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Biomedical subjects

Pierre Jais

Publications and source records attributed to Pierre Jais.

15 recordsLinked to original sources
PubMed2006

Dynamic ventricular dyssynchrony: an exercise-echocardiography study.

OBJECTIVES: We sought to assess the effects of exercise on ventricular dyssynchrony in patients with normal and depressed left ventricular (LV) function. BACKGROUND: Asynchronous myocardial contraction adversely influences ventricular function and is associated with a poor prognosis in heart failure. Exercise-induced changes in ventricular dyssynchrony may be an important determinant of dynamic changes in cardiac output and mitral regurgitation. METHODS: A total of 65 consecutive heart failure patients and 50 matched healthy control patients underwent exercise echocardiography. Conventional and tissue Doppler parameters were measured before and during symptom-limited exercise. Left ventricular dyssynchrony was defined as the standard deviation of 12 LV segmental electromechanical delays. Analysis of the control group allowed delimitation of normal cutoff values. RESULTS: In patients with normal left ventricular function, exercise did not modify the extent of LV asynchrony. In contrast, in heart failure patients, LV dyssynchrony increased by at least 20% in 34%, remained stable in 37%, and decreased by at least 20% in 29%. Moreover, 26% of heart failure patients had either exercise induction or normalization of ventricular dyssynchrony. A significant association was found between exercise-induced changes in dyssynchrony and the presence of ischemic cardiomyopathy (p < 0.05). Rest-exercise differences in ventricular dyssynchrony were correlated with changes in cardiac output and mitral regurgitation (r = -0.63 and 0.56, respectively). CONCLUSIONS: In heart failure patients, exercise can alter the magnitude of ventricular dyssynchrony. Some patients have a response to exertion with induction of ventricular dyssynchrony, whereas others show normalization. Changes in ventricular dyssynchrony during exercise correlate with alterations in cardiac output and mitral regurgitation.

Aged↗
PubMed2006

Echocardiographic assessment during exercise of heart failure patients with cardiac resynchronization therapy.

This prospective echocardiographic study investigated the respective impacts of left ventricular (LV) pacing and simultaneous and sequential biventricular pacing (BVP) on ventricular dyssynchrony during exercise in 23 patients with compensated heart failure and ventricular conduction delays. During exercise, LV pacing and BVP significantly (p <0.05) improved mitral regurgitation and LV dyssynchrony compared with spontaneous activation. LV segmental electromechanical delays were significantly prolonged during LV pacing, leading to increased systolic time (p <0.05), decreased LV filling time (p <0.05), and decreased stroke volume (p <0.05) compared with BVP. After optimization of the interventricular delay with sequential BVP, additional benefit was obtained during exercise in terms of stroke volume and mitral regurgitation (p <0.05). The optimal interventricular delay was different at rest and during exercise in 57% of the patients. Changes from at rest to exercise in LV dyssynchrony were correlated with changes in stroke volume (r = -0.61, p <0.01) and changes in mitral regurgitation (r = 0.60, p <0.01).

Cardiac Pacing, Artificial↗
PubMed2006

An approach to catheter ablation of cavotricuspid isthmus dependent atrial flutter.

Much of our understanding of the mechanisms of macro re-entrant atrial tachycardia comes from study of cavotricuspid isthmus (CTI) dependent atrial flutter. In the majority of cases, the diagnosis can be made from simple analysis of the surface ECG. Endocardial mapping during tachycardia allows confirmation of the macro re-entrant circuit within the right atrium while, at the same time, permitting curative catheter ablation targeting the critical isthmus of tissue located between the tricuspid annulus and the inferior vena cava. The procedure is short, safe and by demonstration of an electrophysiological endpoint - bidirectional conduction block across the CTI - is associated with an excellent outcome following ablation. It is now fair to say that catheter ablation should be considered as a first line therapy for patients with documented CTI-dependent atrial flutter.

Journal Article↗
PubMed2005

[Catheter ablation for atrial fibrillation].

Atrial fibrillation, the most common cardiac arrhythmia, is frequently disabling and drug-resistant, and can be associated with major complications such as thromboembolic events. Non drug approaches, including surgery and catheter-based ablation, are used to treat the most severely symptomatic patients. These new treatment strategies have drastically improved our knowledge of the pathophysiology of this arrhythmia and, importantly, have shown that atrial fibrillation is curable. Since 1994, two main approaches have been used to modify the substrate responsible for AF maintenance, namely the creation of linear lesions, and ablation of triggers located within the pulmonary veins (about 90% of cases). Most teams worldwide now use approaches centered on PV isolation, which, although imperfect, are sufficiently effective to be offered routinely to selected patients in experienced centers. The importance of PVs in the initiation of AF has been clearly demonstrated, and there is also evidence of a role in AF maintenance. However, the existence of non venous foci or a prominent substrate for AF maintenance limits the success rate to about 70%. We are now using a combination of PV isolation and a linear lesion delivered to the mitral isthmus, from the mitral annulus to the ostium of the left inferior pulmonary vein. This more complex procedure carries a significantly higher success rate, about 82% of patients being cured and drug-free. The main problem is to identify patients requiring mitral isthmus ablation in addition to PV isolation. At present, AF ablation is restricted to symptomatic patients in whom at least two antiarrhythmic drugs have failed, but future technical improvements are likely to broaden the indications of ablation therapy for AF.

Atrial Fibrillation↗
PubMed2004

"Dormant" pulmonary vein conduction revealed by adenosine after ostial radiofrequency catheter ablation.

INTRODUCTION: The endogenous nucleoside adenosine is an important intermediate in cellular metabolism, a regulator of function in many organ systems, and a pharmacologic agent with potent electrophysiologic effects. We studied the effects of adenosine on the activation of the pulmonary veins (PVs) after successful ostial isolation in patients with atrial fibrillation (AF). METHODS AND RESULTS: Twenty-nine patients (21 male; mean age 54 +/- 10 years) with refractory highly symptomatic persistent (n = 9) or paroxysmal (n = 20) AF were included in the study. PV isolation was performed using radiofrequency catheter ablation guided by a multipolar basket catheter (Constellation, Boston Scientific). After successful PV isolation, we studied the effects of intravenous adenosine (12-18 mg) on activation of the upper PVs. A total of 83 PVs were successfully isolated. After adenosine, PV activity was recorded in 10 (34%) of 29 left upper PVs studied and in 3 (13%) of 24 right upper PVs, coupled to atrial activity for 20 +/- 7 seconds (adenosine positive). In 8 (62%) of 13 cases, PV potentials were recorded in the distal electrodes of the basket catheter only. Dissociated PV rhythms (N = 8) present after PV isolation disappeared after adenosine for 18 +/- 7 seconds, even if reconduction was missing. In 14 patients (48%), a second EP study was performed for recurrence of AF. Adenosine-positive PVs had a nonsignificant higher rate of recovery of conduction than adenosine-negative veins (71% vs 35%, P = 0.095). CONCLUSION: Adenosine induces transient conduction in 25% of PVs following successful isolation. Further studies are necessary to determine the physiologic or pathophysiologic role of adenosine-induced reconduction in human hearts or other organ systems.

Adenosine↗
PubMed2004

Fever as a precipitant of idiopathic ventricular fibrillation in patients with normal hearts.

INTRODUCTION: Ventricular fibrillation (VF) is the main mechanism of sudden cardiac death. The clinical precipitants of sudden cardiac death due to idiopathic VF are poorly characterized. Emerging evidence implicates triggers originating predominantly from the distal Purkinje arborization and the right ventricular outflow tract. METHODS AND RESULTS: We report three patients without structural heart disease or repolarization abnormalities in whom a febrile illness was the only concurrent disease associated with unexpected sudden cardiac death due to VF storm. An automated defibrillator was implanted in all three patients. In one patient with persistent recurrent VF episodes, mapping demonstrated the origin of these triggers was from the Purkinje arborization of the anterior wall of the right ventricle. Ablation at a site of earliest activation during ectopy, where pace mapping was concordant and Purkinje potential preceded the onset of ventriculogram, resulted in suppression of all arrhythmias. After follow-up of 22, 9, and 18 months in the three patients, no ventricular arrhythmias have been recorded. CONCLUSION: We present a series of patients in whom an apparently benign febrile illness was associated with malignant ventricular arrhythmias in the absence of cardiac disease or other factors known to precipitate sudden cardiac death. Physicians should be aware of this possible phenomenon in cases of febrile illness associated with syncope.

Aged↗
PubMed2003

Radiation exposure during radiofrequency catheter ablation for atrial fibrillation.

RF catheter ablation of paroxysmal atrial fibrillation (PAF) is associated with prolonged fluoroscopy. The procedural duration and fluoroscopic exposure to patients and medical staff were recorded and compared among 43 ablation procedures for PAF, 20 for common atrial flutter, and 16 for accessory pathways. Patient radiation exposure was measured by dosimeters placed over the xyphoid, while that of physicians and nurses was measured by dosimeters placed outside and inside the lead apron. The mean fluoroscopy time was 57 +/- 30 minutes for PAF, 20 +/- 10 minutes for common flutter, and 22 +/- 21 minutes for accessory pathway ablation. The patient median radiation exposure was 1110 microSv for PAF, compared with 500 microSv for common flutter and 560 microSv for accessory pathway ablation (P < 0.01). The median radiation exposure to physician and nurse inside the lead apron were, respectively, 2 microSv and 3 microSv for PAF, 1 microSv and 2 microSv for common flutter, and < 0.5 microSv and 3 microSv for accessory pathway ablations. RF catheter ablation for PAF was associated with prolonged fluoroscopy times and a twofold higher radiation exposure to the patient and physician compared with other ablation procedures. Assuming 300 procedures/year, radiation exposure to the medical staff was below the upper recommended annual dose limit.

Atrial Fibrillation↗
PubMed2003

Nonpulmonary vein foci: do they exist?

Though the majority of foci triggering atrial fibrillation (AF) have been mapped to the pulmonary veins (PV), recurrence of paroxysmal AF after isolation of all four pulmonary veins indicates the presence of other foci. In a series of 160 consecutive patients who underwent PV ablation, endocardial mapping of AF and ectopy recurring after PV isolation was performed. Thirty-six patients (24%) had a total of 85 non-PV foci; 39 were mapped to the ostia of ablated PVs, 30 to the posterior left atrium (LA), 5 to other parts of the LA, 5 to the right atrium (RA), 4 to the coronary sinus (CS), and 3 to the superior vena cava (SVC) (including one persistent left SVC). Mapping was confirmed by successful ablation. At least 16 foci could not be localized and after a follow-up of 8 +/- 6 months, 68% of patients were free of AF without any antiarrhythmic treatment. The occurrence of non-PV foci correlated with recurrence of AF, perhaps as a correlate of insufficient ostial ablation. These data reinforce the requirement for more proximal disconnection of the PVs by performing ablation within the LA. In patients with non-PV foci that are difficult to map conventionally, the use of surface ECG data, or multielectrode contact or noncontact mapping arrays, or substrate modifying/excluding ablation may be helpful in ablating these foci and therefore eliminating AF.

Atrial Fibrillation↗
PubMed2003

Safety and efficacy of cryoablation of accessory pathways adjacent to the normal conduction system.

UNLABELLED: Cryoablation of Septal Accessory Pathways. INTRODUCTION: Catheter ablation has become a routine treatment for patients with Wolff-Parkinson-White syndrome because of its low risk and high efficacy; however, radiofrequency ablation in the septum close to the AV node or His bundle still carries a definite risk for AV block. Cryoenergy catheter ablation has recently become available. This technique has specific features, such as the ability to create reversible loss of function to predict the effects of ablation (ice mapping) and the adherence of the catheter tip to the endocardium with freezing, which avoids the risk for dislodgment. Both of these characteristics may minimize the risk of complications. The aim of this study was to analyze the effectiveness and safety of catheter cryoablation in 20 patients with para-Hisian or midseptal accessory pathways (AP). METHODS AND RESULTS: Eleven patients with para-Hisian and 9 patients with midseptal AP underwent catheter cryoablation. Ice mapping at -30 degrees C was performed to ascertain the disappearance of AP conduction and the absence of impairment of AV nodal conduction. If the expected result was obtained, cryoablation was performed by lowering the temperature to -75 degrees C for 4 minutes in order to create a permanent lesion. Cryoablation was successful in all patients using a mean of 1.2 +/- 0.4 applications. Recurrences occurred in 4 patients (20%) who underwent a second successful cryoablation session. No complications were observed. CONCLUSION: Cryoablation appears to be a safe and effective technique for ablation of APs close to the AV node or His bundle because of the ability to predict the acute effects of ablation with ice mapping before creation of an irreversible lesion.

Arrhythmias, Cardiac↗
PubMed2002

QRST subtraction combined with a pacemap catalogue for the prediction of ectopy source by surface electrocardiogram in patients with paroxysmal atrial fibrillation.

OBJECTIVES: This study evaluated the use of ectopic P-wave morphology to localize pulmonary vein (PV) and non-PV sources of atrial ectopics in patients with paroxysmal atrial fibrillation (PAF). BACKGROUND: The vectorial information embodied in the morphology of ectopic P waves is concealed by overlying T waves. METHODS: The P-wave morphology of 56 ectopics was prospectively analyzed in 44 patients with PAF (age, 52 +/- 12 years; 36 male) by subtracting the adjacent QRST from the QRST-ectopic P-wave complex using custom-designed software. Subtraction fidelity was validated in 15 other patients (55 +/- 19 years, 11 male) by comparing drive beats with simulated ectopics (S2 from the same site) unmasked by subtracting overlying QRST. An algorithm combined with PV pacemaps was used to predict PV sources. Subtracted ectopic P-wave morphologies after PV disconnection were compared with PV and non-PV site pacemaps. Localization was confirmed by mapping and successful ablation. RESULTS: A > or =10-lead electrocardiogram (ECG) match was observed in 92% of 644 simulated ectopics (coupling intervals: 190 to 520 ms). In PAF patients, 37 spontaneous ectopics originated from the PV, while 19 were noted after PV disconnection. Using the P-wave algorithm alone, correct prediction of PV origin was achieved in 30/37 ectopics (81%). Combination with PV pacemaps allowed correct prediction in 34/37 (92%). After PV disconnection, ECG localization predicted successful ablation sites in 16/19 (84%). CONCLUSIONS: Comparison of subtracted ectopic P waves with a pacemap catalogue provides a simple and accurate 12-lead ECG-based method for localization, which can facilitate ablation of arrhythmia triggers irrespective of origin from the PV or elsewhere.

Adult↗
PubMed2002

Left atrial appendage activity masquerading as pulmonary vein potentials.

BACKGROUND: Despite extensive proximal ablation, all potentials frequently cannot be eliminated from the left pulmonary veins (PV). Methods and Results- PV electrograms were analyzed during sinus rhythm, coronary sinus, and left atrial appendage (LAA) pacing, and PV and LAA angiography performed. During pacing, an initial low-amplitude slow potential was recorded on the anterior aspect of the left superior PV and anticipated with shortest activation time by LAA pacing. Its timing coincided with posterior LAA activation, shown to be immediately adjacent to the left superior PV by angiography. In the left inferior PV, the first potential was smaller and less sharp, coinciding with adjacent low LA activation. Angiographically, the LAA was at least 15 mm from the left inferior PV. The second sharper potential in both left PVs was eliminated by proximal ablation. CONCLUSION: Far field LAA activity consistently adds to PV myocardial electrograms in the left superior PV whereas lower, less sharp extravenous potentials in the left inferior PV originate from the inferior LA. They can be identified by LAA and coronary sinus pacing.

Action Potentials↗
PubMed2002

Successful ablation of Hisian ectopy identified by a reversed His bundle activation sequence.

Junctional ectopy or tachycardia have been mapped and ablated in the atrioventricular node or its posterior extensions. There is no report of Hisian ectopy convincingly demonstrated and then successfully treated by ablation. A 39-year-old man presented with a 9-year history of recurrent supraventricular ectopy refractory to medical treatment. Intracardiac mapping revealed that the ectopy originated from the His bundle, which was indicated by a reversed His bundle activation sequence during ectopy compared to that during sinus rhythm, while the right bundle branch potential was anterogradely activated. Low power RF energy delivered to the site of earliest activation completely abolished the ectopic activity without modification of Hisian or atrioventricular conduction. After a 12-month followup, the patient remains free of recurrence.

Adult↗