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Biomedical subjects

S Dunica

Publications and source records attributed to S Dunica.

15 recordsLinked to original sources

[A new cause of acute transitory auriculoventricular block: Lyme disease].

A young man developed syncopal complete paroxysmal atrioventricular block (AVB) over a 36 hour period, on a background of 1st degree AVB which persisted for 6 weeks. During the 3rd week, electrophysiological studies showed an isolated prolonged AH interval. This episode followed skin and articular manifestations occurring one month after being bitten by a tick in Corsica. The clinical picture suggested Lyme's disease which was confirmed serologically. This condition transmitted bu Ixodes ricinus, a tick present in country districts, is due to spirochetal infection. It is characterized by a chronic migrating erythema, and may sometimes be complicated by severe AV conduction defects which are always regressive, as in our case.

Adult

[Fatal hypoxemia following extracorporeal circulation for aortocoronary bypass. A case].

A lethal case of acute respiratory distress syndrome of the adult following extracorporeal circulation for aorto-coronary bypass is reported. This case illustrates the two mechanisms currently thought to be responsible for this pathology: (1) the passage of blood over the synthetic fibres of the cardiopulmonary bypass machine activates the complement, and the systemic inflammatory reaction that ensues accounts for the increased permeability of the alveolar capillary membrane; (2) the haemodilution inherent in extracorporeal circulation explains the hypoproteinaemia usually observed at the end of the procedure; the resulting fall in capillary osmotic pressure upsets the equilibrium of pressures in the capillary vessels.

Coronary Artery Bypass

Acute thrombosis of a St. Jude Medical aortic prosthesis in a pregnant woman.

A 24-year-old, 4-months pregnant woman developed an acute thrombosis of a St. Jude Medical aortic valve prosthesis. Upon admission, she was in cardiogenic shock. A thrombectomy was achieved in emergency under cardiopulmonary bypass. The patient survived but not the fetus. Diagnosis, surgical procedure, anticoagulation drugs and valve prostheses in pregnant women are discussed.

Adult

[Tamponade caused by localized compression of the superior vena cava and right atrium after aortic valve replacement under extracorporeal circulation].

The authors report a case of localised compression of the right atrium due to a loculated intrapericardial haematoma after open heart surgery. The patient suddenly developed signs of superior vena caval obstruction during the third postoperative week. The diagnosis was made by 2D echocardiography and superior vena cavography. The authors review the literature and discuss the main clinical features of localised cardiac tamponade, underlying the value of 2D echocardiography in the postoperative management of cardiac surgical patients.

Adult

[Coronary angiography and coronary bypass in patients over 70 (valvular disease excluded). Indications and results].

Between 1982 and 1984, 30 patients aged 70 or over underwent coronary angiography for isolated coronary artery disease, complicated in 8 cases by an infarct and uncontrolled by major medical treatment, including triple therapy on 28 mmHg (range 5-30 mmHg). Coronary angiography was performed under intravenous trinitrin in 9 cases, under intra-aortic balloon pumping in 1 case, without any serious complications. The majority of patients had triple vessel disease (18 cases) and stenosis of anterior interventricular (27 cases). The left main stem was diseased in 5 patients. Twenty-four patients, with an EF of over 0.40, underwent a coronary bypass with an average of 27 grafts/patients; 4 myocardial infarcts and 5 postoperative deaths were observed. Nineteen patients survived at medium term follow-up and had an excellent clinical result. Of the non operated patients, there was one early death and 3 patients remained severely incapacitated. In the absence of a major contra-indication to surgery, coronary angiography can be offered to patients over 70 years old in cases of severe coronary insufficiency, resistant to major medical treatment. Coronary bypass is justified by the spectacular functional improvement which it alone can bring about.

Age Factors

[2-dimensional echography in the preoperative evaluation of mitral stenosis].

2D echocardiography has become one of the most important investigations in the preoperative assessment of mitral stenosis. This study was undertaken to determine the reliability of the information so obtained, by comparison with the surgical appearances. The study population consisted of 104 patients (average age 45 years, 76% women) undergoing open heart surgery for pure mitral stenosis (72%) or mixed mitral valve disease (28%) between 1980 and 1981. All underwent 2D echo using a phased array Aloka SSD 800 80 degrees sector scanner. Cardiac catheterisation was performed in 102 cases and left ventricular angiography in 89 cases. The echocardiogramme was interpreted by an observer who had no knowledge of the surgical results. The mitral surface area, the condition of the valves and subvalvular apparatus and the predictive value of the possible surgical technique were analysed. The 2D echo mitral surface area was estimated by planimetry and quantitatively by using the Gorlin formula during catheterisation and by the surgical description preoperatively. 2D echo was more sensitive than M mode in the detection of severe mitral stenosis (90% vs 73%, p less than 0,01). The 2D echo-Gorlin correlation was quite good (R = 0,70, p less than 0,01) but was worse when the valves were very thickened. When compared with the surgical observations, 87% of the 2D echo data was correct. The thickness of the valves, their amplitude, the diastolic bowing of the anterior leaflet and the presence of calcification were assessed by 2D echo. The echo-surgical results matched perfectly in 76% of cases. The usual cause of error was underestimation of the degree of valvular damage. The valvular bowing and thickness were the most useful signs. Dense, brilliant echos of valvular calcification were found in only 58% of surgically proven cases of valvular calcification, but the error was often related to fine calcification, not visible on fluoroscopy, or to its localisation on the posterior leaflet. The subvalvular apparatus was evaluated in over 93% of patients, a complete study being possible in 73% of them. The 2D echo-surgical correlations were excellent in 90% of the cases in which it had been completely visualised. The chordal thickening was correctly predicted in 79% of cases. The surgical assessment was more pessimistic in 1/3 of cases in which the chordae appeared to be of normal thickness. The length of the chordae was correctly predicted in 68% of cases. The surgical assessment was more pessimistic in 1/2 of cases in which the chordae appeared to be of normal length.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult

An asanguineous reperfusion solution. An effective adjunct to cardioplegic protection in high-risk valve operations.

The protection afforded by cardioplegia during elective ischemic arrest can be partly compromised by a reperfusion injury, which may impede the recovery of cardiac function. We previously showed experimentally that this postischemic damage could be largely avoided by an appropriate crystalloid reperfusate. The present study was thus undertaken to assess the effects of this "reperfusion solution" clinically. One hundred twelve patients undergoing valve replacement with the aid of hypothermic cardioplegia (K+ 12 mEq, Mg2+ 26 mEq) were prospectively divided in two groups: Group I (n = 49) received an unmodified blood reperfusate. In Group II (n = 63), 1 L of the reperfusion solution was delivered just prior to removal of the aortic clamp. The formulation of the reperfusion solution adhered to the following principles: (1) maintenance of cardioplegia (K+ = 15 mEq), (2) replenishment of Ca2+ stores (Ca2+ = 2.5 mEq), (3) substrate provision (glutamate = 2,942 gm), (4) buffering (pH = 7.70 at 28 degrees C), and (5) hyperosmolarity (370 mOsm). The two groups were matched for preoperative data except for a higher incidence of isolated aortic valve replacement (p = 0.01) in Group II. Also, the cross-clamp time (mean +/- standard error of the mean) was longer in Group II (94 +/- 4 minutes versus 63 +/- 4 minutes, p less than 10(-6]. The reperfusion solution was found to increase both the rate and extent of postischemic functional recovery, as evidenced by (1) a lower proportion of catecholamine-supported patients 48 hours after operation (9/63 [14.28%] versus 16/49 [32.6%] in the control group [p less than 0.03]) and (2) a lower amount (gamma/kg/min) of dobutamine required to achieve stable hemodynamics (11 +/- 1 versus 26 +/- 6 in the control group [p less than 0.03]). A similar recovery pattern was noted in the high-risk subgroup of patients with mitral valve disease. Further, serial postoperative hemodynamic measurements were performed in 31 randomly selected patients (10 control and 21 reperfused). Although the reperfused patients were found to be at higher risk because of lower preoperative cardiac indices and longer cross-clamp times, they consistently achieved better postoperative hemodynamics with a lower incidence of catecholamine support. This hemodynamic improvement was particularly reflected by a higher left ventricular stroke work index throughout the postoperative course, the difference being significant 6 hours and 12 hours postoperatively.(ABSTRACT TRUNCATED AT 400 WORDS)

Catecholamines

The antagonistic effects of ouabain and calcium channel blockers on the contractility of the isolated rat heart.

The simultaneous prescription of a calcium channel blocker and a cardiac glycoside is a frequently used therapeutic combination in cardiology, although its consequences on inotropism have not been really evaluated. This association is studied on isolated rat heart perfused at constant coronary pressure, paced at a constant frequency and working against a left intraventricular balloon. Since the inotropic effects are dependent on the basic level of myocardium contractility, controls were made hypocontractile by lowering external calcium level to 0.25 mM. For the same initial systolic pressure (45 mm Hg) and + dP/dTmax (150 mm Hg X s-1) the inotropic effect of 10(-5) M ouabain was significantly less pronounced in the presence of 10(-6) M verapamil or 10(-7) M nifedipine at 2.5 mM CaCl2 than at the low external calcium concentration of 0.25 mM (increasing the + dP/dtmax by 35% +/- 4, 29% +/- 6 and 110% +/- 18 respectively). Since we know that the inotropic properties of digitalis are probably due to an increase of the slow calcium inward current, we conclude that the observed effect would be due to a blockade of these channels by calcium blockers.

Animals

Genetic approach of family obesity: study of HLA antigens in 10 families and 86 unrelated obese subjects.

HLA A and B typing was performed in 86 unrelated obese subjects and in 10 families including at least one parent and one obese sibling. The results in the series of unrelated subjects show no significant difference in antigen frequencies as compared to the control series. However in the 10 families studied, a group of 5 families is characterized by a high penetrance of obesity. In this group, inheritance of obesity seems to be transmitted through a dominant mode, and antigen B 18 appeared 4 times out of 5. The possible existence of a genetic form of obesity is considered in the discussion.

Female