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Biomedical subjects

K Bühlmeyer

Publications and source records attributed to K Bühlmeyer.

At least 19 recordsLinked to original sources
PubMed1992

[The diagnosis of congenital heart defects today. Part 1: Ventricular septal defect, pulmonary stenosis, patent ductus arteriosus, atrial septal defect].

Most congenital heart diseases are detected in childhood, but some, such as atrial septal defect, can remain undiagnosed until adulthood. In the first part of this review, taking the auscultation findings and the clinical picture as a basis, the diagnosis of four common congenital heart diseases is discussed: ventricular septal defect, pulmonary stenosis, patient ductus arteriosus, and atrial septal defect. In addition, the latest developments in the field of therapy are briefly considered.

Ductus Arteriosus, Patent↗
PubMed1992

[Diagnosis of congenital heart defects today. Part 2: Aortic stenosis, aortic isthmus stenosis, tetralogy of Fallot, transposition of great vessels].

In this second part of our review, the diagnosis of the following congenital heart disease is discussed: aortic stenosis, aortic isthmus stenosis (coarctation of the aorta), Fallot's tetralogy and transposition of the great vessels. Aortic stenosis and coarctation of the aorta each represents a spectrum of cardiac diseases of varying severity. Cases that are clinical less severe may escape diagnosis until late childhood or adolescence. Fallot's tetralogy and transposition of the great vessels in contrast, lead to cyanosis, and are therefore usually diagnosed already in the young infant. In all four conditions, the suspected diagnosis can be established on the basis of clinical or auscultatory findings. Further diagnostic clarification is achieved with the aid of non-invasive procedures such as CT scan, chest X-ray, echocardiography and, where indicated, NMR imaging. Additional cardiac catheterization is required only in the case of the tetralogy of Fallot.

Aortic Coarctation↗
PubMed1992

Comparison of magnetic resonance imaging with cross-sectional echocardiography in the assessment of left ventricular mass in children without heart disease and in aortic isthmic coarctation.

Although left ventricular (LV) mass may be important to judge effects of left-sided cardiac obstruction or hypertension, reproducible noninvasively determined normal data in the pediatric age group are scarce. To validate cross-sectional echocardiographic LV mass determination, our data were compared with LV mass assessed by magnetic resonance imaging (MRI). MRI was considered to be a good reference method because there is usually no problem in defining endo- and epicardial borders with MRI. LV mass was assessed in 14 children aged 5.3 years (10 days to 14.7 years) with a mean body surface area of 0.78 m2 (range 0.25 to 1.61). With cross-sectional echocardiography the epicardial and endocardial volumes were calculated using a Simpsons rule algorithm in the apical 2- and 4-chamber view. The difference between epi- and endocardial volumes was multiplied by 1.05 to yield the mass. Mass was assessed with MRI using a multislice technique; the area of each myocardial slice was calculated and multiplied with the slice thickness, and the resultant slice volumes were added to obtain the myocardial volume. On cross-sectional echocardiography, the mass was 55 g (range 12 to 126) or 64 g/m2 (range 46 to 79); on MRI it was 60 g (range 33 to 87) or 69 g/m2 (range 46 to 89). Regression analysis yielded an r value of 0.98 with a standard error of the estimate of 5.7 g or a 10% difference. In older children, LV mass determined by MRI was bigger than the one derived by echocardiography. It is concluded that cross-sectional echocardiography can reliably assess LV myocardial mass in pediatric patients.

Adolescent↗
PubMed1992

Left ventricular function and myocardial mass after aortic valvotomy in infancy.

Eighteen of 25 survivors of aortic valvotomy in infancy were reinvestigated by cross-sectional echocardiography a mean of 7.5 (2.3-13.4) years after surgery. They had been operated at a median age of 38 (5-330) days. At the follow-up examination the gradient across the aortic valve was 41 +/- 19 (15-85) mmHg and the ejection fraction was 0.73 +/- 0.10 (0.48-0.84). Left ventricular (LV) end-diastolic volume was 66 +/- 17 (33-191) ml/m2. LV mass was 96 +/- 36 (44-204) g/m2 and the LV mass volume index (LVMVI) (mass divided by end-diastolic volume) was 1.43 +/- 0.4 (0.9-2.28). Eleven of 18 patients had an abnormally high mass volume index compared with 95 age-matched controls with structurally normal hearts. The correlation between the residual pressure gradient across the aortic valve and mass volume index yielded an r value of 0.75 (p less than 0.0004). One patient had been reoperated and underwent resection of a subaortic stenosis 4 years after the initial operation. Four patients with a resting gradient of more than 50 mmHg and one with grade 4 aortic regurgitation are scheduled for further surgical treatment. We conclude that, although LV function was normal in most patients who underwent aortic valvotomy in infancy, LV mass remains elevated in a significant number of patients, who may remain at risk of developing subendocardial ischemia.

Aortic Valve↗
PubMed1992

Influence of age at time of surgery on pre-operative left ventricular mass and postoperative outcome of Fontan operation in children with tricuspid atresia and native pulmonary stenosis.

Purpose of this study was to examine the influence of early (less than two and half years) versus later (greater than four years) age at time of Fontan type palliation in tricuspid atresia with native pulmonary stenosis on outcome with special reference to left ventricular mass and function. Among the 21 patients with tricuspid atresia, twelve (group A) underwent a Fontan type palliation at a median age of one (.6 to 2.5) years and nine (group B) at a median age of 7.5 (4.8 to 28) years. Left ventricular mass was assessed by cross-sectional echocardiography in the apical two and four chamber view. Mass was calculated as difference between epicardial and endocardial volume x 1.05 (specific gravity of heart muscle). Mass divided by volume at end-diastole yielded the mass/volume index. There was a weak correlation between age and left ventricular mass with an r-value of 0.74. Ejection fraction was calculated from the endocardial volume measurements at end-diastole and end-systole. Patient data were compared to normal values previously established in 95 controls, who were age-matched for the patients. Immediately before surgery left ventricular mass was significantly higher in the nine patients, who underwent surgery at a later age. While postoperative stay in hospital and duration of treatment in the intensive care unit did not differ significantly between both groups, the incidence of pleural and pericardial effusions and the duration of insertion of drainage tubes for these effusions differed significantly with the group A patients (under two and half years of age) doing better.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Risk factors for perioperative mortality in children with anomalous origin of the left coronary artery from the pulmonary artery.

The present study was conducted on 33 children (median age at initial cardiac catheterization 0.4 years [0.1 to 11.8]) with anomalous origin of the left coronary artery from the pulmonary artery, without associated hemodynamically significant cardiovascular anomalies, who were treated throughout a period of 18 years in our hospital. A two coronary artery circulation was reestablished in 31 of 33 children. One child died before the intended operation, and in one child the left coronary artery was ligated. There were six operative deaths, five intraoperative and one 12 hours after operation. The purpose of the study was to assess which preoperative clinical and angiographic features were associated with a higher perioperative mortality. The following preoperative factors were associated with a statistically significant higher perioperative mortality: young age at operation (p less than 0.03), left and balanced type of coronary circulation (p less than 0.01), and electrocardiographic signs of extensive acute myocardial infarction, namely, marked ST elevation (greater than or equal to 0.2 mV in at least two leads) (p less than 0.03). Left axis deviation on the electrocardiogram was associated with an extreme right dominant type of coronary circulation (p less than 0.005). The latter was also linked with adequate perfusion of the posterolateral left ventricular wall (p less than 0.005). At autopsy, severe increase of heart weight to two or three times the normal heart weight was established in six of seven children. Thus the perioperative mortality was determined primarily by the extent of myocardial ischemia. This in turn is decisively influenced by the dominant type of coronary circulation and the extent of inter-arterial collateralization. Young age, in addition, proved to be a risk factor for mortality at corrective surgery.

Aortography↗
PubMed1992

The influence of pulmonary artery banding on outcome after the Fontan operation.

Thirty-eight patients were selected from a total of 120 patients who underwent the Fontan operation between 1974 and 1988. They were classified into two groups. Group 1 consisted of 18 patients with previous pulmonary artery banding at a mean age of 7 months (2 days to 59 months), and group 2 comprised 20 patients with native pulmonary stenosis. In group 1, 10 children had tricuspid atresia (seven with normally connected and three with transposed great arteries), six had double-inlet ventricle, and two had complex heart malformations. Group 2 consisted of 12 patients with tricuspid atresia and normally connected great arteries, six with double-inlet ventricle, and two with complex malformations. The following clinical and hemodynamic parameters at cardiac catheterization and cineangiocardiography were determined in both groups before the Fontan operation: age and body surface area, hemoglobin concentration and hematocrit value, atrial and pulmonary artery pressures, end-diastolic pressure of the systemic ventricle, arterial oxygen saturation, pulmonary/systemic flow ratio, end-diastolic volume, ejection fraction and mass of the systemic ventricle, cardiac index, and Nakata index. After the Fontan operation in all patients, the presence or absence of pericardial and pleural effusions, ascites, protein-losing enteropathy, and liver and kidney dysfunction was assessed and the clinical status was classified according to New York Heart Association criteria. All preoperative and postoperative parameters were tested for differences between the two groups, and they were compared with normal values. Hematocrit value was higher in group 2 than in group 1 (57.8% versus 53.1%; p less than 0.05). Ventricular mass index was increased in group 1 when compared with group 2 (125.8 gm/m2 versus 87 gm/m2; p less than 0.05). Severe pericardial effusions in the early postoperative period were significantly more frequent in group 1 and were particularly prevalent in the subgroup with long-standing pulmonary artery banding (p less than 0.01). Subaortic stenosis was observed more frequently in group 1. The remaining parameters were not statistically different between the two groups. We conclude that the significant increment in ventricular mass after pulmonary artery banding may represent a risk for unfavorable outcome after the Fontan operation, which increases with time. Therefore, long-standing pulmonary artery banding as a palliative procedure for candidates for the Fontan operation should be avoided.

Adolescent↗
PubMed1992

[Long-term results of Mustard operation in transposition of the great arteries. Angiographic and nuclear medicine study of ventricular function].

The fate of the right ventricle as systemic ventricle after atrial repair of complete transposition of the great arteries has not been clearly elucidated. In order to assess the long-term results of the Mustard operation in patients with complete transposition of the great arteries we present the clinical data of 23 patients who had been operated in the years 1974 and 1975. Twenty of these patients had simple complete transposition of the great arteries with intact ventricular septum, two had an additional small ventricular septal defect and one an additional left ventricular outflow tract obstruction with a 40 mm Hg systolic pressure gradient. The Mustard operation had been performed at a mean age of 2.2 (1 to 3.7) years. Seventeen of the 23 patients underwent a postoperative hemodynamic study with angiocardiography 1.1 (1 to 1.8) years following surgery. At that time the right ventricular ejection fraction, which had been calculated from biplane angiographic right ventricular volume measurements in twelve patients was 62 (52 to 68) %. However the right ventricle was dilated and the mean enddiastolic volume was 132 (108 to 192) % of normal. In twelve of the 23 patients right ventricular function was reassessed 12.6 (11 to 15.3) years after surgery by Technetium-99m-scintigraphy at rest and in ten of those after exercise with a workload of 2 watt/kg. The mean ejection fraction was 51 (38 to 66) % at rest and 52 (40 to 80) % during exercise. Only three patients had a normal response to exercise, which was defined as an increase of ejection fraction with exercise of more than 5%.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗
PubMed1991

Noninvasive assessment of coarctation of the aorta: comparative measurements by two-dimensional echocardiography, magnetic resonance, and angiography.

Fifteen patients, aged between 9 and 21 years (mean, 15.1), with native coarctation of the aorta (CoA) or suspected recoarctation after surgical repair, underwent three different diagnostic procedures. Two-dimensional echocardiography (2D echo) and magnetic resonance imaging (MRI) of the thoracic aorta were performed in all patients; 14 patients underwent aortography, and digital subtraction angiography of the aorta was performed in one (after injection via a central venous catheter). Conventional electrocardiographic (ECG) gated MRI was performed, using the sagittal plane, a 256 x 256 acquisition matrix, multi-slice technique and a slice thickness of 10 mm. Diameters at the coarctation site were determined by all methods. Additional diameters of the descending aorta and the aortic arch were measured by MRI and echocardiography, respectively. All noninvasively obtained diameters were compared with angiographic data. Ultrasound imaging of the aortic isthmus was achieved in seven of 15 patients and of the aortic arch in nine of 15. The mean difference compared with angiographically determined diameters was 1.7 (0-7) mm, being greater for the coarctation site [mean, 2.2 (0-4)]. MRI images of the aortic isthmus were obtained in all patients, but the difference to angiographically determined diameters was slightly higher [mean, 3.2 mm (0-8)] than the ultrasound results. This deviation was presumably due to technical conditions, such as slice thickness and orthogonal imaging planes. Including all diameters, the correlation to invasive measurements was r = 0.82 (SEM = 3.1) for MRI and r = 0.89 (SEM = 2.3) for echo recordings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Left ventricular myocardial mass determined by cross-sectional echocardiography in normal newborns, infants, and children.

Changes in left ventricular muscle mass may be an important diagnostic or prognostic finding in children with congenital heart defects, but there are no data on normal mass as determined by cross-sectional echocardiography (CSE) in children. Fourteen newborns, 12 infants, and 69 children (1.5-17 years old) with a structurally normal heart were studied. End-diastolic and end-systolic volume and mass were calculated from biplane-paired echocardiographic imaging planes-apical two-chamber and apical four-chamber views-using both an area/length and a Simpson's rule geometric method. Data were compared with M-mode measurements. There was a good correlation between area/length and Simpson's rule method [r = 0.94, standard error (SE) 4 g/m2]. To validate the measurements, interobserver data were gathered and end-diastolic and end-systolic mass measurements were compared. Interobserver variability for the measurements on the echocardiographic recordings was low at 4.8%; for end-diastolic mass the correlation between two observers was r = 0.99 (SE 3.3 g/m2) and for end-systolic mass r = 0.97 (SE 7.6 g/m2). Correlation between end-systolic and end-diastolic mass was acceptable (r = 0.88, SE 5.9 g/m2) for the CSE mass determination, but poor for the M-mode measurements (r = 0.51, SE 20.2 g/m2). Similarly, correlation between M-mode mass and mass estimated by CSE was poor, at r = 0.58 for end-diastolic and r = 0.094 for end-systolic mass.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Surface Area↗
PubMed1991

Responsiveness of raised pulmonary vascular resistance to oxygen assessed by pulsed Doppler echocardiography.

OBJECTIVE: To assess whether changes in Doppler echocardiographic indices in the pulmonary artery correlated with changes in pulmonary vascular resistance. DESIGN: Acceleration time, ejection time, maximal flow velocity, and velocity time integrals were measured at the same time as pressure and oxygen saturation measurements in room air and during 10 minutes of oxygen breathing in the catheterisation laboratory. Pulmonary vascular resistance and pulmonary blood flow (Qp) were calculated from catheterisation data by use of the Fick principle. PATIENTS: 14 consecutive patients with a congenital heart defect and a left to right shunt associated with raised pulmonary artery pressure who underwent routine diagnostic cardiac catheterisation to assess their pulmonary vascular resistance. RESULTS: Though pulmonary vascular resistance and systolic pulmonary artery pressure fell significantly during oxygen administration, there was no significant change in the acceleration time or ejection time. Peak velocity increased significantly during oxygen administration. During oxygen breathing Doppler derived measurements of pulmonary flow showed a significant increase in Qp similar to the increase in Qp measured by the Fick principle. There was no significant correlation between the fall in pulmonary vascular resistance and the increase in acceleration time or ejection time, increase in peak velocity, increase in pulmonary artery diameter, or increase in Doppler derived pulmonary blood flow. CONCLUSIONS: Measurements of acceleration and ejection time by Doppler echocardiography did not predict the response of pulmonary artery pressure and resistance to oxygen. Though changes in maximal flow velocity across the pulmonary artery and in Doppler derived pulmonary blood flow measurements became significant during oxygen breathing, the correlation of these changes with fall in pulmonary vascular resistance was poor.

Blood Flow Velocity↗
PubMed1990

Chest X-ray film patterns in children with isolated total anomalous pulmonary vein connection.

Chest-X-ray films of 61 children with isolated total anomalous pulmonary vein connection (TAPVC) were re-evaluated retrospectively. A small heart silhouette with normal pulmonary perfusion and signs of pulmonary oedema is typical of TAPVC with obstruction. There is no typical pattern in TAPVC without obstruction. The "snowman" or "figure of eight" does not develop within the first months of life.

Blood Pressure↗
PubMed1990

Brock transventricular pulmonary valvotomy in patients with pulmonary stenosis: long-term results.

As no long-term results of a blind opening up of the pulmonary valve either by balloon valvoplasty or closed Brock valvotomy have been published, we examined the outcome of 12 patients with valvar pulmonary stenosis 17 +/- 5 (11-22) years after surgery. The Brock valvotomy had been carried out at a mean age of 3 +/- 2.8 (0.2-8.5) years. The mean pressure gradient across the right ventricular outflow tract had been 116 +/- 45 (75-97) mmHg at the catheter study or 106 +/- 43 (40-160) mmHg as measured intraoperatively. The right ventricular pressure after the Brock procedure was measured in the operating room in five patients as 46 +/- 15 (30-60) mmHg. Seven patients had been recatheterized at a mean age of 9.5 +/- 2 (7-12.7) years; at that time the gradient across the pulmonary valve had been 20 +/- 14 (10-37) mmHg. At a mean age of 21.7 +/- 3 (15-26) years these and five further patients were reexamined by echo Doppler. This time the pressure gradient across the pulmonary valve was 13 +/- 6 (7-20) mmHg. Moderate pulmonary incompetence was present in four and mild incompetence in eight patients; two had mild tricuspid insufficiency. All except one patient, who had suffered a cerebrovascular accident before surgery, were in NYHA functional class 1 and pursuing a profession. From these data we conclude that the blind opening-up of the pulmonary valve achieves excellent long-term palliation.

Blood Pressure↗
PubMed1990

Captopril in children with dilated cardiomyopathy: acute and long-term effects in a prospective study of hemodynamic and hormonal effects.

Hemodynamic and hormonal effects of captopril were prospectively studied in 12 children (median age 5.8 years, range 4 weeks to 15 years) with dilated cardiomyopathy. A mean dose of 1.83 mg captopril/kg body weight was administered in three or four single doses depending on age. Left ventricular volume, ejection fraction (EF), cardiac index (CI), and systemic vascular resistance (SVR) were noninvasively determined by two-dimensional (2D) and Doppler echocardiography before and 2 days and 3 months after the onset of treatment. Blood pressure and heart rate were recorded as well. Additionally, on the day hemodynamic measurements were made, plasma renin activity (PRA), serum aldosterone, and plasma atrial natriuretic peptide (ANP) concentrations were determined. Plasma catecholamines were measured before and 2 days after captopril treatment. Concomitant medication was kept constant during the short-term phase of captopril treatment. During long-term therapy, diuretics were reduced according to the clinical status. Stroke volume (SVI) (-7%), end-systolic (ESVI) (-31%), and end-diastolic (EDVI) (-21%) volume indexes were significantly reduced (p less than 0.05) during short- and long-term therapy. The remaining hemodynamic parameters showed only minor, statistically not significant, changes. During short-term therapy, median serum aldosterone levels fell from 138-88.5 pg/ml (p less than 0.05), and plasma ANP decreased from 144-94 pg/ml (p less than 0.05). After 3 months these effects were less marked and statistically no longer significant. Changes in PRA and plasma catecholamines were not statistically significant at any time.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Interobserver and spontaneous variability of Doppler echocardiography measured cardiac output in children with congenital heart defects].

Doppler-derived cardiac output (CO) measurements were performed on 2 consecutive days in 30 children with surgically corrected congenital heart diseases. The children formed three subgroups of 10 patients each according to age (group 1 = less than 1 year, 2 = 1-5 years, 3 = greater than 5 years). Pulsed Doppler recordings were carried out over pulmonary and aortic valves using standard projections. All recordings were "blindly" evaluated by two independent investigators. In each age group day-to-day and interobserver variability were assessed for CO, cross-sectional area of the vessel (A), time-velocity integral (I), and heart rate (HR). Day-to-day variability for CO ranged between 20% and 33% depending on age and sampling site. The corresponding variabilities for A, I, and HR were 19-35%, 14-23%, and 9-11%, respectively. Spontaneous variability did not differ significantly between the three age groups. Interobserver variabilities for CO, I, A, and HR were 13-40%, 14-32%, 20-55%, and 1-3%, respectively. A of the aorta in group 1 and aortic I in group 3 were significantly different (p less than 0.05) for both observers. None of the remaining parameters, measured by both observers, were significantly different. CO and I revealed a higher interobserver variability (p less than 0.01) for infants (group 1) than for older children, when determined over the pulmonary valve. In addition, interobserver variability of aortic cross-sectional area was significantly increased (p less than 0.01) for the young age group (group 1). We conclude that there is a considerable spontaneous and interobserver variability of Doppler-derived CO measurements in pediatric patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1990

[Current risk of heart catheterization study and angiocardiography in children. A prospective study].

Parental permission for cardiac catheterization assumes detailed information about the character and frequency of all potential and inevitable threatening complications despite of maximal care. However, data on this subject were derived mainly from older and/or retrospective studies. In order to evaluate the actual risk we performed a prospective study lasting 11 months. All complications occurring during the 24 h following this invasive procedure were recorded. During 462 consecutive cardiac catheterizations in 421 patients (including 24 balloon-atrio-septostomies and five myocardial biopsies) there were complications requiring treatment in 18.2% of all examinations. There was no lethal complication. The following complications were documented: arrhythmia 6.5%, acidosis 6.1%, problems due to catheterizing an arterial or venous vessel 3.9% and 0.4% respectively; acute blood loss 1.5%, and problems concerning the probe in general 1.1%. In a frequency of less than 1% we encountered hypoxic spells, myocardial ischemia, hypoventilation/respiratory failure, febrile reaction, and allergic reactions due to contrast media. Contrary to data of the literature we could show a significant reduction of the risks involved in this examination. The following factors have contributed to this improvement: 1) a more careful patient selection for this invasive procedure; 2) a more experienced examiner; 3) better monitoring during the procedure; 4) a more detailed diagnostic work-up prior to the examination; and 5) better premedication of the patient.

Acidosis↗