PubMed Health⌕ Search

Biomedical subjects

D Gras

Publications and source records attributed to D Gras.

At least 37 records · Page 2Linked to original sources
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

[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

Multisite pacing for end-stage heart failure: early experience.

Our objective was to improve hemodynamics by synchronous right and left site ventricular pacing in patients with severe congestive heart failure (CHF). Previous studies reported a benefit of dual chamber pacing with a short AV delay in patients with severe CHF. Other works, however, show contradictory results. Deleterious effects due to a desynchronization of right (RV) and left ventricular (LV) contractions have been suggested. This study included eight subjects with widened QRS and end-stage heart failure despite maximal medical therapy, who refused, or were not eligible to undergo heart transplantation, Each patient underwent a baseline, invasive hemodynamic evaluation with insertion of three temporary leads to allow different pacing configurations, including RV apex and outflow tract pacing, and biventricular pacing between the RV outflow tract and LV and RV apex and LV. According to the results of this baseline study, the configuration of preexistent pacemakers was modified or new systems were implanted to allow biventricular pacing, which, in patients with sinus rhythm, was atrial triggered. Biventricular pacing increased the mean cardiac index (CI) by 25% (from a baseline of 1.83 +/- 0.30 L/min per m2, P < 0.006), decreased the mean V wave by 26% (from a baseline of 36 +/- 12 mmHg, P < 0.004), and decreased pulmonary capillary wedge pressure by 17% (from a baseline of 31 +/- 10 mmHg, P < 0.01). Four patients died (1 preoperatively, 1 intraoperatively, 2 within 3 months, and 1 of a noncardiac cause). The four surviving patients have clinically improved from New York Heart Association Functional Class IV to Class II. In these survivors, CI decreased by 15% (P < 0.007) when multisite pacing was turned off during follow-up. In patients with end-stage heart failure, multisite pacing may be associated with a rapid and sustained hemodynamic improvement.

Aged↗
PubMed1996

[Incidence of atrial arrhythmia in patients with long term dual-chamber pacemakers. Contribution of the Holter function of pacemakers].

The extension of the RAM memories in the latest generation of pacemakers has enabled development of Holter function allowing continuous surveillance of the cardiac rhythm. Between October 1991 and February 1995, 213 patients implanted with a Chorus 6234 or 7034 (Ela Medical) pacemaker, functioning in the DDD (R) mode, were followed up using the implanted continuous Holter function. Of the patients with no documented supraventricular arrhythmia (SVA) before implantation (n = 154), 67 (43.5%) developed SVA during an average period of one year. Male patients (p = 0.01; OR = 7.5 on multivariate analysis), high degrees of AVB (p = 0.03) and the presence of isolated or bursts of atrial extrasystoles (p = 0.004) were independent risk factors for SVA. The average time to detection of SVA was 207 days. In patients with documented SVA before implantation (n = 59), 22 (37.3%) had no recurrence during follow-up; in the other 37 cases, the average period before recurrence was 127 days. Multivariate analysis did not reveal any independent risk factor for recurrence of the arrhythmias. On the other hand, persistent but delayed atrioventricular conduction (1 degree AVB, long H-V interval or bifascicular block), seemed to protect against SVA, independently of other variables and of antiarrhythmic therapy (p = 0.008). These results suggest a high prevalence of SVA in patients on long-term pacemaker therapy, most episodes being asymptomatic. The implanted Holter function would therefore seem to be an essential tool for investigating and following up the natural history of arrhythmias in these patients.

Aged↗
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↗
PubMed1996

[First experience in treatment of terminal cardiac insufficiency using multisite stimulation].

We hypothesized that the presence of an abnormal ventricular mechanical activation sequence and/or a delayed left ventricular (LV) contraction may have adverse hemodynamic effects in congestive heart failure (CHF) and could be improved by synchronous RV-LV pacing in a multisite (MS) configuration. 8 NYHA IV CHF patients were included with a LV delay due to 1/ preexistent pacemaker in 4 pts (2 VVI and 2 DDD); 2/ left bundle branch block in 2 pts; 3/ intraventricular conduction delays in 2 pts. An acute hemodynamic evaluation was performed. Hemodynamics were optimized in standard RV pacing by modifying RV lead position from apex to outflow tract (RVOT) in VVI for AF patients and in VDD for sinus rhythm patients at different AV delays. RV pacing did not change hemodynamics whatever the lead position. BV pacing improved CI by 25% (p < 0.006), V wave by 26% (p < 0.004) and PCWP by 17% (p < 0.01). Chronic implantation was performed in 7pts. LV lead was implanted via the coronary sinus in 2 cases and epicardial via a thoracoscopic approach in the remaining ones. 1 pt died during LV lead implantation. Hemodynamics were tested at 2 months followup (FU). Switching BV pacing off was associated with immediate deterioration. At 6 +/- 6 months Followup 4 pts are stable in Class II. 1 pt died of cardiac cause. 1 pt could be transplanted at 17 months FU. In conclusion, BV pacing through a multisite configuration is feasible and can help in CHF patients managing.

Aged↗
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↗
PubMed1995

[Importance of atrioventricular synchrony in hypertrophic obstructive cardiomyopathy treated by cardiac pacing].

This study was undertaken to evaluate the effect of permanent dual-chamber cardiac pacing in hypertrophic obstructive cardiomyopathy resistant to medication, paying particular attention to atrioventricular synchrony. Sixteen patients, mean age 59 +/- 13 years (range 36 to 80 years) were divided into two groups after in initial catheter study performed under temporary VDD pacing between March 1990 and April 1993. In group I (n = 11), the gradient was decreased by more than 50% whereas in group II (n = 5), the gradient was unchanged or reduced by less than 50%. The reduction of the gradient was immediately significant in group I, the mean value falling from 104 +/- 33 mmHg (range 60 to 170 mmHg) to 25 +/- 13 mmHg (range 10 to 60 mmHg) (p < 0.0001). In group II, the gradient only decreased initially from 132 +/- 13 mmHg (range 120 to 150 mmHg) to 88 +/- 25 mmHg (range 50 to 130 mmHg) (p < 0.003) but improved atrioventricular synchrony, obtained secondarily either by pharmacological prolongation of the PR interval (association of betablocker and verapamil) or by ablation of the atrioventricular junction, improved the haemodynamic benefits. The residual gradient recorded on the 7th day was only 26 +/- 15 mmHg (range 10 to 50 mmHg) (p < 0.0001). The comparison of the two populations showed that the mean PR interval was shorter in group II (p < 0.016) and the mean value of the optimal AV Delay (the longest AV Delay with complete ventricular capture) was also lower (p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1995

[Value of cardiac pacing in hypertrophic obstructive cardiomyopathy refractory to medical treatment].

Recent studies have shown that dual-chamber cardiac pacing could improve patients with hypertrophic obstructive cardiomyopathy resistant to medical treatment. After a brief historical review, the authors report the present status of this original therapeutic option. The results of different studies are in agreement and show that the functional improvement is associated with a large reduction of the intraventricular pressure gradient with permanent DDD pacing. Although the exact mechanism of the improvement remains unknown, all groups underline the importance of complete and permanent ventricular capture. This requires precise regulation of the atrioventricular delay which in most cases must be programmed at a value inferior to 90 ms, which compromises ventricular filling which is already abnormal under basal conditions. The inefficacy of pacing in some cases is explained by the necessity of selecting a very short atrioventricular delay which alters diastolic function and finally masks the benefits of ventricular capture. In this particular situation, the authors propose improving atrioventricular synchrony by pharmacological prolongation of the PR interval, or, when unsuccessful, by ablation of the atrioventricular junction. This attitude was adopted in 5 cases when pacing with an AVD programmed between 20 and 70 ms, provided only a partial haemodynamic result. Improved atrioventricular synchrony allowed selection of an AVD of 100 to 150 ms, so reducing the gradient by more than 70%, compared with 30% under the initial programming parameters. The authors conclude that a positive and sustained benefit of cardiac pacing can only be obtained by an individualised regulation of pacing parameters to optimize atrioventricular synchrony which seems to be the key element of success.

Adrenergic beta-Antagonists↗
PubMed1995

[The esophageal approach in rhythmology].

The possibility of detecting the electrical activity of the heart from the oesophageus has been recognised for nearly a century. On the other hand, transesophageal pacing has only been really developped in the last fifteen years, which explains the recent interest for this technique in clinical practice. Easily put into practice, but not always well tolerated, the oesophageal approach has many uses in rhythmology. The principal diagnostic applications are in unlabelled tachycardias whether with narrow or wide QRS complexes, the evaluation of the Wolff-Parkinson-White syndrome, the study of sinus node function or nodal conduction. The therapeutic applications are dominated by the reduction of supraventricular tachycardias especially atrial flutter, with a success rate similar to that of endocavitary stimulation. The facility of realisation, especially at the patient's bedside, without need for fluoroscopie control, makes it a useful tool in emergencies, especially if the endocavitary approach cannot be used. The only reserve is the painful character of pacing in some patients.

Anti-Arrhythmia Agents↗
PubMed1995

[Infections on permanent endocavitary pacemaker leads: value of transesophageal echocardiography].

The prevalence of infection of permanent pacing material ranges from 0.13 to 19.9% of patients according to published series. The seriousness of this condition requires early diagnosis and treatment. Transesophageal echocardiography visualised vegetations on the intracardiac pacing lead in all of 11 patients studied, whereas transthoracic echocardiography and polynuclear leucocyte scintigraphy only provided positive diagnoses in 4 cases for each investigation. Three types of vegetation were visualised; no cases of tricuspid valve endocarditis were observed. Treatment was based on explantation of all implanted material by endovascular traction in 7 cases and by surgery in the other 4 cases according to the results of transesophageal echocardiography. There were no deaths or recurrence of infection. Transesophageal echocardiography is the investigation of choice for imaging a vegetation on an endocavitary pacing lead. Complete explanation is essential for a complete recovery of this infection.

Adult↗
PubMed1994

[Permanent atrial resynchronization by synchronous bi-atrial pacing in the preventive treatment of atrial flutter associated with high degree interatrial block].

UNLABELLED: Interatrial conduction block results in a very delayed and retrograde activation of the left atrium and is associated with a high incidence of atrial tachyarrhythmias, especially a particular (and specific) form of atypical atrial flutter. Electrophysiologic studies have suggested that these arrhythmias were usually due to reentry and could be directly related to the conduction disturbances in the atrium. If so, we can expect reasonably that permanent atrial resynchronization resulting from simultaneous pacing in different target sites in the atria, may not only correct for interatrial dysynchrony, but also may significantly contribute to prevent arrhythmia recurrences. Twenty-eight patients, mean age 68 years, were included. The mean P wave duration in spontaneous sinus rhythm was 181 +/- 28 ms. In all patients, many recurrences of atrial tachyarrhythmia were documented, especially a specific form of atypical atrial flutter. Medical therapy was constantly ineffective. Three different pacing modes were used: 6 patients, with normal A-V conduction were implanted with a SSI device, programmed in AAT mode and connected, using a Y bifurcated connector, to two atrial leads, one positioned in the right atrium, the second one into the coronary sinus-in 14 patients, with A-V conduction defects, a conventional DDDR unit was implanted and connected to a composite biatrial electrode and a ventricular lead. In that configuration atrial resynchronization was only effective on paced atrial cycles -a specific DDD Chorus ELA Medical device with a special algorithm loaded into the RAM memory was implanted in 14 patients (8 new indications, and 6 patients first implanted with a DDDR unit). RESULTS: during sinus rhythm atrial resynchronization induced a reduction of the P wave duration from 181 +/- 28 ms to 116 +/- 12 ms. During permanent pacing the mean value decreased from 209 +/- 38 ms to 108 +/- 13 ms. During follow-up (34 +/- 15 months) arrhythmia prevention was assessed by history, by monthly surface ECG's and by bimonthly 24 hours Holters recordings and telemetric interrogation of the pacemaker statistics. Twenty-one patients did not experienced any recurrence of arrhythmia. One to three recurrences occurred in the other seven patients, including six patients implanted with a conventional DDDR unit. These preliminary results seem validate the new concept of atrial resynchronization for prevention of atrial arrhythmia associated with interatrial conduction block.

Adult↗
PubMed1993

Clinical role of d-sotalol and d,l-sotalol in supraventricular arrhythmias, including pre-excitation.

Numerous trials performed over the last 20 years, although uncontrolled, have shown the racemic d,l-sotalol is effective for the acute conversion and for long-term prevention of recurrences of supraventricular tachyarrhythmias. Sotalol appeared to be moderately effective in atrial fibrillation or atrial flutter, having somewhat greater efficacy in the case of atrioventricular (AV) nodal re-entrant tachycardia due to Wolff-Parkinson-White syndrome or concealed accessory pathway. These effects may stem from the combined class II and class III electrophysiologic properties of this drug. However, studies comparing d,l-sotalol to pure beta blockers in different 'models', especially postsurgical arrhythmias and Wolff-Parkinson-White syndrome, have suggested that the observed clinical benefit may be related to d,l-sotalol's class III properties. Thus, d-sotalol may be efficacious in these indications. Its precise efficacy should be defined in controlled clinical trials.

Adrenergic beta-Antagonists↗
PubMed1993

[Diagnostic and therapeutic strategy in coronary insufficiency in the elderly. Apropos of 65 cases].

As people live longer, so cardiologists are having to manage coronary artery disease in progressively older patients with more severe coronary lesions. The authors tried to determine the feasibility and results of coronary angiography in a retrospective study of 65 patients (44 men and 21 women) over 75 years of age (range 75 to 84 years) with coronary artery disease (excluding valvular heart disease). The study period was 22 months. The commonest indication was unstable or invalidating angina resistant to medical therapy (42 of the 65 cases). Twenty-two patients underwent coronary angiography in the context of myocardial infarction complicated in 3 cases by septal rupture. With the exception of these 3 patients, two of whom underwent surgery, 39 of the 62 remaining patients were judged to be candidates for myocardial revascularisation (63%); 37 underwent a revascularisation procedure (60%), 20 by percutaneous transluminal coronary angioplasty and 17 by coronary bypass surgery. The primary success rate of angioplasty was 90% (18 out of 20). There were no deaths in this group. Two patients who were referred for surgery died, an operative mortality of 12% (2 out of 17). All patients were followed up: 56 out of the 65 were still alive at the time of enquiry, after an average period of 18 months. All surviving patients who were successfully revascularised (by angioplasty or surgery) were pauci- or asymptomatic. Although there is an increased mortality related to revascularisation of elderly patients, this would seem to be acceptable given the quality of the medium term clinical results.

Aged↗