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Biomedical subjects

A Carpentier

Publications and source records attributed to A Carpentier.

At least 271 records · Page 15Linked to original sources
PubMed1988

Dynamic cardiomyoplasty: a surgical approach for ventricular assistance.

Dynamic cardiomyoplasty involves the use of an electrically stimulated skeletal muscle wrapped around part of the heart to restore or augment myocardial contractility. In our approach, a Latissimus Dorsi muscle flap (LDMF) is transferred to the heart via a partial resection of the second rib, and sutured around the ventricles. The muscle flap is stimulated in synchrony with the heart contractions with bursts of impulses delivered by a "Cardio-Myostimulator" implantable pulse generator via intramuscular electrodes. The object of this study was to identify features of muscle stimulation and to measure the efficacy of L.D. cardiomyoplasty in increasing cardiac output, using an ultrasonic Doppler technique. This report shows the results obtained for goats in which such procedures were performed. Ultrasonic measurements were recorded at the time of cardiomyoplasty and 3-6 months later, during which period the muscle was put progressively into use by slowly increasing the burst frequency content, number of pulses as well as the heart-muscle contraction ratio (3:1, 2:1, 1:1). This postoperative muscle stimulation protocol takes into account the delay of gradual conversion of fast-twitch glycolytic muscular fibers into slow-twitch oxidative, fatigue-resistant fibers, as well as the healing time after cardiomyoplasty required for the muscle flap to recover collateral blood circulation and to adhere to the heart. Results show that synchronous burst stimulation of the muscle flap increases the blood peak velocity in the descending aorta (+36 +/- 8%) and increases the left ventricular stroke volume (+70 +/- 14%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

A new reconstructive operation for Ebstein's anomaly of the tricuspid valve.

Ebstein's anomaly is a complex malformation involving the tricuspid valve and the right ventricle. Various surgical techniques, either repair or replacement of the abnormal tricuspid valve, have been used with variable results. In an attempt to enlarge the indications of conservative procedures, we developed a technique of repair that comprises the reconstruction of a normally shaped right ventricle and the repositioning of the tricuspid valve at the normal level. In a series of 14 patients operated on between January 1980 and December 1986 in our institution, only one patient with an associated atrioventricular septal defect required a tricuspid valve replacement. All of the other patients, regardless of the complexity of the tricuspid malformation, were able to benefit from this conservative technique. There were two hospital deaths and no late deaths in this series. All surviving patients displayed a marked improvement over their preoperative status with regard to functional class (92% are in class I or II) and rhythm disturbances. Echocardiographic and Doppler studies demonstrated a normal shape of the right ventricle and good tricuspid valve function in all the patients but one.

Adult↗
PubMed1988

[Histochemical quantification of muscular ischemia: effect of treatment with naftidrofuryl].

Evaluation of degree of muscle ischemia of a limb and its reversibility is a poorly resolved practical problem, and it has not been clarified whether vasodilatory and circulatory spasmolytic substances possess, in addition to an effect of increasing irrigation, any direct action on muscle cell energy metabolism. An experimental study used histochemical techniques to evaluate oxidative enzyme activity of tissues. The compound tetrazolium nitro-blue (NBT), when reduced by tissue dehydrogenases, has the property of producing a dense non-crystalline blue pigment designated "formazan". During muscle ischemia, the time of appearance of this reaction increases with degree of ischemia through the bias of the decrease or disappearance of succinate-dehydrogenases. Transient ischemia of hindpaw, over 3, 6, 9, 12, 15 and 18 hours, was provoked by tourniquet in 49 rats treated with a vasodilator (naftidrofuryl) and 21 untreated (control) rats. Spontaneous revascularization occurred after removal of the tourniquet. Muscles were studied by microsurgical removal of specimens on removal of tourniquet and 1 and 12 hours and 3, 7 and 14 days after its removal (fig. 1 and 2). Times for staining of muscles with tetrazolium were measured and curves of comparative times established (fig. 3 and 4). Histopathologic specimens were also obtained at the same periods (fig. 5, 6, 7). Results of histochemical studies with tetrazolium and with quantitative determination of degree of cellular anoxia showed the action of naftidrofuryl to be related to mitochondrial metabolism of skeletal muscle, specifically for succinate-dehydrogenase. Clinical application in the determination of therapy and of functional prognosis of an ischemic limb is a possibility by the use of the NBT test in vascular surgery.

Animals↗
PubMed1988

Left ventricular outflow obstruction after mitral valve repair (Carpentier's technique). Proposed mechanisms of disease.

Left ventricular outflow tract obstruction (LVOTO) after mitral valve repair by Carpentier's technique has been recently reported in the literature. To assess the mechanisms of this phenomenon, we investigated 307 mitral valve repairs performed between July 1985 and December 1986. Incidence of LVOTO related to the mechanism of the mitral insufficiency and to the etiology demonstrates a direct relation to preoperative mitral valve prolapse (posterior leaflet +/- anterior leaflet) of degenerative origin. No LVOTO occurred after rheumatic mitral insufficiency repair regardless of size of the left heart cavities or of the prosthetic ring. Intraoperative and surficial two-dimensional echocardiography, color Doppler methods, and cardiac catheterization were used to investigate the mechanisms leading to LVOTO. Nonspecific modifications induced by reduction in size of the mitral annulus by the prosthetic ring (anterior displacement of the posterior ventricular wall and of the posterior mitral leaflet and narrowing of the mitroaortic angle) are not sufficient to explain the LVOTO. The association of mitral leaflets (composed of excess tissue and opposed to flow by a perpendicular position attributable to a narrow mitroaortic angle) and geometric left ventricular modifications (responsible for the superposition of mitral inflow to ventricular outflow) also qualifies as a mechanism for the induction of LVOTO after mitral surgical repair.

Cardiac Catheterization↗
PubMed1987

Vasodilator properties of prostacyclin after coronary artery bypass surgery.

The vasodilatory properties of prostacyclin were studied in 12 intubated patients who underwent coronary artery bypass surgery. When infused in doses of 2.5, 5, 10, and 20 ng/kg/min, prostacyclin produced a dose-dependent decrease in systemic vascular resistance from 2,702 +/- 143 to 1,654 +/- 106 dynes/cm5/m2 (p less than 0.05). Heart rate, right atrial pressure, and pulmonary arterial and capillary wedge pressures did not change. Cardiac function was improved, since stroke volume index increased from 29.5 +/- 1.4 to 35.5 +/- 2.0 ml/min/m2 (p less than 0.05) and the rate pressure product decreased from 13.3 +/- 1.3 to 10.9 +/- 0.9 X 10(3) mm Hg/beats/min (p less than 0.05), while stroke work index remained unchanged. These hemodynamic changes were associated with a dose-dependent decrease in arterial oxygen tension which occurred from 278 +/- 25 to 133 +/- 22 mm Hg; however, oxygen transport increased as a result of the prostacyclin-induced increase in cardiac index. This study demonstrates that prostacyclin is a potent arterial vasodilator that may be of interest in the treatment of postoperative vasoconstriction occurring after coronary artery bypass surgery.

Adult↗
PubMed1987

[Traumatic tricuspid insufficiency. Apropos of a case treated by conservative surgery].

Traumatic tricuspid insufficiency is a rare condition which raises the problem of when and how should its surgical correction be performed. Its diagnosis has been considerably facilitated by echocardiography. We report a case of traumatic tricuspid insufficiency with extensive lesions of the tricuspid valve system, which was diagnosed after a 15-year period without functional signs. Echocardiography and Doppler ultrasounds provided very accurate information on the lesions. Optimal correction was obtained by conservative surgery. The excellent results observed at short and medium term suggest that surgical indications should be extended.

Accidents, Traffic↗
PubMed1987

[Valvuloplasties for acquired mitral insufficiency in children (Carpentier's technic). Long-term results in 87 cases].

Between March, 1969 and March, 1984, 89 children aged from 2 to 12 years (mean: 8.3 +/- 2.5 years) and presenting with mitral valve regurgitation underwent valvuloplasty by the Carpentier technique. The cause of the regurgitation was rheumatic fever in 84 cases (94 p. 100), bacterial endocarditis in 4 cases and Barlow's disease in 1 case. Mitral valve regurgitation was divided into 3 types, namely: type I, normal valve motion (5 cases), type II, valve prolapse (74 cases) and type III, restricted valve motion due to fibrosis of the leaflets or chordae (20 cases). The hospital mortality rate was 2.3 p. 100 (2 deaths). The cumulative follow-up was 546 patients/years, and the actuarial survival rate at 10 years was 89.96 +/- 8.5 p. 100. At 10 years the actuarial thromboembolic complication rate was 2 p. 100, or 0.3 +/- 0.2 p. 100 per patient year, and the actuarial valvuloplasty deterioration rate was 27 +/- 8.5 p. 100. The risk of re-operation was 2.2 +/- 0.6 p. 100 per patient year. At 10 years 78.4 +/- 7.2 p. 100 of the children were free of all re-operation, and 69 p. 100 had no complication. Thus, whenever possible (i.e. in 90 p. 100 of the cases, according to our experience) and considering the satisfactory long-term results, all children with acquired mitral valve regurgitation should undergo mitral valvuloplasty as first-line treatment.

Child↗
PubMed1986

Retrograde cardioplegia through the right atrium.

Retrograde cardioplegia through the coronary sinus has been shown to overcome the problems of cardioplegia delivery in aortic valve incompetence and coronary stenosis. Since specific complications, such as coronary sinus injury and lack of perfusion of the thebesian veins, may result from its use, we present a technique of cardioplegia delivery through the right atrium after caval and pulmonary artery exclusion that we believe is safer and more reliable than delivery through the coronary sinus.

Cardiopulmonary Bypass↗
PubMed1986

Inhomogeneity of cellular refractoriness in human atrium: factor of arrhythmia?

Spatial inhomogeneity of refractory periods, as measured during clinical electrophysiological studies, is a known predisposing factor of arrhythmia. We studied effective refractory periods (ERP) and action potential duration (ADP90) on isolated human atrium. Twelve samples of right atrium obtained during cardiac surgery from patients with (n = 6) and without (n = 6) atrial fibrillation (AF) were studied by microelectrode technique. For each preparation, ERP were measured at basic cycle lengths (BCL) of 1,600, 1,200, 800, and 400 msec in five different cells located around (0.8 mm) the stimulating electrode. Dispersion of ERP was significantly greater in the AF group (96.7 +/- 9 versus 70.9 +/- 9 msec, p = 0.01). In the non-AF group, we observed a positive linear correlation between ERP and BCL (r = 0.86) ADP90 and BCL (r = 0.93). On the contrary, in the AF group this correlation was absent between ERP and BCL (r = 0.28), poor between ADP90 and BCL (r = 0.62). These results suggest that nonhomogeneous recovery of excitability (dispersion and poor adaptation) may be an important factor of arrhythmia. This inhomogeneity is present at the cellular level as well as in the entire heart.

Action Potentials↗