significant, transient ischemic changes of the ST segment resulting from alkalosis-induced coronary spasm. A second provocative test was performed under the same conditions, 24 hours later, after the administration of 4 mg of molsidomine. Molsidomine prevented the development of coronary artery spasm in 8 of the 10 patients in the study group. These preliminary results justify further clinical evaluation of molsidomine in the treatment of vasospastic angina.

Alkalosis↗
PubMed1985

[Classification and principles of the use of vasodilators in the treatment of left ventricular insufficiency].

Vasodilators have been widely used in recent years for the treatment of severe left ventricular failure (LVF). However, amongst these drugs, not all have the same therapeutic effects, but they differ from one another in molecular structures, cellular mechanisms, haemodynamic actions and modes of administration. A three tier classification is proposed with the single objective of facilitating the therapeutic choice: mechanism of action: this property distinguishes the alpha-blockers from the beta-2 sympathomimetics, calcium antagonists, angiotensin converting enzyme inhibitors and prostacyclin biosynthesis inducers. Some molecules such as hydralazine, whose mechanism of action remains unclear, cannot be classified in this way; haemodynamic effects: these effects can be used to distinguish vasodilators which act mainly on the venous sector from arterial and mixed vasodilators. The knowledge of the preferential site ol action of these molecules helps to adapt the choice of treatment to the initial haemodynamic profile of each patient; pharmacokinetics: these properties distinguish molecules active only by intravenous administration, better adapted for the treatment of acute LVF in the intensive care unit, from those active orally which can be used for long-term ambulatory therapy of chronic cardiac failure. Trinitrin and its derivatives occupy an intermediate position because of their relatively low bioavailability after oral administration: long-term administration is not always easy and may require special modes of administration (i.e. percutaneous). Vasodilators have been widely used in cardiac failure for about 5 years; the results of some medium term controlled therapeutic trials are now available and confirm the efficacy of these drugs but also define their limitations: variable therapeutic efficacy: the number of responders ranges from 30 to 60 p. 100 according to the molecule used.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium Channel Blockers↗
PubMed1985

[Conservative surgery of the mitral valve. Immediate and late results].

A consecutive series of 130 cases of pure or predominant mitral regurgitation underwent conservative mitral valve surgery between January 1975 and January 1982. The mean age of the patients was 30 +/- 17 years; 25 patients were under 15 years of age. The most common aetiology was rheumatic fever (112/130). Fifty nine patients had associated valvular lesions requiring surgical correction. The patients were divided into 4 groups, according to the surgical technique: Group I: valvular mobilisation (35 cases); Group II: reduction of the amplitude of valvular excursion (48 cases); Group III: mixed valvular mobilisation and reduction of amplitude of excursion (45 cases); Group IV: isolated annuloplasty (2 cases). Hospital mortality was 2.3% (3 patients). Five patients (3.8%) were lost to follow-up. The mean follow-up period was 38 +/- 27 months for the 122 patients followed-up. Seven patients needed reoperation. The long term mortality was 3.1% (4 patients). Four late thromboembolic episodes were observed; they were all transient and regressive in patients with atrial fibrillation. The 7 year actuarial survival rate for the whole series, including hospital mortality, was 92% (1.0 +/- 0.5 patients/year). It was 93.7 +/- 4.9% at 7 years for isolated mitral valvuloplasty and 89.9% +/- 5.6% at 5 years for combined mitro-tricuspid procedures. The actuarial percentage of patients without thromboembolic complications was 91.2% at 7 years with a thromboembolic risk of 1.0 +/- 0.5% patients/year. Eighty eight per cent of patients were not reoperated at 7 years and the reoperation rate was 1.7 +/- 0.7% patients/year.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

[Subvalvular aortic stenosis in adults. Apropos of 31 cases].

The aim of this cooperative study was to analyse the clinical profile of subvalvular aortic stenosis (SVAS) in adults. Thirty one cases were collected : patients aged 17 to 60 years (average 34 years). The diagnosis was confirmed in all patients either at surgery (30 cases) or at autopsy (1 case). The overall incidence of SVAS in patients with fixed obstruction to left ventricular ejection operated in the same period was 3.5%. Associated congenital malformations were detected in 15% of cases but intracardiac shunts were rare. Adult SVAS is a purer malformation than in children, probably because of spontaneous and surgical selection. The anatomical type of stenosing lesion in this series was a subaortic ring or membrane; 45% of patients, usually over 40 years of age (7 out of 9) had localised septal hypertrophy at the level of the diaphragmatic obstruction. The clinical presentation was that of mixed aortic disease with associated stenosis and regurgitation. Over 80% of patients had aortic incompetence diagnosed clinically (26 out of 31 cases) or on aortography (24 out of 25 cases); the regurgitant flow was assessed as mild in 15 cases, moderate in 6 cases and severe in 3 cases. There were obvious valvular lesions at surgery in 19 cases, especially in patients over 40 years of age (8 out of 9 cases). The mechanism was variable : non-specific (8 cases), destructive (6 cases), rheumatic (2 cases) or congenital (3 cases). Bacterial endocarditis was particularly common (26% of cases). Adult SVAS is a particularly difficult clinical diagnosis : the electrocardiogram and chest X-ray are not very informative.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

[Molsidomine prevention of coronary artery spasm caused by alkalosis].

A test provocation of coronary artery spasm by alkalosis was used to evaluate a possible anti-coronary artery spasm effect of molsidomine. The rapid infusion of an alkaline buffer followed by maximal voluntary hyperventilation in 10 patients with angina at rest led to the appearance of angina pain and significant, transient ischaemic changes of the ST segment, due to alkalosis induced coronary spasm. A second provocation test was performed under the same conditions, 24 hours later, after the prior administration of 4 mg of molsidomine. Molsidomine prevented the development of coronary artery spasm in 8 of the 10 patients in the study group. These preliminary results justify further clinical evaluation of molsidomine in the treatment of vasospastic angina.

Alkalosis↗
PubMed1982

[Congenital cardiopathies in adults. 179 cases].

Congenital heart disease in the adult represents less than 25 p. 100 of all congenital heart diseases; 179 out of 800 cases in the authors' experience. Atrial septal defect (ASD) is by far the most common (44 cases) especially in adults over 40 years of age. Practically all large ASD develop complications and systematic repair is recommended in all age groups except in forms with severe pulmonary hypertension and high pulmonary arteriolar resistance. Ventricular septal defect (VSD) is almost as common. They are usually small and only rarely present after 40 years of age, suggesting that spontaneous closure may occur even after 20 years of age. Coarctation of the aorta should be operated on before adulthood as persistant hypertension becomes more common in patients operated later. Eisenmenger's syndrome, the inevitable conclusion of VSD with severe hypertension not operated during childhood, or of some large ASDs in adults is often well tolerated and may survive until an advanced age. Survival of Fallot's tetralogy is very rare after 20 years without surgery; complete repair should therefore be performed early despite its drawbacks. Thus, unoperated congenital heart diseases should no longer be observed in adults excepting minor forms which do not justify the operative risks, and complicated forms for which no surgical cure is yet available.

Adult↗