Biomedical subjects

Jean-Marc Dupuis

Publications and source records attributed to Jean-Marc Dupuis.

5 recordsLinked to original sources

PubMed2006

The reasons of general practitioners for promoting colorectal cancer mass screening in France.

Implementation of colorectal cancer (CRC) mass screening is a public health priority. Obtaining the involvement of general practitioners (GPs) is crucial for ensuring participation by the general public. This study elicited GPs' reasons for promoting CRC screening. The method used was discrete choice modeling. Questionnaires with a set of pairs of hypothetical screening scenarios were sent to 700 GPs. Factors influencing GPs' screening practice were found to be: the effectiveness of the screening program, the proportion of false negatives and false positives, and their remuneration. Hence improving screening test sensitivity and setting up specific remuneration for conducting screening would help to increase GPs' participation in CRC screening in France.

Adult↗

PubMed2005

Late hemodynamic changes during a negative passive head-up tilt predict the symptomatic outcome to a nitroglycerin sensitized tilt.

BACKGROUND: Sublingual nitroglycerin is advocated to sensitize the passive 70 degrees head-upright tilt test (HUTT) of patients with unexplained syncope. We hypothesized that a detailed analysis of hemodynamic responses recorded during a negative HUTT could predict the outcome to a subsequent nitroglycerin sensitized HUTT (NTG-HUTT). METHODS: Thirty-two patients (46 +/- 3 years, 17 males) with recurrent unexplained syncope but a negative HUTT were included. Heart rate, arterial blood pressure, and central hemodynamics assessed by transthoracic impedance (preejection and rapid left ventricular ejection time, slow ejection time, peak amplitude of first derivative, and cardiac index) were recorded during supine rest and 45 minutes HUTT. Changes from supine rest of the variables were retrospectively compared between patients with a negative (n = 15, NTG-HUTT(-)) and positive (n = 17, NTG-HUTT(+)) outcome to 10 minutes subsequent NTG-HUTT. RESULT: Significant differences between groups were observed during the 15th-20th minutes (Italian protocol) and during the last 5 minutes of passive HUTT (Westminster protocol). The combination of cutoff values, determined by receiver operating curves, on hemodynamic variables changes during the last 5 minutes predicted the outcome to a NTG-HUTT with a sensitivity of 76% and a specificity of 87%. The cutoff values determined during 15th-20th minutes gave an attractive sensitivity (85%) but a too weak specificity (53%) to shorten the 45 minutes passive HUTT at 20 minutes. CONCLUSION: Outcome to a NTG-HUTT can be reliably predicted by selected criteria determined from multiple hemodynamic variables recorded during a passive 70 degrees HUTT.

Analysis of Variance↗

PubMed2003

Changes in the transthoracic impedance signal predict the outcome of a 70 degrees head-up tilt test.

We determined whether early changes in central haemodynamics, as determined by transthoracic impedance, induced by a 70 degrees head-up tilt (HUT) test could predict syncope. Heart rate, arterial blood pressure and central haemodynamics [pre-ejection period and rapid left ventricular ejection time ( T (1)), slow ejection time ( T (2)) and d Z /d t (max) (where Z is thoracic impedance), assessed by the transthoracic impedance technique], were recorded during supine rest and during a 45 min 70 degrees HUT test in 68 patients (40+/-2 years) with a history of unexplained recurrent syncope. We found that 38 patients (42+/-3 years) had a symptomatic outcome to 70 degrees HUT (fainters) and 30 (39+/-2 years) had a negative outcome (non-fainters). When measured between 5 and 10 min of 70 degrees HUT, T (2) had increased significantly only in the fainters, and a change in T (2) of >40 ms from baseline predicted a positive outcome with a sensitivity of 68% and a specificity of 70%. During supine rest prior to 70 degrees HUT, the fainters exhibited a shorter T (2) than non-fainters (183+/-10 compared with 233+/-14 ms; P <0.01), and a T (2) of <199 ms predicted a positive outcome to 70 degrees HUT with a sensitivity of 68% and a specificity of 63%. Incorporation of the changes that occurred from rest to 70 degrees HUT in other haemodynamic variables (heart rate >11 beats/min, systolic pressure <2 mmHg, diastolic pressure <7 mmHg and pulse pressure <-3 mmHg) increased the specificity to 97% and the positive predictive value to 93%. Thus transthoracic impedance could detect differences in central haemodynamics between fainters and non-fainters during supine rest and during the initial period of 70 degrees HUT with a consistent sensitivity and specificity when combined with peripheral haemodynamic variables.

Adolescent↗

PubMed2003

Haemodynamic response to peripheral venous congestion in patients with unexplained recurrent syncope.

In patients with recurrent unexplained syncope, exaggerated peripheral venous pooling and impaired circulatory adjustment is thought to contribute to the outcome of a head-up tilt (HUT) test. The present study investigated the role of leg volume changes during venous congestion in the haemodynamic response of patients with recurrent unexplained syncope and the ability to predict the outcome of a HUT test. Changes in calf volume (strain gauge plethysmography), heart rate and arterial blood pressure were recorded in 60 patients with history of unexplained syncope (without postural tachycardia symptom) during venous congestion provoked by pneumatic thigh cuffs while supine at rest and during the initial 10 min of a 45 min 70 degrees HUT test. Twenty-seven patients [age (mean+/-S.D.), 39+/-16 years] exhibited symptoms [HUT(+)] and 33 patients (45+/-14 years) were asymptomatic [HUT(-)]. During venous congestion, mean+/-S.E.M. calf volume increased in both groups [HUT(-), 4.5+/-0.2; HUT(+), 4.8+/-0.4 ml x 100 ml(-1), not significant), but significantly less during head-upright tilt [HUT(-), 3.3+/-0.2, P <0.01; HUT(+), 2.6+/-0.3 ml x 100 ml(-1), P <0.001] without differences between the groups. During venous congestion, arterial pressure increased significantly in asymptomatic HUT(-) patients, but not in the HUT(+) patients. Calf volume changes did not correlate with a symptomatic outcome to a 70 degrees HUT. The lack of exaggerated venous pooling during venous congestion and the inability of calf volume changes to predict a positive HUT suggest that excessive venous pooling does not contribute to the outcome of HUT. Attenuated changes in arterial pressure during venous congestion while supine suggest impaired adjustment of peripheral resistance to leg venous occlusion.

Adult↗

PubMed2003

Programming optimal atrioventricular delay in dual chamber pacing using peak endocardial acceleration: comparison with a standard echocardiographic procedure.

Optimization of programmed atrioventricular delay in dual chamber pacing is essential to the hemodynamic efficiency of the heart. Automatic AV delay optimization in an implanted pacemaker is highly desirable. Variations of peak endocardial acceleration (PEA) with AV delay at rest correlate well with echocardiography derived observations, particularly with end-diastolic filling and mitral valve closure timings. This suggests the possibility of devicing a procedure for the automatic determination of the optimal AV delay. The aim of this study was to compare a proposed algorithm for optimal AV delay determination with an accepted echocardiographic method. Fifteen patients with high degree AV block received BEST-Living pacing systems. Automatic AV delay scans were performed at rest (60-300 ms in 20-ms steps with 60 beats per step) in DDD at 90 ppm, while simultaneously recording cycle-by-cycle PEA values, which were averaged for each AV delay to obtain a PEA versus AV delay curve. Nonlinear regression analysis based on a Boltzmann sigmoid curve was performed, and the optimal AV delay (OAVD) was chosen as the sigmoid inflection point of the regression curve. The OAVD was also evaluated for each patient using the Ritter echocardiographic method. Good sigmoid fit was obtained in 13 of 15 patients. The mean OAVD obtained by the PEA sigmoid algorithm was 146.9 +/- 32.1 ms, and the corresponding result obtained by echocardiography was 156.4 +/- 34.3 ms (range 31.8-39.7 ms). Correlation analysis yielded r = 0.79, P = 0.0012. In conclusion, OAVD estimates obtained by PEA analysis during automatic AV delay scanning are consistent with those obtained by echocardiography. The proposed algorithm can be used for automatic OAVD determination in an implanted pacemaker pulse generator.

Aged↗