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Biomedical subjects

J C Daubert

Publications and source records attributed to J C Daubert.

At least 37 records · Page 2Linked to original sources
PubMed2002

[MUSTIC trial].

The atrio-bi-ventricular pacing has been used for hemodynamic improvement since 1994, and the MUSTIC trial is the first controlled study assessing this concept. It collected 67 patients with severe and stable heart failure with optimised medical therapy, with sinus rhythm and without any traditional indication for pacing. After two periods of three months with blinded randomisation and cross-over, the bi-ventricular pacing mode showed its superiority to the inactive mode concerning all study endpoints, for example with an improvement of the functional capacity of 23% assessed by the 6-minutes-walk test. Thus the MUSTIC trial opens up the way for morbidity and mortality studies.

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PubMed2002

[Medium-term results of multisite biventricular stimulation in severe cardiac failure].

Since its introduction in cardiac failure in 1994, biventricular cardiac stimulation has been widely applied with many clinical trials and the development of new specific technology. The authors present the results observed in the first 125 consecutively implanted patients at the Rennes University Hospital. After a mean follow-up of 22 months, the mortality rate was 40%. The causes of death were sudden death in 42% of patients, progression of cardiac failure in 34% and non-cardiac in 24%. The functional benefits of biventricular cardiac stimulation were seen through significant improvement in HYHA Class, 3.3 +/- 0.5 before implantation to 2.3 +/- 0.8 at the end of follow-up, and by a significant increase of 40% of peak VO2 and of maximal duration of exercise. With the learning curve and development of new technology, the left ventricular catheterisation via a coronary sinus vein, increased from 56% to over 95% during the last two years with an acceptable rate of complications. These results, with the reserve of not being a controlled trial, show the feasibility, safety and efficacy of biventricular cardiac stimulation in terms of functional benefit. Clinical trials are currently underway to assess the impact of this method on morbi-mortality and to assess the concept in association with ventricular defibrillation.

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PubMed2002

[Magnetocardiography: principles and potential uses in cardiology].

Magnetocardiography (MCG) is a non-invasive technique of studying cardiac electrophysiology activity. It appears that electric and magnetic measurements are not only complementary but provide independent information. Described over 25 years ago, recent technical progress in the field of supraconductivity has provided MCG with real clinical applications. It is still mostly used in research, but its clinical applications are beginning to develop. The most interesting clinical application of the MCG is certainly its capacity to provide a non-invasive anatomical localisation of the arrhythmogenic substrate or of accessory pathways. Nowadays, however, the accuracy of these localisations needs to be improved. When this has been accomplished, MCG could play a significant role in non-invasive cardiological investigation with well-defined clinical applications.

Arrhythmias, Cardiac↗
PubMed2001

Effects of multisite biventricular pacing in patients with heart failure and intraventricular conduction delay.

BACKGROUND: One third of patients with chronic heart failure have electrocardiographic evidence of a major intraventricular conduction delay, which may worsen left ventricular systolic dysfunction through asynchronous ventricular contraction. Uncontrolled studies suggest that multisite biventricular pacing improves hemodynamics and well-being by reducing ventricular asynchrony. We assessed the clinical efficacy and safety of this new therapy. METHODS: Sixty-seven patients with severe heart failure (New York Heart Association class III) due to chronic left ventricular systolic dysfunction, with normal sinus rhythm and a duration of the QRS interval of more than 150 msec, received transvenous atriobiventricular pacemakers (with leads in one atrium and each ventricle). This single-blind, randomized, controlled crossover study compared the responses of the patients during two periods: a three-month period of inactive pacing (ventricular inhibited pacing at a basic rate of 40 bpm) and a three-month period of active (atriobiventricular) pacing. The primary end point was the distance walked in six minutes; the secondary end points were the quality of life as measured by questionnaire, peak oxygen consumption, hospitalizations related to heart failure, the patients' treatment preference (active vs. inactive pacing), and the mortality rate. RESULTS: Nine patients were withdrawn from the study before randomization, and 10 failed to complete both study periods. Thus, 48 patients completed both phases of the study. The mean distance walked in six minutes was 22 percent greater with active pacing (399+/-100 m vs. 326+/-134 m, P<0.001), the quality-of-life score improved by 32 percent (P<0.001), peak oxygen uptake increased by 8 percent (P<0.03), hospitalizations were decreased by two thirds (P<0.05), and active pacing was preferred by 85 percent of the patients (P<0.001). CONCLUSIONS: Although it is technically complex, atriobiventricular pacing significantly improves exercise tolerance and quality of life in patients with chronic heart failure and intraventricular conduction delay.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

The CARE-HF study (CArdiac REsynchronisation in Heart Failure study): rationale, design and end-points.

BACKGROUND: Cardiac resynchronisation is a promising new intervention for patients with heart failure, left ventricular systolic dysfunction and ventricular dyssynchrony. OBJECTIVE: The CARE-HF trial is designed to evaluate the long-term effects of cardiac (atrio-bi-ventricular) resynchronisation on the mortality and morbidity of patients with heart failure due to left ventricular systolic dysfunction already receiving diuretics and optimal medical therapy with ACE inhibitors and beta-blockers (where indicated and tolerated). METHODS AND RESULTS: Approximately 800 patients will be randomised to device therapy or control and followed for a minimum of 18 months. A pragmatic study design has been chosen that does not attempt to conceal allocation from investigators or patients because it is impossible to guarantee maintenance of blinding for the duration of the study. The end-points committee will adjudicate events in a blinded fashion. Since cardiac resynchronisation may alter other aspects of the management of the patient, as would occur in clinical practice, the study should be considered a comparison of strategies rather than simply of a device. The primary end-point is all-cause mortality or unplanned cardiovascular hospitalisation. The study should complete recruitment during 2002 and report in 2004.

Adrenergic beta-Antagonists↗
PubMed2001

Six year experience of transvenous left ventricular lead implantation for permanent biventricular pacing in patients with advanced heart failure: technical aspects.

BACKGROUND: Biventricular pacing has been proposed as an adjuvant to optimal medical treatment in patients with drug refractory heart failure caused by chronic left ventricular systolic dysfunction and intraventricular conduction delay. OBJECTIVE: To assess the technical feasibility and long term results (over six years) of transverse left ventricular pacing with the lead inserted into a tributary vein of the coronary sinus. SUBJECTS: From August 1994 to February 2000, left ventricular lead implantation was attempted in 116 patients who were eligible for biventricular pacing (mean (SD) age 67 (9) years, New York Heart Association (NYHA) functional class III/IV, left ventricular ejection fraction 22 (6)%, QRS duration 185 (26) ms). RESULTS: The overall implantation success rate was 88% (n = 102). A learning curve was indicated by a progressive increase in success from 61% early on to 98% in the last year. The mean pacing threshold was 1.1 (0.7) V/0.5 ms at the time of implantation and increased slightly up to 1.9 (0.9) V/0.5 ms at the end of the follow up period (15 (13) months). The rate of acute and delayed left ventricular lead dislodgement decreased from 30% in the early years to 11% after 1999. During follow up, 19 patients required reoperation for delayed lead dislodgement or increase in left ventricular pacing threshold (n = 15), phrenic nerve stimulation (n = 3), or infection (n = 3). CONCLUSIONS: Transverse left ventricular pacing through the coronary sinus is feasible and safe. The rate of implantation failure and of lead related problems has decreased greatly with increasing experience and with improvements in the equipment.

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PubMed2001

[Patient information and coronary angiography: experience of the Rennes group].

The object of this study was to assess the degree of patient information of subjects referred for coronary angiography and their reaction to a detailed protocol of information. The enquiry was performed in 3 stages: an oral evaluation of the degree of information with a standardised questionnaire; the giving of written documents from the French Federation and Society of Cardiology mentioning the risks of the procedure; the continuation of the interview with evaluation of the degree of satisfactions with the information provided. Two hundred and thirty one patients referred by cardiologists for non-urgent coronary angiography were interrogated (175 men, 56 women; mean age 63 years, range: 27-83 years). In the 164 subjects who had never had this investigation: 56 (34.1%) did not appreciate the invasive nature of the procedure 111 (67.6%) totally ignored the risks of the procedure 70 (42.6%) were not informed of the possibility of a surgical procedure or of an angioplasty as a result of the procedure. 89% were satisfied with the information concerning the risks of the investigation. In a second group of 100 patients, the comprehension of the information was checked by the same questionnaire used a posteriori. These results show that patient information is very often incomplete. Despite some reticence, the new procedures seem to be globally well accepted but would be more effective if used before hospital admission.

Adult↗
PubMed2000

Homozygotes for a R869G mutation in the beta -myosin heavy chain gene have a severe form of familial hypertrophic cardiomyopathy.

UNLABELLED: Familial Hypertrophic Cardiomyopathy (FHC) is an autosomal dominant disease characterised by ventricular hypertrophy, with predominant involvement of the interventricular septum. It is a monogenic disease with a high level of genetic heterogeneity (nine genes and more than 110 mutations reported so far). We describe a family with a new R869G mutation in the beta -myosin heavy chain gene (MYH7). This mutation was found in the heterozygous status in both parents and in the homozygous status in the two children. A haplotype analysis on the MYH7 locus with microsatellite markers showed that the same haplotype is transmitted within the family, suggesting a founder effect. Clinically, the father was asymptomatic with mild left ventricular hypertrophy on echocardiography. The mother had a mild form of hypertrophic cardiomyopathy and remained asymptomatic until 60 years old when an atrial fibrillation occurred. For the two children, clinical diagnosis was performed at 12 and 8 years and atrial fibrillation occurred at 17 years. For both children, the evolution was characterized by left ventricle (LV) systolic dysfunction and a severe dilatation of the left atrium before 40 years of age. CONCLUSIONS: In this family, a new R869G mutation in the MYH7 gene was found. Interestingly, a mutation was found at the homozygous status for the first time in FHC. This finding suggests that this particular mutation is compatible with life, but for homozygous subjects, age at onset of symptoms was earlier and the disease much more severe than in the heterozygous subjects, suggesting a gene-dose effect.

Adult↗
PubMed2000

A pilot experience with permanent biventricular pacing to treat advanced heart failure.

BACKGROUND: The prognosis and quality of life of patients with advanced heart failure remain poor. The purpose of this study was to evaluate new nonpharmacologic approaches. Biventricular pacing was proposed in this indication, based on the encouraging results of acute hemodynamics studies. METHODS: Fifty patients with drug-resistant heart failure (New York Heart Association [NYHA] class III/IV, 16 of 34) were consecutively implanted with biventricular pacemakers. All patients had severe dilated cardiomyopathy and intraventricular conduction delay. Survival, NYHA class, electrocardiogram, echocardiographic data, and exercise tolerance were assessed over a mean follow-up period of 15.4 +/- 10. 2 months. RESULTS: At the end of follow-up, 55% of patients were alive without heart transplantation or left ventricular assistance device. The mortality rate was significantly lower in class III (12. 5%) than in class IV patients (52.5%). In survivors, biventricular pacing significantly improved symptoms (NYHA class 2.2 +/- 0.5 at follow-up vs 3.7 +/- 0.5 at baseline) and exercise tolerance ((. )VO(2) peak 15.5 +/- 3.4 mL/min per kilogram at follow-up vs 11.1 +/- 3 mL/min per kilogram at baseline). CONCLUSIONS: Biventricular pacing appears to improve the functional status of patients with dilated cardiomyopathy with advanced heart failure. The technique appears to be attractive as an additive treatment, especially in class III patients. Controlled randomized studies are needed to validate this novel concept.

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PubMed2000

Long-term effects of biatrial synchronous pacing to prevent drug-refractory atrial tachyarrhythmia: a nine-year experience.

INTRODUCTION: Results of previous studies suggest that atrial resynchronization by multisite atrial pacing may contribute to prevention of recurrences in patients with drug-refractory atrial tachyarrhythmias and significant intra-atrial conduction delay. METHODS AND RESULTS: To verify this hypothesis, a prospective noncontrolled study of 86 patients (mean age 66 +/- 10 years) was conducted in a single center between January 1989 and February 1998. Inclusion criteria were P wave duration > or = 120 msec with interatrial conduction time > or = 100 msec, and history of multiple recurrences of atrial tachyarrhythmias (mean 7 +/- 4.8 episodes) evolving in a persistent mode for at least 6 months despite optimized drug treatment (mean 2.7 +/- 1.8 drugs/patient). Patients were chronically implanted with a pacing system that ensured permanent biatrial pacing using two atrial leads, one placed in the high right atrium and the other one into the mid or the distal part of the coronary sinus. P wave duration decreased from a mean value of 187 +/- 29 msec before implant to 106 +/- 14 msec (P < 0.0001) under biatrial pacing. After a 33-month mean follow-up (range 6 to 109), 55 patients (64%) remained in sinus rhythm, including 28 patients (32.6%) without any documented recurrence and 27 patients with one or more recurrences in a paroxysmal or in a persistent form. In these 55 patients, drug treatment was significantly reduced in relation to the preimplantation period (1.4 +/- 0.6 vs 1.7 +/- 0.5 drugs/patient; P = 0.011). The other 31 patients went into chronic atrial arrhythmia after a mean period of 26 months. The only predictive factor of positive response was a spontaneous P wave duration < 160 msec at baseline. CONCLUSION: The results are consistent with a preventive effect of permanent biatrial pacing on recurrent and drug-refractory atrial arrhythmias associated with intra-atrial conduction delay.

Adult↗
PubMed1999

Electrocardiographic predictive factors of long-term clinical improvement with multisite biventricular pacing in advanced heart failure.

Biventricular pacing has recently been proposed for treating patients with drug refractory heart failure and intraventricular conduction delay. The purpose is to restore ventricular relaxation and contraction sequences as homogeneously as possible. The aim of this study was to determine if some factors could predict the long-term clinical effectiveness of that new treatment. This study included 26 patients, aged 66 +/- 7 years, with drug refractory heart failure and wide QRS. Patients were implanted with a biventricular pacemaker. The left ventricle was paced through a coronary sinus tributary. New York Heart Association functional class, exercise tolerance, and left ventricular (LV) ejection fraction were collected at baseline and after pacemaker implantation. Patients were divided into 2 groups: group I = responders; group II = nonresponders. QRS duration and axis at baseline and during biventricular pacing, interventricular conduction time, and LV and right ventricular lead positions were compared between the 2 groups. Group I patients (n = 19) had a mean reduction of 1.3 in functional class and an increase in peak oxygen consumption rate by a mean of 50%. The only parameter that differed between the 2 groups was the QRS duration during biventricular pacing, with a significantly shorter value in group I than in group II (154 +/- 17 vs 177 +/- 26 ms; p = 0.016). Thus, a positive response to biventricular pacing is correlated with the quality of electrical resynchronization. The optimal positions of the right and LV leads would be those that could induce the greatest shortening of QRS duration.

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PubMed1999

Effects of permanent dual-chamber pacing on mitral regurgitation in hypertrophic obstructive cardiomyopathy.

AIMS: To assess the effects of chronic dual-chamber pacing on mitral regurgitation in hypertrophic obstructive cardiomyopathy. METHODS AND RESULTS: Twenty-three patients with hypertrophic obstructive cardiomyopathy and mitral regurgitation. treated with DDD pacing for 16 +/- 14 months, were included in the study. Mitral regurgitation was assessed by Doppler-echocardiography using semi-quantitative analysis (grades I-IV) and by measuring the maximum regurgitant jet area/left atrial area ratio. At the end of follow-up, DDD pacing reduced the outflow gradient from 93 +/- 37 mmHg to 31 +/- 30 mmHg (P<0.0001). Nine of the 14 patients who initially had > or =grade II mitral regurgitation improved by at least one grade, two of them exhibiting dramatic improvement (from grade IV and III to grade I). The regurgitant jet area/left atrial area ratio was reduced with DDD pacing from 20 +/- 13% to 11 +/- 6% (P<0.0001). Patients who had significant mitral regurgitation despite pacing were those whose outflow gradient remained high or those with mitral valve organic abnormalities (mitral annulus calcification or mitral valve prolapse). In the absence of organic abnormalities other than leaflet elongation, there was a significant correlation between the gradient value achieved with DDD pacing and the extent of mitral regurgitation (P<0.05). CONCLUSION: In the absence of organic mitral valve abnormalities, DDD pacing reduces in parallel mitral regurgitation and left ventricular outflow gradient. In such patients therefore, significant mitral regurgitation is not a contraindication to pacing.

Adult↗
PubMed1998

Acute hemodynamic effects of biventricular DDD pacing in patients with end-stage heart failure.

OBJECTIVES: The aim of this study was to assess the potential acute benefit of multisite cardiac pacing with optimized atrioventricular synchrony and simultaneous biventricular pacing in patients with drug-refractory congestive heart failure (CHF). BACKGROUND: Prognosis and quality of life in severe CHF are poor. Various nonpharmacological therapies have been evaluated but are restricted in their effectiveness and applications. In the early 1990s, dual chamber pacing (DDD) pacing was proposed as primary treatment of refractory CHF but results were controversial. Recently, tests to evaluate the effect of simultaneous pacing of both ventricles have elicited a significant improvement of cardiac performance. METHODS: Acute hemodynamic study was conducted in 18 patients with severe CHF (New York Heart Association class III and IV) and major intraventricular conduction block (IVCB) (QRS duration = 170+/-37 ms). Using a Swan-Ganz catheter, pulmonary artery pressure, pulmonary capillary wedge pressure (PCWP) and cardiac index (CI) were measured in different pacing configurations: atrial pacing (AAI) mode, used as reference, single-site right ventricular DDD pacing and biventricular pacing with the right ventricular lead placed either at the apex or at the outflow tract. RESULTS: The CI was significantly increased by biventricular pacing in comparison with AAI or right ventricular (RV). DDD pacing (2.7+/-0.7 vs. 2+/-0.5 and 2.4+/-0.6 l/min/m2, p < 0.001). The PCWP also decreased significantly during biventricular pacing, compared with AAI (22+/-8 vs. 27+/-9 mm Hg; p < 0.001). CONCLUSIONS: This acute hemodynamic study demonstrated that biventricular DDD pacing may significantly improve cardiac performance in patients with IVCB and with severe heart failure, in comparison with intrinsic conduction and single-site RV DDD pacing.

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