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Biomedical subjects

M Hofbeck

Publications and source records attributed to M Hofbeck.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Aortic root abscess without involvement of the aortic valve: diagnosis and therapy in a 2.5-year-old child].

Although formation of an aortic root abscess is a frequent complication of aortic valve endocarditis in adults, this complication has been rarely observed in children. In the majority of cases it has been described in children without underlying congenital heart disease. Due to the rarity of this complication, diagnosis and treatment is frequently delayed in childhood. We report a 2 1/2 year old girl who developed pericardial effusion in the course of pneumonia. Echocardiographic examinations, which were performed because of the pericardial effusion, revealed after 6 days the development of a cystic structure posterior to the aortic root. There was a perforation of this aortic root abscess to the left ventricular outflow tract; the aortic and mitral valves however were normal without endocarditic vegetations. Surgery was performed on the 10th day following a rapid increase in the size of the abscess. During surgery the abscess was drained and the perforation to the left ventricle was closed with direct sutures. Intraoperative transesophageal echocardiography confirmed a good surgical result. Blood cultures remained negative; in the material from the abscess however we found staphylococcus aureus. The postoperative course was uneventful. Our case demonstrates the necessity of detailed and repeated echocardiographic examinations in children with possible symptoms of bacterial endocarditis (in our case pericardial effusion) as well as the requirement of cultures of the abscess for identification of the infective organism. Intraoperative transesophageal echocardiography allows exact description of an aortic root abscess, its relation to other cardiac structures and immediate evaluation of the surgical result.

Abscess↗
PubMed2001

Transcatheter occlusion of a large coronary arterial fistula with new detachable platinum microcoils.

We report a 17 year old boy with a large fistula from the right coronary artery to the right ventricle. The fistula consisted of two major branches. The smaller branch could be embolised with three detachable platinum microcoils without problems. The high flow of blood in the larger branch, however, prevented conventional occlusion using coils. Interventional occlusion of this branch was achieved in a second attempt. Following creation of an arterio-venous wire-loop, we advanced a balloon catheter into the distal end of the fistula. Under temporary occlusion of the fistula, complete closure was achieved by delivery of 7 detachable platinum microcoils. Thus, even large coronary arterial fistulas can be closed safely with these new platinum detachable microcoils. The procedure, however, requires temporary control of the flow of blood by balloon occlusion.

Adolescent↗
PubMed2001

Impaired compliance of the intracranial vessels in complicated childhood migraine. Demonstration by transcranial Doppler-sonography--a vascular model approach.

AIM: To increase the diagnostic value of Doppler sonography a uniform lumped parameter model of pulsatile blood flow in human arteries was derived from the serial and/or parallel connection of parallel oscillatory circuits. METHODS AND PATIENTS: In this setting the current (I) in the ohmic resistor (R) represents the volume flow in the vessel, the voltage (V) the blood pressure. The vessel compliance corresponds to the capacitance (C), the inductivity (L) represents the accelerated mass. The flow velocity (v) which is assessable non-invasively is given by v = I/A, where A is the cross-sectional area of the vessel. Mathematically, the model represents a two-dimensional Fourier-series of the input signal by the segments. Thus it seems to be evident that almost all forms of flow and pressure pulses can be generated. The equations of the model were solved numerically. Doppler-sonographically measured flow velocities in the ascending aorta were used as input signal. The parameters for A, R, L and C were optimized to gain the measured flow spectrum in the target vessel as model response. RESULTS: Application in 14 children (aged 3-16 yrs.) with complicated migraine during a symptom-free interval revealed a significantly lowered cross sectional area of the middle cerebral artery on the side of the higher flow velocities. For both middle and posterior cerebral arteries, a decreased vessel compliance (C) (mean -30%) was found, whereas values for R and L were within normal limits. CONCLUSION: These findings suggest an altered vascular compliance even between attacks. This may contribute to the pathogenesis of migraine through increased cerebral impedance resulting in impaired cerebral perfusion.

Adolescent↗
PubMed2001

[Echocardiographic findings before and after interventional occlusion of persistently patent ductus arteriosus with the amplatzer duct occluder].

AIM: The Amplatzer duct occluder(R) is a new system for interventional occlusion of persistently patent ductus arteriosus. The purpose of our study was to determine, whether adequate evaluation of this occluder system can be obtained by echocardiography. METHOD: From 11/1999 until 12/2000, 18 patients were included in the study. All underwent interventional occlusion of a patent ductus arteriosus with the Amplatzer duct occluder(R). Echocardiography was performed on admission, on day one and three and six months following the intervention. RESULTS: The mean age of our patients was 4.8 years (9 months - 18.7 years, median 3.2 years), the mean weight was 18.4 kg (6.5 - 66 kg, median 14 kg). All echocardiographic findings prior to intervention were confirmed during cardiac catheterization. Following intervention we were able to visualize the occluder system and its relation to surrounding structures in all patients. In none of our patients we found an obstruction of the left pulmonary artery. In 1/18 patients there was a minor protrusion of the distal occluder into the descending aorta. Doppler-sonography however revealed no obstruction. Complete occlusion of the ductus arteriosus was confirmed by color Doppler echocardiography in all patients within 5 days, in 17/18 patients no residual shunt was detectable within 24 hours. CONCLUSION: According to our experience the results of interventional occlusion of patent ductus arteriosus in children and adolescents can be well determined by echocardiography.

Adolescent↗
PubMed2001

Fetal sinus bradycardia and the long QT syndrome.

OBJECTIVE: Recent evidence in literature shows that the long QT syndrome accounts for a fraction of the sudden infant death syndrome. Newborn infants with prolongation of the Q-T interval often show sinus bradycardia, which led us to test whether children who were diagnosed with long QT syndrome also show sinus bradycardia in the cardiotocogram before birth. STUDY DESIGN: We identified 18 children who were born from singleton pregnancies at or near term in whom long QT syndrome (corrected QT interval, >0.440 second) was diagnosed after birth or in childhood. Cardiograms during pregnancy and delivery were available from 17 of the 18 children. RESULTS: The cardiotocogram showed persistent fetal sinus bradycardia (baseline heart rate permanently below 120 beats/min) in 12 of 17 fetuses (71%) with long QT syndrome. Two fetuses had additional intermittent tachyarrhythmias. CONCLUSION: Sinus bradycardia in the cardiotocogram during delivery or in pregnancy may indicate long QT syndrome in the fetus. Postnatal electrocardiography should be performed in these children to rule out or confirm a prolongation of the Q-T interval.

Arrhythmia, Sinus↗
PubMed2000

[Partial anomalous origin of the left pulmonary artery].

The pulmonary sling or aberrant left pulmonary artery has an incidence of 3% to 6% of all anomalies of the aortic arch system. We report a boy with coexistence of a normal and an anomalous left pulmonary artery. Associated congenital anomalies were coarctation, mitral stenosis, and imperforate anus. Cardiac catheterization and angiocardiography at the age of 5 months demonstrated an inconspicuous pulmonary trunk dividing into left and right branches. There was a normal right pulmonary artery, and a main left pulmonary artery supplying the left upper lobe, lingula, and anterior segments of the left lower lobe. In addition, an anomalous left lower lobe artery originated from the proximal right pulmonary artery, passed inferior to the tracheal bifurcation to the left supplying posterior segments of the left lower lobe. Chest X-rays and bronchoscopy could not detect any malformation of the trachea and pulmonary lobulation. There are only three reports of partial anomalous origin of the left pulmonary artery, and only one had a similar course of the accessory artery. This report is the first to present selective angiography and echocardiographic findings of the partial anomalous left pulmonary artery. The development of the partial anomalous pulmonary artery can be explained by the plexiform nature of the primary pulmonary vascular bed and can help to understand the embryology of the pulmonary arteries.

Abnormalities, Multiple↗
PubMed2000

[Late postoperative cardiac arrhythmias after total cavopulmonary anastomosis and correlation with age of the patients at operation].

Late postoperative arrhythmias are a common problem associated with significant morbidity following Fontan operations. We analyzed in our patients whether age at the time of a modified Fontan procedure (total cavopulmonary connection) has an influence on the frequency of late postoperative arrhythmias. We examined all 66 long-term surviving patients who underwent a total cavopulmonary connection (TCPC) in our center during a nine year period. At the time of TCPC, 31 children were younger (group I) and 35 children were older than 4 years (group II). The follow-up period was almost identical in both groups (group I: 4.29 years, group II: 4.52 years). We evaluated all ecgs performed at maximum intervals of 6 months and all Holter ecgs performed at intervals of 12 months. Atrial tachyarrhythmias (supraventricular tachycardias, atrial flutter) were registered in six patients (9%). All of these patients belonged to group II (17%). Ventricular arrhythmias (couplets, ventricular tachycardia) were found in 3% of the younger and 17% of the older patients. Abnormalities of sinus node function were registered in equal frequency in younger and older children (group I: 35%, group II: 31%), while pauses with a duration of > 2 s where present only in older children (group II: 14%). Pacemaker implantation or antiarrhythmic therapy became necessary in 10/66 patients (15%) affecting none of the children who underwent the TCPC < 4 years (group I) but 10/35 children (group II) who underwent the TCPC at an older age (29%). According to our findings in the medium-term follow-up after TCPC, atrial tachyarrhythmias and complex ventricular arrhythmias are registered less frequently in children who underwent the modified Fontan procedure at an age of less than 4 years. Although further studies will have to show whether these differences persist in the long-term follow-up, these findings represent an additional argument for the elective performance of modified Fontan operations at an age of less than 4 years.

Adolescent↗
PubMed2000

Safety and efficacy of interventional occlusion of patent ductus arteriosus with detachable coils: a multicentre experience.

UNLABELLED: In order to define the safety and efficacy of Cook detachable coils for interventional closure of patent ductus arteriosus, we performed a retrospective analysis of all patients who underwent cardiac catheterization in seven centres for intended interventional occlusion of patent arterial duct. From January 1995 until March 1998, cardiac catheterization for intended interventional occlusion of patent arterial duct was performed in 317 consecutive children. Successful placement of at least one coil was achieved in 282 children (89%). The mean diameter of the ductus in children treated with Cook detachable coils was 1.65 mm, mean fluoroscopy time was 10.7 min. Occlusion rates were 62% 10 min after the procedure, 82% at the time of discharge, 91% at 4 months and 95% at late follow-up (2 years). In children with a ductus diameter of < or = 2.5 mm the rate of successful coil deployment was 94% with a 98% occlusion rate at late follow-up. Complications occurred in 11 procedures (3.5%) including haemolysis (3 patients), embolization of a coil to the pulmonary artery (7 patients, 2.3%) and inability to release a coil (1 patient). CONCLUSION: In our opinion, Cook detachable coils are safe and effective especially in the treatment of persistent ductus arteriosus with a diameter < or = 2.5 mm. Due to the low costs these coils appear to be superior to other devices in this subgroup of patients.

Adolescent↗
PubMed2000

Similarities and differences in the exercise performance of patients after a modified Fontan procedure compared to patients with complete transposition following a Senning operation.

OBJECTIVE: To investigate cardiopulmonary performance in patients after a Fontan procedure, comparing it to patients following a Senning operation. METHODS: We studied 21 children, with a mean age of 11.1 years, after a total cavopulmonary anastomosis, comparing them to 13 with complete transposition after a Senning procedure, having a mean age of 11.8 years, and 21 control subjects with a mean age of 11.2 years. All were tested on a bicycle ergospirometer. RESULTS: Peak consumption of oxygen, maximal work rate, peak oxygen pulse and endexpiratory pressure of carbon dioxide at a work rate of 1.5 Watt/kg were lowest in patients with a modified Fontan procedure, and highest in the control group (p < or = 0.0278). Production of carbon dioxide, and minute ventilation at a work rate of 1.5 Watt/kg, was highest in the patients after Fontan procedure, and lowest in the healthy subjects (p < or = 0.0163). Production of carbon dioxide per single breath was lower in those having a Fontan procedure (28.9 ml) than in the two other groups (35.1 ml; p = 0.0243). The tidal volume showed no significant differences between the three groups. CONCLUSIONS: The reaction to exercise was identical qualitatively in both groups of patients, and comparable to the behaviour of patients with chronic heart failure. Quantitatively, the results of the patients following a Senning procedure lay between those of control subjects and those who had undergone a Fontan operation. The only exception was dead space ventilation, where the patients after a Fontan procedure differed from the two other groups because of their increased ventilation-perfusion mismatch.

Anastomosis, Surgical↗
PubMed2000

Balloon dilatation of critical left heart stenoses in low birthweight infants.

UNLABELLED: We describe the results of balloon angioplasty in 5 infants with body weights of 850-2400 g. Three patients with severe aortic valve stenosis and two patients with isthmic coarctation of the aorta experienced relief of stenosis. Two patients with aortic valve stenosis developed thrombosis of the femoral artery; however, complete resolution of the compromised pulse occurred following thrombolytic therapy. In both patients with isthmic coarctation, pulses on the right leg remained diminished. All patients are doing well 0.28 to 3.32 y after the procedure; none has required additional therapy. Our results in a limited number of consecutive low birthweight infants show that balloon dilatation is feasible and can be performed successfully even in neonates with body weights < 1500 g. According to our experience, balloon dilatation in infants with body weights > 2000 g does not differ significantly from standard procedures. In very small infants, however, balloon angioplasty requires special precautions to avoid temperature loss. Arterial access is the major problem in small children, and requires further improvement. CONCLUSION: Balloon dilatation is feasible even in neonates < 1500 g. However, special precautions to avoid temperature loss are required and arterial access is the major problem.

Aortic Coarctation↗
PubMed2000

Prenatal diagnosis of QT prolongation by magnetocardiography.

Magnetocardiography constitutes a new tool for monitoring fetal cardiac activity. The fetal magnetocardiogram (FMCG) recorded noninvasively over the maternal abdomen is detectable with high temporal resolution and permits analysis of all parts of the PQRST waveform. In this way measurements of cardiac time intervals, including the QT interval, become possible. The following article constitutes the first report of antenatal detection of QT prolongation in two fetuses by FMCG.

Adult↗
PubMed2000

Hemostatic changes following the modified Fontan operation (total cavopulmonary connection).

Thromboembolism is a serious complication after Fontan operation, which may be caused by alterations of the coagulation system. We therefore investigated pro- and anticoagulant factors in 20 patients aged 4 to 21 years, 4 to 63 months following total cavopulmonary connection. Furthermore we compared markers of thrombin activation and fibrinolysis and in vitro clotting and clot-lysis to age-matched healthy subjects. Compared to results of age-matched controls, the Fontan operated individuals had significant decreases in levels of protein C (0.88 U/ml in controls, 0.67 U/ml in patients; p <0.001) and protein S (1.05 in controls, 0.93 U/ml in patients; p <0.05). Moreover, half of the patients had high values of FVIII (>1.5 IU/ml), which are associated with an increased thrombotic risk. These changes may result in enhanced generation of thrombin and plasmin, indicated by our finding of increased thrombin-antithrombin III (TAT) and plasmin-antiplasmin (PAP) levels and a similar trend in prothrombin fragments F1+2. Clot lysis tests, global coagulation tests, red blood cell count, liver enzymes AST, ALT, but not GGT, were generally within the normal ranges.

Adolescent↗
PubMed2000

Paravertebral and intraspinal malposition of transfemoral central venous catheters in newborns.

We report permanent tetraplegia in a newborn resulting from intraspinal malposition of a transfemoral catheter. In 2 other neonates paravertebral malposition of indwelling Silastic lines was detected. We suggest that left-sided transfemoral catheterization and conditions enhancing collateral flow through the vertebrolumbar pathway may predispose to inadvertent paravertebral catheter placement.

Catheterization, Central Venous↗
PubMed1999

[The prognosis of total cavo-pulmonary anastomosis in relation to age at surgery].

The purpose of this study was to evaluate the relations between the age of surgery and the postoperative results in children after a total cavopulmonary anastomosis (TCPA). Between February 1990 and August 1995, 53 patients underwent a TCPA in our institution. At the time of the operation 26 of the patients were younger than 4 years, 27 patients were more than 4 years old. The perioperative mortality for all patients was 9.4%. Among the young children the perioperative mortality was higher than in the older patients (15.4% vs 3.7%). The only 2 patients who died late after surgery (2.8 and 2.6 years postoperatively) had been 8.3 and 9.0 years old at the time of their TCPA and represent 7.7% of the initially surviving patients of that group. The follow-up was based on routine heart catheterizations in 25 of our patients carried out 3.6 +/- 0.7 (m +/- SD) years postoperatively. Sixteen patients underwent a bicycle exercise test 4.0 +/- 1.0 years postoperatively and in 32 patients a Holter-ECG was obtained 3.2 +/- 1.2 years postoperatively (Table 1). The systemic cardiac index (CI), obtained at the catheterization laboratory, was only slightly reduced with 3.0 +/- 1.0 l/min/m2 (normal 3.5-5.5 l/min/m2). We saw a weak but significant negative correlation between the CI and the age at the TCPA (r = -0.43; p = 0.03; Figure 1). The maximal work load at the exercise test also showed a weak negative correlation to the age of surgery (r = -0.50; p = 0.05; Figure 2). Only 43.75% of our patients had no arrhythmias at the Holter-ECG. Again the group of children with no arrhythmias had been operated on at a significant lower age than the group of patients with arrhythmias (3.9 vs 7.3 years; p = 0.02; Figure 3). At follow-up the patients were all in good condition. Patients who had the TCPA in a relatively young age showed a better cardiac output, a higher work load at exercise testing and less arrhythmias than patients who were operated on when they were older. Therefore in suitable patients we recommend to carry out the TCPA at the 3rd or 4th year of life. The higher intraoperative mortality in young children should be overcome by excluding patients with additional preoperative risk factors.

Adolescent↗
PubMed1999

Emergency correction of coagulation for mitral valve replacement in an orally anticoagulated 17-year-old patient with pronounced hepatic dysfunction.

A 17-year-old patient with Shone's disease had to be readmitted to the hospital 3 months after implantation of an artificial aortic valve because of extreme mitral insufficiency with consecutive pulmonary edema and hepatic dysfunction. He had been orally anticoagulated and presented with a high international normalized ratio of 6.7. Emergency replacement of the mitral valve was possible only after administration of prothrombin-complex concentrate, as vitamin K(1) and fresh frozen plasma did not correct the hemostatic defect sufficiently.

Adolescent↗
PubMed1999

[Hypocalcemia-induced heart failure as the initial symptom of hypoparathyroidism].

Hypocalcemia is a relatively uncommon reversible cause of congestive heart failure. There are a few reports of hypocalcemic children who developed congestive heart failure associated with hypoparathyroidism. In all these patients, however, cardiac failure did not occur before the age of nine years. In addition, other striking noncardial manifestations of hypoparathyroidism, e.g., convulsive seizures, had been present prior to cardiac symptoms. We report on a 3.7 year old girl with mitral insufficiency and severe cardiac failure due to hypocalcemia secondary to familial hypoparathyroidism. The infant's mother was suffering from idiopathic hypoparathyroidism, but her own history lacked any evidence for parathyroid hormone deficiency. On admission, she presented with fatigue, dyspnea, and pedal edema. Liver edge was palpable 4 cm below the right costal margin, and a 3/6 systolic murmur was heard. A chest x-ray showed cardiac enlargement; electrocardiogram demonstrated a prolonged QTc interval of 0.46 s. The echocardiography revealed a cleft in the mitral valve with mitral insufficiency and markedly reduced contractility of the left ventricle. Laboratory studies demonstrated a low total serum calcium level of 1.3 mmol/l; serum magnesium level was slightly decreased (0.5 mmol/l), and parathyroid hormone level was not detectable. Partial monosomy of chromosome 22 was excluded. Ophthalmological examination, audiometry, and renal ultrasonogram were normal. Oral calcium supplementation and anticongestive therapy with metildigoxin, furosemid, and captopril was initiated but no improvement of the heart failure occurred. However, normalization of serum calcium level by calcium infusions caused prompt clearing of the clinical symptoms, complete normalization of liver size, reduction of cardiac enlargement (thoracic ratio decreased from 0.68 to 0.57), and marked improvement in contractility (left ventricular shortening fraction increased from 21% to 34%). The QTc interval decreased to 0.39 s. The successful treatment following normalization of serum calcium level proved the superiority of hypocalcemia over mitral valve insufficiency in the etiology of the cardiac failure. To our knowledge, this is the first report of congestive heart failure due to hypocalcemia as the first manifestation of hypoparathyroidism in childhood. Hypocalcemia should be kept in mind in any congestive heart failure in children with or without underlying cardiac malformation.

Calcium↗
PubMed1999

[Incidence and treatment of reactive infundibular obstruction after balloon dilatation of critical pulmonary valve stenoses].

Seventeen consecutive newborn and premature babies with critical pulmonary stenosis underwent a technically successful balloon valvuloplasty at our institution from March 1991 to February 1998. The only major complication was a thrombosis of the femoral vein in one patient, causing no clinical problems. Four patients (24%) showed a reactive infundibular obstruction after balloon valvuloplasty. The outflow tract obstruction became evident immediately after successful dilatation of the pulmonary valve with persistently high pressures in the right ventricle. Pathognomonic was a typical notch in the ascending part of the right ventricular pressure curve. We were unable to predict this reaction based on echocardiography or angiography. To relieve the muscular subvalvar obstruction, we treated the first two patients with i.v. Propranolol (0.05 mg/kg over 2 min). The last 2 patients received Esmolol (0.5 mg/kg over 2 min followed by a continuous infusion with 100 micrograms/kg/min), a very short acting beta-blocker. In the medium-term follow-up, all 17 patients had a very good result with only mild pulmonary valve regurgitation. All 4 patients with a reactive infundibular obstruction required no repeat intervention. In the medium-term follow-up there were no differences between these 4 patients and the whole group.

Angiography↗