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Christophe Leclercq

Publications and source records attributed to Christophe Leclercq.

29 records · Page 2Linked to original sources
PubMed2004

Intensity and daily reliability of the six-minute walk test in moderate chronic heart failure patients.

OBJECTIVE: To assess the intensity and daily reliability of the six-minute walk test (6MWT) in patients with moderate chronic heart failure (CHF). DESIGN: Evaluation of testing protocol. SETTING: Hospitalized care. PARTICIPANTS: CHF patients under optimal drug treatment (CHF-D, n=12) or optimal drug treatment plus multisite cardiac pacing (CHF-P, n=12). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Peak values of oxygen uptake (VO2) and heart rate during a symptom-limited, treadmill exercise test and VO2, heart rate, and distance during 2 6MWT sessions (morning and afternoon). The 6MWT intensity was estimated by the ratio (%) of VO2 and heart rate values measured at the end of this test in relation to the respective peak values obtained during the treadmill exercise test. RESULTS: Subjects' VO2 and heart rate during the 6MWT were lower (P<.001) and were about 90% of the peak values (VO2: CHF-D, 90.5%+/-11.1%; CHF-P, 93.0%+/-13.2%; heart rate: CHF-D, 90.6%+/-6.6%; CHF-P, 91.4%+/-9.6%). The distance walked during both 6MWT sessions did not differ significantly, with low coefficients of variation (< or =2.0%) and high intraclass correlation coefficients (> or =.98). In CHF-D only, the patients' VO2 and heart rate were significantly (P<.01, P<.05, respectively) higher during the afternoon session. CONCLUSIONS: Despite an intensity significantly lower but close to that of the symptom-limited exercise test, the 6MWT was well tolerated in both CHF groups. In these populations, the 6MWT is reliable on a daily basis, for the distance walked. However, for assessing VO2 and heart rate values in CHF-D patients, the 6MWT must always be performed at the same time of day.

Aged↗
PubMed2004

Cardiorespiratory adaptations during the six-minute walk test in chronic heart failure patients.

BACKGROUND: The six-minute walk test (6-MWT) is widely used to assess exercise tolerance in chronic heart failure patients (CHF). The aim of this study was to analyse cardiorespiratory parameters kinetics during the 6-MWT in CHF and in healthy subjects. METHODS: A treadmill, symptom-limited exercise test and a 6-MWT were performed by 14 CHF under optimal drug treatment (CHFD), 17 CHF with cardiac resynchronization (CHFP), and 12 healthy subjects. Cardiorespiratory responses were assessed by a validated portable system. RESULTS: All subjects exceeded their ventilatory threshold during the 6-MWT. Healthy subjects and CHF performed the 6-MWT around 75 and 90% of peak oxygen uptake (V'O2) respectively (P<0.001). In CHF, a steady state was observed only for walking speed and V'O2, with a slight delay in comparison with healthy subjects, for whom a steady state was also observed for carbon dioxide production and ventilation (V'E). During the 6-MWT, the V'E adaptation was due mainly to an increase in tidal volume (VT) in CHFD, whereas in CHFP, it was due to a similar increase in VT and breathing frequency (f). In these patients, the 6-MWT VT/f slope was lower than in CHFD (P<0.01). CONCLUSIONS: During the 6-MWT, the V'O2 steady state is slightly delayed in CHF, which could be related partly to their higher exercise intensity. Moreover, each CHF group is characterized by a specific ventilation components response during the 6-MWT.

Adaptation, Physiological↗
PubMed2003

Regional alterations in protein expression in the dyssynchronous failing heart.

BACKGROUND: Left ventricular (LV) mechanical dyssynchrony induces regional heterogeneity of mechanical load and is an independent predictor of mortality and sudden death in heart failure (HF) patients. We tested whether dyssynchrony also induces localized disparities in the expression of proteins involved with mechanical stress, function, and arrhythmia susceptibility. METHODS AND RESULTS: Eleven dogs underwent tachycardia-induced HF pacing, either from the right atrium or high right ventricular free wall. Whereas global LV dysfunction was similar between groups, LV contractile coordination assessed by tagged MRI was markedly dyssynchronous with right ventricular pacing but synchronous with right atrial pacing. In dyssynchronous failing hearts, the lateral LV endocardium displayed a 2-fold increase in phosphorylated erk mitogen-activated protein kinase expression (with no change in phospho-p38 or phospho-jnk), a 30% decline in sarcoplasmic reticulum Ca2+-ATPase, an 80% reduction in phospholamban, and a 60% reduction in the gap junction protein connexin43, relative to neighboring myocardial segments. In contrast, hearts from both right atrial-paced HF dogs and an additional 4 noninstrumented control animals showed minimal regional variability in protein expression. CONCLUSIONS: LV dyssynchrony in failing hearts generates myocardial protein dysregulation concentrated in the late-activated, high-stress lateral endocardium. Such molecular polarization within the LV creates transmural and transchamber expression gradients of calcium handling and gap junction proteins that may worsen chamber function and arrhythmia susceptibility.

Animals↗
PubMed2003

Cardiac resynchronization therapy is an important advance in the management of congestive heart failure.

Cardiac resynchronization therapy (CRT) is an emerging therapy that improves symptoms and exercise tolerance in patients with advanced heart failure, left ventricular systolic dysfunction, and intraventricular conduction delay. By correcting the AV, interventricular, and intraventricular dyssynchrony induced by conduction disorders, controlled studies have shown that CRT improved functional status, decreased heart failure hospitalization rate, and might have a positive effect on left ventricular remodeling. Recent and preliminary data from the COMPANION trial suggest that CRT alone or in association with defibrillator capacity significantly reduced total mortality and hospitalization and that total mortality was significantly reduced only in the CRT plus implantable cardioverter defibrillator (ICD) group. Many questions remain unanswered, particularly the selection of responder patients.

Cardiac Pacing, Artificial↗
PubMed2002

Systolic improvement and mechanical resynchronization does not require electrical synchrony in the dilated failing heart with left bundle-branch block.

BACKGROUND: Biventricular (BiV) and left ventricular (LV) pacing similarly augment systolic function in left bundle-branch block (LBBB)-failing hearts despite different electrical activation. We tested whether electrical synchrony is required to achieve mechanical synchronization and functional benefit from pacing. METHODS AND RESULTS: Epicardial mapping, tagged MRI, and hemodynamics were obtained in dogs with LBBB-failing hearts during right atrial, LV, and BiV stimulation. BiV and LV both significantly improved chamber hemodynamics (eg, 25% increase in dP/dt(max) and aortic pulse pressure) compared with atrial pacing-LBBB, and this improvement correlated with mechanical resynchronization. Electrical dispersion, however, decreased 13% with BiV but increased 23% with LV pacing (P<0.01). CONCLUSION: Improved mechanical synchrony and function do not require electrical synchrony. Mechanical coordination plays the dominant role in global systolic improvement with either pacing approach.

Animals↗
PubMed2002

Long-term benefits of biventricular pacing in congestive heart failure: results from the MUltisite STimulation in cardiomyopathy (MUSTIC) study.

OBJECTIVES: The main objective of this study was to assess if the benefits of biventricular (BiV) pacing observed during the crossover phase were sustained over 12 months. BACKGROUND: MUltisite STimulation In Cardiomyopathies (MUSTIC) is a randomized controlled study intended to evaluate the effects of BiV pacing in patients with New York Heart Association (NYHA) class III heart failure and intraventricular conduction delay. METHODS: Of 131 patients included, 42/67 in sinus rhythm (SR) and 33/64 in atrial fibrillation (AF) were followed up longitudinally at 9 and 12 months by 6-min walked distance, peak oxygen uptake (peak VO(2)), quality of life by the Minnesota score, NYHA class, echocardiography, and left ventricular ejection fraction by radionuclide technique. RESULTS: At 12 months, all SR and 88% of AF patients were programmed to BiV pacing. Compared with baseline, the 6-min walked distance increased by 20% (SR) (p = 0.0001) and 17% (AF) (p = 0.004); the peak VO(2) by 11% (SR) and 9% (AF); quality of life improved by 36% (SR) (p = 0.0001) and 32% (AF) (p = 0.002); NYHA class improved by 25% (SR) (p = 0.0001) and 27% (AF) (p = 0.0001). The ejection fraction improved by 5% (SR) and 4% (AF). Mitral regurgitation decreased by 45% (SR) and 50% (AF). CONCLUSIONS: The clinical benefits of BiV pacing appeared to be significantly maintained over a 12-month follow-up period.

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PubMed2002

[Epidemiology and etiology of atrial fibrillation].

Atrial fibrillation is the most common sustained rhythm disturbance, with a heterogeneous presentation, occurring in the presence or absence of detectable heart disease or related symptoms, evolving in paroxysmal, persistent or permanent forms. Prevalence and incidence are mainly depending on age and congestive heart failure. Atrial fibrillation is frequently observed in elderly population. Prognosis can be poor, owing to the risk of embolic events, mainly ischaemic strokes, with a rate of 5% yearly, and to an increased mortality rate, about twice that of persons in normal sinus rhythm. Atrial fibrillation can present as an isolated arrhythmia (20 to 40% of cases) or be associated with an underlying cardiac disease which exerts a main influence on prognosis.

Age Factors↗
PubMed2002

Retiming the failing heart: principles and current clinical status of cardiac resynchronization.

Left or biventricular (BiV) pacing, or cardiac resynchronization therapy, was proposed nearly 10 years ago as an adjunctive treatment for patients with advanced heart failure (HF) complicated by discoordinate contraction due to intraventricular conduction delay. Since then, both short-term and a growing number of long-term clinical trials have reported on the mechanisms and short- and mid-term efficacy of this approach, with encouraging results. Therapy is implemented with novel pacing systems incorporating an endocardial lead to stimulate the lateral free wall via a cardiac vein, and often a right ventricular (RV) apex lead to provide BiV stimulation. A third atrial sensing lead monitors intrinsic rhythm and provides timing data to ensure ventricular pre-excitation. Modulation of the electronic atrial-ventricular (AV) time delay can optimize contractile synchrony, enhance the contribution of atrial systole, and reduce mitral regurgitation. Individuals with advanced HF, a wide QRS complex often with an AV time delay, and evidence of contraction dyssynchrony in viable myocardium represent the target patient group. Short-term studies reveal systolic augmentation and chamber efficiency from pacing resynchronization that can be substantial. Long-term studies reveal improved symptoms and exercise capacity, and some report reversal of chronic cardiac dilation. However, important questions regarding long-term efficacy and mortality impact, optimal mode for pacing stimulation, and role of combined pacing/cardioverter/defibrillation devices remain unresolved. Here we review pathophysiologic mechanisms, short- and long-term clinical results, and future directions of this new and promising therapy.

Cardiac Pacing, Artificial↗
PubMed2002

Cardiac resynchronization therapy in advanced heart failure the multicenter InSync clinical study.

BACKGROUND: recent short-term observations have shown an improvement in cardiac function and heart failure symptoms from atrio-biventricular pacing. This study was designed to assess the safety and feasibility of an atrio-biventricular transvenous pacing system, and examine the long-term effects of cardiac resynchronization in patients with advanced heart failure and ventricular conduction abnormalities. METHODS AND RESULTS: between August, 1997 and November, 1998, 103 patients received a cardiac resynchronization system (CRS) consisting of a pulse generator interfaced with an atrio-biventricular lead system, including a lead designed for left ventricular (LV) pacing via cardiac veins. Baseline evaluation included 12-lead electrocardiogram, estimation of New York Heart Association (NYHA) functional class, assessment of quality of life (QOL), and distance covered during a 6-min walk (6-MW). Detailed echocardiographic data were also collected in a subset of 46 patients. Measurements were repeated in all surviving patients at 1, 3, 6 and 12 months after implantation of the CRS. A single, self-limiting procedure-related complication occurred. Over a follow-up of 12 months, 21 patients died. The 12-month actuarial survival was 78% (CI 70-87%). Nine surviving patients were withdrawn from the study during long-term follow-up for miscellaneous reasons. At each point of follow-up, a significant shortening of QRS duration was measured. In addition, significant improvements were observed in mean NYHA functional class, 6-MW and QOL score. In the 46 patients with complete echocardiographic data, LV ejection fraction increased from 21.7+/-6.4% at baseline to 26.1+/-9.0% at last follow-up (P = 0.006), LV end diastolic dimension decreased from 72.7+/-9.2 to 71.6+/-9.1 mm (P = 0.233), interventricular mechanical delay decreased from 27.5+/-32.1 to 20.3+/-25.5 ms (P = 0.243), mitral regurgitation apical four-chamber area decreased from 7.66+/-5.5 to 6.69+/-5.9 cm(2) (P = 0.197), and left ventricular filling time increased from 363+/-127 to 408+/-111 ms (P = 0.002). CONCLUSIONS: long-term cardiac resynchronization can be safely and reliably achieved by transvenous atrial synchronized right and left ventricular pacing. These changes were accompanied by clinically relevant improvements in functional status and QOL, as well as a measurable increase in LV performance. The outcome of randomised controlled trials is awaited.

Aged↗
PubMed2002

[Heart re-synchronization with biventricular stimulation: new treatment for refractory heart failure].

Despite continuous progress in drug therapy, many patients are still progressing into advanced heart failure, a very poor condition in terms of quality of life and prognosis. Therapeutic resources are quite limited at that end-stage. Heart transplantation may only be proposed to a small minority of patients. New non-pharmacological alternatives like cellular cardiomyo-plasty or left ventricular (LV) implantable assist device are still under evaluation. So simpler and cheaper approaches have imperatively to be developed for treating this highly invalidated and rapidly growing and ageing population. Cardiac resynchronization therapy (CRT) with multisite biventricular pacing has been initiated in France in early 90's. The aim of CRT is to try and correct the electromechanical abnormalities that result from antrioventricular and intraventricular conduction delay (IVCD), a very common observation (30-50%) in patients with chronic heart failure (CHF). IVCD worsens progressively overtime and is responsible for discoordinated interventricular and left-intraventricular contraction-relaxation which in turn enhances the hemodynamic consequences of the baseline LV systolic dysfunction. This new therapeutic concept was first assessed in acute hemodynamic studies with temporary pacing, then in pilot studies with permanent transvenous biventricular pacing. Several controlled studies (MUSTIC, MIRACLE, CONTAKCD...) were conducted afterwards and demonstrated that CRT might improve significantly symptoms, quality of life and exercise tolerance in patients with severe heart failure (NYHA class III -- IV) under optimized drug treatment, low ejection fraction and significant IVCD as indicated by an intrinsic QRS duration QRS> 150 MS. The rehospitalization rate was also significantly reduced with CRT. The clinical benefit was preserved over at least 1 year follow-up. The first validation stem is now completed. There are however several important questions yet to be answered. Which is the impact of CRT on all-cause mortality and sudden cardiac death? Two large-scale studies, CARE-HF in Europe and COMPANION in USA, are ongoing to try and answer this question. Which type of implantable devices has to be developed preferentially: multisite pacemakers or multisite pacemaker-defibrillators? May CRT induce LV reverse remodelling and thus help at preventing heart failure progression? Which cost-effectiveness ratio for heart faulure management? How to better select potential responders?... The whole validation process of CRT should be completed on 2004-2005.

Cardiac Pacing, Artificial↗