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Biomedical subjects

K Bühlmeyer

Publications and source records attributed to K Bühlmeyer.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1989

Coronary arteries in the hypoplastic left heart syndrome. Histopathologic and histometrical studies and implications for surgery.

The subepicardial coronary arteries (CAs) in the hypoplastic left heart syndrome (HLHS) were studied for pathology dependent on the patency of the mitral valve and the presence of endocardial fibroelastosis (EFE) of the left ventricle (LV). Nine heart specimens with aortic and mitral atresia (group 1) were studied and compared with 19 hearts with aortic atresia and mitral stenosis (group 2) (EFE of the LV was present in all cases) and 10 normal hearts. The median age at death was 3 days. For the histological and histometrical studies, 5-mm blocks from six comparable sites of the left (L) and right (R) CAs were serially sectioned and routinely processed. The arterial size and wall thickness were measured. Macroscopically, the CAs in group 1 were normal except for the prevalence of left dominance (56%). In contrast in group 2, the CAs were thicker and tortuous. Histopathology was restricted almost exclusively to group 2 specimens (11 of 19), with the proximal LCAs being the most affected. However, eight hearts with EFE in group 2 had no structural wall changes of the CAs. Histometrically, the sizes (external diameters) of the LCAs and RCAs were similar (0.5-1.0 mm) in groups 1 and 2 and in the normal group; however, we noted an increase in percent medial thickness in group 2 specimens, especially of the LCAs. Furthermore, in some group 2 hearts, the wall thickness (intima and media) relative to the luminal size (internal radius) of proximal and middle LCAs was significantly increased, suggesting the presence of ventricle-CA communications.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1989

[The accuracy of Doppler echocardiography determination of shunt volume in children with isolated atrial septal defect and left-right shunt].

The accuracy of shunt calculations derived from Doppler echocardiography was assessed in 15 children (5-15 years, mean 8.5 yrs.) with secundum-type atrial septal defect and left-to-right (L-R) shunt. Qp/Qs was calculated by measuring stroke volumes over the aorta and pulmonary artery prior to and 4-15 days after corrective surgery. The measuring error of the Doppler method was defined as deviation of the postoperative shunt value from zero. A residual shunt was excluded by careful intraoperative testing and physical examination. Intraoperative inspection revealed normal pulmonary venous drainage. L-R-shunt, as calculated by Doppler echo, significantly decreased after surgery (p less than 0.001). Although all septal defects were closed, calculations by Doppler echo resulted in a median residual shunt of 16% (0-50.7%). IN 2/15 children a L-R shunt of more than 40% was derived by echo recordings. The size of the measuring error increased in children with great preoperative shunts. There was a significant correlation between the ratio of pulmonary to aortic cross-sectional area and the measuring error (p less than 0.03, r = 0.59). Poor estimation of cross-sectional areas in dilated pulmonary arteries was the most important limiting factor in shunt calculation. Doppler echocardiography provides a valuable noninvasive method for shunt calculation. Similarly to Fick's principle, in some patients the measuring error may be considerable and become relevant for clinical decisions. Thus Doppler-derived shunt calculations must be complemented by additional information of two-dimensional echo and physical examination.

Adolescent↗
PubMed1988

[Hemodynamic effect of captopril in children with dilated cardiomyopathy].

Hemodynamic effects of captopril were prospectively studied in 12 children suffering from dilative cardiomyopathy. Before the administration of the drug all patients were put on a stable medication of diuretics and/or glycosides. A median daily dose of 1.83 mg captopril/kg body weight was given in 3 or 4 single doses depending on age. Median body weight of the children was 18.6 kg (range 2.7-42.2) and the median age was 5.8 years (range 0.2-15). Left ventricular volume was determined in systole and diastole using 2-D echo, and the stroke volume als well as the ejection fraction were calculated. Cardiac index (CI) and systemic resistance (Rs) were measured by Doppler echo. Blood pressure and heart rate were recorded at each echo registration. ESVI (-32%), EDVI (-21%) and SVI (-7%) were significantly (p less than 0.05) reduced by short-term captopril treatment. This effect was maintained under long-term therapy. EF, CI, Rs, blood pressure and heart rate showed only minor changes under captopril. Adverse effects were recorded only in one child. They disappeared after dose reduction.

Adolescent↗
PubMed1988

[Spontaneous variability and reproducibility of Doppler echocardiography determination of heart minute volumes in infancy].

UNLABELLED: Day-to-day variability in Doppler derived cardiac output measurements was assessed in 10 infants (0-6 months of age) and in 12 older children (1-13 years, mean: 7.4 years) with congenital heart disease which had been treated surgically. There was no valvular stenosis or ventricular septal defect, all patients had technically excellent imaging quality. Standard commercial equipment (Mark 8, ATL; 3, 5 or 7.5 MHz scanheads) was used for echo recordings, which were stored on video tapes and blindly evaluated by an independent investigator. Cardiac outout (CO) was measured over the aortic and pulmonary valves on two consecutive days using standard projections. Mean CO variability of the infants was 32% and 41% for the aortic and pulmonary valves, respectively. The corresponding variability in CO in the older children was 41% and 32% for the aortic and pulmonary valves respectively. The greatest difference existed in measuring cross-sectional areas of aorta and pulmonary artery (29-37%). The Doppler parameters showed the lowest variability (13-26%), except for the pulmonary artery in the infants (46%). On heart rate, there was a "physiological" day-to-day variability of 10-20%. CONCLUSION: There is a considerable variability in Doppler derived CO measurements. The detection of CO changes in critically ill children might be missed by this error. CO measurements over the aortic valve seem to be more reliable than over the pulmonary valve.

Adolescent↗
PubMed1988

Competition of coronary arteries and ventriculo-coronary arterial communications in pulmonary atresia with intact ventricular septum.

Pulmonary atresia with intact ventricular septum can be complicated by the presence of large ventriculo-coronary arterial communications which disturb normal myocardial perfusion. In the selection of patients for surgery the presence of these communications provides an additional problem. On the basis of previous cineangiocardiographic study, we performed a histopathological study of 16 cases. Twelve presented with ventriculo-coronary arterial communications and four only showed myocardial sinusoids. A tripartite right ventricle was seen in the latter group but not exclusively. It is shown that subepicardial coronary arterial pathology is exclusively present in cases with ventriculo-coronary arterial communications although not solely at a connection site between a communication and an artery. The affected coronary artery is itself focally abnormal and hypoplastic and can be blocked or even absent. The interruption of such an artery can also occur after birth and not necessarily at a site of connection with a communication. This implies that infants with communications either already have a coronary circulation partly or completely dependent on ventriculo-coronary arterial communications at birth or can develop such a condition in time. This hazard to myocardial perfusion, often compromised by a large "steal" from the aorta to the right ventricle, limits the choice of surgical procedures.

Child, Preschool↗
PubMed1986

Interrupted aortic arch: natural history and operative results.

The chances of survival for patients with interruption of the aortic arch depend mainly on early recognition and medical treatment before symptoms of cardiogenic shock appear, and specifically on early operative repair after the exact diagnosis has been established. Accurate angiography with visualization of the interrupted aortic arch and delineation of associated cardiac malformations is of prime importance for the surgical management and prognosis. Among our 36 patients with interrupted aortic arch, 27 were operated on. The operative mortality in 22 patients with associated ventricular septal defect (VSD) and persistent ductus arteriosus (PDA) was reduced from 43% (in seven patients seen up until 1979) to 7% (in 15 patients seen since 1980). One patient with interrupted aortic arch type C and another infant with associated truncus arteriosus were successfully corrected on day 9 and day 17 of life, respectively. In the patients with associated VSD and PDA as well as in the one patient with associated truncus arteriosus, the primary correction--direct anastomosis of the interrupted segments without prosthesis and VSD closure and in the case with truncus, the additional positioning of a valve-bearing allograft conduit from the right ventricle to the pulmonary artery--has been more successful than a two-step approach with initial pulmonary artery banding.

Aorta, Thoracic↗
PubMed1986

Early diagnosis and medical treatment of the persistent ductus arteriosus in infants.

Diagnosis of an isolated patent ductus arteriosus (PDA) is usually straightforward. If at later age it is associated with pulmonary hypertension, however, the symptoms may be variable and more difficult to assess. In the age group primarily discussed here, pulmonary hypertension is frequently present, so diagnosis cannot be based on physical findings alone. Echocardiography and Doppler echocardiography are essential diagnostic procedures; however, cardiac catheterization and angiography may still be needed especially in cases with associated heart defects. At present, surgical closure of the PDA is the therapy of choice in infants. In preterm newborns, an attempt by medical treatment is indicated and often promising. Unfortunately, there are no interventional techniques available at present for duct closure in this age group, whereas in some centers catheter closure of a PDA is successfully employed in older children.

Ductus Arteriosus, Patent↗
PubMed1985

Non-invasive oscillometric measurement of systolic, mean and diastolic blood pressure in infants with congenital heart defects after operation. A comparison with direct blood pressure measurements.

The accuracy of indirect oscillometric blood pressure measurements has been evaluated in 32 infants up to 11 months of age undergoing heart surgery. In a number of 1029 simultaneous measurements the indirect blood pressure was compared with the direct value obtained from a radial artery catheter. Cuffs of different sizes were applied. The main results were as follows: Regarding the ratio of cuff width to arm circumference, the best correlation between oscillometric and direct blood pressure measurements was obtained with a ratio of 0.38-0.41. The value of indirect blood pressure measurements depends on the absolute height of the blood pressure. In low blood pressure there is a tendency to underestimate and in high blood pressure there is a tendency to overestimate by the oscillometric blood pressure measurement. By applying an appropriate cuff size and by using our diagrams it should be possible to derive a direct value for the blood pressure on the basis of indirect oscillometric blood pressure measurements.

Blood Pressure↗
PubMed1985

Hypoplasia of the intrapulmonary arteries in children with right ventricular outflow tract obstruction, ventricular septal defect, and major aortopulmonary collateral arteries.

Postmortem injection studies have been carried out on the pulmonary vasculature of four children dying with pulmonary atresia and ventricular septal defect or severe tetralogy of Fallot with major aortopulmonary collateral arteries, in which nearly all bronchopulmonary segments had more than one source of blood supply. Despite regional variations in the source of blood supply, there was remarkable uniformity of arterial size and number within the respiratory unit throughout each case. In all cases, there was a normal number of arterial pathways, but both pre- and intraacinar arteries were considerably smaller than normal. The need for early operative intervention to ensure growth of pre- and particularly intraacinar arteries is emphasized.

Aorta↗
PubMed1985

[Extrasystole in the neonatal period].

We investigated the clinical course in 35 healthy newborn with premature beats and studied the literature with regard to their frequency, pathogenesis, and therapy with the following results: Investigations with continuous monitoring or long-term ECG registration show a frequency of 7-25%. In literature, almost one-fourth, in our patients one-half of the newborn have ventricular premature beats. These will probably disappear later than atrial premature beats, but their prognosis is not worse. The premature beats of newborn are often complex (blocked or aberrant conduction, bigeminus, tachycardia). Atrial flutter is sometimes associated. In one-half of cases they disappear spontaneously during the first month of life. However, they lasted for longer than 4 months in 7 out of 35 infants. The disorder increased after birth in 2 children, which is unusual. Therapy was indicated if there were signs of heart failure, frequent or increasing rate of tachycardia or atrial flutter. Premature beats do not indicate primary operative delivery. Immaturity of the central and autonomous nervous system and of the conduction-tissue of the heart may be the reason for frequent perinatal premature beats.

Anti-Arrhythmia Agents↗