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Biomedical subjects

B Diebold

Publications and source records attributed to B Diebold.

At least 55 records · Page 3Linked to original sources
PubMed1991

[Transesophageal echography in the investigation of left atrial ball thrombi. Apropos of a case of migration of a left atrial thrombus].

The authors report the case of a pediculated left atrial ball thrombus whose embolisation and ejection through the aortic valve was recorded during transesophageal echocardiography. The value and risks of transesophageal echocardiography for the diagnosis of left atrial masses are reviewed in the light of this case and a review of the literature. The prognosis and therapeutic implications of a left atrial ball thrombus are also described.

Aged↗
PubMed1990

In vitro analysis of a model of intracardiac jet: analysis of the central core of axisymmetric jets.

In order to provide physical information supporting the clinical use of flow mapping, an in vitro model was designed to measure the velocity fields in a pulsatile hydraulic turbulent jet. We used a peak velocity ranging from 2.5 to 5.5 m.s-1, an orifice diameter ranging from 5.8 to 11.3 mm and confined the jet in a receiving tube whose diameter ranged from 16 to 30 mm, thus simulating a large variety of valvular leaks. In steady flow conditions, our results agreed with previously reported descriptions. Under pulsatile conditions, the same structure was found at peak velocity and during the beginning of the deceleration. Below a threshold velocity, the length of the central core was independent of the peak velocity and proportional to about six times the orifice diameter. Above the threshold velocity, this relationship was no longer true, the threshold value being related to the ratio of the orifice diameter to the diameter of the receiving tube.

Blood Flow Velocity↗
PubMed1990

Is pulsed Doppler echocardiography an adequate method to evaluate left ventricular function during filling in hypertensive patients?

Pulsed Doppler tracings of the mitral inflow are often proposed to describe left ventricular function during filling in hypertensive patients. The tracings are determined by the complex interaction of left atrial pressure and left ventricular relaxation, diastolic compliance and contractility of the left atrium. They strongly depend on preload and, thus, do not allow precise characterization of the left ventricle. In addition, they vary with age, heart rate and the site of measurement. The modifications caused by the presence of hypertensive hypertrophy are not specific: similar changes are seen for example, in the presence of hypertrophic cardiomyopathy or coronary heart disease, but are absent in highly trained athletes in spite of very significant physiologic hypertrophy.

Aging↗
PubMed1990

[Blood flow and compliance of great arterial trunks].

The important technical advances in the last few years in the field of ultrasonic imaging and Doppler velocimetry now enable an accurate evaluation of the vasomotricity, blood flow and compliance of the large peripheral arteries. The information provided by these new non-invasive techniques in clinical pharmacology is considerable as they make possible repeated measurements of different parameters of regional circulation (diameters, flow, pulse wave velocity and modulus of elasticity) and the assessment of the efforts of different vasoactive drugs on these values. Some limitations are nevertheless inherent to the non-invasive nature of the examination.

Arteries↗
PubMed1990

[Study of valvular prostheses by Doppler echography].

Doppler echocardiography is a reliable non-invasive method of following up patients with prosthetic heart valves. Transthoracic M mode and two-dimensional echo allow evaluation of the movement of the mobile element of the prosthesis and of the size of the cardiac chambers. Doppler studies (transprosthetic pressure gradient, valve surface area, trans- and periprosthetic regurgitation) give an indication of the hemodynamic profile of the prosthesis. Transesophageal echocardiography is especially useful when there are abnormalities suggestive of prosthetic valve dysfunction (fever, systemic embolism, clinical symptoms, haemolysis...).

Aortic Valve↗
PubMed1990

[Evaluation of 90 normal aortic valve prosthesis of the Saint-Jude Medical type by echocardiography].

Between September 1986 and February 1989, ninety patients undergoing isolated aortic valve replacement were studied on the 15th postoperative day, in the Department of Cardiac Surgery at St Joseph's Hospital, Paris. Patients with a diastolic murmur, fever, significant, pericordial effusions and poor quality Doppler recordings were excluded. The aim of the study was to determine normal Doppler echocardiographic parameters of St Jude medical aortic valve prostheses. Maximum and mean transprosthetic pressure gradients were calculated by the simplified Bernoulli equation. Functional value surface area was assessed by the continuity equation using the diameter of the left ventricular output tract measured by 2D echocardiography (continuity) and the external diameter of the prostheses (modified surface area) to calculate the subaortic surface area. The transprosthetic pressure gradients G max and G mean were inversely correlated to the size of the prostheses (r = 0.42 and r = 0.45). The functional valve surface area calculated by the continuity method gave a poor correlation but this improved considerably when the diameter of the prosthesis (modified surface area) was considered. Finally, the permeability index which is the ratio of subaortic and transaortic velocities seemed to be a good parameter for assessing prosthetic valve function.

Adolescent↗
PubMed1990

[The value of recording the pulmonary insufficiency flow by continuous Doppler for the evaluation of systolic pulmonary artery pressure].

Systolic, diastolic and mean pulmonary artery pressures can be evaluated by Doppler recordings of the maximal velocity of tricuspid regurgitation and early and late diastolic pulmonary regurgitant flow. The aim of this study was to assess the reliability of the calculation of systolic pulmonary artery pressure from pulmonary regurgitant flow by comparing the values with those obtained from the tricuspid regurgitant flow in the same patient. With this objective in mind, we investigated 70 patients with an average age of 45 +/- 34 years, in sinus rhythm, all of whom had tricuspid and pulmonary regurgitant jets which could be recorded with continuous wave Doppler. Systolic pulmonary artery pressure was calculated as follows: from tricuspid regurgitation: maximum pressure gradient + 10 mmHg; from pulmonary regurgitation: 3 x early diastolic gradient - 2 x late diastolic gradient + 10 mmHg. The systolic pulmonary artery pressures calculated from tricuspid and pulmonary regurgitation were: 42 +/- 16 mmHg and 43 +/- 17 mmHg respectively (r = 0.97) with an estimated standard error of 4.7 mmHg. These results show that the recording of pulmonary regurgitation by continuous wave Doppler allows accurate estimation of pulmonary artery pressures. The calculation by the two methods using tricuspid and pulmonary regurgitant jets increases the reliability of the results and provides a means of internal validation of the Doppler technique.

Adolescent↗
PubMed1990

[Dynamic left ventricular obstruction increased by nitroglycerin in elderly patients with hypertension and concentric left ventricular hypertrophy].

Left ventricular outflow tract (LVOT) obstruction has been observed in elderly patients with concentric hypertrophic hypertensive cardiomyopathy (HHCM) and no significant valvular disease or regional wall motion abnormalities. In order to determine whether nitroglycerin (NTG) can increase the intraventricular obstruction, we performed echocardiographic (echo) and doppler studies, before and during administration of sublingual NTG (0.8 mg). Twenty patients (n = 20) with long-standing hypertension (19 women and 1 man, mean age 78 +/- 8 yr, mean duration of hypertension 13 +/- 10 yrs were examined. The clinical findings in 17 patients were: angina 5 (29%), dyspnea 9 (53%), syncope or malaise 4 (23%). Electrocardiographic criteria of left ventricular hypertrophy was present in 4 patients and an increased cardio-thoracic ratio (greater than 0.5) in 9 cases. The following echo parameters were determined using M-mode echocardiograms: LV end-diastolic (LVID) and systolic diameter (LVIS), fractional shortening (FS), ventricular septum thickness (IVST), posterior wall thickness (PWT) and the ratio ISVT/PWT (less than 1.3 in all patients). LVM could be calculated in 15 patients and was corrected for body surface area (LVMI). Pulsed and continuous wave Doppler study showed a characteristic late-peaking velocity waveform. We localized the elevated velocities in the LVOT and determined before and during administration of NTG: LVOT peak velocities (V) and peak intraventricular gradients (G) using simplified Bernoulli equation. Results were as follows: [table: see text] Mild mitral regurgitation was observed in 14 patients (70%) and mitral annular calcifications in 11 (55%). Systolic function, as assessed by FS, was normal in all patients. NTG induced a significant acceleration of the LVOT velocities in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Pulsatile diameter and elastic modulus of the aortic arch in essential hypertension: a noninvasive study.

A noninvasive evaluation of the aortic arch diameter was performed in 16 subjects with sustained essential hypertension and in 15 normal subjects of similar age, gender and body surface area. In all subjects, measurements were obtained of brachial mean arterial pressure and pulse pressure, cardiac mass (judged on echocardiography) and carotid-femoral pulse wave velocity together with ultrasound determinations of aortic arch diastolic and systolic diameter (suprasternal window). For each subject, pulsatile change in aortic diameter, strain and aortic arch elastic modulus were calculated. Compared with normal subjects, the hypertensive subjects showed an increase in aortic arch diameter (diastolic diameter 29.6 +/- 1.0 versus 25.4 +/- 1.0 mm, p less than 0.01), in elastic modulus (1.071 +/- 0.131 versus 0.526 +/- 0.045 10(5) N.m-2, p less than 0.001) and pulse wave velocity (11.8 +/- 0.5 versus 8.9 +/- 0.3 m/s, p less than 0.001). In the study group, a positive correlation was observed between diastolic aortic arch diameter and mean arterial pressure (r = 0.54, p less than 0.01) and between elastic modulus and cardiac mass (r = 0.60, p less than 0.01). Elastic modulus and age were positively correlated (r = 0.73, p less than 0.01) in hypertensive but not in normal subjects (r = 0.08, NS). This study is the first to demonstrate noninvasively that both the aortic arch diameter and the elastic modulus are increased in patients with sustained uncomplicated essential hypertension. These findings suggest that the increase in elastic modulus could influence the development of cardiac hypertrophy, and that both age and blood pressure act independently as factors that alter the arterial wall of subjects with sustained essential hypertension.

Adult↗
PubMed1989

Detection of pulmonary hypertension by Doppler echocardiography of the inferior vena cava in chronic airflow obstruction.

Pulsed Doppler echocardiography of the inferior vena cava is an accurate method for the diagnosis of tricuspid regurgitation and impaired right ventricular compliance, two features of pulmonary hypertension. The purpose of this study was to assess the value of Doppler echocardiography of the inferior vena cava for the detection of pulmonary arterial hypertension in patients with chronic obstructive lung disease. Pulse Doppler echocardiography of the inferior vena cava and right heart catheterisation were performed in 29 patients with severe chronic obstructive lung disease. The mean pulmonary arterial pressure was 27 (10) mm Hg for the entire group; 62% of patients (18/29) had pulmonary arterial hypertension (mean pulmonary arterial pressure greater than 20 mm Hg). An adequate Doppler signal could be obtained in 25 of the 29 patients (86%). Pulsed Doppler echocardiography of the inferior vena cava gave normal results in 10 patients and disclosed tricuspid regurgitation in seven patients, impaired right ventricular compliance in seven patients, and both of these abnormalities in one patient. An abnormal Doppler echocardiogram of the inferior vena cava (tricuspid regurgitation or impaired right ventricular compliance, or both) predicted the presence of pulmonary arterial hypertension with a sensitivity of 87% and a specificity of 80%. These results suggest that pulsed Doppler echocardiography of the inferior vena cava may be a useful though imperfect method of detecting pulmonary arterial hypertension in patients with chronic obstructive lung disease.

Echocardiography, Doppler↗
PubMed1989

Noninvasive estimation of systolic pulmonary artery pressure using Doppler echocardiography in patients with chronic obstructive pulmonary disease.

In patients with acquired or congenital heart diseases, the systolic pulmonary artery pressure (PAPs) can be predicted using continuous-wave Doppler ultrasound (CWD) measurement of the peak velocity of a tricuspid regurgitation (TR) jet. The aim of this study was to determine whether CWD could be used to accurately estimate PAP in patients with chronic obstructive pulmonary disease (COPD). In 41 patients with stable COPD, we prospectively performed CWD and right heart catheterization. The mean value of PAPs for the entire group was 38.5 +/- 14.9 mm Hg. Pulmonary arterial hypertension (PAPs greater than or equal to 35 mm Hg) occurred in 51 percent (21/41) of patients. Doppler estimation of PAP was impossible in 34 percent (14/41) because of poor signal quality (n = 3), absence of Doppler-detected TR (n = 8), and inadequate TR Doppler signal (n = 3). The PAP could be estimated in 66 percent (27/41) of patients. A statistically significant correlation was found between the Doppler-estimated PAP and the catheter-measured PAPs (r = 0.65; p less than 0.001; SEE = 9 mm Hg). Therefore, CWD appears to be useful for the noninvasive estimation of PAP in patients with COPD. However, this method is associated with two limitations: (1) the high percentage of patients in whom the PAP cannot be estimated by CWD, mainly because of the absence of Doppler-detected TR, and (2) the high value of the standard error of the estimate. The combination of CWD with other Doppler methods should increase the feasibility and accuracy of Doppler echography for the prediction of PAP in patients with COPD.

Aged↗
PubMed1989

[Clinical application of echocardiography using a transesophageal approach].

Transesophageal echocardiography is a new method of cardiac imaging with well-defined indications. In view of the absence of hindering anatomical obstacle between the probe and cardiac structures, the images obtained are of high definition, especially as regards the atria and atrial appendages, the mitral, aortic and tricuspid valves and the thoracic aorta. Being easy to perform and little traumatic, this method can be used in ambulatory patients. It is also valuable in intensive care patients and in the peri-operative period. Transesophageal echocardiography is primarily indicated to explore cardiac valve prostheses, notably those of the mitral valve, to identify vegetations and abscesses in infective endocarditis, to detect intra-atrial tumours and thrombi, to evaluate dissections of the aorta, to study the mechanism of mitral regurgitation, to investigate some congenital cardiopathies in adults, such as interatrial septal defects, and to monitor left ventricular function before and after surgery. Owing to its major contribution to the diagnosis of these potentially dangerous diseases, it should soon become a very useful and even indispensable complement of transthoracic exploration in certain cases.

Aortic Diseases↗
PubMed1989

[Aortic and mitral endocarditis caused by Haemophilus paraphrophilus with abscess of the aortic ring and cerebral embolism].

We report the first case of aortic and mitral Haemophilus paraphrophilus endocarditis complicated by abscess of the aortic annulus in a 30-year old man with post-rheumatic mitral regurgitation. We recall the peculiar clinical features and course of this bacterial endocarditis of uncommon origin. We insist, in particular, on the occurrence of cerebral embolism and on the two-dimensional echocardiographic diagnosis of an aortic annulus abscess confirmed at surgery. Cure was obtained by aortic and mitral valve replacement and by the prolonged antibiotic therapy made necessary by the presence of cerebral lesions. After 3 months, there were no neurological sequelae, but doppler-echocardiography showed a persistent washed out pouch the reports of which with the surrounding structures were determined by transoesophageal echocardiography: moderate aortic regurgitation was detected at that level.

Abscess↗
PubMed1989

[Evaluation by Doppler echocardiography of systolic and diastolic functions of the left ventricle of the athlete's heart].

A doppler-echocardiographuc study of left ventricular hypertrophy and systolic functions was performed in 99 professional cyclists and 26 age, body surface and blood pressure-matched controls. The following T-mode echocardiographic parameters were determined: wall thickness and cavitary diameter, left ventricular mass (LVM), fibre shortening fraction (FSF) and ejection fraction (EF). The following doppler parameters were measured at the annulus (a) and tip (p) of the mitral valve leaflets: protodiastolic velocity peak (E), velocity peak during atrial systole (A) and A/E ratio. Compared with controls, the cyclists showed a significant increase of LVM (305 +/- 53 vs 174 +/- 41 g, p less than 0.0001) and of the h/R ratio of mean wall thickness (h) to cavitary radius (R) (0.40 +/- 0.04 vs 0.35 +/- 0.06, p less than 0.001). There was no significant difference between the two groups as regards FSF, EF and protodiastolic filling peak (E). In contrast, subjects in the cyclist group showed a significant increase of Ap (0.39 +/- 0.07 vs 0.47 +/- 0.09, p less than 0.001), Aa (0.36 +/- 0.07 vs 0.41 +/- 0.08, p less than 0.01) and A/Ep (0.54 +/- 0.12 vs 0.62 vs 0.62 +/- 0.11, p less than 0.0001). It is concluded that professional cyclists have an increase in size of their left ventricle and that repercussions of this enlargement on ventricular filling only appear during the atrial systole and are related to a slower heart rate.

Adult↗
PubMed1988

[Indirect approach of stenosis of transplanted kidneys by Doppler echography].

Pulsed Doppler ultrasound for the detection of rejection and renal artery stenoses involving transplanted kidneys was evaluated. Using mean velocity curves, the time interval between the ECG R wave and the onset of peak velocity was measured successively on the renal and ipsilateral iliac arteries and divided by the R-R interval. In 27 patients, a Doppler index defined as the ratio of the standardized renal artery and iliac artery time intervals, was determined and compared to angiographic data. The DI index failed to detect stenoses associated with rejection; conversely, in the absence of rejection, clear separation of patients without (n = 14, DI = 1.03 +/- 0.6) and with (n = 6, DI = 1.24 +/- 0.05) stenosis (t = 7.48, p less than 0.001) was achieved. Thus renal artery stenoses in transplant recipients can be detected by the comparative study of time intervals calculated for renal vessels and for the neighbouring iliac artery.

Adult↗
PubMed1987

Quantification of aortic regurgitation using Doppler imaging.

Aortic insufficiency induces the development of a jet within the left ventricular outflow tract. The cross sectional area of this jet at its origin is the major determinant of the severity of the regurgitation. M mode Doppler imaging reportedly allows the measurement of jet diameter. This study was designed to evaluate the quantification of aortic regurgitation using a measurement of the jet diameter by M mode Doppler imaging. The left ventricular outflow tract of 32 patients was imaged using either a multigate pulsed Doppler velocimeter of color flow mapping system (Hewlett Packard). The jet diameter was compared to a 4 grade semiquantification derived from supravalvular aortography. Adequate imaging was obtained in the 32 patients. Four of them had no regurgitation: no diastolic flow image could be found during their Doppler investigation. A clear jet image was obtained in the 28 remaining patients. We found a close relationship between the jet diameter (jd in mm) and the angiographic grade (ag): jd = 2.4 + 6.1 ag, r = 0.88, the most significant differences being found between grade 0 and grade 1, and grade 1 and grade 2. In conclusion, direct M mode measurement of the regurgitant jet of aortic insufficiency at its origin offers an additional approach of the severity of the leak.

Adult↗
PubMed1987

Doppler imaging of regurgitant jet in aortic insufficiency: experimental validation and preliminary clinical evaluation.

Aortic insufficiency induces the development of a jet within the left ventricular outflow tract. The diameter of a laminar jet is a well-defined hydraulic parameter. This study was designed to evaluate, both experimentally and in patients, the accuracy of its measurement using a Doppler imaging performed with a multigate pulsed Doppler velocimeter. The experimental validation was conducted on a water tank pulsatile model including calibrated orifices. Jet images appeared clearly delineated and were not modified when changing imaging angulation (from 85 degrees to 65 degrees), pump frequency (from 60 to 100 c min-1), pump output (from 0.5 to 3.8 l min-1), wall filtering, orifice shape, or signal-to-noise ratio. The measured jet diameter (jd) correlated closely with the orifice diameter (od): jd (mm) = 1.22 + (0.79 X od), r = 0.98. A preliminary clinical evaluation was performed on jets of aortic insufficiency on a series of 26 patients. Jet cross-section was studied within the left ventricular outflow tract using a parasternal approach. A high setting of wall filters allowed good quality imaging in 24 patients. In the absence of a diastolic jet, jd was taken equal to 0. Measured jet diameters were compared to the angiographic grade (ag): jd (mm) = 2.7 + (3.9 X ag), r = 0.86. In conclusion, jet diameter measurement using M-mode Doppler imaging is experimentally accurate and potentially valuable in patients with aortic insufficiency.

Aortic Valve Insufficiency↗