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Biomedical subjects

I Luhmer

Publications and source records attributed to I Luhmer.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Atrial arrhythmias after modified Fontane operation: effect of preoperative hemodynamics and the kind of operation (atriopulmonary vs. total cavopulmonary anastomosis)].

UNLABELLED: Between October 1986 and March 1992, occurrence of supraventricular tachycardia and sinus node dysfunction was investigated pre- and postoperatively by serial ECG and Holter monitors in 63 consecutive patients with univentricular circulation after modified Fontan operation (total cavopulmonary connection 39 patients, atriopulmonary connection 24 patients). Mean age at operation was 7.2 (0.1-20.3) years. Of the 63 patients, 14 (22%) had early (< 14 d) supraventricular tachycardia or sinus node dysfunction, which was not related to the type of operation. None of nine patients with a preoperative mean right atrial pressure < or = 2.5 mm Hg had early supraventricular tachycardia or sinus node dysfunction, in contrast to 16/54 patients (30%) with a preoperative mean right atrial pressure > or = 2.5 mm Hg. 6/63 patients died during the early (< 14 d) postoperative period. In only one child death was related to a dysrhythmia (junctional ectopic tachycardia). During a mean follow-up of 2.5 years, 12 patients (21%) had late supraventricular tachycardia or sinus node dysfunction. Early supraventricular tachycardia/sinus node dysfunction was a predictor of late atrial dysrhythmias, as it occurred in eight of the surviving 14 patients with early dysrhythmias, in contrast to four children without early atrial dysrhythmias (p < 0.001). After creation of an atriopulmonary connection, 10/22 patients (45%) had late supraventricular tachycardia/sinus node dysfunction, but only 2/35 patients (6%) with a total cavopulmonary connection had late atrial dysrhythmias (p < 0.001). CONCLUSIONS: Early atrial dysrhythmias after the Fontan operation were related to preoperative hemodynamics. Early supraventricular tachycardia/sinus node dysfunction and the atriopulmonary type of Fontan connection were significant risk factors for late atrial dysrhythmias.

Adolescent↗
PubMed1993

[Emergency 12-hour transesophageal stimulation in a 21-month-old infant].

In a 21-month-old child with complex cyanotic congenital heart disease an aortopulmonary shunt was created as preparation for a modified Fontan operation. During the early postoperative period low cardiac output with right atrial pressures of 20 mm Hg developed due to a slow ventricular tachycardia (ventricular rate 135 bpm). Pharmacological interventions (isoprenaline 0.01 mg/kg hourly and lidocaine 1 mg/kg hourly were without any effect. As epicardial pacing leads had not been implanted during surgery, atrial pacing was performed via the transoesophageal route using a 9.5-F bipolar electrode catheter with an interelectrode distance of 15 mm. Atrial capture could be established with an impulse width of 9.9 ms and 10 mA output at a rate of 150 bpm. With restoration of atrioventricular synchronicity, right atrial pressure finally decreased to 10 mm Hg with consecutive stabilization of the cardiovascular status. After 12.5 h transoesophageal pacing could be stopped without any problems due to spontaneous cessation of ventricular tachycardia. No clinical signs of oesophageal injury were noted. It is concluded that transoesophageal pacing is a practical, safe and effective method for emergency cardiac pacing.

Cardiac Output, Low↗
PubMed1993

[Definitive therapy of supraventricular tachycardia using high frequency current catheter ablation].

BACKGROUND: Catheter ablation using radiofrequency current has been proven to be an effective and save tool for the treatment of adult patients with accessory atrioventricular pathways and with atrioventricular nodal reentry tachycardia. This study was designed to analyse the efficacy of this method in children and adolescents. PATIENTS AND METHODS: Using radiofrequency current, catheter ablation of an accessory pathway or of AV nodal reentry tachycardia was performed in 13 patients (mean age 12.7 years) with drug-refractory supraventricular tachycardia. Radiofrequency current was applied through a 6 French steerable catheter positioned against the mitral or tricuspid anulus. Criteria for radiofrequency current application (at 70 degrees C or with 30 W) were the recording of an accessory pathway potential or a local atrioventricular interval < 40 ms. In the patient with atrioventricular nodal reentry tachycardia, a potential of the slow pathway was recorded. RESULTS: In 6 of 7 patients with left-sided accessory pathways and in 4 of 5 patients with right-sided connections, conduction over these pathways was permanently interrupted. In the patient with atrioventricular nodal reentry tachycardia, radiofrequency current eliminated the tachycardia without affecting normal atrioventricular nodal conduction. In a patient with an anteroseptal pathway, induction of atrioventricular block was inevitable. No other complications were noted. CONCLUSION: Catheter ablation using radiofrequency current is a highly effective method for definite treatment of supraventricular tachycardia in children and adolescents.

Adolescent↗
PubMed1992

Thoracic organ transplantation in the paediatric age group. The Hannover experience.

Growing experience in terms of immunosuppression, recipient and donor selection as well as organ preservation has established thoracic organ transplantation as a therapeutic option for many children with end-stage cardiopulmonary diseases. While dilated cardiomyopathy and isolated myocardial failure represent the main indications for cardiac transplantation, replacement of the lungs or heart and lungs is necessitated in cystic fibrosis, primary and secondary pulmonary hypertension as well as some types of complex congenital heart defects involving the pulmonary arteries. We have performed a total of 20 heart, 4 heart-lung, 2 single lung and 1 double lung transplantation in the paediatric group up to 17 years of age. While with respect to the limited experience worldwide, early mortality after lung and heart-lung transplantation is still high (50%), long-term results in isolated cardiac transplantation using triple drug immunosuppression are excellent (79% survival after 6 years) without major impairment of renal function, arterial blood pressure, growth development and physical rehabilitation as well as social reintegration. Freedom from graft atherosclerosis of the allografted heart is documented over a 5 year follow up, while no data are available on the incidence of obliterative bronchiolitis after lung transplantation in the paediatric group. Despite only limited evidence of long-term dysfunction, diagnosis and prevention of chronic rejection should be given utmost attention to allow for a normal life span in this younger age group.

Adolescent↗
PubMed1992

Staged chest closure in pediatric cardiac surgery preventing typical and atypical cardiac tamponade.

Chest closure after cardiac surgery occasionally results in cardiac compression leading to circulatory failure. In shunt-dependent circulation, the arterial oxygen saturation may decrease significantly due to the increase in pulmonary vascular resistance caused by chest closure. Temporary patch implantation with delayed sternal closure facilitates circulatory and/or pulmonary stabilization (temporary chest wall patch plasty, TCWPP). Between July 1986 and June 1991, 42 patients underwent staged chest closure (TCWPP) after open heart surgery for congenital lesions (4.9% of 854 patients). TCWPP was performed when either primary hemodynamic deterioration or an increase in cyanosis (palliative procedures only) followed by hemodynamic deterioration occurred during attempted or shortly after sternal closure. Overall mortality was 40.4% (17/42). It was 32.3% (11/34) when the patch was inserted primarily at the end of the operation. If the patch was inserted emergently 4-24 h postoperatively, mortality was 75% (6/8). Definite chest closure was performed from 4 h to 6 days (mean 72 h) postoperatively. In 2 patients closure had to be performed emergently (single ventricles); 7 patients died before chest closure. One mediastinal microbiology examination was positive. Deep sternal infection necessitating operative revision occurred in one other patient. In conclusion, TCWPP may considerably lower mortality of the illest patients after surgery for complex congenital heart disease. A timely decision as to the performance of staged chest closure is mandatory. This procedure rarely causes infection. We now apply this technique liberally, by cardio-mediastinal size judgement in over 30% of our TCWPP candidates even without a prior trial of primary closure.

Adolescent↗
PubMed1992

[Complex progressive palliation for univentricular circulation].

The type of palliative procedures (PP) for complex univentricular circulation (UC) changed significantly during the 80ies. Between 07/86 and 02/91 77 patients (pts) presented with UC to eventually undergo a modified Fontan-Kreutzer-type-operation (MFKTO). 33 pts had been previously palliated, 22 of whom were accepted for MFKTO as well as an additional 9 not palliated pts (group A: 31 pts; 20 PP). 11 previously palliated pts and 35 new pts required new palliations (group B: 46 pts; 89 PP), 34 of which resulted in 13 MFKTO. Prerequisites to be met for MFKTO are: undistorted PA-anatomy; absence of subaortic stenosis (SAS); Qp greater than 2.5 l/min/m2; PAP less than 20 mm Hg; Rp less than 3 Wood Units. All earlier PP in group A (31 BTS, 3 PAB, 2 PA-valvotomy/dil.) merely prolonged survival by only adjusting Qp. In group B PP comprise reconstruction of pulmonary arteries, aortic arch and isthmus as well as bypass or resection of SAS or atrial septectomy. Mortality for complex PP (group B) was 32.5% (15/46). 9 of these pts were neonates, 7 after modified Norwood procedures. In an attempt to plan a MFKTO for all pts presenting with UC (group B), complex PP was necessary. The high mortality is due to lesions in pts who would not have survived if only closed PP were applied.

Child↗
PubMed1992

[Assessment with magnetic resonance tomography of anatomy and ventricular function after Mustard correction of transposition of the great arteries].

In order to evaluate postoperative sequelae and ventricular function after Mustard-operation in patients with transposition of the great arteries (TGA), 30 patients were assessed by magnetic resonance imaging in EKG-triggered spin-echo (SE) and gradient-echo (GE) technique. Twenty-three patients, aged 4.7 to 15.8 years, had transposition of the great arteries with intact ventricular septum with or without left-ventricular outflow tract obstruction (TGA+IVS +/- SPS). Seven patients aged 9.5 to 21.7 years had transposition of the great arteries with ventricular septal defect (TGA+VSD). Five patients showed a residual baffle leak, one had a pulmonary venous obstruction, five an obstruction at the caval veins, 13 a left-ventricular outflow tract obstruction, and 14 a tricuspid regurgitation. Right-ventricular enddiastolic volume in patients with TGA+VSD (77.0 +/- 25.5 ml/m2) was significantly higher than in patients with TGA+IVS +/- SPS (61.2 +/- 12.0 ml/m2). In TGA+VSD right-ventricular ejection fraction (47.6 +/- 13.0%) was significantly lower than in patients with TGA+IVS +/- SPS (56.7 +/- 10.7%). The ratio of muscle masses of right to left ventricle was 1.8:1 in patients with TGA+IVS +/- SPS and 2.5:1 in patients with TGA+VSD. In conclusion, after Mustard-operation in patients with transposition of the great arteries (TGA) magnetic resonance imaging provides a comprehensive and noninvasive assessment of postoperative sequelae, residuae, and ventricular function and will, therefore, become the method of choice for postoperative evaluation.

Child, Preschool↗
PubMed1991

Magnetic resonance imaging of cardiac function and morphology in patients with transposition of the great arteries following Mustard procedure.

In order to assess the diagnostic possibilities of magnetic resonance imaging (MRI), 30 children (mean age 11.5 years) with d-transposition of the great arteries (TGA) corrected by the Mustard procedure were studied. Patient values were compared to those of 10 healthy volunteers. The most important postoperative abnormalities such as baffle leaks, systemic or pulmonary venous obstructions, left ventricular outflow tract (LVOT) stenosis and tricuspid regurgitation were assessed. Cardiac volumes and muscle mass were measured. Baffle leaks were found in 5 and obstruction of the baffle limbs in 6 patients. On gradient echo images 13 patients showed signs of LVOT stenosis and 12 tricuspid incompetence. Right ventricular end diastolic volumes in patients were significantly higher than the left ventricular volumes, but slightly lower than right ventricular volumes in the normals. In patients with TGA and ventricular septal defect (VSD) (n = 7) right ventricular (RV) volumes were found to be higher than in patients with intact ventricular septum (n = 23) and in normals. In contrast to the normal RV function of patients after Mustard surgery only patients with previous VSD showed a diminished RV ejection fraction. The muscular mass in TGA patients showed a ratio of 1.9:1 between right and left ventricles. In normals the ratio was 1:1.5. Magnetic resonance imaging allows a quantitative insight into the ventricular function and the morphology of the heart after inflow correction. Thus, it supplements the noninvasive evaluation of TGA patients.

Adolescent↗
PubMed1991

Renal involvement in patients with congenital cyanotic heart disease.

Patients with congenital cyanotic heart disease may develop a glomerulopathy with proteinuria and impaired renal function. In order to investigate this problem we conducted a study on 27 patients with uncorrected cyanotic heart disease who were between 1 day and 25 years old. As a consequence of hypoxaemia haematocrit was elevated to 57%. Proteinuria was above 150 mg/day/1.73 m2 body surface in 12 patients. Only one of 9 children under 10 years of age had pathological proteinuria presenting as isolated albuminuria. Seven out of 10 patients between 11 and 20 years had an elevated proteinuria with a glomerular pattern. Creatinine clearance was normal in these patients. All four patients above 20 years of age had a considerable glomerular proteinuria with a mean excretion of 5.7 g/24 h/1.73 m2 body surface. These patients suffered additionally from chronic cardiac failure and creatinine clearance was below the normal range. There was a clear relationship between pathological proteinuria and age of the patients and thus duration of hypoxaemia. Patients with pathological proteinuria had a significant higher erythrocyte count (7.3 +/- 1.3 vs 5.6 +/- 1.4 10(12)/l p less than 0.01) and a lower mean corpuscular haemoglobin. In summary, children with persistent congenital cyanotic heart disease have substantial risk of developing a glomerulopathy if the cyanosis remains unchanged for more than ten years.

Adolescent↗
PubMed1990

Coarctation of the aorta in complex congenital heart disease: simultaneous repair via sternotomy.

Coarctation of the aorta (CoA) is often associated with complex congenital heart disease. Patients with such a combination may not benefit from coarctectomy alone. Eight children who presented with complex malformations of the heart underwent simultaneous repair of CoA and intracardiac surgery via sternotomy. After extensive mobilization of the aortic arch, cardiopulmonary bypass was established. During the cooling phase for deep hypothermic circulatory arrest (six cases), a persistent temperature gradient between the upper and lower half of the body confirmed the significance of CoA. One child was operated upon in deep hypothermia with low flow and one underwent valve repair on cardiopulmonary bypass. Mobilization of the descending aorta enabled CoA resection and end-to-end anastomosis with a running absorbable suture. The average descending aortic cross-clamping time was 15 min. By this time, the patient had been cooled sufficiently for the intracardiac procedure. There were two operative deaths not related to coarctectomy. The remaining children showed no arm-to-leg pressure gradient. Five were discharged from hospital and one patient died late from septicaemia. In our hands, this technique has served to accomplish simultaneous relief of CoA and repair of the intracardiac lesion thus sparing critically ill infants the hazards of repeated procedures.

Aorta, Thoracic↗
PubMed1990

[Clinical and magnetic resonance imaging follow-ups of children after dilatation of aortic isthmus stenosis (CoA)].

Aortic aneurysm and stenosis are the most severe post-interventional complications after angioplasty of CoA and require regular follow-up. Twenty children (4 2/12-13 11/12 years old) underwent MRI within 3 months to 5 7/12 years after dilatation. All children were in a good state of health and showed no signs of heart failure. Three patients suffered from arterial hypertension; seven children showed hypertension on exertion. In six children, a resting gradient (minimal 20 mm Hg, maximal 40 mm Hg) between the upper and lower extremities could be measured. Four children showed pathological changes of the ascending aorta, three had a moderate ectasia, one had severe dilatation of more than 5 cm in diameter. In three cases, a circumscript aneurysm of the descending aorta was found. In many cases, there were mild changes in the aortic wall in the region of dilatation. In 12 children, there was a moderate spindly dilatation distal to the aortic isthmus, which, however, could be seen in the pre-dilatation angiography. After dilatation of CoA, several patients continue to have hypertension and pathological changes of the thoracic aorta. With regard to adequate therapy, regular controls are necessary. Besides routine examinations, MRI is an effective non invasive imaging method for the initial investigation and short-time follow-up evaluation of CoA.

Adolescent↗
PubMed1989

Anatomically corrected malposition of the great arteries, inflow ventricular septal defect, and subaortic stenosis: diagnostic and operative implications.

Intracardiac correction of the combination of rare congenital heart lesion of anatomically corrected malposition of the great arteries, severe muscular as well as fibrous subaortic stenosis, and ventricular septal defects in the inflow and the trabecular septum in a 2 1/2 years old boy is reported. There was an additional large secundum atrial septal defect. The operation consisted of resection of the subaortic stenosis by a combined transatrial and transaortic approach, thereby regaining a wide outflow tract of the systemic ventricle. Both the ventricular and atrial septal defects were closed with Dacron patches. Reinvestigation 10 days after the operation revealed a residual pressure gradient across the outflow of the systemic ventricle of less than 10 mmHg. A secondary ventricular septal defect was detected in the anterior muscular septum at the same time and closed with a patch in a reintervention. At discharge from the hospital two weeks later the child was in excellent condition and had a stable sinus rhythm. The preoperative differential diagnosis of a double outlet right ventricle with L-malposition of the aorta as well as possible surgical approaches are discussed.

Angiocardiography↗
PubMed1988

[Percutaneous intraluminal balloon dilatation of valvular pulmonary stenoses in infancy and childhood. Presentation of results with special reference to balloon size].

34 percutaneous balloon valvuloplasties (BVP), including four repeat procedures, were performed in 30 patients (aged 3 months to 19.4 years, mean 5.8 years) with congenital pulmonary valve stenosis. Out of six failures four were due to dysplastic thickened valves; in two children a significant part of obstruction was on the subvalvular level. After first BVP a significant reduction of the right ventricular outflow tract (RVOT) gradient (mean 58.8 +/- 13.2%) was achieved in 24 of 30 cases. The mean pre-BVP RVOT gradient of 67 +/- 24.4 mm Hg was reduced to 27.2 +/- 10.2 mm Hg. Of 24 patients, 14 had a residual RVOT gradient of 25 mm Hg or less. Of the 24 patients, nine were recatheterized 12 to 24 months later, and a further RVOT gradient reduction (33.4 +/- 9.9 mm Hg to 24.2 +/- 14.5 mm Hg) was observed. In four patients additional RVOT gradient reduction (37.3 +/- 11.6 mm Hg to 18.5 +/- 10.5 mm Hg) was achieved by repeat BVP. Balloon size exceeded valve annulus diameter by up to 58% (mean 22%). No definite correlation between balloon size related to pulmonary valve annulus diameter and magnitude of right ventricular systolic pressure reduction was observed. Even using a maximal balloon size of 158%, no significant complications were noted, not even pulmonary valve insufficiency.

Adolescent↗
PubMed1988

[Surgery of congenital heart defects in deep hypothermic cardiovascular arrest: postoperative renal function].

We investigated early postoperative renal function in 55 consecutive infants who underwent cardiac surgery in deep hypothermic circulatory arrest (DHCA). In 15 of these patients detailed studies of glomerular and tubular function of the kidneys were performed. Mean time of circulatory arrest at 20 degrees Celsius rectal temperature was 53 +/- 15 minutes. Acute renal failure was seen in four patients due to cardiogenic shock from which they died on the second and third postoperative day. Urine flow in the surviving 51 infants ranged from 120 to 150 ml/h/1.73 m2. The preoperative creatinine clearance was 50 +/- 23 ml/min/1.73 m2. Postoperatively, creatinine clearance was slightly decreased (42 +/- 16 ml/min/1.73 m2), but had completely recovered after 7 days. The renal transport of phosphate, glucose and uric acid remained unchanged. There was a marked increase in urinary excretion of protein, albumin, alpha-1-microglobin and N-acetyl-glucosaminidase which peaked 7 hours after the operation and then normalized. If sufficient surgical hemodynamics are provided postoperatively, there is only slight impairment of glomerular and tubular function, which demonstrates that DHCA has no negative effect on renal function.

Acute Kidney Injury↗
PubMed1987

Truncus arteriosus type A3: complex repair with cryopreserved pulmonary homograft.

A 6-year-old girl with truncus arteriosus type A3, one of the rarest anatomic types, underwent corrective surgery using a cryopreserved valved pulmonary homograft. The special anatomic features in this case were individual origin of the pulmonary arteries. The right pulmonary artery came directly off the truncal vessel, whereas the left pulmonary artery was connected to the aortic arch via a stenotic ductus or ductus-like vessel. The preoperative pulmonary blood flow distribution was 94% on the right versus 6% on the left side. The underperfusion of the left lung may have been related to pulmonary hypoplasia due to long lasting stenosis at the left pulmonary artery take off. The postoperative pulmonary blood flow distribution was 67% on the right versus 33% on the left side. The operative and postoperative course has been uneventful; presently, 6 months after the operation, the patient is in improved clinical condition.

Angiocardiography↗