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J Clémenty

Publications and source records attributed to J Clémenty.

At least 19 recordsLinked to original sources
PubMed2002

[Measurement of arterial distensibility by the QKd method a new vascular marker].

INTRODUCTION: Distensibility is the ability of large elastic arteries to increase in diameter from diastole to systole. Pulse wave velocity (PWV) is one of the ways to measure this parameter. Several techniques, including QKd, are able to measure PWV. PURPOSE: QKd is the time interval between the Q wave on EKG and auscultation of the second Korotkoff's sound at the brachial artery. QKd is measured by a specific apparatus that registers ambulatory blood pressure as well as EKG (normal > 200 ms). Arterial distensibility seems to be able to predict cardiovascular morbidity and QKd has been demonstrated to predict such morbidity in a sample of elderly hypertensives. Currently the relationship between QKd and prognosis is under investigation in systemic sclerosis (ERAMS study). CONCLUSION: QKd is a noninvasive ambulatory method that measures arterial distensibility as well as blood pressure.

Age Factors↗
PubMed2002

Successful laparoscopic operation of bilateral pheochromocytoma in a patient with Beckwith-Wiedemann syndrome.

We report the case of a 20-year-old female patient with Beckwith-Wiedemann syndrome presenting with high blood pressure and bilateral adrenal pheochromocytoma successfully removed with laparoscopy in the same time. To our knowledge, the present case is the first observation of a bilateral pheochromocytoma occurring in the Beckwith-Wiedemann syndrome. It provides further support for a genetic anomaly in this condition. Our case also indicates the interest of laparoscopy for the surgical treatment of adrenal pheochromocytoma, even in bilateral tumors.

Adrenal Gland Neoplasms↗
PubMed2002

[Role of electric stimulation in apnea syndromes].

The sleep apnoea syndrome is the best known apnoeic syndrome. It is observed in 4% of men and 2% of women. Nasal ventilation with continuous positive pressure is the best treatment for most patients. To date, electrical stimulation has a limited role in its treatment as it is used only when the apnoea requires ventilation by tracheotomy. This electrogenic ventilation requires so-called diaphragmatic stimulators. Although severe bradycardia may occur during sleep apnoea, there is usually no indication for cardiac pacing. However, recent publications have reported an anti-apnoeic effect of permanent atrial pacing. The modes of action remain unclear but these results support other recently reported data concerning the value of pacing in cardiac failure, the high incidence of sleep apnoea in cardiac failure patients and the possibility of diagnosing and monitoring apnoea by minute ventilation sensors. Therefore, there appears to be a field of research for cardiac pacing in apnoea syndromes. The authors review the principal reported data on the indications and possibilities of extra-cardiac and cardiac stimulation in apnoeic syndromes.

Electric Stimulation↗
PubMed2002

[Role of radiofrequency ablation in atrial fibrillation].

Atrial fibrillation is the most frequently encountered arrhythmia in the human species. Its danger is widely appreciated but it remains for certain patients and their practitioners an awkward or even exasperating problem. Only surgery and radiofrequency ablation allow certain patients to be cured. The surgical approach is of course warranted in the case of an otherwise necessary cardiac intervention. In the absence of a surgical indication, endovenous ablation, which is less aggressive, is preferred. The procedure consists of disconnecting the pulmonary veins which "house" 80 to 95% of the foci, together with the ablation of further non-venous foci, which are always difficult to treat. Side effects in experimental centres are rare and 70% of patients are cured, which allows cessation of antiarrhythmic and anticoagulant treatments. The procedure is currently offered to symptomatic patients having had at least one episode every ten days in spite of antiarrhythmics.

Anti-Arrhythmia Agents↗
PubMed2002

[Placement of an implantable defibrillator via the endocavitary route in a patient presenting with a univentricular heart and a Glenn anastomosis].

We report the observation of a female 45 year old patient presenting with a post-surgery complex congenital cardiopathy, associated with serious ventricular rhythm disorders necessitating the placement of an implantable defibrillator. The palliative surgery performed (cavo-pulmonary Glenn anastomosis) does not allow the usual access to the right ventricle via the superior vena cava. The different possibilities for defibrillator implantation are discussed. These include associating a surgical approach to introduce the bipolar probe with subcutaneous tunnelling to connect the probe to the box.

Arrhythmias, Cardiac↗
PubMed2001

Morphological characteristics of P waves during selective pulmonary vein pacing.

OBJECTIVES: We sought to assess the value of 12-lead electrocardiogram (ECG) P-wave morphology to recognize the paced pulmonary vein (PV). BACKGROUND: Prediction of arrhythmogenic PVs producing ectopy or initiating atrial fibrillation (AF) using 12-lead ECG may facilitate curative ablation. METHODS: In 30 patients P-wave configurations were studied during sinus rhythm and during pacing at six sites from the four PVs: top and bottom of each superior PV and both inferior PVs. The P-wave amplitude, duration and morphology were assessed, and predictive accuracies were calculated for the most significant parameters. An algorithm predicting the paced PV was developed and prospectively evaluated in a different population of 20 patients. RESULTS; Three criteria were used to distinguish right from left PV: 1) a positive P-wave in lead aVL and the amplitude of P-wave in lead I > or =50 microV indicated right PV origin (specificity 100% and 97%, respectively); 2) a notched P-wave in lead II was a predictor of left PV origin (specificity 95%); and 3) the amplitude ratio of lead III/II and the duration of positivity in lead V(1) were also helpful in distinguishing left versus right PV origin. In addition, superior PVs could be distinguished from inferior according to the amplitude in lead II (> or =100 microV). In prospective evaluation, an algorithm based on the above four criteria identified 93% of left versus right PV and totally 79% of the specific PVs paced. CONCLUSIONS: Pacing from the different PVs produced a P-wave with distinctive characteristics that could be used as criteria in an algorithm to identify the PV of origin with an accuracy of 79%.

Aged↗
PubMed2001

Validation by serial standardized testing of a new rate-responsive pacemaker sensor based on variations in myocardial contractility.

AIMS: Preliminary studies have shown that peak endocardial acceleration (PEA), measured by a micro-accelerometer at the right ventricular apex, is highly correlated with left ventricular contractility (dp/dt max). Furthermore, changes in PEA are closely correlated with sinus node rate changes during exercise and during pharmacological interventions. Peak endocardial acceleration has, therefore, been used to drive a rate-responsive DDD pacemaker. This study compared the chronotropic performance of such devices implanted in 14 patients suffering from chronotropic incompetence with that observed in 18 control subjects in normal sinus rhythm. METHODS AND RESULTS: Five standardized daily life activities (hall walk, climbing up and down stairs, squatting and hyperventilation) and two types of exercise (Bruce treadmill protocol and bicycle ergometry) were performed in a random order after individual programming of each pacemaker. For each test, a correlation coefficient was calculated between changes in PEA and variations in paced rate, between instantaneous variations in heart rate monitored by telemetry and continuous measurement of heart rate by the pacemaker, and between sensor-driven rate in patients and normal sinus rhythm in controls. The variations in paced heart rate were closely correlated with those observed in subjects with normal sinus rhythm, and proved to be sensitive, specific, rapid and independent of the type of exercise. After optimal programming of the sensor, PEA modulates the heart rate as expected during normal sinus rhythm. CONCLUSIONS: In this study, a single PEA sensor successfully restored chronotropic response in a population of paced patients with severe chronotropic incompetence. Peak endocardial acceleration can be monitored on a beat-to-beat basis, in parallel with heart rate, and the pacemaker can be accurately programmed with a single exercise test.

Aged↗
PubMed2001

[Ablation of atrial fibrillation: where are we now?].

Atrial fibrillation is the commonest arrhythmia. Besides the risk of complications, a significant number of patients remain symptomatic despite the different anti-arrhythmic drugs currently available. The only curative treatment is by surgery or catheter ablation. Since 1994, several approaches have been developed based on two main concepts: modification of the arrhythmogenic substrate by linear lesion to prevent the perpetuation of the arrhythmia and ablation of the foci initiating the atrial fibrillation. The later approach is the most popular one at the moment because the concentration of foci at the site of the pulmonary veins makes it possible to isolate them relatively easily. The presence of atrial foci in some patients complicates matters and limits the success rate to 70%. Despite these limitations and with an acceptable rate of complications, this approach appears preferable to His bundle ablation in young patients with symptomatic paroxysmal atrial fibrillation resistant to antiarrhythmic therapy.

Adult↗
PubMed2000

Efficacy and safety of an irrigated-tip catheter for the ablation of accessory pathways resistant to conventional radiofrequency ablation.

BACKGROUND: Radiofrequency catheter ablation of accessory pathways (APs) is very effective in all but a minority of patients. We examined the usefulness and safety of irrigated-tip catheters in treating patients with APs resistant to conventional catheter ablation. METHODS AND RESULTS: Among 314 APs in 301 consecutive patients, conventional ablation failed to eliminate AP conduction in 18 APs in 18 patients (5.7%), 6 of which were located in the left free wall, 5 in the middle/posterior-septal space, and 7 inside the coronary sinus (CS) or its tributaries. Irrigated-tip catheter ablation was subsequently performed with temperature control mode (target temperature, 50 degrees C), a moderate saline flow rate (17 mL/min), and a power limit of 50 W (outside CS) or 20 to 30 W (inside CS) at previously resistant sites. Seventeen of the 18 resistant APs (94%) were successfully ablated with a median of 3 applications using irrigated-tip catheters. A significant increase in power delivery was achieved (20.3+/-11.5 versus 36.5+/-8.2 W; P:<0.01) with irrigated-tip catheters, irrespective of the AP location, particularly inside the CS or its tributaries. No serious complications occurred. CONCLUSIONS: Irrigated-tip catheter ablation is safe and effective in eliminating AP conduction resistant to conventional catheters, irrespective of the location.

Adult↗
PubMed2000

Electrophysiological breakthroughs from the left atrium to the pulmonary veins.

BACKGROUND: The extent of ostial ablation necessary to electrically disconnect the pulmonary vein (PV) myocardial extensions that initiate atrial fibrillation from the left atrium has not been determined. METHODS AND RESULTS: Seventy patients underwent PV mapping with a circumferential 10-electrode catheter during sinus rhythm or left atrial pacing. After assessment of perimetric distribution and activation sequence of PV potentials, ostial ablation was performed at segments showing earliest activation, with the end point of PV disconnection. A total of 162 PVs (excluding right inferior PVs) were ablated. PV potentials were present at 60% to 88% of their perimeter, but PV muscle activation was always sequential from a segment with earliest activation (breakthrough). Radiofrequency (RF) application at this breakthrough eliminated all PV potentials in 34 PVs, whereas a secondary breakthrough required RF applications at separate segments in 77; in others, >2 segments were ablated. A median of 5, 6, and 4 bipoles from the circular catheter were targeted in the right superior, left superior, and inferior PVs, respectively, to achieve PV disconnection. Early recurrence of arrhythmia was observed in 31 patients as a result of new venous or atrial foci or recovery of previously targeted PVs, most related to a single recovered breakthrough that was reablated with local RF application. CONCLUSIONS: Although PV muscle covers a large extent of the PV perimeter, there are specific breakthroughs from the left atrium that allow ostial PV disconnection by use of partial perimetric ablation.

Angiography↗
PubMed2000

Mapping-guided ablation of pulmonary veins to cure atrial fibrillation.

Catheter ablation of triggers inducing paroxysms of atrial fibrillation (AF) is an emerging therapy for this common arrhythmia. In a series of 225 consecutive patients with AF resistant to multiple drugs, 96% presented with triggering foci originating from 1 or multiple pulmonary veins (PV), independently of whether or not the patient had ectopy or structural heart disease. The present article describes the mapping and ablation techniques applicable to individual patients: (1) criteria to define an arrhythmogenic PV; (2) use of provocative maneuvers; and (3) the role of circumferential mapping catheters to provide extent, distribution, and activation of PV muscle as well as monitoring distal PV potentials (PVP) during ablation. Radiofrequency ablation can be performed by targeting the PVP during sinus rhythm (right PV) or left atrial pacing (left PV) with the procedural endpoint of PVP elimination, which is more effective in predicting a successful outcome than suppression of acute ectopy. Complete elimination of AF is presently obtained in 70% of patients, allowing interruption of arrhythmias and in use anticoagulants. It is anticipated that continued technologic improvements will improve and facilitate this technique of curative treatment of AF.

Atrial Fibrillation↗
PubMed2000

Differential pacing for distinguishing block from persistent conduction through an ablation line.

BACKGROUND: Because complete linear conduction block is necessary to minimize the recurrence of reentrant tachycardias such as typical atrial flutter, we investigated a simple technique to recognize a persistent gap or complete linear block. METHODS AND RESULTS: We prospectively evaluated cavotricuspid isthmus conduction in 50 patients (age 63+/-8 years, 43 men) after radiofrequency ablation. The distal and proximal bipoles of a quadripolar catheter placed close to the ablation line were successively stimulated during recording from the ablation line. We hypothesized that because the initial and terminal components of local potentials reflected activation at the ipsilateral and contralateral borders of the ablation lesion, a change to a more proximal pacing site without moving the catheter would prolong the stimulus to the initial component timing, whereas the response of the terminal component would depend on the presence of block or persistent conduction. A shortening or no change in timing of the terminal component would indicate block, whereas lengthening would indicate persistent gap conduction. The results were compared with previously described criteria for isthmus block. Ninety-two sites were assessed: 17 before and 75 after the achievement of complete isthmus block. The timing of the initial component was delayed by 19+/-9 ms, and the terminal component was advanced by 13+/-8 ms after block and delayed by 12+/-9 ms in case of persisting conduction. The sensitivity, specificity, and positive and negative predictive values for linear block were 100%, 75%, 94%, and 100%, respectively. CONCLUSIONS: An accurate assessment of isthmus block or persistent isthmus conduction is possible with this technique of differential pacing.

Aged↗
PubMed2000

Mapping and ablation of left atrial flutters.

BACKGROUND: Typical right atrial isthmus-dependent flutters have been described in detail, but very little is known about left atrial (LA) flutters. METHODS AND RESULTS: We performed conventional and 3D mapping of the LA for 22 patients with atypical flutters. Complete maps in 17 patients demonstrated macroreentrant circuits (n=15) with 1 to 3 loops rotating around the mitral annulus, the pulmonary veins, and a zone of block or a silent area. In 2 patients, a small reentry circuit with a zone of markedly slow conduction was identified. Linear ablation performed across the most accessible part of the circuit cured 16 patients (73%) with a follow-up of 15+/-7 months. CONCLUSIONS: LA reentrant tachycardias are related to individually varying circuits and are amenable to mapping guided radiofrequency ablation.

Adult↗
PubMed2000

Electrophysiological end point for catheter ablation of atrial fibrillation initiated from multiple pulmonary venous foci.

BACKGROUND: The end point for catheter ablation of pulmonary vein (PV) foci initiating atrial fibrillation (AF) has not been determined. METHODS AND RESULTS: Ninety patients underwent mapping during spontaneous or induced ectopy and/or AF initiation. Ostial PV ablation was performed by use of angiograms to precisely define targeted sites. Success defined by elimination of AF without drugs was correlated with the procedural end point of the abolition of distal PV potentials. A total of 197 arrhythmogenic PV foci (97%)-single in 31% and multiple in 69%-and 6 atrial foci were identified. A discrete radiofrequency (RF) application eliminated the PV potentials in 9 PV foci, whereas 2 foci from the same PV required RF applications at separate sites in 19 cases. In others, a wider region was targeted with progressive elimination of ectopy. In 49 patients, multiple sessions were necessary owing to recurrent or new ectopy. The clinical success rates were 93%, 73%, and 55% in patients with 1, 2, and > or =3 arrhythmogenic PV foci. Recovery of local PV potential and the inability to abolish it were significantly associated with AF recurrences (90% success rate with versus 55% without PV potential abolition). PV stenosis was noted acutely in 5 of 6 cases, remained unchanged at restudy, and was associated with RF power >45 W. CONCLUSIONS: Multiple PV foci are involved in initiation of AF, and elimination of PV muscle conduction is associated with clinical success.

Adult↗
PubMed2000

Prospective randomized comparison of irrigated-tip versus conventional-tip catheters for ablation of common flutter.

BACKGROUND: Radiofrequency (RF) ablation of common flutter requires the creation of a complete ablation line to produce bidirectional conduction block in the cavotricuspid isthmus. An irrigated-tip ablation catheter has been shown to be effective in patients in whom conventional ablation has failed. This randomized study compares the efficacy and safety of this catheter with those of a conventional catheter for de novo flutter ablation. METHODS AND RESULTS: Cavotricuspid ablation was performed with a conventional (n=26) or an irrigated-tip catheter (n=24). RF was applied for 60 minutes with a temperature-controlled mode: 65 degrees C to 70 degrees C up to 70 W with a conventional catheter or 50 degrees C up to 50 W (with a 17-mL/min saline flow rate) with the irrigated-tip catheter. The end point was the achievement of bidirectional isthmus block, and a crossover was performed after 21 unsuccessful applications. Procedural ablation parameters as well as number of applications, x-ray exposure, procedure duration, impedance rise, and clot formation were compared for each group. A coronary angiogram was performed before and after each ablation for the first 30 patients. Complete bidirectional isthmus block was achieved for all patients. Four patients crossed over from conventional to irrigated-tip catheters. The number of applications, procedure duration, and x-ray exposure were significantly higher with the conventional than with the irrigated-tip catheter: 13+/-10 versus 5+/-3 pulses, 53+/-41 versus 27+/-16 minutes, and 18+/-14 versus 9+/-6 minutes, respectively. No significant side effects occurred, and the coronary angiograms of the first 30 patients after ablation were unchanged. CONCLUSIONS: Irrigated-tip catheters were found to be more effective than and as safe as conventional catheters for flutter ablation, facilitating the rapid achievement of bidirectional isthmus block.

Aged↗
PubMed2000

Atrial fibrillation: role of arrhythmogenic foci.

UNLABELLED: Atrial fibrillation, the most common of all sustained cardiac arrhythmias can be cured by Surgical atriotomies or linear RF catheter ablation. We have investigated the role of focal RF ablation in paroxysmal atrial fibrillation. METHODS: sixteen patients with focal atrial fibrillation (extrasystoles, atrial tachycardia and atrial fibrillation due to the same focus firing irregularly at different rates) and 45 with common AF initiated by extrasystolic foci were included. The ablation site was determined on the basis of earliest bipolar activity relative to a stable atrial electrogram reference or to the P wave onset during atrial fibrillation initiation. RESULTS: All the patients with focal atrial fibrillation were treated with a mean of 5 +/- 4 RF applications delivered on a right atrial site (n = 4) or on a pulmonary venous site (n = 13), (one patient had 2 foci). Sixty nine foci (located in the pulmonary veins in 94%) were identified in the 45 patients with common atrial fibrillation initiated by extrasystoles. They were ablated with a mean of 4.5 +/- 2 RF applications. Using a mean follow up of 8 +/- 6 months, 28/45 (62%) were cured without antiarrhythmic drugs. CONCLUSION: Pulmonary veins play an important role in paroxysmal atrial fibrillation. They are the most frequent source of focal atrial fibrillation and of initiating foci amenable to RF ablation.

Adult↗