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E Grenadier

Publications and source records attributed to E Grenadier.

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

Quantitative characterization and sorting of three-dimensional geometries: application to left ventricles in vivo.

A procedure for automatic sorting of three-dimensional (3-D) shapes is proposed. The procedure is applied to sort into normal and abnormal categories, human left ventricles (LV) using in vivo data from 19 subjects (ten normal and nine abnormal LV's) studied by ultrafast tomography (Cine-CT). The procedure starts by utilizing a vector in a helical coordinate system to describe the spatial geometry of each individual LV cavity. This individual vector is then anatomically aligned and normalized to eliminate effects due to size, yielding a dimensionless vector, denoted as "geometrical cardiogram" (GCG). The GCG characterizes the instantaneous 3-D geometrical information of the individual LV. For the group of healthy subjects, the Karhunen-Loeve Transform (KLT) is then applied to compress the geometric information contained in their individuals' GCG vectors, at end diastole (ED) and end systole (ES), and yield a unique set of basis vectors. The "normal shape domain" is next defined as a truncated set of the KLT basis vectors from which a normal GCG can be reconstructed with a mean squared error (MSE) smaller than a defined threshold. The calculated MSE of any individual GCG reconstructed in this domain is then used as a criterion for sorting the 3-D shapes. Hearts which yield MSE greater than the threshold are considered abnormal. When applied to the study group of 19 subjects a significant difference (p less than 0.0001) between the MSE values obtained for the normal LV's, and those obtained for the abnormal LV's was detected, thus leading to a successful sorting of all the studied LV's. Finally, the KLT is applied to yield a compact representation of the 3-D geometry of any LV (normal or abnormal).

Adolescent↗
PubMed1988

Von Willebrand factor and mitral valve prolapse.

The levels of von Willebrand factor (vWF:Ag) were measured in 27 patients with mitral valve prolapse (MVP) and compared to 27 age matched controls. Decreased levels of vWF:Ag (less than 80%) were found in 59% (16/27) of those with MVP compared to only 7% (2/27) of the controls (p less than 0.001). Mean vWF: Ag levels were also significantly lower in those with MVP (68 +/- 30% versus 100 +/- 23%, p less than 0.001). In those with MVP and congestive heart failure secondary to rupture chordae tendineae, however, the mean level of vWF: Ag was not significantly different from control values (95 +/- 32). There was an increased incidence of recurrent nose bleeds in those with MVP and low levels of vWF:Ag. We conclude that there is a relationship between MVP and low levels of vWF:Ag which may explain the increased incidence of epistaxis in such patients. Increased release of vWF:Ag in those with MVP and concomitant congestive heart failure may account for the normal levels found in this subgroup.

Antigens↗
PubMed1986

The von Willebrand factor in myocardial infarction and unstable angina: a kinetic study.

Recent studies have demonstrated elevations of von Willebrand Factor following acute myocardial infarction (AMI). In order to determine if this parameter may serve as a marker for AMI, we tested the blood levels of vWF and Factor VIII:C in 28 patients with AMI, 9 patients with unstable angina, 7 patients with atypical chest pain, and 25 healthy volunteers. The level of ristocetin cofactor activity of vWF was between 70 and 144% in the control group. In patients with AMI, the mean level of this activity was 175% on the first day following infarction, rose to a peak of 270% on the fifth and sixth days, and was still significantly greater than normal in all patients on the 14th day. The vWF:Ag level closely paralleled the rise of ristocetin cofactor activity of vWF, with a peak of 336% on day 5. FVIII:C was not significantly changed. No significant elevation of vWF was observed in patients with unstable angina. The ristocetin cofactor activity of vWF and vWF:Ag thus are sensitive biochemical indicators for recent AMI, and may serve as useful markers for up to 14 days following infarction, when the traditional enzymes have returned to normal levels.

Angina Pectoris↗
PubMed1985

Ruptured mitral chordae tendineae may be a frequent and insignificant complication in the mitral valve prolapse syndrome.

In this study, we performed 512 echocardiographic studies on 264 consecutive unselected patients with the idiopathic mitral valve prolapse syndrome. Twenty-eight patients (10.6%) had evidence of ruptured chordae tendineae of the mitral valve on M-mode examination and in 24 the diagnosis was confirmed by two-dimensional echocardiography. Mild to severe mitral insufficiency was proven in all of them by left ventriculography during cardiac catheterization. Eight patients underwent surgery to relieve symptomatic severe mitral regurgitation. At operation all had myxomatous degeneration of the mitral valve, two patients were found to have rupture of anterior mitral chordae, and six had rupture of posterior mitral chordae. Twenty (71%) patients with chordal rupture had either mild symptoms or were completely asymptomatic. It is concluded that chordal rupture in patients with the mitral valve prolapse syndrome may be present in asymptomatic patients and go undetected clinically in a substantial number of patients unless a high index of suspicion is maintained. Serial M-mode and two-dimensional echocardiographic studies are of importance in identifying the progression of prolapse findings and may reveal the natural history of this pathologic condition in asymptomatic patients.

Adolescent↗
PubMed1984

Polymorphous ventricular tachycardia in acute myocardial infarction.

Polymorphous ventricular tachycardia (VT) is thought to be uncommon in acute coronary heart disease, but its prevalence has not been determined. Seven hundred seventy-one consecutive patients admitted with acute myocardial infarction (MI) were reviewed for the occurrence of this arrhythmia. Nine patients (1.2%) had polymorphous VT. No patient had any of the predisposing factors previously associated with polymorphous VT. The arrhythmia was resistant to multiple drugs, and repeated cardioversion was effective in only 3 patients. Overdrive pacing was ineffective in the 3 patients in whom it was attempted. Verapamil was effective in 3 of 4 patients in whom it was tried. Six patients with polymorphous VT died during hospitalization; the remaining 3 died within 6 months of discharge. It is concluded that, when compared with regular VT, polymorphous VT in MI carries a poor prognosis. When the arrhythmia occurs in the context of acute ischemia, it appears to be more difficult to treat compared with its occurrence due to other predisposing factors. Verapamil, not usually indicated for ventricular arrhythmias, should be tested in a therapeutic trial.

Aged↗
PubMed1984

Two-dimensional echo Doppler study of congenital disorders of the mitral valve.

To define the use of two-dimensional echocardiography (2DE) and Doppler methods for diagnosis of forms of congenital mitral stenosis, we studied 16 children, age range 2 months to 13 years, with congenital deformities of the mitral valve documented at cardiac catheterization. Thirteen had additional congenital heart defects, most commonly aortic stenosis or aortic coarctation. In eight patients features of mitral valve anatomy were observed and described during cardiac surgery and in one child the anatomy was verified by postmortem examination. 2DE studies allowed anatomic subclassification of 10 valves which had asymmetric or single dominant papillary muscles (parachute) and six which had arcade mitral valve attached by short chords to multiple diminutive papillary muscle heads. All patients' echoes exhibited shortened and thickened mitral chordae and doming of the mitral leaflets during diastole, and seven children had restricted mitral orifices imaged on the short-axis imaging plane. All seven of the patients studied by Doppler echocardiography had increased maximal transmitral inflow velocity (range 111 to 260 cm/sec) greater than the 95% confidence limits for mitral flow velocities in 34 normal children who served as the control group. Our study suggests that 2DE studies, especially when combined with Doppler interrogation, are sensitive for defining forms of congenital mitral stenosis.

Adolescent↗
PubMed1984

Left ventricular wall motion abnormalities in Kawasaki's disease.

Two-dimensional (2DE) and M-mode echocardiographic examinations were reviewed for 21 patients with Kawasaki's disease. Cardiac catheterization including coronary angiography was performed in 14 patients. 2DE detected regional myocardial contraction deficits in four patients later proven to have coronary disease. Coronary aneurysms were detected by echocardiography in two of four patients with proven coronary lesions. Although a minor pericardial effusion was detected in two patients and an increased left ventricular (LV) cavity dimension was found in one patient, M-mode function studies were not helpful for detection of cardiac involvement. ECG and chest x-ray examination were also noncontributory. We conclude that 2DE detection of LV wall contraction abnormalities may be a sensitive method for detecting cardiac contraction abnormalities may be a sensitive method for detecting cardiac involvement in Kawasaki's disease. 2DE may be better for assessing LV contraction than for imaging aneurysms in Kawasaki patients.

Aneurysm↗
PubMed1984

Normal intracardiac and great vessel Doppler flow velocities in infants and children.

Normal two-dimensional pulsed Doppler echocardiographic velocity profiles for sites within the heart and great vessels in a group of 102 normal infants and children are presented. Qualitatively, waveforms mimic expected hemodynamic events at the various sites. All waveforms had a rapid initial deflection followed by spectral broadening after attainment of peak velocity. Quantitative angle-corrected peak velocities were generally lower on the right side than on the left side of the heart. Differences in tricuspid (mean 61.8 cm/s) versus mitral (mean 81.1 cm/s) outflow and pulmonary (mean 76.1 cm/s) versus aortic (mean 88.5 cm/s) outflow were significant (p less than 0.01). The only significant age-related differences were in the pulmonary artery (mean for newborns 67.7 cm/s versus 79.6 cm/s for older children, p less than 0.01). Aortic data obtained from interrogation sites in which flow was close to 0 or 180 degrees were similar, whereas aortic peak velocity data obtained from apical long-axis or subcostal views were greater. These differences were probably induced from inaccuracies in azimuthal (elevational) angles that cannot be measured. These normal Doppler data should be useful for comparisons with data obtained for children with various forms of congenital heart disease that affect flow dynamics.

Adolescent↗
PubMed1984

Clinical utility of two-dimensional doppler echocardiographic techniques for estimating pulmonary to systemic blood flow ratios in children with left to right shunting atrial septal defect, ventricular septal defect or patent ductus arteriosus.

Range gated two-dimensional Doppler echocardiographic methods were evaluated for quantifying pulmonary (QP) to systemic (QS) blood flow ratios. Twenty-one patients were studied, 4 with patent ductus arteriosus, 6 with atrial septal defect and 11 with ventricular septal defect. The Doppler pulmonary to systemic flow (QP:QS) estimation method involved calculating volume flow (liters/min) at a variety of intracardiac sites by using imaging information for flow area and Doppler outputs to calculate mean flow velocity as a function of time. Area volume flows were combined to yield QP:QS ratios. The sites sampled were main pulmonary artery, ascending aorta, mitral valve orifice and subpulmonary right ventricular outflow tract. The overall correlation between Doppler QP:QS estimates and those obtained at cardiac catheterization (n = 18) or radionuclide angiography (n = 3) was r = 0.85 (standard error of the estimate = 0.48:1). These preliminary results suggest that clinical application of this Doppler echocardiographic method should allow noninvasive estimation of the magnitude of cardiac shunts.

Adolescent↗