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Biomedical subjects

P Penther

Publications and source records attributed to P Penther.

At least 37 records · Page 2Linked to original sources
PubMed1989

[Anatomic lesions in bacterial endocarditis of the aortic valves. Practical implications].

Bacterial infection of aortic valves remains frequent and worrying. The virulence of the pathogen in question, the history of the infection and the topography of valvular involvement account for certain lesional features, notably cardiac abscess and contiguous lesions, which are seen in 50% of cases with autopsy material. Clinically suspected cardiac abscesses can be detected by echocardiography when their size reaches or exceeds 4 mm. Their active nature is such that emergency surgery is an additional indication to be added to conventional ones such as uncontrolled infection, heart failure refractory to treatment, and repeated systemic embolism.

Abscess↗
PubMed1989

[Hemodynamic effects of intravenous magnesium sulfate in man].

The haemodynamic effects of a single 3 g dose of magnesium sulfate administered by slow (1 min) intravenous injection were evaluated in 16 patients with coronary disease about to be explored by coronary arteriography. The haemodynamic effects were transient, with maximal values at the end of the injection and return to baseline values within less than 3 min. They consisted of peripheral vasodilatation with a decrease in systolic aortic pressure (128 +/- 18 mmHg versus 113 +/- 17 mmHg, p less than 0.05), an increase of cardiac index (3.0 +/- 0.4 versus 3.8 +/- 0.06 1/min/m2, p less than 0.001) and a fall in peripheral arterial resistance (1168 +/- 203 versus 919 +/- 29 dyn/s/cm-5, p less than 0.01). This action was accompanied by a moderate increase in contractility (Vmax) (1.63 +/- 0.34 versus 1.87 +/- 0.47 CIR/s, p less than 0.01) without changes in the relaxation index T (37 +/- 8 versus 67 +/- 9 s-1, NS), but with concomitant increase in heart rate (80 +/- 12 versus 67 +/- 10 beats/min, p less than 1.10(-4]. It is concluded that the haemodynamic effects of magnesium sulfate are moderate and transient and that this substance can be used safely as antiarrhythmic agent, even in case of marked deterioration of the left ventricular function.

Adult↗
PubMed1989

[Left auricular dilatation in calcified aortic stenosis in adults].

Two groups of patients of comparable age, one comprising 12 subjects without detectable cardiac disease and the other comprising 38 patients with calcific aortic stenosis (CAS) underwent clinical, electrocardiographic, echocardiographic and haemodynamic studies to assess the degree and significance of left atrial hypertrophies in CAS. The volume of the left atrium (LA) was globally increased in CAS (maximum volume 68 per cent: 26/38) and LA ejection fraction was decreased in 60 per cent of patients (23/38). However, the maximum volume was only moderately greater than that of normal subjects (+38 per cent). The most specific non-invasive investigation for left atrial assessment is echocardiography. There was a linear relationship between LA angiographic volume and echocardiographic antero-posterior dimension (r = 0.43; p less than 1 x 10(-2)). The duration of the P wave in S2 was a specific (75 per cent) but relatively insensitive (27 per cent) sign of LA dilatation in pure CAS. On the other hand, the Morris index based on the surface of the P terminal force in V1 was quite sensitive (77 per cent) but not very specific (25 per cent). The maximum LA volume was not related to left ventricular volume, the severity of CAS, diastolic indices of compliance or left ventricular mass. However, the minimum LA volume (after atrial systole) was related to left ventricular end diastolic (r = 0.35, p less than 0.05) and end systolic volume (r = 0.34, p less than 0.05). The LA ejection fraction was inversely related to mean pulmonary capillary pressure (r = 0.34, p less than 5 x 10(-2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Calcified aortic valve stenosis in adults. Analysis of supra- and infra-hissian conduction disorders].

The association of intraventricular or atrio-ventricular conductive disorders with a calcified aortic stenosis, is a classical notion demonstrated by the close anatomical relationships between aortic valve and conduction pathways. These conductive disorders have been, for quite some time, analyzed on standard electrocardiograms, but, since a few years, the recording of the bundle of His potential has become the technique of choice. However, studies regarding this subject are few, based on very small and sometimes heterogeneous groups of patients. Sixty six consecutive patients hospitalized for a narrow aortic stenosis have agreed to be subjected, before valve replacement, to a recording of the bundle of His potential. Thirteen of them (19.7%) show a HV interval exceeding 55 ms or a pathological H deflexion (twisted and lasting 35 ms). None of the pre-operative parameters that were analyzed (black-out, left ventricular function, ventriculo-aortic gradient, calculated valvular area, magnitude of valvular and ring calcifications), seem correlated with the increased HV interval. These results cross-check those reported in most of the literature.

Adolescent↗
PubMed1988

[Tight calcified aortic valve stenosis in adults aged from 50 to 69. Anatomical study of 50 cases].

The results of anatomical examination in fifty patients aged from 50 to 69 years presenting with calcified and tight aortic stenosis are reported. The calcifications were located mostly on the aortic side of the valves, and the aortic orifice area was less than 1 cm2. The macroscopic features of the aortic valve system fell into three categories: bicuspid valve in 28 patients (21 men, 7 women), trivalve orifice with commissural adhesion (calcified in every case) in 21 patients (18 men, 3 women), and trivalve orifice without commissural adhesion in 1 patient (a 68-year old man). Male predominance was obvious (40/50; 80 p. cent). From an analysis of the various anatomical data recorded three differences emerged: the aortic annulus was wider in cases with bicuspid valve (P less than 0.01); the calcifications did not involve the free border of the valves in cases with bicuspid valve or trivalve orifice without commissural adhesion, but they involved this free border in 1 out of 2 cases with trivalve orifice and commissural adhesion; the aortic stenosis was minimal to moderate in all cases with trivalve orifice and commissural adhesion. In patients of that age group, the main cause of stenosis was bicuspid valve which seemed to be congenital in all cases. Dilatation with the finger through the left ventricle - which cannot by any means be assimilated to inflation of a balloon passed into the aortic orifice - resulted in significant opening of the aortic orifice by compression and/or disruption of the calcareous formations in patients with bicuspid valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

[Narrow and calcified aortic valve stenosis in subjects in their 8th and 9th decades. An anatomic study of 64 cases].

Anatomical data obtained from 64 patients aged from 70 to 86 years with calcified and tight aortic orifice stenosis (functional area less than 1 cm2) were divided into three types according to the macroscopic appearance of the aortic valve: (1) tricuspid valve without commissural fusion: 44 cases (18 men, 26 women, mean age 76 years); (2) tricuspid valve with commissural fusion: 12 cases (8 men, 4 women, mean age 72 years); (3) calcified congenital bicuspid valve: 8 cases (6 men, 2 women, mean age 73 years). Thus, the distribution of patients by sex became the same starting from the eighth decade of life. Calcified aortic orifice stenosis (CAOS) of degenerative origin was the most common lesion (69 p. 100), with a strong female predominance. There were several differences between degenerative CAOS and bicuspid valve stenosis on the one hand and aortic orifice stenosis with commissural fusion on the other hand. In the first group, calcification did not involve the free edge of the aortic cusps, large calcifications of the mitral ring were extremely frequent, and there was little or no aortic regurgitation. Moreover, the aortic ring clearly was wider in cases with bicuspid valve. In patients with degenerative CAOS and bicuspid valve, attempts at digital dilatation by the left ventricular route succeeded in most cases in obtaining a fairly important widening of the aortic orifice by compression and/or disruption of the valvular calcium deposits, without causing significant regurgitation of injuring the valve; the cusps recovered some mobility.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

[Rheumatic involvement of the tricuspid valve. Anatomical types and possibilities of dilatation].

In 194 cases of rheumatic cardiac valve diseases (41 men, 153 women), macroscopic examination singled out 21 lesions of the tricuspid valve (11 p. 100). These lesions were found exclusively in women and were always associated with a mitral valve disease (18 cases) or a mitral and aortic valve disease (3 cases). The fairly uncommon tricuspid valve lesions were of two different types, the incidence of which did not seem to be influenced by age. There were 7 cases of moderately tight (n = 5) or tight (n = 2) stenosis (TS) and 14 cases of tricuspid valve disease (TD), where a moderately tight stenosis coexisted with a varying degree of regurgitation (TR). In subjects with pure TS the three commissures were regularly fused by fibrosis, whereas the only lesion of the tricuspid leaflets was thickening of their free border. In TD the commissural fusions were less extensive, but the fibrous thickening was retractile and invaded the entire leaflet. The other anatomical data (perimeter of the tricuspid annulus, condition of the right cardiac cavities, heart weight, etc.) were approximately the same in both types. On anatomical specimens, percutaneous dilatation seemed possible only in pure TS; TD did not lend itself to this of treatment. In most cases two-dimensional echocardiography combined with doppler ultrasound can provide an accurate evaluation of the lesions from which can be deduced roughly the possibilities of percutaneous valvuloplasty limited to pure TS.

Adult↗
PubMed1988

[Anti-arrhythmic effects of intravenous magnesium sulfate in paroxysmal supraventricular tachycardia].

The anti-arrhythmic effects of intravenous magnesium sulfate, on bouts of supraventricular tachycardia (SVT) secondary to reentry phenomenon, are evaluated in twelve patients undergoing an electrophysiological testing, because of paroxysmal SVT, the pathway of which is an intranodal reentry (eight patients) or includes an atrio-ventricular accessory route (orthodromic SVT: four patients). At the completion of the basic testing, a stable SVT is induced and an intravenous bolus of 3 grams of magnesium sulfate is administered in three minutes. The length of the SVT cycle is significantly increased from 349 +/- 71 ms to 394 +/- 70 ms (p 0.001). The injection of magnesium relieves the SVT in less than five minutes in three patients (intranodal reentry: two cases; accessory pathway: one case), or an efficacy of 25 p. cent. No incident is reported following administration of the product; but the functional tolerance may be considered as poor, mainly consisting of flushing sensations of brief duration. This study demonstrates the antiarrhythmic properties of intravenous magnesium sulfate during bouts of SVT; however, its efficacy appears moderate at the dose mentioned.

Adult↗
PubMed1987

[Electrophysiological effects of intravenous magnesium sulfate in man].

Magnesium salts have been used for many years to correct a wide variety of arrhythmias. A few experimental studies have been devoted to their electrophysiological effects, but these remain poorly documented in man, hence this study. An electrophysiological investigation was conducted in 24 patients before, and immediately after a bolus intravenous injection of magnesium sulphate in doses of 1.5 g to 12 patients (group I) and 3 g to 12 other patients (group II), followed by a continuous infusion at the rate of 1 mg/min. The drug had no influence on heart rate, duration of QRS, QT and QTc intervals and ventricular refractory period. A small, but statistically significant prolongation of HV (from 57 to 59 ms, p less than 0.05) was observed in group II. Analysis of the results in group I revealed a moderate but significant prolongation of the PR and AH intervals. The electrophysiological effects were distinctly more pronounced in group II patients, with significant prolongation of: PR and AH intervals, effective refractory period of the right atrium and AV node, Wenckebach's point, corrected sinus node recovery time and sinoatrial conduction time. These results demonstrate that magnesium sulphate principally acts on the sinus node, the AV node and the atrium, suggesting a blocking effect on calcium channels.

Adult↗
PubMed1987

[Radioisotope and ultrasonic diagnosis of a localized form of infarction of the right ventricle].

We are reporting the case of a localized form of right ventricle infarction. The right catheterization, on which the diagnosis usually rests, is completely normal. Cardiac gamma-angiography and bi-dimensional sonography demonstrate, on the contrary, a localized dyskinesis of the inferior wall of the right ventricle which is not dilated and retains its ejection fraction. The failure of right catheterization in the diagnosis of infarction of the right ventricle is usually attributed to hypovolemia or a delay in the performance of the catheterization, which is not the case here. Therefore, this case demonstrates the existence of infarction of the right ventricle without total diastolic or systolic dysfunction, the diagnosis of which may be made with isotopic and sonographic methods.

Aged↗
PubMed1986

[Mitral insufficiency, excluding ruptured papillary muscles, in the acute phase of posterior primary infarction. Anatomical study].

Mitral regurgitation (MR) was demonstrated by water testing valve closure in 23 out 46 cases of patients dying in the 8 days following primary posterior wall infarction due to occlusion of the right coronary or left circumflex arteries (normal valves and chordae; no chronic fibrosis of the papillary muscle). MR was less common with right coronary artery occlusion (14 out of 32; 44%) than with left circumflex occlusion (9 out of 14; 64%). Two anatomical conditions seem to be necessary (all cases but one) for MR to occur: ischaemic necrosis of all or nearly all of the posterior papillary muscle and its base of implantation on the posterior wall. These valvular leaks are usually mild (papillary muscle rupture was excluded) and do not seem to play a major role in the haemodynamic deterioration of these patients, the majority of whom die of irreducible cardiac failure caused by extensive myocardial destruction. The mechanism of the majority of these MR was systolic eversion of the posterior part of the posterior leaflet in the left atrium (6 cases) of the posterior juxtacommissural part of both leaflets (13 cases), of the posterior part of the anterior leaflet (3 cases). Ischaemic destruction of the posterior papillary muscular system and its base of mural implantation (anatomical criteria that we retained) correlated with the occluded artery.

Aged↗
PubMed1986

[Comparison of 2 groups of patients hospitalized at 10 years' interval for recent myocardial infarction].

The aim of this study was to compare two groups of patients admitted consecutively to the Coronary Care Unit in 1972-73 (223 cases) and in 1982-83 (243 cases) for recent myocardial infarction, and followed up for at least 15 days, to try and appreciate the influence of changes in treatment which had taken place during this interval on outcome and mortality. The two groups were comparable with regards to age, sex, time of admission with respect to onset of symptoms, previous vascular disease, and principal coronary risk factors. The clinical presentation of myocardial infarction and its common complications (cardiac failure, arrhythmias) were unchanged at 10 years' interval. The only statistically significant but unexplained difference was the lower proportion of posterior infarctions in 1982-1983 compared to 1972-1973. This decrease was partly due to the increased detection of rudimentary infarcts by more specific enzyme methods. The decrease in the proportion of posterior infarcts probably also explained the lower numbers of atrioventricular blocks. Other differences between the two groups were not statistically significant (slight increase in age, fewer women, lower incidence of cardiac failure). The mortality rate was exactly the same at 20.6%, and the causes of death were identical. The results support those of other rare studies of the same subject showing the lack of effect of recent therapeutic innovations on the majority of patients with myocardial infarction.

Adult↗
PubMed1986

[Antiarrhythmic effects of intravenous magnesium sulfate in torsade de pointes. Apropos of 6 cases].

The antiarrhythmic properties of magnesium salts, known for many years, are periodically recalled but rarely used in daily clinical practice. They are usually used in digitalis-induced arrhythmias and are rarely indicated in other conditions; they are often reserved for cases in which a magnesium deficiency is suspected. In 6 cases of torsades de pointes, magnesium sulphate was administered at a dose 1 to 3 g by direct intravenous injection. Although hypokalaemia was a common finding, a low magnesium concentration was only found in one case. The ventricular arrhythmia regressed completely at the end of the injection in 4 cases (one after two injections). One positive but incomplete response was observed in the only case of magnesium deficiency, probably due in retrospect to inadequate dosage. Finally, one patient with very poor ventricular function had recurrence after a good initial response. The diversity of the clinical and biological findings in this series suggests a specific antiarrhythmic action of the magnesium ion, apparently independant of the correction of magnesium deficiency; experimental studies suggest that the mode of action is a direct antagonism of Mg++-K+ and/or Mg++-Ca++. Compared to usual means of treatment of torsades de pointes (isoprenaline infusion or pacing) the advantages of intravenous magnesium sulphate are clear-cut: innocuity, simplicity and rapidity of administration, and almost immediate efficacy.

Aged↗
PubMed1986

Constrictive perivenous mesh prosthesis for preservation of vein integrity. Experimental results and application for coronary bypass grafting.

Saphenous veins undergo dramatic morphologic changes when used as coronary bypass grafts, and careful preparation of the graft alone is inadequate in preventing these changes. In this study, the use of a constrictive mesh for vein graft was evaluated. Fourteen sheep were subjected to a 5 cm resection of the carotid artery. Six sheep (Group A) received a jugular vein interposition graft, and the other eight sheep (Group B) received a jugular vein graft on which the constrictive mesh had been applied. The diameter of grafts in Group A was 14 +/- 1 mm compared with 7 +/- 0.5 mm for Group B (p = 0.05). The animals were put to death 4 months later. Scanning electron microscopy showed a disruption of the endothelial lining in Group A and a normal endothelium in Group B. Microscopy showed a statistical difference between Groups A and B regarding regularity and thickness of the intimal hyperplasia. Group B showed a moderate and regular intimal thickening and increased vasa vasorum. This indicates that distention and subsequent damage of the vein graft may be minimized by use of a constrictive mesh. Saphenous grafts surrounded by this constrictive mesh were inserted in four patients. Vein diameters were, respectively, 5, 4.3, 3.5, and 3.5 mm before meshing. After insertion in the mesh, vein diameters were 4.3, 3.5, 2.8, and 2.5 mm, respectively. Angiography performed 2 months later showed patent grafts of regular caliber.

Animals↗