Biomedical subjects

R Mocellin

Publications and source records attributed to R Mocellin.

At least 19 recordsLinked to original sources

PubMed1999

[Interventional occlusion of persistent ductus arteriosus Botalli with Gianturco spirals].

Interventional duct occlusion is increasingly performed with detachable coils. In a series of 33 patients (34 procedures), we consistently used Gianturco-coils which were the initially employed coils. They are not securable but can be implanted in a simple manner. The rate of embolization was high (28%) in the first 14 procedures; however, it declined to 5% in the last 20 patients. We modified the technique by partially blocking the duct, when necessary, with a catheter which was advanced from the pulmonary artery and by implanting up to three coils. There was only one embolization and one small residual shunt in the last 20 patients. The mean fluoroscopy time in these patients was 11.0 +/- 5.8 minutes and decreased to 7.0 +/- 3.2 minutes in the last 10 patients with successful closure. Considering our experience, we continue to recommend the use of Gianturco-coils especially in the small duct which can be closed quickly at low cost.

Adolescent↗

PubMed1998

[Recanalization of Botalli's ductus arteriosus after catheter occlusion with a Rashkind double umbrella device].

Interventional duct occlusion with the Rashkind PDA occluder has become a widespread alternative treatment to surgery. Whereas residual shunting is well-known, reopening of a completely occluded duct has been published in only 3 cases. We report another case of a young adult in whom ductal shunting reappeared after he had restarted physical exercise and sports activities soon after the occlusion procedure. Recanalization might have been due to changing of the device position without embolisation. A second Rashkind PDA occluder was successfully implanted 6 months after the first procedure with complete closure of the residual shunt.

Adult↗

PubMed1995

[Comparative studies of hemodynamics under prostacyclin and nifedipine in patients with Eisenmenger syndrome].

In 10 patients 4-20 years of age with obstructive pulmonary vascular disease after Eisenmenger reaction pulmonary arterial and aortic pressure, pulmonary and systemic flow (Qp, Qs), and pulmonary and systemic vascular resistance (Rp, Rs) were determined before and during stepwise increasing doses of prostacyclin and nifedipine. Prostacyclin caused a significant decrease of pulmonary and systemic vascular resistance and a significant decrease of pressures in the aorta and the pulmonary artery, whereas no significant changes of hemodynamics were realized following nifedipine. The individual hemodynamic changes during prostacyclin were favorable in only two patients who demonstrated a marked decrease of Rp with no substantial change of Rs resulting in an increase in arterial oxygen saturation. In the other patients prostacyclin resulted in an adverse effect with a decrease of Rs exceeding that of Rp in 5 patients, a paradoxical increase of Rp in 1 patient, and a critical decrease of Qs with respective low central venous blood oxygen saturation and consequently low arterial oxygen saturation caused by a small right-to-left shunt in 2 patients. Nifedipine did not bring about a significant general change of hemodynamic parameters. The individual control showed no effect in 5 patients, an unfavorable effect by a decrease of Rs exceeding that of Rp in 2 patients, and a favorable net effect in only 3 patients, induced in 1 patient only after a very high dosage of nifedipine and leading to a certain increase of arterial oxygen saturation in only 1 other patient. From our results a beneficial effect of nifedipine in an average dosage on the hemodynamics of patients with Eisenmenger syndrome cannot be recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Oxygen uptake transient kinetics during constant-load exercise in children after operations of ventricular septal defect, tetralogy of Fallot, transposition of the great arteries, or tricuspid valve atresia.

Cardiovascular function accounts for endurance performance and, by a rapid increase in oxygen supply at the onset of exercise, contributes to short-lasting intensive exertion prevailing in many kinds of sports activities. This study determined the time for oxygen uptake (VO2) to reach one half of its asymptotic level above rest, and the respective oxygen deficit following the onset of a constant-load exercise corresponding to 80% to 90% of the maximal oxygen uptake (VO2max) in 35 children after surgical closure of a ventricular septal defect, after corrective surgery for tetralogy of Fallot, or after the Senning, Mustard, or Fontan procedures. In addition, VO2max and maximal blood lactate were determined. The half-time of VO2 response and oxygen deficit was lowest in patients after closure of a ventricular septal defect, whereas children had the most unfavorable VO2 transient kinetics after Fontan operation or with a transannular patch after correction of tetralogy of Fallot. A negative correlation was evaluated between half-time of VO2 response and VO2max, whereas maximal blood lactate varied independently of VO2max. It is concluded that many children with decreased VO2max after cardiac surgery also have unfavorable VO2 transient kinetics. In addition to being less qualified for endurance performance, they are also less prepared for short-lasting intensive energy expenditure. Therefore, the primary aim of training in these children is to improve the economy of motion of the respective tasks.

Adolescent↗

PubMed1993

Oxygen deficit and blood lactate in prepubertal boys during exercise above the anaerobic threshold.

Recent studies have shown that in boys a steady-state of blood lactate is maintained at exercise levels above the anaerobic threshold. Therefore, the explanation hitherto provided for the steeper increase in blood lactate beyond the anaerobic threshold, i.e. the onset of anaerobic metabolism, needs modification. Investigations were carried out in ten boys, aged 11-12 years, during treadmill running. Maximal oxygen uptake (VO2max) and maximal blood lactate were determined during incremental exercise. Subsequently each boy performed four runs at different high constant speeds of 16 min duration, in order to determine maximal steady-state blood lactate. The underlying data also served to estimate roughly the lactate anaerobic threshold. Oxygen uptaken (VO2) was measured at 0.5 min intervals during the initial 7.5 min of each constant-speed run. Maximal steady-state blood lactate was 5.6 mmol/l corresponding to 92% of VO2max. The mean blood lactate at which the anaerobic threshold was reached or just exceeded was 2.7 mmol/l corresponding to 82% of VO2max. Oxygen transport transient kinetics were computed from the mean 0.5 min VO2-values during the constant-speed runs near the maximal steady-state blood lactate and from runs near the anaerobic threshold. Half-times of VO2 response were shorter than values previously reported for adults due to a faster increase in VO2 at the onset of exercise. Half-times increased with increasing work rates as did the oxygen deficit, due to a slower increase in VO2 along with a longer time required to attain a steady-state at higher work rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗

PubMed1993

Complete heart block in a 9 year old girl caused by borreliosis.

A complete atrioventricular block was seen in a nine year old girl in whom an infection with Borrelia burgdorferi was confirmed by serological testing. There were no other symptoms or cutaneous manifestations of the disease. Though a rash on the right ear was later recalled by her parents. The patient was treated with high dose penicillin and orciprenaline was given intermittently. The complete heart block disappeared within four days.

Child↗

PubMed1991

Anaerobic threshold and maximal steady-state blood lactate in prepubertal boys.

To elucidate further the special nature of anaerobic threshold in children, 11 boys, mean age 12.1 years (range 11.4-12.5 years), were investigated during treadmill running. Oxygen uptake, including maximal oxygen uptake (VO2max), ventilation and the "ventilatory anaerobic threshold" were determined during incremental exercise, with determination of maximal blood lactate following exercise. Within 2 weeks following this test four runs of 16-min duration were performed at a constant speed, starting with a speed corresponding to about 75% of VO2max and increasing it during the next run by 0.5 or 1.0 km.h-1 according to the blood lactate concentrations in the previous run, in order to determine maximal steady-state blood lactate concentration. Blood lactate was determined at the end of every 4-min period. "Anaerobic threshold" was calculated from the increase in concentration of blood lactate obtained at the end of the runs at constant speed. The mean maximal steady-state blood lactate concentration was 5.0 mmol.l-1 corresponding to 88% of the aerobic power, whereas the mean value of the conventional "anaerobic threshold" was only 2.6 mmol.l-1, which corresponded to 78% of the VO2max. The correlations between the parameters of "anaerobic threshold", "ventilatory anaerobic threshold" and maximal steady-state blood lactate were only poor. Our results demonstrated that, in the children tested, the point at which a steeper increase in lactate concentrations during progressive work occurred did not correspond to the true anaerobic threshold, i.e. the exercise intensity above which a continuous increase in lactate concentration occurs at a constant exercise intensity.

Anaerobic Threshold↗

PubMed1990

Maximal steady state blood lactate levels in 11-year-old boys.

To evaluate whether anaerobic threshold criteria evaluated in adults are pertinent to children, ten boys with a mean age of 11.2 years were investigated during treadmill running. Maximal running velocity was determined at stepwise increasing load, with determination of blood lactate following exercise. On the following days four runs each lasting 16 min were performed at a constant speed starting with a speed corresponding to about 70% of the maximal speed and increasing it during the next run in order to determine maximal steady state levels of blood lactate. Blood lactate was measured at the end of every 4 min period. From this date the anaerobic threshold was calculated. The correlation between anaerobic threshold values and maximal steady state levels of blood lactate was poor, however, a steady state of blood lactate was present at 4.6 mmol/l, whereas the mean anaerobic threshold value was determined at 2.6 mmol/l. In view of our results, the anaerobic threshold during increasing work does not correspond to the true anaerobic threshold, which can be assumed to occur at much higher lactate values. The meaning of the term anaerobic threshold is therefore to be questioned.

Anaerobic Threshold↗

PubMed1990

Special problems in Fontan-type operations for complex cardiac lesions.

Four patients with complex cardiac lesions, who underwent successfully a Fontan type of operation are presented, each case representing a particular problem in surgical management. The first exhibited displacement of a trileaflet straddling and overriding left atrioventricular valve in addition to tricuspid atresia, while the second one had unilateral lung perfusion. In the third case, a stenosis had developed near the origin of the right pulmonary artery, and pulmonary vascular resistance could not be determined prior to the definite palliation procedure, whereas the fourth patient presented with stenosis of the left atrioventricular valve. Surgery was planned after detailed evaluation of the morphologic and hemodynamic features by means of echocardiography and cardiac catheterization. Our results illustrate the common tendency to extend the limits for modified Fontan procedures, which also includes revision of the original criteria for selection.

Cardiac Catheterization↗

PubMed1989

Atrioventricular septal defect with double-outlet right atrium.

A rare type of primum atrial septal defect is described in which the atrial septum deviated to the left, resulting in a double-outlet right atrium. The obstruction at the site of the small atrial septum defect led to an elevation of the left atrial mean pressure and to pulmonary arterial hypertension. The presence of mixed blood in the right atrium caused systemic arterial desaturation. A cleft in the septal leaflet of the left atrioventricular (AV) valve caused a left ventricular-right atrial shunt, which-added to the left-to-right atrial shunt--totaled 60% of the pulmonary circulating volume. Preoperative knowledge of the anatomic features facilitated surgical repair, which consisted in resection of the abnormal septum, construction of a new septum with a Dacron patch, and closure of the septal commissure of the left-sided AV valve.

Abnormalities, Multiple↗

PubMed1989

Successful palliation of the "absent" pulmonary valve syndrome by banding of the pulmonary trunk.

The "absent" pulmonary valve syndrome is associated with aneurysmal dilatation of the pulmonary trunk, stenosis of the ventriculo-arterial junction with or without malalignment of the outlet septum, and ventricular septal defect. When the outlet septum is malaligned, the morphology resembles that of tetralogy of Fallot. We report our experience with 4 infants with this syndrome. All were in severe respiratory distress and cardiac failure when first seen. Cardiac catheterization was performed at 0.5-4.5 months of age in 3 of them. In the other, the clinical and echocardiographic features were considered sufficient to establish the diagnosis. Banding of the pulmonary trunk was carried out at the age of 2.5-5 months. The distal pulmonary arterial pressure in 3 cases dropped to 12-19 mm Hg. These patients could be extubated within one week postoperatively. Their course 1-3 years later is excellent, with rare episodes of mild respiratory problems only and markedly diminished pulmonary insufficiency. One child, weighing 3250 g at surgery, whose pulmonary arterial pressure did not drop below 29 mm Hg, could not be weaned off the respirator. Corrective surgery was undertaken 17 days later, but the patient died of respiratory complications. Based on clinical and Doppler sonographic findings, on control catheterization data and on haemodynamic findings in 3 surviving infants and two further patients with an uneventful course who, as yet, have not undergone surgery, we conclude that the beneficial effect of banding is the combined result of reduced pulmonary arterial pressure and decreased pulmonic regurgitation.

Child, Preschool↗

PubMed1988

Left atrial isomerism combined with right-sided heart, common atrium, incomplete atrioventricular septal defect and partial anomalous systemic and pulmonary venous drainage. Report of a case with successful surgical correction.

Precise preoperative diagnostic clarification was accomplished in an infant with left atrial isomerism. The inner/outer arrangement of the pulmonary/systemic veins in relation to the posterior wall of the common atrium necessitated a specific baffle in order to prevent pulmonary or systemic venous obstruction. The development of a sick sinus syndrome six months after surgery is in keeping with the natural history of the disease.

Blood Vessel Prosthesis↗

PubMed1988

[Modified Blalock-Taussig anastomosis. Its significance within the scope of surgical treatment of tetralogy of Fallot].

We report our results with 14 cases of tetralogy of Fallot, which were treated with a modified Blalock-Taussig shunt first, total correction having been performed in 9 of them after a mean interval of 15 months. The age of the patients ranged from 12 days to 3.3 years, with a mean of 4.7 months in 12 patients below the age of one year. In 11 cases we used a 5 mm Gore-Tex prosthesis, in 2 a 6 mm prosthesis and in one a 4 mm prosthesis. All children survived the operation. In one case shunt thrombosis occurred after a bout of pneumonia and a second shunt had to be constructed on the other side. Control angiography, performed after a mean period of 15 months in 13 patients revealed a patent shunt, though angulation of the ipsilateral pulmonary artery was noted in one case. The ratio of the diameter of the pulmonary artery to the aorta increased by 20%. The significance of these findings with regard to the question of primary or two-stage repair in infants less than one year old is discussed in view of different risk factors.

Anastomosis, Surgical↗

PubMed1987

[Transluminal extraction of intracardiac embolized catheter fragments in children].

The frequent use of central venous catheters for administration of fluids and especially ventriculovenous shunts in children sometimes lead to embolisations of catheter fragments. Because of the potential complications, extraction of the fragments is mandatory. In 5 children aged 1.8 to 7.8 years fragments were removed from the right heart and the pulmonary artery by use of a loop snare, a helical basket or a myocardial biopsy catheter. In four cases the fragment was the distal part of a ventriculoatrial shunt, in one case the central part of a silastic catheter had accidentally advanced into the pulmonary artery. In two cases adhesions of the fragment to the wall of the pulmonary artery impeded the extraction.

Angioplasty, Balloon↗

PubMed1986

[Sports fitness in pulmonary hypertension].

In patients with pulmonary hypertension caused by a large ventricular septal defect, the cardiopulmonary performance capacity (CPC) depends on the relation of pulmonary to systemic vascular resistances. Changes in this relation occurring on exercise are mainly due to an exercise - induced fall of the systemic vascular resistance. If the ratio of pulmonary to systemic resistance is below 1 at maximal exercise, the CPC is reduced as a result of the left to right shunt. In case of a pulmonary to systemic resistance ratio of higher than 1 at maximal exercise hypoxemia will be a limiting factor. Only in cases of a moderate degree of pulmonary vascular changes, resulting in a relation of resistances at maximal exercise in the range of 1, will the CPC be normal. Patients with primary pulmonary hypertension always present with reduced CPC as a main symptom. Cardiac output cannot be adequately increased during exercise. Only by excessive peripheral oxygen desaturation can a certain adaptation to the oxygen demand of the exercising organism be possible to a certain degree, though only at low work rates. Uneven perfusion and the corresponding ventilation-perfusion inequality are only moderate. However, due to the widened arterial-venous oxygen difference, ventilation-perfusion inequality with its distinct alveolar-arterial oxygen pressure difference can result in a considerable degree of venous admixture. In adolescents, pulmonary hypertension caused by obstructive lung disease is seen almost only in patients with advanced stages of cystic fibrosis. It is then combined with increased venous admixture, and often with CO2-retention.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗

PubMed1986

Exercise testing in children with congenital heart disease.

In children with congenital heart disease, interest concerning cardiovascular performance capacity is directed mainly to the operated patient. Indirect and/or submaximal tests to assess cardiovascular ability are based on assumptions that are at least partially incorrect, so that test results may not be valid. Standardization of values should be performed according to body height, but should also account for age. There is a lack of information concerning the cardiovascular performance capacity of children following Senning or Mustard operations for transposition of the great arteries and following Fontan procedures for different malformations. In considering participation in sports, it should be realized that it is not the cardiovascular performance capacity that generally plays a dominant role. In technical disciplines and in short-term efforts, motor performance may be more important. Endurance training cannot be recommended in view of the anatomical disorders still present in many patients after cardiac surgery. Ergometry can add information on dysrhythmias, which may cause problems postoperatively, but may also be present without organic heart disease.

Adolescent↗

PubMed1983

[Intraoperative electrophysiological localization of the origin of sinoatrial activity and examination of the location of the sinus node using microscope anatomic studies. Animal experiment study].

Many electrophysiological and histological investigations have demonstrated that post-operative dysrhythmias which occur in children with heart disorders requiring extensive surgical treatment in the area of the right atrium, are often caused by intraoperative lesions of the sinoatrial node. Accordingly, accurate determination of that epicardial area which is closest to the primary pacemaking area of the sinoatrial node could prevent injuries and, thus, reduce the risk of postoperative arrhythmias. To localize the relevant area we developed a method which is based on the mapping technique in a series of experiments in dogs. The electrophysiological results were confirmed by histological or gross anatomical methods. After right lateral thoracotomy in the fifth intercostal space, the epicardial surface of the right atrium is subdivided into numbered fields by means of an imaginary grid. The local electrical activities are recorded as bipolar electrograms with the aid of two tripolar electrode probes, one fixed on the epicardium of the right atrial appendage and one placed onto the individual grid fields by the investigator. Intervals thus occur between those potentials derived from the mobile electrode probe and those derived from the fixed probe. Electrical activity originating from the sinoatrial node arrives earlier at the individual fields lying closer to the node than at the field of the fixed probe at the atrial appendage. Thus, the individual field associated with the longest interval between probe potentials must lie closest to the sinoatrial node. An electronic device with digital display of the interval length has been developed which enables, within three minutes, determination of the individual field with the longest interval. Comparison of the digital values with those measured from the electrograms shows good agreement. The experiments were carried out on eleven sheep dogs and large mongrels. In seven cases the location of the sinoatrial node was determined by subsequent histological examination. The assumption that the area associated with the longest interval between the probe potentials lies closest to the primary pacemaking region of the sinus node could be confirmed, since in all these cases the cranial portion of the sinoatrial node was located in the field with the greatest interval measured. In the other four cases the sinoatrial node was localized by dissection with the aid of a stereomicroscope. In three of the four cases, the cranial part of the sinoatrial node was also situated in the field associated with the longest interval.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1983

[Unusual contrast medium distribution in the left ventricular myocardium in infants with a high degree of aortic valve stenosis and endocardial fibroelastosis. Pathologico-morphologic findings].

In 5 newborn infants with severe valvular aortic stenosis, left ventricular angiocardiography revealed conspicuous pathologic-morphologic findings consisting of a fine network of contrast medium opacification in the region of the posterior wall. Subsequently performed histologic examination of tissue removed from the involved regions showed, in addition to endocardial fibroelastosis, two structures which were assumed to be the morphologic substrates for the unusual distribution of contrast medium. On the one hand, antler-like spaces with a well-demarcated lining of fibroelastic tissue, similar to the thickened endocardium, were found in the inner half of the left ventricular wall connected to the lumen of the left ventricle through bottle-necked communications. On the other hand, oval or oblong lumina, substantially larger in caliber than capillaries but showing only a single endothelial layer could be demonstrated. With the sectioning technique employed, anastomoses of the latter spaces with the left ventricle or the previously mentioned system of spaces could not be established. The cause of the development or maintenance of these sinusoidal spaces may be attributable to the elevated diastolic left ventricular pressure, while the elevated systolic pressure may have been a decisive etiologic factor for the endocardial fibroelastosis. Whether the intratrabecular spaces represent persistent embryonic myocardial sinusoids cannot be differentiated unequivocally. In support of the stated contentions, however, are other results indicating that the extent of structural changes in the ventricular wall increases proportionately with the duration of existence of the obstructive lesion in the embryonic period.

Angiocardiography↗