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Biomedical subjects

C Daubert

Publications and source records attributed to C Daubert.

At least 19 recordsLinked to original sources
PubMed2005

Valve replacement in patients with critical aortic stenosis and depressed left ventricular function: predictors of operative risk, left ventricular function recovery, and long term outcome.

OBJECTIVES: To identify predictors of operative and postoperative mortality and of functional reversibility after aortic valve replacement (AVR) in patients with aortic stenosis (AS) and severe left ventricular (LV) systolic dysfunction. METHODS AND RESULTS: Between 1990 and 2000, 155 consecutive patients (mean (SD) age 72 (9) years) in New York Heart Association (NYHA) heart failure functional class III or IV (n = 138) and with LV ejection fraction (LVEF) < or = 30% underwent AVR for critical AS (mean (SD) valve area index 0.35 (0.09) cm2/m2). Thirty day mortality was 12%. NYHA class (3.7 (0.6) v 3.2 (0.7), p = 0.004), cardiothoracic ratio (CTR) (0.63 (0.07) v 0.56 (0.06), p < 0.0001), pulmonary artery systolic pressure (63 (25) v 50 (19) mm Hg, p = 0.03), and prevalence of complete left bundle branch block (22% v 8%, p = 0.03) and of renal insufficiency (p = 0.001) were significantly higher in 18 non-survivors than in 137 survivors. In multivariate analysis, the only independent predictor of operative mortality was a CTR > or = 0.6 (odds ratio (OR) 12.2, 95% confidence interval (CI) 5.4 to 27.4, p = 0.002). The difference between preoperative and immediate postoperative LVEF (early-DeltaEF) was > 10 ejection fraction units (EFU) in 55 survivors. In multivariate analysis, CTR (OR 5.95, 95% CI 3.0 to 11.6, p = 0.006) and mean transaortic gradient (OR 1.05, 95% CI 1.0 to 1.1, p < 0.05) were independent predictors of an early-DeltaEF > 10 EFU. During a mean (SD) follow up of 4.6 (3) years, 50 of 137 (36%) 30 day survivors died, 31 of non-cardiac causes. Diabetes (OR 3.8, 95% CI 2.4 to 6.0, p = 0.003), age > or = 75 years (OR 2.6, 95% CI 2.1 to 4.5, p = 0.004), and early-DeltaEF < or = 10 EFU (OR 0.96, 95% CI 0.94 to 0.97, p = 0.01) were independent predictors of long term mortality. Among 127 survivors, the percentage of patients in NYHA functional class III or IV decreased from 89% preoperatively to 3% at one year. The decrease in functional class was significantly greater in patients with an early-DeltaEF > 10 EFU than patients with an early-DeltaEF < or = 10 EFU (p = 0.02). In addition, the mean (SD) LVEF at one year was 53 (11)% in patients with an early-DeltaEF > 10 EFU and 42 (11)% in patients with early-DeltaEF < or = 10 EFU (p < 0.001). CONCLUSIONS: Despite a relatively high operative mortality, AVR for AS and severely depressed LVEF was beneficial in the majority of patients. Early postoperative recovery of LV function was associated with significantly greater relief of symptoms and longer survival.

Aged↗
PubMed2004

[Role of cardiac resynchronisation in the treatment of cardiac failure].

For 10 years cardiac resynchronisation has seen considerable development, as much on the technological side as at the level of its scientific validation. Several prospective studies have shown the functional benefits of cardiac resynchronisation in a selected population of refractory cardiac failure patients with improvement in symptoms, exercise tolerance and quality of life. Equally, cardiac resynchronisation allows a significant reduction in hospital episodes for cardiac failure and also has a beneficial effect on left ventricular inverse remodelling. Finally, the first results of morbidity/mortality trials are very encouraging with a significant reduction in overall mortality at one year in the COMPANION study with the biventricular defibrillator. However, numerous important, unresolved questions remain such as the problem of non-responders and thus patient selection, or such as the place of cardiac resynchronisation in patients with permanent atrial fibrillation. The choice of the type of implantable prosthesis (pacemaker or biventricular defibrillator) and the choice of the mode of pacing (biventricular or solely left ventricular) are still under discussion. New indications for cardiac resynchronisation could be seen next, for example such as the optimisation of stimulation mode in already paced patients or "systematic" biventricular pacing in patients with a conventional indication for pacing..... In 2004, cardiac resynchronisation must be considered as an effective adjuvant therapy in cardiac failure patients refractory to optimal medical treatment with left ventricular dysfunction and intraventricular conduction disorders.

Cardiac Pacing, Artificial↗
PubMed2002

Isolated left main coronary artery stenosis: long term follow up in 106 patients after surgery.

OBJECTIVE: To analyse the long term prognosis in patients with isolated stenoses of the left main coronary artery (LMCA) following surgical revascularisation. PATIENTS: 106 patients (71 men and 35 women, mean age 61 years) were operated on between 1982 and 1998. Before surgery, 103 patients presented with angina pectoris and only 10 had a history of myocardial infarction. Their mean left ventricular ejection fraction was 62%. Stenoses were localised on the LMCA ostium in 19 patients, a subgroup characterised by a high proportion of women (68%). Three patients presented with chronic LMCA occlusion. Forty six patients were operated on as an emergency. The mean (SD) number of grafts per patient was 2.0 (0.5), and only one patient had no left anterior descending (LAD) coronary artery bypass. Bypass of the LAD using the internal thoracic artery was performed in 88 cases. RESULTS: Early postoperative mortality was 4.7% and the five year survival was 86.8%. Late mortality occurred in nine cases, and in three of these it was linked to a coronary condition. Of the 92 long term survivors, 81.5% were totally symptom-free and 77% of those of working age were able to resume work. The postoperative outcome of patients with isolated ostial LMCA stenosis did not differ significantly from that of the other patients. CONCLUSIONS: The postoperative prognosis of isolated LMCA stenosis appears good in terms of mortality and symptoms.

Adult↗
PubMed2000

Comparative effects of permanent biventricular pacing for refractory heart failure in patients with stable sinus rhythm or chronic atrial fibrillation.

This study aimed to compare the long-term benefit of biventricular pacing in drug-refractory heart failure in patients with dilated cardiomyopathy who were in stable sinus rhythm or had persistent atrial fibrillation. The results showed that permanent biventricular pacing in such patients significantly improves exercise tolerance in both groups of patients; however, the benefit tended to be greater in patients with atrial fibrillation.

Aged↗
PubMed2000

Junctional rhythm during slow pathway radiofrequency ablation in patients with atrioventricular nodal reentrant tachycardia: beat-to-beat analysis and its prognostic value in relation to electrophysiologic and anatomic parameters.

INTRODUCTION: Junctional rhythm usually is considered a sensitive but nonspecific marker of successful ablation of the slow pathway in AV nodal reentrant tachycardia. Nevertheless, this junctional rhythm has been little studied, and its relations to recognized predictors of successful radiofrequency (RF) application were never established in any study. METHODS AND RESULTS: Thirty-nine patients underwent RF ablation of the slow pathway for AV nodal reentrant tachycardia. Ninety RF applications were delivered, and each ablation site was determined using three different fluoroscopic projections. Six anatomic zones were defined from low posterior septum to the site of distal His-bundle recording (P1, P2, M1, M2, A1, and A2). Characteristics of junctional rhythm during RF applications were analyzed. Atrial electrogram characteristics at the ablation sites also were studied. All patients had successful slow pathway ablation, without any complication. The ablation sites were located as follows: 41 at P1, 26 at P2, 20 at M1, and 3 in M2. Forty RF applications were successful: 14 of 41 attempts at P1, 7 of 26 at P2, 16 of 20 at M1, and 3 of 3 at M2. Mid-septal ablation site (M1 and M2) was associated with higher occurrence of junctional rhythm (P < 0.0001), earlier first junctional beat (P = 0.008), and earlier occurrence of the longest junctional burst (P = 0.03) compared with posterior ablation site (P1 and P2). The combination of a mid-septal ablation site and a first junctional beat occurring < or = 3 seconds after onset of RF application identified successful RF application with 100% accuracy. Using multivariate analysis, the ablation site, duration of atrial electrogram (including slow pathway potential when present), and occurrence of junctional rhythm were independent predictors of success. CONCLUSION: Successful slow pathway ablation depends on many factors. Junctional rhythm characteristics are related to the site of RF delivery and can be helpful in assessing successful slow pathway ablation.

Adolescent↗
PubMed1999

Optimal right ventricular pacing site in chronically implanted patients: a prospective randomized crossover comparison of apical and outflow tract pacing.

OBJECTIVES: To evaluate the long-term functional and hemodynamic effects of right ventricular outflow tract (RVOT) pacing by comparison with right ventricular apical (RVA) pacing. BACKGROUND: Acute studies have suggested that RVOT pacing could significantly improve cardiac performance in comparison with RVA pacing but no data are available in chronically implanted patients. METHODS: Sixteen patients with chronic atrial tachyarrhythmia and complete AV block were included. Left ventricular ejection fraction (LVEF) was > or =40% in ten and <40% in six. Patients were implanted with a standard DDDR pacemaker connected to two ventricular leads. A screw-in lead was placed at the RVOT and connected to the atrial port. A second lead was positioned at the RVA and connected to the ventricular port. Right ventricular outflow tract and RVA pacing was achieved by programming either the AAIR or the VVIR mode respectively. Four months later patients were randomized so as to undergo either RVOT or RVA pacing for three months according to a blind crossover protocol. Apart from the pacing mode, programming remained unchanged throughout the study. At the end of each period, NYHA class, LVEF, exercise time and maximal oxygen uptake were assessed. RESULTS: No significant difference was observed between the two modes for all the parameters analyzed. These identical results were observed in all patients globally, in patients with LVEF > or =40% as in those with LVEF <40%. CONCLUSIONS: Within the limits of this study, no symptomatic improvement or hemodynamic benefit was noted after three months of RVOT pacing, by comparison with RVA pacing.

Aged↗
PubMed1999

Significant improvement of quality of life following atrioventricular synchronous pacing in patients with hypertrophic obstructive cardiomyopathy. Data from 1 year of follow-up. PIC study group. Pacing In Cardiomyopathy.

AIMS: Atrioventricular synchronous pacing exerts beneficial effects, including reduction of left ventricular outflow tract gradients, in patients with hypertrophic obstructive cardiomyopathy. The Pacing in Cardiomyopathy study was initiated to explore the effects of pacing in a double-blind randomized crossover fashion. The aims were to ascertain the beneficial effects of pacing in a controlled study and to rule out a placebo effect by pacing. This paper deals with the outcome of pacing on quality of life during 1 year of follow-up. METHODS: Quality of life was evaluated with the Karolinska questionnaire, validated for patients paced for bradyarrhythmias and ischaemic heart disease. Drug-refractory patients with hypertrophic obstructive cardiomyopathy were recruited for the study and after a temporary pacing procedure implanted with permanent pacemakers. Patients were randomized to two study arms defining the sequence of pacemaker programming. In one arm the pacemaker was inactive, in the other active. After 3 months the pacemaker was reprogrammed to the alternate mode and a further 3 months followed. After this period subsequent pacemaker programming corresponded to the mode preferred by the patient. A last assessment was made 1 year after baseline examinations. RESULTS: Eighty patients completed the first crossover period and 75 completed the full 1 year of follow-up. Active pacing induced significant quality of life improvements, in the order of 9-44%, regardless of programming sequence. Discontinuation of pacing after a first active period resulted in the return of symptoms. Fourteen patients requested early reprogramming after having been programmed to inactive pacing after a first period of active pacing. Seventy-six patients preferred active pacing after the crossover period. A further 6 months of pacing induced progressive improvement in symptoms already favourably influenced. CONCLUSION: Atrioventricular synchronous pacing has a profound beneficial effect on most domains of quality of life in patients with hypertrophic obstructive cardiomyopathy refractory to drug treatment.

Adult↗
PubMed1999

Clinical progress after randomized on/off pacemaker treatment for hypertrophic obstructive cardiomyopathy. Pacing in Cardiomyopathy (PIC) Study Group.

BACKGROUND: The therapeutic options for hypertrophic obstructive cardiomyopathy (HOCM) classically include medical treatment with beta-blockers and calcium antagonists or myectomy-myotomy as a surgical possibility for refractory cases. The observation that pacemaker activation of the heart in HOCM reduces the subaortic gradient is well known but less well investigated. METHODS: Eighty-three patients (33 female and 50 male) mean age 53 (18-82) years, with symptoms refractory to drug treatment and a resting gradient above 30 mmHg, who responded favourably to temporary pacing, were included in this prospective study and had a pacemaker (DDD) implanted. After an initial double-blind crossover phase of 6 months, patients were reinvestigated at 12 months and followed for a mean of 36 months. RESULTS: As observed during a screening investigation, the obstruction was significantly reduced from 72 +/- 35 mmHg to 29 +/- 24 mmHg (P < 0.01) when the pacemaker was on, while no major effect was seen during the sham phase. The effect was persistent at 1 year with a remaining resting gradient of 28 +/- 24 mmHg. In parallel, we documented an improvement in functional capacity, according to the NYHA classification and by quality of life analysis, and a significant improvement in dyspnoea and angina. Exercise on treadmill improved only in patients with reduced initial tolerance (< 8 min). During the mean follow-up of 36 months, 65 patients remained on pacing alone, with eight patients having additional AV-node ablation and five patients finally having surgery. CONCLUSION: This controlled multicentre study shows that pacemaker treatment is an option for HOCM patients; it is inoffensive and does not exclude alternative methods, but satisfies 79% of patients beyond 3 years.

Adolescent↗
PubMed1999

Pacemaker lead infection: echocardiographic features, management, and outcome.

OBJECTIVE: To compare transthoracic and transoesophageal echocardiography (TTE, TOE) in patients with permanent pacemaker lead infection and to evaluate the safety of medical extraction in cases of large vegetations. METHODS: TTE and TOE were performed in 23 patients with definite pacemaker lead infection. Seventeen patients without previous infection served as a TOE reference for non-infected leads. RESULTS: TTE was positive in seven cases (30%) whereas with TOE three different types of vegetations attached to the leads were visualised in 21 of the 23 cases (91%). Of the 20 patients with vegetations and lead culture, 17 (85%) had bacteriologically active infection. Left sided valvar endocarditis was diagnosed in two patients. In the control group, strands were visualised by TOE in five patients, and vegetations in none. Medical extraction of vegetations >/= 10 mm was performed in 12 patients and was successful in nine (75%) without clinical pulmonary embolism. After 31.2 (19.1) months of follow up (mean (SD)), all patients except one were cured of infection; three died from other causes. CONCLUSIONS: Combined with bacteriological data, vegetations seen on TOE strongly suggest pacemaker lead infection. Normal TTE examinations do not exclude this diagnosis because of its poor sensitivity. Medical extraction of even large vegetations appeared to be safe.

Adult↗
PubMed1998

[Pacing and heart failure].

Conventional dual-chamber cardiac pacing with the right ventricular pacing catheter positioned at the apex of the right ventricle was proposed eight years ago by Hochleitner as primary treatment of refractory cardiac failure. Although the preliminary results were encouraging, those at long-term and subsequent studies were less favourable in this indication. Biventricular pacing is now a technical possibility and allows at least partial correction of the electromechanical abnormalities observed in dilated cardiomyopathy. The preliminary results of biventricular pacing in patients with refractory cardiac failure due to dilated cardiomyopathy with major intraventricular conduction defects are very encouraging. This new therapeutic approach should now be validated by controlled, randomised therapeutic trials.

Cardiac Catheterization↗
PubMed1997

Pacing in hypertrophic obstructive cardiomyopathy. A randomized crossover study. PIC Study Group.

BACKGROUND: Uncontrolled studies have shown that short atrioventricular delay dual chamber pacing reduces outflow tract obstruction in hypertrophic obstructive cardiomyopathy. Although the exact mechanism of this beneficial effect is unclear, this seems a promising potential new treatment for hypertrophic obstructive cardiomyopathy. METHOD: In order to evaluate the impact of pacing therapy, were performed a randomized multicentre double-blind cross-over (pacemaker activated vs non activated) study to investigate modification of echocardiography, exercise tolerance, angina, dyspnoea and quality of life in 83 patients with a mean age of 53 (range 22-87) years with symptoms refractory or intolerant to classical drug treatment. RESULTS: After 12 weeks of activated or inactivated pacing, independent of which phase was first, the pressure gradient fell from 59 +/- 36 mmHg to 30 +/- 25 mmHg (P < 0.001) with active pacing. Exercise tolerance improved by 21% in those patients who at baseline tolerated less than 10 min of Bruce protocol; symptoms of dyspnoea and angina also improved significantly from NYHA class 2.4 to 1.4 and 1.0 to 0.4, respectively (P < 0.007). Quality of life assessment with a validated questionnaire objectivated the subjective improvement. CONCLUSION: Pacemaker therapy is of clinical and haemodynamic benefit for patients with hypertrophic obstructive cardiomyopathy, left ventricular outflow gradient at rest over 30 mmHg who are symptomatic despite drug treatment.

Adult↗
PubMed1997

Permanent left atrial pacing with a specifically designed coronary sinus lead.

This article reports the original use of a specifically designed coronary sinus (CS) lead for permanent left atrial (LA) pacing. The device is characterized by its distal end shape featuring a double 45 degree angulation, which ensures very close contact with the CS upper wall. The device was successfully implanted in 39 out of 40 patients (97.5%). The tip electrode was eventually positioned in the distal CS in 9 patients, in the middle CS in 21 patients, and close to the ostium in the proximal CS in 9 patients. The mean acute pacing threshold voltage was 0.9 +/- 0.5 V with a mean impedance of 578 +/- 144 omega as measured in unipolar distal configuration at 0.5 ms pulse width (PW). The mean A wave amplitude was 3.5 +/- 2.1 mV. Early lead dislodgment occurred only once (3%) when the tip electrode was placed in the distal or middle CS, but more often (4/9 cases) when it was placed in the proximal CS. After a mean follow-up duration of 14 +/- 8.5 months, 35 of the 39 successfully implanted leads (89.7%) were still functional in terms of LA pacing and sensing. The mean chronic pacing threshold voltage was 1.5 +/- 0.8 V and the mean A wave amplitude was 2.7 +/- 1.6 mV. There were no lead related complications. In conclusion, the device proved to be safe and highly effective for permanent LA pacing, provided the distal tip could be positioned in the distal or middle part of the CS.

Aged↗
PubMed1997

Human stress cardiomyopathy mimicking acute myocardial syndrome.

Two cases of transient acute cardiomyopathy occurring in the immediate aftermath of intense emotional stress and without any identified aetiology are described. These two cases reports, mimicking cases of acute cardiomyopathy described in patients with pheochromocytoma, suggest the possibility in man of acute catecholamine induced cardiomyopathy related to major emotional stress alone, a phenomenon so far reported only in animal experimental models.

Acute Disease↗
PubMed1997

[Accessory pathways of decremential conduction (Mahaim fibers). Treatment by endocavitary ablation; apropos of 8 cases].

Mahaim fibres are rare, right sided accessory pathways comparable with respect to certain properties (slow, decremential conduction) with "accessory atrioventricular node" located on the lateral tricuspid annulus at a distance from the Aschoff-Tawara node. Atriofascicular and atrioventricular fibres may be distinguished, both responsible for wide complex tachycardia (left bundle branch block pattern with left axis deviation). The authors report a series of 8 patients (6 women, 2 men: age: 27 +/- 11 years) without underlying cardiac disease, incapacitated by episodes of antidromic reciprocating tachycardia related to the atriofascicular fibres and justifying the indication of treatment by endocavitary ablation. In all cases, the authors tried to identify a specific potential of the Mahaim fibres on the lateral aspect of the tricuspid annulus. When the potential was recorded (7 out of the 8 cases) ablation was successful (procedure time 160 +/- 11 min; average number of applications: 9). It was not possible to identify a specific Mahaim potential in 1 case and so ablation was performed on the distal right ventricular site of insertion with no criterion of efficacy. In one woman, manipulation of the ablation catheter led to prolonged mechanical block in the Mahaim fibres, so suppressing the usual criteria of evaluation of the initial result of ablation: an early recurrence of tachycardia was observed in this case. No complications occurred during the 8 procedures. These results and those of other published cases, showed that radiofrequency ablation of Mahaim fibres is feasible with a high success rate without any immediate or long-term complications. This reliable and effective technique should form one of the therapeutic options for these invalidating junctional tachycardias.

Adolescent↗
PubMed1996

[Is isolated atrial fibrillation genetically determined? Apropos of a familial history].

The authors report five cases of apparently lone atrial fibrillation in five members of the same family from three generations. The atrial fibrillation occurred at an early age and rapidly became permanent in all cases. With time, in the absence of complications, structural cardiac abnormalities were documented by echocardiography (biatrial dilatation and mitral and tricuspid regurgitation). These observations raise the question of genetic predisposition to lone atrial fibrillation at least in this particular clinical context.

Adult↗
PubMed1996

[Acute relapsing pericarditis induced by screw-in atrial pacing lead. Apropos of 3 cases].

Contrary to the ventricle where pacing leads remain passively implanted, the use of active screw-in atrial pacing leads has rapidly developed during the last few years. This type of fixation in a thin and fragile cardiac wall carries a risk of perforation and thereby of pericardial complications. The authors report three original cases of a period of time. The responsibility of the atrial lead was highly probable given the presence of suggestive symptoms (pericardial pain) or of pericardial complications confirmed at surgery, of the presence of radiological changes in 2 cases (localised bulges of the cardiac silhouette opposite the site of implantation of the pacing lead), the absence of any other detectable cause and, finally, cure after explantation of the causal pacing lead and anti-inflammatory drug therapy. Some simple preventive measures based on the properties of the material (screw length < 2 mm), the technique of implantation, should help avoid these complications or, at least, to reduce their frequency.

Acute Disease↗
PubMed1995

Hemodynamic importance of preserving the normal sequence of ventricular activation in permanent cardiac pacing.

Pacing the right ventricle in the apex profoundly modifies the sequence of activation and thus the sequence of contraction and relaxation of the left ventricle. To evaluate the relative importance of preserving normal ventricular activation sequence and optimal atrioventricular (AV) synchrony in permanent pacing, we compared the effects of three pacing modes: AAI, preserving both normal AV synchrony and normal activation sequence; DDD, with complete ventricular capture that preserves only AV synchrony; and VVI, disrupting both, at rest and during exercise. Hemodynamic and radionuclide studies were performed in 11 patients who had normal intrinsic conduction and who were implanted on a long-term basis with a DDDR pacemaker for isolated sinus node dysfunction. AAI versus DDD and VVI significantly increased cardiac output at rest (6.6 +/- 1.3 L/min vs 6 +/- 0.9 L/min vs 5 +/- 1 L/min; p < 0.01) and during exercise (13.5 +/- 2 L/min vs 12.1 +/- 2.2 L/min vs 14.4 +/- 2.1 L/min; p < 0.01). Pulmonary capillary wedge pressure was lowest with AAI (15.4 +/- 4.5 mm Hg), with an average reduction of 17% compared with DDD (19.6 +/- 5 mm Hg; p < 0.01) and of 30% compared with VVI (25.8 +/- 7 mm Hg; p < 0.01) during exercise. Identical benefits were observed for all other hemodynamic parameters: right atrial pressure, pulmonary artery pressure, left ventricular (LV) stroke work index, and systemic vascular resistances. LV ejection fraction was significantly higher in AAI than in DDD at rest (61% vs 58%, respectively; p < 0.05) and during exercise (65% vs 60%, respectively; p < 0.05). This improvement in LV systolic function resulted principally from the increase in septal ejection fraction. LV filling also was improved in AAI as demonstrated by a significant increase in peak filling rate at rest and during exercise. These data show the importance of preserving, whenever possible, not only normal AV synchrony but also normal ventricular activation sequence in permanent cardiac pacing.

Adult↗