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Biomedical subjects

E W Keck

Publications and source records attributed to E W Keck.

At least 19 recordsLinked to original sources
PubMed1992

Improved neurological outcome following early anatomical correction of transposition of the great arteries.

The incidence of neurological residuals following anatomical correction of transposition of the great arteries (d-TGA) has not been described so far. Clinical examination, EEG recordings, and computed tomography (CT) scans were carried out in a consecutive series of 38 children with d-TGA surviving anatomic corrective surgery. The patients were classified into one of three groups according to the type of operation: 15 patients after two-stage approach (TSA) (Stage 1: pulmonary artery banding+aortopulmonary shunt; Stage 2: anatomic correction); 12 patients with primary anatomic correction within the first 2 weeks of life (early switch, ES); 11 patients with primary anatomic correction later in infancy (later switch, LS). In 26 patients (68%) we found no abnormalities on neurologic examination, CT scan, or EEG. Four patients suffered from spastic hemiplegia, 3 of these had cortical brain damage visible on CT scan, and 3 had focal epilepsy as well. In 2 otherwise clinical normal patients cortical infarction could be seen on a CT scan. Thus, in 5 cases (13% of 38 patients) cerebral infarcts were diagnosed by CT scan. The cortical vascular infarction was seen in 4 patients after TSA and in 1 after LS. In 6 patients we found other neurological abnormalities. Early anatomic correction in patients with d-TGA reduces the risk of cortical vascular infarction.

Cerebrovascular Disorders↗
PubMed1992

Hemodynamic findings during exercise on a bicycle ergometer following balloon valvuloplasty of pulmonary stenosis in children and adolescents.

Eleven patients (4 female, 7 male), age range 3.3 to 24.8 years (mean 11.10 years) treated for isolated pulmonary stenosis underwent cardiac catheterization and percutaneous transluminal balloon valvuloplasty (PTVP). The right ventricular systolic pressure (RVSP) before valvuloplasty ranged from 31 to 127 mmHg (mean 79 mmHg) decreasing to 28 to 62 mmHg (mean 42 mmHg) immediately after the dilatation. The peak systolic gradient of the pulmonary valve (delta p RV-PA) before valvuloplasty ranged from 22 to 107 mmHg (mean 61 mmHg) and decreased to a range of 14 and 45 mmHg (mean 23 mmHg) immediately after the dilatation. Balloon valvuloplasty was performed using balloons of 13 to 31 mm in diameter. On 11 patients cardiac catheterization and Doppler echocardiography were repeated between 11 months and 5.3 years (mean 3.11 years) after the balloon valvuloplasty showed a further significant fall in the gradient of pressure. The right ventricular systolic pressure ranged from 20 to 51 mmHg (mean 31.7 mmHg) while the transpulmonary gradient varied from 3 to 24 mmHg (mean 11.6 mmHg). At the time of follow-up examination the patients were aged between 7.2 and 25.7 years (mean 15.9 years). On average the second catheterization was performed 3.11 years following the first hemodynamic study. The follow-up examination encompassed clinical examination, electrocardiogram, Doppler echocardiography, and right heart cardiac catheterization. During right heart cardiac catheterization the children exercised on a bicycle ergometer for three min at 50 or 100 W depending on their body surface area. During this exertion, pressures of the right ventricle and the pulmonary artery as well as heart rate and oxygen saturation were recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Left ventricular contractile state after surgical correction of tetralogy of Fallot: risk factors for late left ventricular dysfunction.

The purpose of this study was to analyze potential "risk-factors" for late left ventricular dysfunction after surgical correction of Fallot's tetralogy (FT). As the ejection-phase indices cannot distinguish abnormalities of contractility from altered loading conditions, the slope values of the end-systolic pressure-length and stress-shortening relationships were analyzed by increasing afterload. Thirty-two patients were studied after surgical correction of FT in infancy. The age at investigation was 19.2 +/- 5.6 years, total correction had been performed at the age of 7.7 +/- 3.3 years. In 20 patients a one-stage operation was performed, and in 12 patients a two-stage correction. The control group consisted of 30 healthy volunteers, aged 18-30 years. The following potential risk factors for left ventricular dysfunction were evaluated: one-stage vs. two-stage correction, age at total correction, preoperative systemic oxygen saturation, preoperative hematocrit, occurrence of hypoxic spells, preoperative ratio of left-to-right ventricular peak systolic pressure, and preoperative ratio of left-to-right ventricular end-diastolic volume. In most patients the baseline data for end-systolic wall stress lay outside the normal range, indicating abnormal loading conditions. Thus, analysis of load-independent indices of the contractile state seems to be mandatory in these patients. Our data show that the severity of preoperative hypoxemia is an important risk factor for late dysfunction of the left ventricle (p less than 0.01). Additionally, the relation of left and right ventricular peak systolic pressures and end-diastolic volumes were related to the contractile state (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Pulmonary hypertension and pulmonary vascular disease in congenital heart defects].

Pulmonary vascular disease (PVD) is a serious complication of several congenital heart defects (CHD). The post-tricuspid heart lesions, such as AVSD, VSD, PDA, TGA with VSD, Ao-pulmonary window, Truncus arteriosus, DORV and DILV (univentricular heart) with a high pressure and increased flow in the pulmonary circulation are earlier and more often the cause of PVD than such pretricuspid shunts as ASD or TAPVD. The pathogenesis of PVD is only partially known. The endothelial cell of the pre- and intraacinar arteries releases substances (eicosanoids and mitogens) which cause functional and structural changes in the wall of arteriols and precapillary arteries: media hypertrophy, intima proliferation, obliterations, and necroses. The number and size of small arteries is reduced. Advanced changes are irreversible. Subtle diagnostic tools are necessary to evaluate the clinical, hemodynamic and morphologic status of the pulmonary circulation. Clinical signs, ECG, echocardiogram, x-ray of the chest, cardiac catheterization and special angiograms of the lung vessels have to be performed and their results have to be viewed in a synopsis. The type of tapering of the small arteries in the wedge-angio, the transit time of contrast media in the digital function angio, and changes of pressure and flow under test conditions give further information. Biopsy and histologic studies are difficult and not without risk. Treatment means prevention of advanced changes of PVD. Earlier correction of operable defects, banding of the pulmonary artery in complex heart lesions can avoid the development of PVD. A potent dilator of the small pulmonary arteries, applicable orally and over a long time, is not available at present.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial Occlusive Diseases↗
PubMed1988

Evaluation of left ventricular contractile performance from baseline stress-shortening data in humans: comparison with pharmacological afterload challenge.

The purpose of this study was to evaluate whether the baseline stress-shortening data reflect the contractile state adequately and give results comparable to the evaluation of the end-systolic stress-shortening relationships using pharmacological manipulation of afterload. Five groups were studied (total 152 patients): a control group of 30 healthy volunteers, 32 patients after surgical correction of infantile tetralogy of Fallot, 50 patients treated for childhood malignancies with doxorubicin, 17 patients with left ventricular hypertrophy due to systemic hypertension, and 23 patients with congestive cardiomyopathy. In all patients except those with congestive cardiomyopathy, afterload was altered pharmacologically to evaluate the individual stress-shortening relationship. In all patients the baseline stress-shortening data were evaluated, as well as their relative positions to two predefined normal ranges for the relationship between end-systolic stress and shortening. Additionally, a slope value was calculated from the baseline data of the five groups studied and compared with the data obtained by pharmacological afterload increment. Our data show that the comparison of individual baseline data of end-systolic wall stress and fractional shortening with predefined normal ranges for the relationship between end-systolic stress and shortening is inadequate. The appropriate normal range to compare with is the 95% confidence interval of baseline stress-shortening data in normal subjects. Also the calculation of a slope value from the baseline stress-shortening data of a group of patients seems to be inappropriate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Digital cine angiographic evaluation of pulmonary blood flow velocity in ventricular septal defect.

Forty-one routine right ventricular cineangiograms of children with ventricular septal defect (VSD) were evaluated with a digital image processing system. The purpose was to extract from the cineangiogram functional images that would provide information about pulmonary blood flow in these patients. The time delay of the contrast bolus between the main pulmonary artery and peripheral lung fields was measured and called "arrival time." By measuring the arrival time in three different points of each lung (apex, horizontal, basis), it was possible to express the mean arrival time for both lungs in a single figure. A group of patients without heart disease showed an arrival time of 1.3 +/- 0.3 seconds. In VSD with increased pulmonary blood flow from the left to right shunt, the arrival time decreased to 0.76 +/- 0.2 seconds. An increase in pulmonary vascular resistance with reduced L-R shunt led to an increased arrival time of 1.4 +/- 0.4 seconds.

Blood Flow Velocity↗
PubMed1988

Up to 9 years of follow-up after anatomic correction of simple transposition of the great arteries.

For a continued assessment of the two-stage anatomic correction, we have evaluated the postoperative results in terms of clinical status, ECG, ventricular function, aortic root size and stiffness for up to 9 years in all 18 survivors. Weight and height were normal, the ECG was normal except for complete (n = 3) and incomplete (n = 11) right bundle branch block and supraventricular tachyarrhythmias post Blalock-Hanlon septectomy (n = 1) and p-wave abnormalities (n = 6). The pressures and ejection fraction of the left and right ventricles were within normal limits. The end-diastolic and endsystolic left ventricular volume and the muscle volume index were elevated. Six of 17 patients were outside the normal range of the left ventricular ejection fraction-endsystolic stress relationship. The diameter of the aortic root was larger than normal in all patients. There was a relation between the size of the patients at banding and the stiffness of the aortic root after anatomic correction. Patients with simple transposition of the great arteries up to 9 years after anatomic correction develop normally without atrio-ventricular conduction delay, arrhythmias or signs of coronary and myocardial insufficiency. The stiff and enlarged aortic roots do not seem to dilate. The reasons for the elevated left ventricular volumes and muscle volume indices are not clear at present. Primary anatomic correction may prevent these abnormalities.

Aorta↗
PubMed1988

Long term doxorubicin cardiotoxicity in childhood: non-invasive evaluation of the contractile state and diastolic filling.

Cardiac performance was evaluated at least two years after doxorubicin treatment in childhood in 55 patients without overt congestive cardiomyopathy. None of the patients had received mediastinal irradiation. Computer-assisted analysis of digitised echocardiograms showed impaired rapid diastolic filling and an increased change of dimension between minimal cavity dimension and mitral valve opening. This impairment of diastolic function was related to the cumulative dose of doxorubicin. In contrast when angiotensin II was infused to increase the afterload the end systolic pressure-length and stress-shortening relation indicated normal left ventricular systolic function. But during baseline conditions the end systolic wall stress was significantly increased in patients in whom the cumulative dose of doxorubicin exceeded 360 mg/m2.

Adolescent↗
PubMed1987

Effects of persisting myocardial sinusoids on left ventricular performance in pulmonary atresia with intact ventricular septum.

The effects of persisting right ventricular myocardial sinusoids on left ventricular global and regional function were studied in 13 patients with pulmonary atresia and intact ventricular septum. Persisting myocardial sinusoids allow the inflow of undersaturated blood into the coronary circulation with subsequent myocardial ischaemia. 7 patients had myocardial sinusoids (group 1). 6 patients had normal coronary perfusion (group 2) The measures of global left ventricular function (ejection fraction, left ventricular enddiastolic volume, left ventricular enddiastolic pressure and shape index) showed no differences between the groups. All patients in group 1 showed disturbances of regional wall motion (P less than or equal to 0.005). There was a high degree of coincidence between the disturbances of regional wall motion and the topography of myocardial perfusion from persisting myocardial sinusoids. In group 1 apical hypokinesia was a regular finding, reflected by a significantly reduced shortening of the left ventricular long axis (P less than or equal to 0.01). As all of these patients had communications between the myocardial sinusoids and the left anterior descending coronary artery, this probably resulted from apical left ventricular ischaemia.

Coronary Circulation↗
PubMed1985

[Ventricular septal defect: late spontaneous closure].

25 patients who had a proven isolated small ventricular septal defect (VSD) when they were children were re-examined 3 to 19 years later, at the age of 20-21 years. Spontaneous closure was diagnosed if the murmur had disappeared and all other cardiological findings were normal. This was so in nine patients. Six of them had previously been followed to eight years or more with the definite diagnosis of VSD. In the three others who had only been followed to the age of 3-5 years the time of closure, whether early or late, could not be assessed.

Adult↗
PubMed1985

Pitfalls in the diagnosis of tricuspid atresia: report of a new angiocardiographic sign.

Two patients with the classical clinical, angiographic, and echocardiographic signs of tricuspid atresia are reported, where the correct diagnoses were made at operation; one child had cor triatriatum dexter, the other child total anomalous systemic venous drainage to the left atrium. The literature on cor triatriatum dexter and total anomalous systemic venous drainage is discussed and a new angiographic sign for the differentiation from tricuspid atresia is reported: nonopacification of the right atrial appendage with right atrial angiocardiography.

Angiocardiography↗
PubMed1985

[Echocardiographic pressure-dimension analysis following anatomically corrective operation of d-transposition of the great arteries].

The major theoretical advantage of anatomic correction of transposition of the great arteries compared with intraatrial repair is that the left ventricle becomes the systemic pump. In 10 patients we analysed 5-12 months after anatomic correction the left ventricular echocardiographic pressure-dimension loop, meridional wall stress and left ventricular stiffness from the simultaneous recordings of the left ventricular pressure and M-mode echocardiogram. The low left ventricular diameters, left ventricular hypertrophy in 4 patients, and increased peak meridional wall stress in 3 patients indicate that left ventricular adaption to systemic impedance is still incomplete 5-12 months after anatomic correction. The cycle efficiency was reduced in 2 patients, indicating incoordinate left ventricular contraction and relaxation. In one of these patients the left ventricular stiffness was severely increased, while in another patient there was a slight increase in left ventricular stiffness. In all patients the right ventricular internal diameter was increased due to the long-standing preoperative pressure and volume overload.

Blood Pressure↗
PubMed1981

Further experience with the two-stage anatomic correction of simple transposition of the great arteries.

Between May 1976 and January 1981 a two-stage anatomic correction was performed in 25 patients with simple transposition of the great arteries, ranging in age from 41/2 to 46 1/2 months (mean 14.8). A first-stage operation, consisting of banding of the pulmonary artery to redevelop the left ventricle, including a Blalock-Taussig-anastomosis in 4 patients was performed prior to anatomic correction. Of 33 patients, who underwent first-stage correction there were 3 early deaths (9%). The interval between the first and second stages was 5 weeks to 9 months (mean 4.3 months). After the first-stage operation, the peak systolic left ventricular pressure rose from 34 +/- 11 mmHg to 80 +/- 16 mmHg with no significant change in enddiastolic pressure. After anatomic correction there were 5 early deaths (20%) of whom 4 were due to left heart failure. There was no correlation between death and the age of the patients at the time of anatomic correction. By our current criteria the ventricles were not adequately prepared for correction in these four patients. The coronary arteries, with different types of origin, could be reimplanted to the posterior vessels without kinking, tension or torsion in all cases. After correction, the ECG and vectorcardiogram rapidly changed toward normal. The arterial oxygen saturation was higher than 95% in all patients. Recatheterization performed in 11 patients, 3 weeks to 27 months after correction, showed normal left ventricular pressure at rest in all children, except in 2 recatheterized early after correction, who had moderately elevated left ventricular enddiastolic pressure. Right ventricular peak systolic pressure decreased to normal limits. The aortic and coronary anastomoses showed normal growth in cineangiography. Although the two-stage corrections of simple TGA may have its own problems, investigation suggests that results are encouraging.

Child, Preschool↗
PubMed1981

[Neurologic disorders and cerebral lesion in children with TGA (transposition of the great arteries) (author's transl)].

118 consecutive patients with TGA were examined for neurologic disorders (ND) and cerebral lesions (CL) between 1967--1979 of whom 43 are alive. 66 had simple TGA, 52 had VSD, PS and/or coarctation as additional lesion.--43 were corrected surgically of whom 32 are alive.--Neurologic examination was performed in all, EEG, CT, arteriography, scintigraphy and autopsy when necessary or possible. Patholog. findings (CL, ND) were detected in 66; 47 had definite ND or CL, while 19 showed gross motor development delay. 52 of 118 children with TGA were without neurolog. or cerebral pathology. --Several factors were investigated for their etiologic influence: 1. Additional cardiac lesions played no significant role. 2. The lower O2 saturation in the ascending aorta of the fetal circulation in TGA may be of importance. 3. Red blood count, hemoglobin, hematocrit were higher in the group with ND or CL. 4. Early appearance of cerebral lesion should suggest earlier corrective surgery.

Brain Damage, Chronic↗
PubMed1978

[Pulmonary hypertension and cor pulmonale complicating ventricular vascular shunting for hydrocephalus (author's transl)].

Obstructive pulmonary vascular disease and pulmonary hypertension are facts daily encountered by pediatric cardiologists. However longterm thromboembolism, pulmonary vascular obstruction and cor pulmonale are rare conditions in children. The case report of a four years old child treated by a Pudenz ventriculo venous shunt for hydrocephalus is presented. Due to fibrin thromboembolism from the Pudenz shunting tube pulmonary vascular obliteration, pulmonary hypertension and chronic cor pulmonale developed. The autopsy findings are in agreement with the ECG, x-ray, cardiac catheterization data and the angiocardiogram.

Cerebrospinal Fluid Shunts↗