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Biomedical subjects

K G Schmidt

Publications and source records attributed to K G Schmidt.

At least 91 records · Page 5Linked to original sources
PubMed1989

Diverticulum of the right ventricle associated with ventricular septal defect.

A true diverticulum of the ventricle is a very rare congenital cardiac lesion which is characterized by a normal myocardial wall and active participation in the ventricular contractions. Diverticula of the right ventricle may originate from the apical or anterosuperior wall. We report three patients with an anterosuperior diverticulum of the right ventricle associated with a perimembranous ventricular septal defect, one of whom additionally had obstruction of the right ventricular outflow tract. These patients presented clinically with symptoms related only to their associated defects. The right ventricular diverticulum was diagnosed by angiography in all, but was also seen on cross-sectional echocardiography in one patient. The ventricular septal defect was repaired through an incision of the diverticulum, which was reduced in size at the same time. Complete resection appears necessary only if severe endocardial fibrosis is present within the diverticulum, because such a diverticulum does not contribute to right ventricular contraction, but rather is at risk of rupture.

Child↗
PubMed1989

Assessment of right ventricular performance by pulsed Doppler echocardiography in patients after intraatrial repair of aortopulmonary transposition in infancy or childhood.

The purpose of this study was to determine whether measurement of aortic blood flow velocity and acceleration by pulsed Doppler ultrasound can be used to assess the global performance of the systemic right ventricle noninvasively in young patients who have undergone intraatrial repair of aortopulmonary transposition. The effect of age at surgery on right ventricular performance in these patients was also studied. Pulsed Doppler velocity profiles of aortic blood flow were analyzed at a mean age of 5.5 years in 24 patients who had undergone intraatrial repair of aortopulmonary transposition either in early infancy (mean age 3.4 +/- 1.3 weeks) or later (mean age 8.5 +/- 6.5 months). Velocity and acceleration variables in these patients were compared with the same variables in 24 age-matched normal subjects and with the performance of their own right ventricle as assessed by two-dimensional echocardiographic measurement of ejection fraction. The 12 patients who underwent early repair had a higher ejection fraction than did the 12 who underwent later repair (mean +/- SD 0.60 +/- 0.07 versus 0.42 +/- 0.10; p less than 0.001). Aortic flow velocity was similar in all patients. Aortic acceleration was normal in patients after early intraatrial repair of aortopulmonary transposition (20.8 +/- 2.3 m/s2), but was abnormally slow in patients after late repair (11.1 +/- 1.8 m/s2; p less than 0.001), thus suggesting that the latter group had diminished right ventricular performance. Concomitantly, acceleration time and ratio of acceleration time to ejection time were increased in patients after late repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1989

Diagnosis of coronary artery fistula by two-dimensional echocardiography, pulsed Doppler ultrasound and color flow imaging.

Ten consecutive patients with a coronary artery fistula, aged 1 day to 4 years, were studied by two-dimensional echocardiography, pulsed Doppler ultrasound and color flow imaging. All patients underwent cardiac catheterization, and seven patients had surgical closure of the fistula. The origin, course and site of drainage of the coronary artery fistula were correctly identified prospectively by echocardiographic examination in all patients. Color flow imaging was particularly helpful in visualizing the site of drainage of the fistula. Diameters of the right and left coronary arteries at their origin and of the aortic root were measured from two-dimensional echocardiographic frames and compared with measurements obtained in normal children. The ratio of coronary artery diameter to aortic root diameter in normal children was 0.14 +/- 0.03 (mean +/- SD) for the right coronary artery and 0.17 +/- 0.03 for the left coronary artery. These normal ratios were greatly exceeded for coronary arteries feeding the fistula, and ranged from 0.68 to 0.84 for the right coronary artery and from 0.34 to 0.52 for the left coronary artery. All anatomic information needed for surgical treatment of coronary artery fistula was consistently obtained by echocardiography with color flow imaging. The fistula was closed from within the heart in five patients and by ligation from the epicardial surface in two patients. In these latter patients, intraoperative color flow imaging at the time of ligation proved to be extremely valuable in achieving complete closure.

Cardiac Catheterization↗
PubMed1989

High-output cardiac failure in fetuses with large sacrococcygeal teratoma: diagnosis by echocardiography and Doppler ultrasound.

With two-dimensional echocardiography and Doppler ultrasound, we demonstrated high-output cardiac failure in three fetuses with large sacrococcygeal teratomas. All fetuses had normal cardiac structure, dilated ventricles maintaining a normal fractional shortening index, a dilated inferior vena cava reflecting the increased venous return from the lower body, pericardial and pleural effusions as a manifestation of fetal hydrops, and a markedly thickened placenta. When fetal hydrops was present, the combined ventricular output was very high (mean 1280 ml/min/kg; normal 553 +/- 153 (SD)). Descending aortic flow was also sharply increased (mean 930 ml/min/kg; normal 184 +/- 20), as was placental flow (mean 480 ml/min/kg, normal 110 +/- 26). High-velocity arterial flow signals were also found within the tumor. In one fetus studied serially, placental thickness and tumor diameter increased rapidly; placental flow as a percentage of descending aortic flow decreased, indicating a further increase of flow to the tumor. These abnormal hemodynamic changes were reversed after the fetus's teratoma was surgically removed. We conclude that the sacrococcygeal teratoma acts as a large arteriovenous fistula, which causes high-output cardiac failure. Surgical removal of the teratoma in a previable fetus with such hemodynamic findings may prove to be the most effective treatment.

Echocardiography↗
PubMed1989

Effects of increasing afterload on left ventricular output in fetal lambs.

Fetal ventricular performance has been considered limited because ventricular output does not increase with rapid volume expansion above mean left atrial pressures (mLAPs) of 5-7 mm Hg. To explore relations between preload, afterload, and stroke volume (SV) in the fetal left ventricle, we instrumented 126-129 days gestation fetal lambs with ascending aortic electromagnetic flow transducers, vascular catheters, and inflatable occluders around the aortic isthmus (n = 8) or descending aorta (n = 7). At 24-48 hours after surgery, blood was withdrawn or infused to reach various mLAPs. The aorta was then slowly occluded as aortic flow and mean arterial pressure (MAP) were measured continuously. Isthmus constriction produced linear decreases in SV as MAP increased; mLAP was unchanged. Descending aortic constriction produced no decrease in SV until high MAPs were reached. SV decreased as MAP increased further, and mLAP rose significantly. The curve relating mLAP and SV before constriction showed little increase in SV above mLAPs of 5-7 mm Hg; however, when curves were derived relating SV and mLAP at relatively constant MAPs, SV continued to increase even above an mLAP of 8-10 mm Hg. Our studies indicate that the fetal left ventricle responds to progressive increases in mLAP to at least 10 mm Hg. The lack of increase in SV above an mLAP of 5-7 mm Hg with rapid volume expansion is related to the concomitant increase in MAP and afterload.

Animals↗
PubMed1989

The current role of Doppler echocardiography in the diagnosis of heart disease in children.

New Doppler ultrasound technology has caused a change in the approach to the diagnosis of congenital heart disease. Pulsed Doppler ultrasound continues to be of great value for measuring cardiac output ventricular performance and for calculating pulmonary to systemic flow ratios. Continuous wave Doppler ultrasound by virtue of its ability to detect high velocity accurately remains the premier technique for determining pressure drop across valves or across shunts. Pulsed Doppler ultrasound remains a valuable test for defining many lesions including patent ductus arteriosus.

Aortic Coarctation↗
PubMed1988

Pulmonary artery origin of the left coronary artery: diagnosis by two-dimensional echocardiography, pulsed Doppler ultrasound and color flow mapping.

Five children, aged 0.2 to 6.7 years, with pulmonary artery origin of the left coronary artery proved by angiography underwent echocardiographic examination from 1985 through 1986. Prospective identification of this condition was achieved by two-dimensional echocardiography alone in two patients. Using a parasagittal plane from the second or third intercostal space, identification of the anomalous origin from the pulmonary artery was also possible in the other children on subsequent examination. In all of these studies the right coronary artery was considerably enlarged. The ratio of the diameters of the right coronary artery and the aortic root was 0.25 to 0.33 (normal 0.12 +/- 0.02). Flow mapping by color Doppler ultrasound in three children studied most recently and peripheral arterial or aortic root contrast echocardiography identified the site of entry of the coronary flow into the pulmonary artery. The flow disturbance was detected on the aortic surface of the pulmonary artery opposite the portion from where the flow from a patent ductus is usually identified. Pulsed Doppler ultrasound identified the flow disturbance in the pulmonary artery in only three of the children. The two youngest patients did not demonstrate turbulence on pulsed Doppler ultrasound, but they were not examined by color Doppler ultrasound. The accuracy of noninvasive detection of pulmonary artery origin of the left coronary artery by ultrasound is improved by the use of a combined echocardiographic approach.

Aorta↗
PubMed1988

Determination of pulmonary to systemic blood flow ratio in children by a simplified Doppler echocardiographic method.

Doppler echocardiographic determination of the pulmonary to systemic blood flow (Qp/Qs) ratio requires calculation of pulmonary artery and aortic luminal areas and integrals of the Doppler systolic velocity curves. To simplify the Doppler calculation of the Qp/Qs ratio, the square of the ratio of pulmonary to aortic luminal diameters, substituted for the ratio of vessel areas, was multiplied by the ratio of pulmonary to aortic peak flow velocities, substituted for the ratio of velocity time integrals. The Qp/Qs ratios were calculated by both the conventional and the simplified Doppler method in 42 children, 1 month to 16 years of age. Fifteen children had no evidence of shunt and 27 had an intracardiac left to right shunt at the atrial or ventricular level, or both. In children with a shunt, the Qp/Qs ratio obtained at cardiac catheterization by oximetry ranged from 1.4:1 to 4.3:1. Both the conventional and the simplified Doppler Qp/Qs ratios correlated well with the oximetric Qp/Qs ratios (r = 0.94 and 0.93, respectively). Since the pulmonary to aortic luminal area ratio and velocity time integral ratio varied in each patient, neither measurement alone correlated well with the oximetric Qp/Qs ratio and, therefore, neither alone could be used as an estimate of the Qp/Qs ratio. The simplified Doppler calculation of the Qp/Qs ratio, which requires less time and no computer facilities, provides an excellent estimate of the Qp/Qs ratio in children.

Adolescent↗
PubMed1988

Doubly committed subarterial ventricular septal defects: echocardiographic features and surgical implications.

Doubly committed subarterial (supracristal, subpulmonary) ventricular septal defects are often complicated by aortic regurgitation resulting from aortic valve herniation into the defect. The clinical, echocardiographic and catheterization findings in 48 patients aged 0.3 to 46.4 years (median 9.5) with a doubly committed subarterial ventricular septal defect were reviewed. Aortic valve herniation was present in 38 (79%) and 55% of these had aortic regurgitation. The prevalence of both findings increased gradually with advancing age. The defect was closed surgically in 41 patients. Surgery during the first 2 years of life (median 0.4 year) was performed in 13 patients (group I), mainly because of a large shunt with a pulmonary to systemic flow ratio (Qp/Qs) 3.8 +/- 1.4 (mean +/- SD). Aortic regurgitation was present preoperatively in two patients (15%), persisted postoperatively in one patient and did not develop in any after repair (median duration of follow-up 2.3 years, range 0.1 to 7.4). In the other 28 patients (group II) surgery was performed between 4.8 and 46.4 years of age (median 11.5). These patients were generally less symptomatic and had a smaller shunt (Qp/Qs 1.5 +/- 0.5, p less than 0.001). Preoperative aortic regurgitation was present in 18 (64%). It persisted in 15 postoperatively, but in 13 of these it had diminished. Two-dimensional echocardiography in multiple views identified the site of the ventricular septal defect in all patients. Serial echocardiographic examinations demonstrated the progressive nature of aortic valve herniation, the partial occlusion of the defect by the herniated sinus and the development of aortic regurgitation. These findings suggest that timely surgical closure of these defects may prevent aortic regurgitation.

Adolescent↗
PubMed1988

Analysis of factors that may affect the speed of accumulation of 111In-labelled granulocytes at sites of inflammation.

The mechanisms governing the accumulation of granulocytes in inflammatory lesions are poorly understood. Using a sensitive method of sequential 111In-granulocyte scintigraphy, we recorded the speed of focal 111In-granulocyte accumulation in 70 patients with non-osseous inflammatory and infectious foci, with special reference to the influence exerted by the duration of disease, patient age, body temperature, antibiotic therapy and initial trapping of granulocytes in the lungs. About 50% of the images had turned positive at 30 min after injection. Except for patients with urinary tract infections, the age of the patient did not influence the speed of 111In-granulocyte accumulation; nor did the duration of disease, antibiotic therapy or degree of initial granulocyte hold-up in the lungs. High fever, on the other hand, presumably reflecting an intense inflammatory reaction, was associated with an accelerated focal 111In-granulocyte accumulation, indicating that properties of the inflammatory process per se are major determinants of the speed of accumulation of 111In-labelled granulocytes in inflammatory processes.

Aging↗
PubMed1988

Accumulation of indium-111-labeled granulocytes in malignant tumors.

In a retrospective study of 220 [111In]granulocyte scintigrams from 208 patients, 25 patients had malignant neoplasms. Among these, tumor uptake of 111In activity was observed in ten patients (intense activity in two patients with non-Hodgkin's lymphoma and colonic carcinoma, respectively; moderate uptake in a patient with non-Hodgkin's lymphoma, and in a patient with an ovarian carcinoma; weak activity in three patients with cerebral neoplasms; and activity within otherwise "cold" metastatic lesions of the liver in three patients). Microscopic investigation following specific granulocyte staining revealed the greatest extent of granulocyte infiltration in the tumors which took up 111In activity, emphasizing the importance of tumor granulocyte infiltration as the single most important factor underlying tumor accumulation of 111In activity during [111In]granulocyte scintigraphy.

Adolescent↗
PubMed1987

Prenatal detection of truncus arteriosus by ultrasound.

This report describes the echocardiographic findings of truncus arteriosus, right aortic arch, and persistent left superior vena cava draining into the coronary sinus in a 32-week-old fetus, in whom the diagnosis was confirmed by autopsy.

Adult↗
PubMed1987

Cross-sectional and contrast echocardiography in the diagnosis of interatrial communications through the coronary sinus.

An interatrial communication through the mouth of the coronary sinus is a rare cardiac anomaly. It is usually associated with a left superior caval vein draining into the coronary sinus and is frequently part of a complex congenital malformation of the heart. Failure to recognize this defect before surgical repair of the primary cardiac lesion may lead to persistent interatrial shunting, which may in turn cause postoperative cyanosis. This report describes two cases of interatrial communication through the coronary sinus diagnosed prospectively by echocardiography. It demonstrates the important role of contrast echocardiography in the evaluation of patients suspected of having this malformation.

Coronary Circulation↗
PubMed1987

Speed of accumulation of 111In-labelled granulocytes in focal non-osseous inflammatory processes.

Using a method of 111In-oxine granulocyte labelling in diluted plasma, we performed 162 scintigraphic studies in 159 patients with suspected non-osseous infection. We obtained a positive predictive value of 82%, and a negative predictive value of 97%, i.e. the method is very sensitive, albeit less specific. Sequential imaging showed around 50% of the scintigrams to turn positive at 30 min after the injection, the most rapid accumulation being seen in cases of superficial soft tissue infections and in pulmonary and pleural infections, cerebral abscesses showing a rather sluggish accretion of activity, urinary tract infections, abdominal abscesses and bowel inflammation accumulating activity at an intermediate rate. Our results indicate that the described method is sensitive, and that the sequential scintigraphic approach allows an early diagnosis in most cases, and facilitates the interpretation of delayed scans.

Focal Infection↗
PubMed1987

Indium-111-granulocyte scintigraphy in the evaluation of patients with fever of undetermined origin.

32 patients with at least 3 weeks' unexplained fever and no established diagnosis after at least one week's in-hospital evaluation underwent scintigraphy after injection of 111In-labelled granulocytes. Focal infectious processes were correctly identified in 5 patients (1 dental and 4 abdominal infections). In a patient with non-Hodgkin's lymphoma the lymphomas took up 111In-granulocytes. Intestinal activity was observed in a patient eventually diagnosed as Whipple's disease. Apart from these findings, weak and slowly appearing focal tracer accumulations of uncertain significance were seen in 4 cases. So far, no sources of infection have been identified in any of the patients outside the infectious disease group with a negative scintigram during a median follow-up period of 8 months. Our results support the suggestion that the 111In-granulocyte scintigraphy method is a sensitive method for the detection of occult infections, and it may prove useful in the evaluation of patients with protracted fever of undetermined origin.

Adolescent↗
PubMed1987

[Primary pulmonary hypertension in childhood--clinical course and morphologic correlations with particular reference to the endocrine heart].

This is a case report of a 13-year-old girl who developed clinical symptoms of primary pulmonary hypertension (PPH). The prognosis is determined by progressive overloading of the right heart. Tissue from both the right and the left atria was examined using immunohistochemical methods. Cardiodilatin/alpha-ANP (atrial natriuretic peptide)-producing myoendocrine cells were analysed. As recent investigations have shown, the atrium and especially the atrial appendages of the heart function as an endocrine organ which is stimulated by pressure and volume overload, and which produces a natriuretic and vasodilatory peptide hormone from myoendocrine cells. In our case we found a general hyperplasia of the myoendocrine cells of the right atrium which is interpreted as a secondary reaction towards an increasing overload. This also means a temporary compensation of the progressive obstruction of the small pulmonary arteries, initiated by vasodilatory heart peptides. These investigations are in agreement with those of other groups who found an increased production of cardiac hormones in atrial overload. In the perinuclear area, electron microscopy shows zones of autophagolysis and the typical specific atrial granules which account for a dysfunction of atrial myoendocrine cells, as seen in other cardiac diseases. Our results may contribute to a better understanding of the pathogenesis of PPH and may help in diagnosis and therapy.

Adolescent↗