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Biomedical subjects

J P Broustet

Publications and source records attributed to J P Broustet.

At least 19 recordsLinked to original sources
PubMed1999

Irregular ventricular stimulation in the DDI mode of a dual chamber pacemaker with atrial-based lower rate timing.

This report describes two patients with atrial fibrillation in whom an implanted CHORUS DDD pacemaker programmed to the DDI mode produced an irregular ventricular stimulation rate. The lower rate timing of these devices is atrial-based only when an atrial event opens an AV interval shorter than the programmed AV delay. In the DDI mode, if Api represents the time when an atrial paced event (Ap) would have occurred if it had not been inhibited by a previous atrial sensed event (As), then Api-Vp constitutes the implied AV interval where Vp is a paced ventricular event. Although the As-Vp interval (As-Api + Api-Vp) generates an atrial refractory period during its entire duration, the pacemaker can sense an atrial event (AR) during the implied AV interval. AR cannot start another AV delay, but it can initiate the atrial-based lower rate interval. This timing mechanism can cause irregular prolongation of Vp-Vp intervals to a value longer than the programmed lower interval with a maximal extension equal to the programmed AV delay. Such behavior of the CHORUS pacemaker should not be interpreted as malfunction.

Atrial Fibrillation↗
PubMed1999

[Third degree atrio-ventricular block induced by interferon alpha. Report of a case].

Iatrogenic third degree atrioventricular block due to alpha interferon is rare. The authors present a case which occurred with low dosage, regressed when treatment was withdrawn and reappeared when treatment was reintroduced. The physiopathological mechanism of disease of the conduction pathways and its general cardiotoxicity is not yet understood. The secondary effects of this increasingly widely used anti-tumoral and anti-infectious drug should be recognised in order to prevent them. Initial cardiological investigation and follow-up are indicated to ensure this prevention.

Cardiomyopathies↗
PubMed1998

[Study of the cardiorespiratory response and chronotropic function after correction of tetralogy of Fallot. Important role of residual pulmonary regurgitation].

Effort tolerance is reduced after correction of Tetralogy of Fallot. This prospective study investigated the cardiorespiratory response and the chronotropic function (mean follow-up 11.1 years) of 70 patients (43 boys and 27 girls) with an average age of 14.9 +/- 7.2 years (group 1) compared with 65 normal, sedentary subjects paired red for age and gender (group 2). All underwent exercise testing (Bruce protocol) with measurement of respiratory gases. Quantification of pulmonary regurgitation was performed by Doppler echocardiography. The chronotropic response to exercise was assessed by calculating the mean of slopes established by chronotropic metabolic relationship of Wilkoff. The cardiorespiratory response to exercise was abnormal in group 1: the duration of exercise (11.3 vs 13.6 min; p = 0.005), peak VO2 (35.5 vs 46 ml/min/kg; p < 0.001) and anareobic threshold (8.3 vs 9.2 min; p = 0.001) were decreased. Maximal heart rate (172 vs 190bpm; p < 0.001) and the mean of the metabolic-chronotropic slopes (0.68 vs 0.83; p < 0.001) were decreased in the patient group, showing abnormal chronotropic response to exercise. The latter seemed to be related to the severity of pulmonary regurgitation. The duration of exercise (10.6 vs 11.5 min; p = 0.001), peak VO2 (33 vs 37 ml/min/kg; p < 0.001), maximal heart rate (161 vs 177 bpm; p = 0.002) and the mean of the slopes of the metabolic-chronotropic relationship (0.59 vs 0.72; p < 0.001) were decreased in patients with moderate to severe pulmonary regurgitation. This study shows that significant pulmonary regurgitation is responsible for a poor cardiorespiratory response to exercise and for an abnormal chronotropic response which seems to be multifactorial but probably related to an adaptation favouring left ventricular filling during exercise.

Adolescent↗
PubMed1998

[Diagnostic value of ST depression corrected for heart rate in the post-exercise recovery period].

This study assessed the diagnostic value of two new electrocardiographic criteria of coronary artery disease: the ST/HR index and the slope of the linear relationship between ST segment changes and the heart rate during the first three minutes of the post-exercise recovery period. These two criteria were compared to the standard criteria (> or = 1 mm horizontal or descending ST depression or > or = 2 mm ascending ST depression) to Detrano's ST/HR exercise index (> 1.6 microV/bpm in coronary patient), the exercise ST/HR slope (> or = 2.4 microV/bpm in coronary patients) and the exercise recovery loop (clockwise in normal and anticlockwise in coronary patients) in 88 subjects investigated for suspected coronary artery disease who underwent a computerised exercise stress test and coronary angiography (25 single vessel, 21 double vessel, 20 triple vessel disease; 22 with no significant coronary disease). The ROC identified thresholds of abnormality of the ST/HR recovery index at > or = 2.1 microV/bpm and of the ST/HR recovery slope at > or = 2.52 microV/bpm. Global comparison of the areas under the ROC showed the diagnostic superiority of the exercise ST/HR indices (0.96) over the standard criteria (0.92) and recovery indices (0.86) but without statistically significant values (p = 0.65 and p = 0.15 respectively). The ST/HR index and slope during recovery identify coronary disease with a diagnostic accuracy of 80% and 77% respectively which is similar to that (84%) of the standard ST criteria. The exercise-recovery loop was less accurate (64%).

Aged↗
PubMed1998

[Preoperative management of patients with high-risk cardiovascular conditions].

The growing numbers of elderly and cardiac patients are the consequence of progress in the prevention of the complications of coronary artery and valvular heart disease by surgery and revascularisation and improved treatment of hypertension which delays target organ complications by at least fifteen years. The elderly are particularly exposed to surgical risk: nearly half the patients with ischaemic heart disease die of cancer; a high proportion of elderly people require orthopaedic surgery either as an emergency (fractured femur) or as a standard procedure (knee surgery); nearly a quarter of patients requiring peripheral vascular surgery have coronary artery disease which may be silent. A preoperative consultation with the anaesthetist has been made compulsory, except in emergencies, giving time for preoperative investigations. The decrees of the Court of Cassation have also affected the traditional relationship of trust between patients and their doctors, leading to an increase in the cost of preoperative investigations without an accurate assessment of their benefits with regards to postoperative complications and the cost that they entail. Contrary to present tendencies reflected in the literature, the screening of risks should be simplified: clinical history and examination and resting ECG, often completed by stress testing, are sufficient in the large majority of cases. More importance should be attributed to the functional status than to the lesions. When the cardiac disease is asymptomatic, the chances are that it will remain so during and after surgery.... The main difficulty is not in identifying high risk patients: it is preventing cardiovascular events when surgery is unavoidable. The experience and collaboration between the quartet of anaesthetist, surgeon, cardiologist and general practitioner, are much more useful than the very incomplete bibliographical data concerning this side of the problem.

Anesthesia↗
PubMed1998

[Rehabilitation by physical exercise in chronic heart failure].

The aim of rehabilitation is to improve exercise capacity and, thereby, the autonomy of patients with cardiac failure. For many years, these patients were considered inapt to perform physical exercise and they are in the same situation at the dawn of the year 2000 as patients with myocardial infarction forty years ago. The symptoms of cardiac failure (dyspnoea of effort and muscular fatigue) are not only the consequence of pulmonary hypertension and decreased muscular perfusion. Prolonged interruption of exercise and long stays in bed or in a chair lead to anatomical and functional amyotrophy, which, in turns, incites to further inactivity. Deconditioned respiratory muscles cannot tolerate the increased load of hyperventilation. Neurohormonal changes cause vasoconstriction which reduces muscular perfusion. Physical training can significantly improve these abnormalities, though it does not seem to have a measurable effect on cardiac function; based on segmental work which enables performance of substantial efforts with a minimum of haemodynamic changes, it provides a 20 to 30% gain in capacity, mainly increasing the duration of submaximal exercise rather than maximum performance. Muscular fatigue is the symptom which is the most improved. Unfortunately the organisation, which is more difficult than in the post-infarction period, and the generalisation of the practice of long-term, well adapted physical training remains marginal although hundreds of thousands of patients could benefit; more than the inertia of the official instances concerning anything related to cardiac rehabilitation, it is the lack of interest shown by cardiologists and the absence of flexible structures within the health care organisation for elderly people which are responsible.

Aged↗
PubMed1997

Predictive factors of maximal aerobic capacity after cardiac transplantation.

Exercise capacity in cardiac transplanted patients has been reported to remain decreased in some studies; however, functional results after transplantation may vary, ranging from modest to spectacular improvement. The aim of the study was to quantify exercise capacity in a large series of transplanted patients and to search for factor predictive of a good functional result. Eighty-five patients (mean 52.1 +/- 11.8 years) underwent exercise testing with respiratory gas exchange measurements 1 to 100 months after transplantation. Mean performance was 112.4 +/- 33 W with a peak VO2 of 21.1 +/- 6 ml.min-1.kg-1. Heart rate was 103 +/- 14 at rest, reaching 142 +/- 22 beats.min-1 at the end of exercising. In univariate analysis, maximal or submaximal aerobic capacity parameters were strongly correlated with chronotropic reserve (r = 0.63; P < 0.001) without correlation with cold ischaemic time, number of rejection episodes or right bundle branch block. In multiple regression analysis, chronotropic reserve, time from transplantation, age of donor and age of patient were proved to be the variables best correlated with peak VO2. Our study confirms the persistence of a large decrease in aerobic functional capacity despite cardiac transplantation; limited exercise capacity does not improve over time, and is limited not only by the patient's age but by that of the donor, and especially by chronotropic reserve.

Adolescent↗
PubMed1997

Physical training improves exercise capacity in patients with mitral stenosis after balloon valvuloplasty.

BACKGROUND: Haemodynamic measurements taken at rest and during exercise showed that percutaneous transvenous mitral commissurotomy results in both acute and long-term improvement. However, the time lag before there is an increase in exercise and in peak oxygen uptake appears to be delayed and irregular. PATIENTS AND METHODS: To assess the potential of physical training to restore better physical capacity after percutaneous transvenous mitral commissurotomy, 26 patients with mitral stenosis were studied after the procedure. The group was split into two. Thirteen underwent a 3-month rehabilitation programme, and the other 13, who did not, acted as controls. RESULTS: The mitral valve orifice area increased similarly, from 1.12 +/- 0.17 to 1.88 +/- 0.28 cm2 in the training group and from 1.04 +/- 0.16 to 1.88 +/- 0.19 cm2 in the control group. Cardiopulmonary parameters were similar before percutaneous transvenous mitral commissurotomy (peak VO2: 19.9 +/- 2.4 vs 18.9 +/- 4.5 ml. min-1.kg-1; peak workload: 94.6 +/- 29.3 vs 96.1 +/- 25 watts; VO2 at anaerobic threshold: 17 +/- 3.4 vs 16.1 +/- 5.2 ml.min-1.kg-1; all P = ns). Three months later the results were higher in the training group 1 (peak VO2: 26.6 +/- 4.7 vs 21.6 +/- 3.8 ml.min-1.kg-1, P = 0.03; peak workload: 125.4 +/- 26.6 vs 108.5 +/- 23 watts, P = 0.03; VO2 at anaerobic threshold: 19.6 +/- 5.8 vs 15.8 +/- 2.9 ml.min-1.kg-1; P = 0.02). CONCLUSION: These results indicate that patients should take up exercise after successful percutaneous transvenous mitral commissurotomy for better functional improvement.

Adult↗
PubMed1997

Cardiorespiratory response to exercise after venous switch operation for transposition of the great arteries.

STUDY OBJECTIVES: This study reports on the cardiorespiratory response to graded exercise in patients after venous switch operation for transposition of the great arteries. DESIGN: Several small studies have documented a diminished exercise tolerance after Mustard repair for transposition of the great arteries, little information exists, however, about long-term cardiorespiratory exercise performance in patients who have had the Senning procedure. PATIENTS: This prospective study reports on the serial long-term (mean, 11 +/- 2.8 years) cardiopulmonary exercise performance of 43 patients (age, 12 +/- 3.1 years) who underwent a Senning procedure, with no significant postoperative abnormalities. Forty-three matched healthy children were also studied as a control group. MEASUREMENTS AND RESULTS: All underwent exercise testing (Bruce protocol) with metabolic gas exchange to determine parameters at 3 min, anaerobic threshold, similar heart rate (150 beats/min), and peak exercise. Time of exercise was 10.5 +/- 1.9 min in patients and 13.4 +/- 2 min in control subjects (p = 0.0001). Overall, patients reached 73% of peak oxygen uptake achieved by control subjects (32.6 +/- 5.6 vs 44.7 +/- 6 mL/kg/min). Chronotropic response (188 +/- 15.7 vs 166.5 +/- 19.6 beats/min [p = 0.0001]) and oxygen pulse (7.4 +/- 2.9 vs 10.7 +/- 4.2 mL/beat [p = 0.0002]) were lower in patients at peak exercise. Patients had a greater respiratory response to exercise: both respiratory rate and ventilatory equivalent for carbon dioxide were significantly higher at all stages of exercise. Exercise capacity assessed by peak oxygen uptake was correlated with time elapsed since surgical repair (r = 0.48; p = 0.001). CONCLUSIONS: It is concluded that even in asymptomatic patients, exercise endurance and respiratory response are generally altered as much as 11 +/- 2.8 years after venous switch operation, although early surgical repair is predictive of a better long-term functional result.

Child↗
PubMed1997

[Alteration of myocardial viability and systemic ventricular dysfunction after Senning procedure].

After a Senning procedure for transposition of the great arteries (TGA), systolic dysfunction of the right ventricle (RV) is common. Pre and peroperative chronicale hypoxia may be the cause of this ventricular myocardial alteration. In order to detect abnormalities of myocardial viability and to study their relationship to RV function, the authors studied 41 patients (pts), 11.3 +/- 3 years after a Senning procedure. All patients underwent myocardial scintigraphy of the RV under basal conditions. 1 hour after injection of 1.5 mCi of Thallium 201. The RV ejection fraction (n = 41) and at peak effort (n = 25). Exercise ability and aerobic capacity were assessed by exercise testing (Bruce) with gas exchange measurement and compared with 41 normal matched subjects. The cardiorespiratory response to exercise was altered in the Senning group : duration of effort (10.5 +/- 2 vs 13.2 +/- 2 min; p < 0.0001), peak VO2 (33 +/- 5 vs 44.4 +/- 6 ml/min/kg; p < 0.0001), anaerobic threshold (6 +/- 1 vs 8.4 +/- 1.9 min; p < 0.05) were lower compared to controls. Abnormalities of RV viability were observed in 18/41 pts (44%), moderate in 12 cases and severe in 6 cases. Resting and exercise RVEF were significantly lower in patients with myocardial defects (45 +/- 5 vs 51 +/- 7%; p < 0.0005, and 49 +/- 9 vs 58 +/- 9%; p < 0.05 respectively). In conclusion, after the Senning procedure for TGA, scintigraphic abnormalities of the systemic ventricule are common and associated with an alteration of systolic function at rest and on exercise.

Adolescent↗
PubMed1996

[Value and limits of exercise radionuclide ventriculography in chronic aortic insufficiency. Apropos of 47 operated cases].

The role of exercise radionuclide angiography in the therapeutic strategy of chronic aortic insufficiency remains controversial. In order to assess the value of this technique, 47 patients with pure chronic aortic insufficiency were evaluated before and one year after valve replacement. The preoperative EF decreases or does not increase on exercise (51.9% vs 48 +/- 10%; p < 0.001) in the majority of patients (78%), whereas, after surgery, the EF tends to increase on exercise (55 +/- 11% vs 57 +/- 11%; NS). Despite optimal surgical correction, 16 of the surviving 46 patients still had left ventricular dysfunction at one year after surgery. The preoperative parameters correlating with this dysfunction were, in order, resting radionuclide EF (r = 0.65; p = 0.0001) and the echocardiographic parameters: left ventricular endosystolic dimension, fractional shortening, and the radius/thickness ratio. The preoperative exercise radionuclide parameters did not correlate with postoperative left ventricular dysfunction. In patients without postoperative left ventricular dysfunction, the EF increased on exercise, contrary to the other group. The exercise EF remains valuable for retrospective evaluation of surgical benefit. The exercise radionuclide EF does not reflect myocardial contractile reserve alone but also the conditions of left ventricular load. This study confirms the superiority of the resting radionuclide EF and echocardiographic parameters over exercise radionuclide EF for the prediction of postoperative left ventricular dysfunction.

Aged↗
PubMed1996

[Segmental rehabilitation in cardiac failure: short and long-term results].

Many patients with chronic cardiac failure may benefit from exercise rehabilitation. However, the usual protocols, which may lead to haemodynamic disturbances or induce arrhythmias, are rarely applicable in the most severe cases. Therefore, the authors developed a protocol of segmental rehabilitation where the same muscle groups as in global readaptation are involved, but successively and not simultaneously. This study included 25 patients in the NYHA class III. Many parameters were analysed before and after forty sessions. Although the resting isotopic ejection fraction (0.26 +/- 0.1 vs 0.27 +/- 0.11; p = NS), oxygen consumption at the ventilatory threshold (14.3 +/- 3.5 vs 18.3 +/- 5.2 ml/kg/min; p = NS) or at peak effort (17.4 +/- 4.7 versus 18.3 +/- 5.2 ml/kg/min, p = NS) were unchanged, three other parameters were significantly improved: the duration of exercise (9.2 +/- 2.4 vs 10.4 +/- 3.4 min; p < 0.02) maximum work load (3 046 +/- 1 510 vs 3 992 +/- 2 482; p < 0.01) and muscular force (151 +/- 35 versus 220 +/- 41 kg; p < 0.0001). In addition, after a follow-up period of 43 +/- 18 months, a close inverse relationship was observed between the gains obtained in terms of duration of exercise and maximum work load and the number of hospital readmissions. Similarly, the 10 patients having undergone rehabilitation with this protocol had 11.7 times fewer hospital readmissions than the other 15. Segmental rehabilitation would therefore seem to be a safe technique for patients with severe cardiac for significantly increasing exercise capacity and lowering the number of readmissions to hospital.

Aged↗
PubMed1996

[Fortuitous discovery of Brugada syndrome in an asymptomatic 70-year-old sportsman].

The authors report the case of an elderly sportsman presenting with the electrical signs of the syndrome described by Brugada. The absence of any serious clinical events in this patient questions the pejorative prognosis usually reported and the specific identity of this syndrome in relation to right ventricular arrhythmogenic dysplasia.

Aged↗