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Biomedical subjects

F Wyler

Publications and source records attributed to F Wyler.

At least 19 recordsLinked to original sources
PubMed1997

Dilated cardiomyopathy and thrombo-embolism.

UNLABELLED: The purpose of this study was to investigate the incidence, outcome and prevention of thrombo-embolism in children with dilated cardiomyopathy. From 130 patients with dilated cardiomyopathy, 17 (14%) showed evidence of thrombo-embolism. Seven had initial cardiac thrombus, 7 exhibited initial embolus and in 3 thrombo-embolism was only diagnosed at autopsy. All 17 patients showed seriously impaired systolic function of the left ventricle with fractional shortening (FS) of 10 +/- 3%, range 5%-17%, as compared to those without thrombo-embolism with FS of 17% +/- 6%, range 5%-26% (P < 0.0001). Seven patients were treated with oral anticoagulants once thrombo-embolism had been diagnosed; one of them experienced a further embolic event as opposed to three out of four patients not treated with anticoagulants. CONCLUSION: All children with dilated cardiomyopathy and fractional shortening below 20% should be treated with prophylactic anticoagulative agents.

Adolescent↗
PubMed1996

Arm-leg pressure gradients on late follow-up after coarctation repair. Possible causes and implications.

Seventeen years after coarctation repair, 36 patients were studied by magnetic resonance imaging and exercise testing to measure residual anatomical stenosis and hormonal response to exercise, and to evaluate their effect on arm-leg gradients and on exercise hypertension. The systolic arm pressure, leg pressure and arm-leg gradient were measured at rest and during exercise. Active renin and catecholamines were measured in the plasma at rest and after peak exercise. On magnetic resonance imaging 18 patients had residual stenosis of less than 30% (group I) and 18 had residual stenosis of equal to or more than 30% (group II). At peak exercise, the arm pressure was 235 (133-296) mmHg in group I and 241 (157-286) mmHg in group II (ns), the leg pressure was 138 (111-173) mmHg in group I and 114 (75-154) mmHg in group II (P = 0.002). The adrenalin increase from rest to exercise was 32.7 +/- 9.1 pg.ml-1 in the patients with exercise hypertension and 3.1 +/- 4.7 pg.ml-1 in the patients who remained normotensive during exercise (P = 0.02). In conclusion, residual anatomical stenosis leads to a pressure drop in the legs, which influences the arm-leg gradient. Arm hypertension is not related to anatomical narrowing but to interaction of enhanced sympathetic nerve activity and structural and functional abnormality of the precoarctation vessels.

Adolescent↗
PubMed1996

Effects of morphologic restenosis, defined by MRI after coarctation repair, on blood pressure and arm-leg and Doppler gradients.

Ten years after coarctation repair, 36 adolescents and young adults were studied in order to evaluate the relationship of anatomy at the resection site to blood pressure and arm-leg and Doppler gradients. The patients underwent magnetic resonance imaging (MRI), exercise testing, and continuous wave (CW) Doppler echocardiography. On MRI, residual narrowing at the resection site was measured as 1-(phi anastomosis/ phi descending aorta) and expressed as percent stenosis. Residual stenosis on MRI was negatively correlated with the leg pressure at rest (P = 0.0003) and during exercise (P = 0.002). Residual stenosis correlated positively with the arm-leg gradient at rest (P < 0.0001) and during exercise (P < 0.0001) and with the peak CW Doppler gradient across the anastomosis (P < 0.0001). However, residual stenosis was not related to the systolic blood pressure of the arm at rest or during exercise. The systolic arm pressures did not differ between patients with residual stenosis of less than 30% (group I), patients with residual stenosis of equal to or greater than 30% but less than 45% (group II), and patients with residual stenosis of equal to or greater than 45% (group III). In conclusion residual anatomic stenosis influences blood pressure in the legs, the arm-leg gradient, and the Doppler gradient across the anastomosis. Arm hypertension late after coarctation repair seems not to be related to residual stenosis, and the benefit of reintervention in these patients remains questionable.

Adolescent↗
PubMed1995

Exercise-induced hypertension in the arms due to impaired arterial reactivity after successful coarctation resection.

Exercise-induced hypertension of the arms is a well-known late complication after coarctation repair. Residual narrowing at the anastomosis site as well as abnormalities of the precoarctation arterial system may be the cause of this problem. Blood pressure response to exercise and flow-mediated arterial dilatation of the arms and legs were studied in 29 young adults after successful coarctectomy in childhood and compared with 13 control subjects. Peak exercise systolic blood pressure was significantly higher in patients than in control subjects: 238 versus 199 mm Hg (p = 0.007). Both groups had a positive systolic arm-leg gradient during exercise: 59 versus 37 mm Hg (p = 0.05). Flow-mediated dilatation of the brachial artery was significantly reduced in patients compared with that in control subjects: 4.2% (range 0% to 9.4%) versus 9.4% (range 3.7% to 16%) (p < 0.0001). Flow-mediated dilatation of the femoral artery was similar in both groups. Dilatation of the brachial artery was inversely correlated to peak exercise systolic pressure in the study patients (r = -0.427, p = 0.02). A positive arm-leg exercise gradient partly represents physiologic circulatory adaptation to ergometry and is therefore not appropriate for evaluation of residual narrowing. Exercise-induced hypertension of the arms late after coarctation repair is caused by impaired arterial reactivity, which results from structural or functional abnormality, or both.

Adolescent↗
PubMed1995

Cardiomyopathy in respiratory chain disorders.

Disorders of mitochondrial oxidative phosphorylation may disturb cardiac energy metabolism and cause cardiomyopathy. Twenty one cases from the literature and one further patient with cardiomyopathy due to biochemically defined respiratory chain defects were reviewed for clinical course, morphology, and pathophysiological mechanisms of the cardiomyopathy. All cases showed concentric hypertrophy of the myocardium without an outflow tract obstruction. In most patients the cardiomyopathy was diagnosed early in infancy and showed rapid deterioration with death before the age of 2 years. Hypertrophy of the myocardium appears to result from swelling of the cardiomyocytes caused by accumulation of mitochondria and by morphologically abnormal megamitochondria.

Cardiomyopathy, Hypertrophic↗
PubMed1994

Possible genes for left heart formation on 11q23.3.

A case of balanced translocation t (10; 11) (q 24; q 23) is presented. This female newborn showed no other malformation than hypoplastic left heart syndrome. According to several cases of 11q- and hypoplastic left heart in the literature and to this observation the authors postulate genes for left heart formation on chromosome 11q23.3.

Adult↗
PubMed1994

[Pediatric cardiological emergencies].

Emergencies in pediatric cardiology are heart failure, cyanosis and rhythm disturbances. The signs of heart failure are tachycardia, tachypnea and hepatomegaly. The therapy consists of oxygen, diuretics and digoxin. Occasionally, intubation with mechanical ventilation and intravenous catecholamines are needed. Cyanosis is often the only sign of a severe heart malformation, and prompt hospitalization is mandatory. Oxygen and warm environment is important during transport, correction of a possible metabolic acidosis and prostaglandin infusion are done in the hospital. Beyond the newborn period, so-called cyanotic spells are seen, particularly in tetralogy of Fallot. In supraventricular tachycardia, vagal manoeuvres can be tried first, if not successful, intravenous adenosine or electroconversion will restore sinus rhythm. In the older child, intravenous isoptin can be given. Slow heart rates from total AV block or sinus node affection are treated with atrophic, isuprel or electrical pacing.

Arrhythmias, Cardiac↗
PubMed1993

[Early detection of critical aortic isthmus stenosis in the neonate].

Between 1985 and 1992 7 newborns with critical coarctation of the aorta were referred with clinical signs of beginning or manifest cardio-vascular shock and subsequently underwent a primary operative correction. All of the children were noticed by their parents as having unspecific clinical symptoms such as poor feeding and tachypnoea. The aim of our clinical effort should be to detect all newborns with critical coarctation of the aorta before manifestation of a cardiogenic shock, i.e. before the complete closure of the ductus arteriosus. This might be possible with a careful clinical examination of the cardio-vascular system between the 3rd and 4th day of life and the correct interpretation of unspecific early symptoms.

Aortic Coarctation↗
PubMed1990

[Translocation trisomy 4q in 2 siblings as a sequela of paternal balanced reciprocal translocation: t(1;4)(q44;q31)].

In a sister and a brother with striking similarity of facial dysplasias, severe disturbance of expressive speech, and mild mental retardation a partial trisomy of the long arm of chromosome 4 was identified as cause of these anomalies. The partial trisomy 4q was due to a balanced translocation between the chromosomes 1 and 4 in the father of both children.

Abnormalities, Multiple↗
PubMed1987

Cognitive task influence on relative hemispheric motor control: mouth asymmetry and lateral eye movements.

While strictly verbal cognitive tasks showed a strong left-hemisphere dominance, the presence of visualization and emotion in cognitive tasks resulted in increased involvement of the right hemisphere in motor control of speech as measured by mouth asymmetry. Spontaneous smiles showed right-hemisphere dominance. Lateral eye movements showed an unexpected shift to left gaze during speech which may suggest a dual task interference between speech and gaze motor control.

Adolescent↗
PubMed1987

Successfully treated mitral valve endocarditis in a neonate.

We report on a newborn with severe congestive heart failure where echocardiography was leading to the correct diagnosis and the treatment. Endocarditis in the newborn is a rare disease, and the diagnosis is possible from the echocardiographic demonstration of vegetations. It is therefore important to search for vegetations in the very ill newborn with cardiac symptoms, in order to start early antibiotic treatment independently of positive cultures and to avoid the usual fatal outcome of this disease.

Anti-Bacterial Agents↗
PubMed1987

Influence of rehydration on organ blood flow after hypernatremic shock in the unrestrained young minipig.

Hypernatremic shock was produced in the minipig by feeding hyperosmolar solutions, which led to osmotic diuresis and dehydration. Weight loss was 14%, serum values (in mmol/L) were, for Na, 168; urea, 12.1; bicarbonate, 10.5; and pH 7.25 (mean values). Cardiac output was reduced by 51%, arterial pressure was unchanged (-5.1%); organ blood flow, measured with radioactive microspheres, was as follows: heart, -56%; brain, -35%; gastrointestinal tract, -60%; and kidneys, -57%. Intravenous rehydration for 24 h normalized weight, serum electrolytes, and pH; but had little effect on cardiac output and organ blood flow. Even prolongation of fluid therapy to 48 h did not restore the circulatory changes, which showed an arterial pressure of +4.3%; cardiac output, -31%; and flow to heart, -21%; brain, -24%; gastrointestinal tract, -30%; and kidneys, -47%. This pattern of diminished cardiac output, normal arterial pressure, and reduced organ blood flow not only in the splanchnic organs but also in heart and brain is similar to the hemodynamic response to vasopressin. Increased vasopressin release probably plays an important role after rehydration in hypernatremic shock.

Animals↗
PubMed1984

Reference values of various blood constituents in young minipigs.

In the Göttinger minipig, the reference values of 18 parameters in whole blood or plasma were determined. The results are expressed both as the mean value and +/- 2 SD presuming a symmetrical normal distribution and as the median value with the corresponding range. For most blood constituents, the results of the two modes of calculation were similar. Comparison of the values from young minipigs with those from children shows that these animals are well suited in this respect for experimental work related to human medicine.

Animals↗
PubMed1984

Hypernatraemic dehydration revisited.

After discussing earlier concepts of hypernatraemic dehydration, experiments on infantile mini-pigs are reported. After giving osmolar NaCl and NH4Cl solution, dehydration with chloride acidosis was produced and then rehydration was started for 24 h. From the findings the conclusion was drawn that in hypernatraemic dehydration cerebral lesions are not primarily due to an overall impairment of brain blood flow and that blood pressure is a misguiding criterion of fluid loss and circulatory assessment.

Animals↗
PubMed1983

Hemodynamics in experimental hypernatremic dehydration with special reference to individual organ blood flow in shock and after rehydration.

Shock after hypernatremic dehydration in the mini-pig is characterized by low cardiac output but little reduction of arterial blood pressure. Maintenance of pressure is due to extensive arteriolar vasoconstriction in the splanchnic and renal vascular bed, as calculated from their markedly diminished blood flow. The expected preservation of flow to vital organs did occur in the brain and the adrenals, but not in the heart. Sufficient oxygen was probably provided by the elevated hematocrit. After 24 h, intravenous fluid therapy produced adequate rehydration as seen from the correction of azotemia, metabolic acidosis, and hypernatremia; only serum creatinine remained elevated. Although cardiac output increased, it did not reach the initial value. Blood flow to most organs was back to normal, but gastrointestinal and particularly renal blood flow remained diminished.

Animals↗
PubMed1980

Successful palliation by means of a bovine artery graft in a 4-day-old infant with type B interruption of aortic arch and right descending aorta.

In a 4-day-old baby a unique form of interrupted aortic arch was diagnosed, where the interruption was located between the right carotid and the right subclavian arteries in a right descending aorta. The additional large ductus was ligated, the VSD was palliated with pulmonary arterial banding. For the repair of the interrupted aortic arch with its long distance between the ascending and descending portions and the complicating proximity of the superior vena cava, a long pliable material had to be used. The anastomosis was successfully performed with a bovine arterial heterograft.

Animals↗
PubMed1980

Hemodynamic changes in hypernatremic dehydration in the mini-pig.

Hypernatremic dehydration with metabolic acidosis and azotemia was experimentally induced in the mini-pig by feeding a hypertonic NaCl and NH4Cl solution wit nasogastric tube. After a loss of 19% of initial body weight within 32 hours, the following hemodynamic changes were observed: the heart rate rose, the arterial blood pressure was maintained, but cardiac output fell to 80% of its initial value. There was a redistribution of this lowered cardiac output with unchanged blood flow to heart, brain, adrenals and skeletal muscle. The flow to these vital organs was diverted to selective vasoconstriction of spleen, pancreas, gastrointestinal tract and kidneys. Quantitatively the contribution from the latter two organs was the most important.

Animals↗