Daniel Scherr

Université Victor Segalen Bordeaux 2, Burdeos, Aquitaine, France

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Publications (55)225.71 Total impact

  • Daniel Scherr, Pierre Jais
    Nature Reviews Cardiology 10/2014; · 10.40 Impact Factor
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    ABSTRACT: -Rapid pulmonary vein (PV) activity has been shown to maintain paroxysmal AF. We evaluated in persistent AF (PsAF) the cycle length (CL) gradient between PVs and the left atrium (LA) in an attempt to identify the subset of patients where PVs play an important role. -97 consecutive patients undergoing first ablation for PsAF were studied. For each PV, the CL of the fastest activation was assessed over 1 min (PVfast) using Lasso recordings. The PV to LA CL gradient was quantified by the ratio of PVfast to LA appendage (LAA) AFCL. Stepwise ablation terminated AF in 73 patients (75%). In the AF Termination group, the PVfast CL was much shorter than the LAA CL resulting in lower PVfast/LAA ratios compared to the Non-termination group (71±10% vs 92±7%, p<0.001). Within the Termination group, PVfast/LAA ratios were notably lower if AF terminated after PVI or limited adjunctive substrate ablation compared to patients who required moderate or extensive ablation (63±6% vs 75±8%, p<0.001). PVfast/LAA ratio <69% predicted AF termination after PVI or limited substrate ablation with 74% positive predictive value and 95% negative predictive value. After a mean follow-up of 29±17 months, freedom from arrhythmia recurrence off-antiarrhythmic drugs was achieved in most patients with PVfast/LAA ratios <69% as opposed to the remaining population (80% vs 43%, p<0.001). -The PV to LA CL gradient may identify the subset of patients in whom PsAF is likely to terminate after PVI or limited substrate ablation and better long-term outcomes are achieved.
    Circulation Arrhythmia and Electrophysiology 05/2014; · 5.95 Impact Factor
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    ABSTRACT: IntroductionThe atrial outcome after extensive ablation is unknown. We sought to quantify atrial structure and function years after successful ablation for persistent atrial fibrillation (PsAF).Methods and ResultsWe studied after 80±15 months 26 patients (54±8 yrs, 1 women) with PsAF successfully treated by ablation (2.2±0.7 stepwise approach procedures, cumulative RF duration 126±37 min). At follow-up atrial scar burden and atrial outflows were quantified using delayed-enhanced and velocity encoded MRI, respectively. Cine imaging was used to quantify atrial conduit function (CF), active emptying fraction (AEF), expansion index (EI), and the inter-appendage mechanical activation delay. Patients underwent exercise testing at baseline and follow-up. LA and RA scar extent were 29±6 and 4.3±2.8%, respectively. LA and RA AEF were 10.0±5.3 and 30±8%. Mean inter-appendage delay was 83±47ms [42–217]. Complete LAA isolation was found in 3 patients. A wave was absent in 9/26 patients. LA scar extent related to the number of procedures (R = 0.58, P = 0.002) and total RF duration (R = 0.56, P = 0.003). Among follow-up characteristics, LA scar extent related to LAAEF (R = -0.73, P<0.0001), LAEI (R = -0.64, P = 0.0003), A wave peak (R = -0.72, P<0.0001), and inter-appendage mechanical delay (R = 0.47, P = 0.02). At multivariable analysis, LA scar extent was independently related to LAAEF and LAEI. LA AEF and LA scar extent correlated with exercise capacity at follow-up (R = 0.44, P = 0.02, and R = -0.40; P = 0.04).ConclusionLA contractility and compliance are markedly impaired years after successful PsAF ablation. LA dysfunction is closely related to scar burden.This article is protected by copyright. All rights reserved.
    Journal of Cardiovascular Electrophysiology 05/2014; · 3.48 Impact Factor
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    ABSTRACT: Objectives We evaluated the feasibility and safety of epicardial substrate elimination using endocardial radiofrequency (RF) delivery in patients with scar-related ventricular tachycardia (VT). Background Epicardial RF delivery is limited by fat or associated with bleeding, extra-cardiac damages, coronary vessels and phrenic nerve injury. Alternative ablation approaches may be desirable. Methods Forty-six patients (18 ischemic cardiomyopathy [ICM], 13 non-ischemic dilated cardiomyopathy [NICM], 15 arrhythmogenic right ventricular cardiomyopathy [ARVC]) with sustained VT underwent combined endo- and epicardial mapping. All patients received endocardial ablation targeting local abnormal ventricular activities in the endocardium (Endo-LAVA) and epicardium (Epi-LAVA), followed by epicardial ablation if needed. Results From a total of 173 endocardial ablations targeting Epi-LAVA at the facing site, 48 (28%) applications (ICM: 20/71 [28%], NICM: 3/39 [8%], ARVC: 25/63 [40%]) successfully eliminated the Epi-LAVA. Presence of Endo-LAVA, most delayed and low bipolar amplitude of Epi-LAVA, low unipolar amplitude in the facing endocardium, and Epi-LAVA within a wall thinning area at CT scan were associated with successful ablation. Endocardial ablation could abolish all Epi-LAVA in 4 ICM and 2 ARVC patients, whereas all patients with NICM required epicardial ablation. Endocardial ablation was able to eliminate Epi-LAVA at least partially in 15 (83%) ICM, 2 (13%) NICM, and 11 (73%) ARVC patients, contributing to a potential reduction in epicardial RF applications. Pericardial bleeding occurred in 4 patients with epicardial ablation. Conclusions Elimination of Epi-LAVA using endocardial RF delivery is feasible and may be used first to reduce the risk of epicardial ablation.
    Journal of the American College of Cardiology 01/2014; · 14.09 Impact Factor
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    ABSTRACT: Local abnormal ventricular activities (LAVA) in patients with scar-related ventricular tachycardia (VT) may appear at any time during or after the far-field electrogram. While they may be separated from the far-field signal by an isoelectric line and extend beyond the end of surface QRS, they may also appear fused or buried within the QRS. To characterize LAVA in post-infarction VT patients with respect to their anatomical locations. Thirty-one patients with post-infarction VT underwent mapping/ablation during sinus rhythm with 3-dimensional electroanatomic mapping system. From a total of 18,270 electrograms reviewed in all study subjects, 1,104 LAVA (endocardium: 839, epicardium: 265) were identified and analyzed. The interval from the onset of QRS-complex to the ventricular electrogram (EGM-onset) on the endocardium was significantly shorter than the epicardium (p<0.001). EGM-onset was shortest in the septal endocardium and longest in the inferior and lateral epicardium. There was a significant positive correlation between EGM-onset and LAVA lateness as estimated by the interval from surface QRS-onset to LAVA (r=0.52, p<0.001). LAVA were more frequently detected after the QRS-complex in the epicardium (241/265 [91%]) than in the endocardium (551/839 [66%])(p<0.001). Only 43% of endocardial septal LAVA were detected after the QRS-complex. Lateness of LAVA is affected to a large extent by their locations. The chance of detecting late LAVA increases when the electrogram onset is later. Substrate-based approach targeting delayed signals relative to the QRS-complex may miss critical arrhythmogenic substrate, particularly in the septum and other early-to-activate regions.
    Heart rhythm: the official journal of the Heart Rhythm Society 08/2013; · 4.56 Impact Factor
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    ABSTRACT: OBJECTIVES: We prospectively evaluated the role of a novel three-dimensional(3D), non-invasive, beat by beat mapping system, Electrocardiographic Mapping(ECM), in facilitating the diagnosis of atrial tachycardias(AT). BACKGROUND: Conventional 12-lead electrocardiogram, a widely used non-invasive tool in clinical arrhythmia practice, has diagnostic limitations. METHODS: Various ATs (de novo and post atrial fibrillation(AF) ablation) were mapped using ECM followed by standard of care electrophysiological(EP) mapping and ablation in 52 patients. The ECM consisted of recording body surface electrograms from a 252-electrode-vest placed on the torso combined with CT-scan-based biatrial anatomy (CardioInsight Inc., USA). We evaluated the feasibility of this system in defining 1) the mechanism of AT: macroreentrant (perimitral, cavotricuspid isthmus-dependent and roof-dependent circuits) vs. centrifugal (focal-source) activation and 2) the location of arrhythmia in centrifugal ATs. The accuracy of the non-invasive diagnosis and detection of ablation targets was evaluated vis-a-vis subsequent invasive mapping and successful ablation. RESULTS: Comparison between ECM and EP diagnosis could be accomplished in 48 patients (48 ATs) but was not possible in 4 patients where the AT mechanism changed to another AT (1), AF (1) or sinus rhythm (2) during the EP procedure. ECM correctly diagnosed AT mechanisms in 44/48 (92%) ATs; macroreentry: 23/27, focal-onset with centrifugal activation: 21/21. The region of interest for focal ATs perfectly matched in 21/21 (100%) ATs. The 2:1 ventricular conduction and low-amplitude P waves challenged the diagnosis of 4/27 macroreentrant (perimitral) ATs that can be overcome by injecting atrioventricular node blockers and signal averaging, respectively. CONCLUSIONS: This prospective multicenter series shows high success rate of ECM in accurately diagnosing the mechanism of AT and the location of focal arrhythmia. Intraprocedural use of the system and its application to AF mapping is underway.
    Journal of the American College of Cardiology 05/2013; · 14.09 Impact Factor
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    ABSTRACT: OBJECTIVES: We evaluated the relationship between fibrosis imaged by delayed enhancement (DE) MRI and atrial electrograms in persistent atrial fibrillation. BACKGROUND: Atrial fractionated electrograms (CFAE) are strongly related to slow anisotropic conduction. Their relationship to atrial fibrosis has not yet been investigated. METHODS: Atrial high resolution MRI of 18 patients with persistent AF (11 long-persistent) was registered with the mapping geometry (NavX). DE areas were categorized as dense or patchy, depending on their DE content. Left atrial electrograms (Egm) during AF were acquired using a high-density 20-pole catheter (514+/-77 sites/map). Fractionation, organisation/regularity, local mean cycle length, and voltage were analysed with reference to DE. RESULTS: Patients with long-persistent vs persistent AF had larger LA surface area (134+/-38cm2 vs 98+/-9cm2, p=0.02), higher amount of atrial DE (70+/-16cm2 vs 49+/-10cm2, p=0.01), more CFAE extent (54+/-16cm2 vs 28+/-15cm2, p=0.02) and a shorter baseline AF cycle length (147+/-10ms vs 182+/-14ms, p=0.01). Continuous CFAE (CFEmean<80ms) occupied 38+/-19% of total LA surface area. Dense DE was detected at the left posterior LA. In contrast, the right posterior LA contained predominantly patchy DE. Most CFAE (48+/-14%) occurred at non-DE LA sites, followed by 41+/-12% CFAE at patchy DE and 11+/-6% at dense DE regions (p=0.005 and p=0.008 respectively). 19+/-6% CFAE sites occurred at border zones of dense DE. Egms were less fractionated, with longer cycle length and lower voltage at dense DE vs non-DE regions: CFEmean: 97ms vs 76ms, p<0.0001; local cycle length: 153ms vs 143ms, p<0.0001; mean voltage: 0.63mV vs 0.86mV, p<0.0001. CONCLUSIONS: Atrial fibrosis as defined by DE MRI is associated with slower and more organized electrical activity but with lower voltage than healthy atrial areas. Ninety percent of continuous CFAE sites occur at non-DE and patchy DE left atrial sites. These findings are of importance for the choice of ablation strategy in persistent AF.
    Journal of the American College of Cardiology 05/2013; · 14.09 Impact Factor
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    ABSTRACT: BACKGROUND: -Atrial tachycardias (AT) during or after ablation of AF frequently pose a diagnostic challenge. We hypothesized that both the patterns and timing of coronary sinus (CS) activation could facilitate AT mapping. METHODS AND RESULTS: -140 consecutive post-persistent AF ablation patients with sustained AT were investigated by conventional mapping. CS activation pattern was defined as "chevron" or "reverse chevron" when the activations recorded on both the proximal and distal CS dipoles were latest or earliest, respectively. The local activation of mid-CS was timed with reference to Ppeak-Ppeak (P-P) interval in lead V1. A ratio, mid-CS activation time to AT cycle length, was computed. Out of 223 diagnosed ATs, 124 were macroreentrant (56%) and 99 were centrifugal (44%). When CS activation was "chevron"/"reverse chevron" (n = 44, 20%), macroreentries were mostly roof-dependent. With reference to P-P interval, mid-CS activation timing showed specific consistency for peritricuspid and perimitral AT. Proximal to distal CS activation pattern and mid-CS activation at 50-70% of the P-P interval (n = 30, 13%) diagnosed peritricuspid AT with 81% sensitivity and 89% specificity. Distal to proximal CS activation and mid-CS activation at 10-40% of the P-P interval (n = 44, 20%) diagnosed perimitral AT with 88% sensitivity and 75% specificity. CONCLUSIONS: -The analysis of the patterns and timing of CS activation provides a rapid stratification of most likely macroreentrant ATs and points towards the likely origin of centrifugal ATs. It can be included in a stepwise diagnostic approach to rapidly select the most critical mapping maneuvers.
    Circulation Arrhythmia and Electrophysiology 04/2013; · 5.95 Impact Factor
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    ABSTRACT: BACKGROUND: Patients commonly present for atrial fibrillation (AF) ablation while taking antiarrhythmic (AA) medications. It is unknown if AA use at the time of ablation affects procedural outcome. This study compares the AF ablation outcomes of patients who underwent ablation while on AA medications to those who were not on AA medications. METHODS AND RESULTS: A total of 180 consecutive patients who underwent their first catheter ablation of AF were identified from the Johns Hopkins Hospital AF registry and divided into 2 cohorts: those On AA at the time of ablation (127 patients, mean follow-up 24.6 months) and those Off AA at the time of ablation (53 patients, mean follow-up 20.3 months). Follow-up was performed to identify recurrent AF. There was no statistically significant difference in the percentage of patients without a recurrence of symptomatic AF (single procedure success rate) in the On and Off AA groups at 6 months postablation (53.5% vs 50.1%, P = 0.75), or by the end of follow-up (37.8% vs 41.5%, P = 0.64). For those patients who had symptomatic AF recurrence, the average time to recurrence was 6.2 ± 9.0 months in the On AA group and 4.2 ± 7.2 months in the Off AA group (P = 0.27). CONCLUSIONS: There was no statistically significant difference in the rate of symptomatic AF recurrence between the On AA and Off AA groups in this study. The use of AA medications at the time of ablation does not appear to affect procedural outcomes in this population.
    Journal of Cardiovascular Electrophysiology 03/2013; · 3.48 Impact Factor
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    ABSTRACT: BACKGROUND: -A majority of patients undergoing ablation of ventricular tachycardia (VT) have implanted devices precluding substrate imaging with delayed-enhancement magnetic resonance imaging (MRI). Contrast-enhanced multi-detector computed tomography (MDCT) can depict myocardial wall thickness with submillimetric resolution. We evaluated the relationship between regional myocardial wall thinning (WT) imaged by MDCT and arrhythmogenic substrate in post-infarction VT. METHODS AND RESULTS: -We studied 13 consecutive post-infarction patients undergoing MDCT before ablation. MDCT data was integrated with high-density 3D-electroanatomic maps acquired during sinus rhythm (endocardium: 509±291 points/map, epicardium: 716±323 points/map). Low-voltage areas (<1.5 mV) and local abnormal ventricular activities (LAVA) during sinus rhythm were assessed with regard to the WT. A significant correlation was found between the areas of WT<5mm and endocardial low-voltage (correlation-R=0.82, p=0.001), but no such correlation was found in the epicardium. The WT<5mm area was smaller than the endocardial low-voltage area (54cm2 [Q1-Q3: 46-92] versus 71cm2 [Q1-Q3: 59-124], p=0.001). Among a total of 13,060 electrograms reviewed in the whole study population, 538 LAVA were detected and analyzed. LAVA were located within the WT<5mm (469/538 [87%]) or at its border (100% within 23mm). Very late LAVA (>100ms after QRS complex) were almost exclusively detected within the thinnest area (93% in the WT<3mm). CONCLUSIONS: -Regional myocardial WT correlates to low-voltage regions and distribution of LAVA critical for the generation and maintenance of post-infarction VT. The integration of MDCT WT with 3D-electroanatomic maps can help focus mapping and ablation on the culprit regions, even when MRI is precluded by the presence of implanted devices.
    Circulation Arrhythmia and Electrophysiology 03/2013; · 5.95 Impact Factor
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    ABSTRACT: INTRODUCTION: Entrainment criteria for the diagnosis of reentrant atrial tachycardia can be difficult to apply and cannot detect double-loop reentry. We sought to develop and clinically test a new criterion for the diagnosis of single- and double-loop reentry. METHODS AND RESULTS: (1) Proposed criterion: after sequential overdrive pacing at 2 different locations and assessing the first ensuing beats of tachycardia, the difference in activation time recorded between 2 appropriate stationary positions changes by 1 or 2 tachycardia cycle lengths; a change of 2 tachycardia cycle lengths usually indicates double-loop reentry rather than only a single-loop. (2) Clinical testing: multiple overdrive pacing maneuvers were undertaken and analyzed in 5 patients with common flutter (single-loop reentry). In total, 23 pairs of overdrive pacing maneuvers were performed using electrodes in the coronary sinus and a distribution of positions in the right atrium. In 22/23 pairs of maneuvers, the change in Activation Difference was within 2.6 ± 12.4 milliseconds of the tachycardia cycle length, confirming single loop reentry. For double-loop reentry, the literature was reviewed and 3 cases of double-loop reentry were identified with sufficient data. In all of these cases, double-loop reentry was detected and also the zone containing the common isthmus was identified. CONCLUSION: The proposed criterion can diagnose single- and double-loop reentry atrial tachycardia using intracardiac recordings from any pair of well separated positions. The criterion does not require precise electrode placement or extensive activation mapping.
    Journal of Cardiovascular Electrophysiology 12/2012; · 3.48 Impact Factor
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    ABSTRACT: MDCT/MRI Fusion for the Guidance of VT Ablation. Background: Delayed enhancement (DE) MRI can assess the fibrotic substrate of scar-related VT. MDCT has the advantage of inframillimetric spatial resolution and better 3D reconstructions. We sought to evaluate the feasibility and usefulness of integrating merged MDCT/MRI data in 3D-mapping systems for structure-function assessment and multimodal guidance of VT mapping and ablation. Methods: Nine patients, including 3 ischemic cardiomyopathy (ICM), 3 nonischemic cardiomyopathy (NICM), 2 myocarditis, and 1 redo procedure for idiopathic VT, underwent MRI and MDCT before VT ablation. Merged MRI/MDCT data were integrated in 3D-mapping systems and registered to high-density endocardial and epicardial maps. Low-voltage areas (<1.5 mV) and local abnormal ventricular activities (LAVA) during sinus rhythm were correlated to DE at MRI, and wall-thinning (WT) at MDCT. Results: Endocardium and epicardium were mapped with 391 ± 388 and 1098 ± 734 points per map, respectively. Registration of MDCT allowed visualization of coronary arteries during epicardial mapping/ablation. In the idiopathic patient, integration of MRI data identified previously ablated regions. In ICM patients, both DE at MRI and WT at MDCT matched areas of low voltage (overlap 94 ± 6% and 79 ± 5%, respectively). In NICM patients, wall-thinning areas matched areas of low voltage (overlap 63 ± 21%). In patients with myocarditis, subepicardial DE matched areas of epicardial low voltage (overlap 92 ± 12%). A total number of 266 LAVA sites were found in 7/9 patients. All LAVA sites were associated to structural substrate at imaging (90% inside, 100% within 18 mm). Conclusion: The integration of merged MDCT and DEMRI data is feasible and allows combining substrate assessment with high-spatial resolution to better define structure-function relationship in scar-related VT. (J Cardiovasc Electrophysiol, Vol. pp. 1-8).
    Journal of Cardiovascular Electrophysiology 11/2012; · 3.48 Impact Factor
  • Cardiac electrophysiology clinics 09/2012; 4(3):335–342.
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    ABSTRACT: Background- To identify and understand clinically encountered pitfalls in the assessment of transmitral conduction block using differential coronary sinus and left atrial appendage pacing techniques in patients with left mitral isthmus linear ablation. Methods and Results- All the available assessments of mitral isthmus block were thoroughly reviewed in 271 mitral isthmus ablation procedures undertaken among 236 patients from October 2008 to April 2011. Bidirectional block was established in 186 of 271 (69%) procedures. Careful evaluation of electrograms recorded on the multipolar coronary sinus and ablation catheters was undertaken to identify and understand the characteristics of pitfall, if any. Pitfall was encountered in 55 of 271 (20%) procedures among 51 patients and categorized into 6 types (types 1, 3, 4, and 5 led to spurious diagnosis of block; types 2 and 6 led to erroneous diagnosis of absence of block). There were 14, 10, 17, 2, 15, and 3 (total=61) cases of pitfall types 1 through 6, respectively. Operator recognized 42 of 61 (69%) pitfalls intraprocedurally. Recognition of types 1 and 5 was difficult because of indiscernible electrograms at usual amplifier settings or presence of slow conduction mimicking block. Conclusions- Every fifth assessment of bidirectional block across mitral isthmus linear lesion using differential coronary sinus and left atrial appendage pacing techniques encounters a pitfall, which can lead to erroneous clinical diagnosis of block or absence of block. Recognition of pitfall during the procedure is feasible and necessitates careful distinction of far-field left atrium from the local coronary sinus electrograms besides appropriate adjustments in catheter position and pacing outputs.
    Circulation Arrhythmia and Electrophysiology 08/2012; 5(5):957-67. · 5.95 Impact Factor
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    ABSTRACT: Atrial fibrillation (AF) ablation has evolved to the treatment of choice for patients with drug-resistant and symptomatic AF. Pulmonary vein isolation at the ostial or antral level usually is sufficient for treatment of true paroxysmal AF. For persistent AF ablation, drivers and perpetuators outside of the pulmonary veins are responsible for AF maintenance and have to be targeted to achieve satisfying arrhythmia-free success rate. Both complex fractionated atrial electrogram (CFAE) ablation and linear ablation are added to pulmonary vein isolation for persistent AF ablation. Nevertheless, ablation failure and necessity of repeat ablations are still frequent, especially after persistent AF ablation. Pulmonary vein reconduction is the main reason for arrhythmia recurrence after paroxysmal and to a lesser extent after persistent AF ablation. Failure of persistent AF ablation mostly is a consequence of inadequate trigger ablation, substrate modification or incompletely ablated or reconducting linear lesions. In this review we will discuss these points responsible for AF recurrence after ablation and review current possibilities on how to overcome these limitations.
    Current Cardiology Reviews 08/2012;
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    ABSTRACT: BACKGROUND: Inferolateral early repolarization (ER) and Brugada syndrome manifest with J waves. Isoproterenol suppresses recurrent ventricular arrhythmias while reducing J waves in both disorders. OBJECTIVE: To characterize the effect of isoproterenol on J waves. METHODS: We analyzed the impact of isoproterenol on J waves in 20 patients with Brugada-type electrocardiogram (Br group) and 38 patients with ER (ER group). RESULTS: In the ER group, J waves were present in inferior leads in 32 patients (84%) and in lateral leads in 23 patients (61%). Isoproterenol increased the heart rate by 75 beats/min in the ER group and by 71 beats/min in the Br group (P = .20). The incidences of persistent (≤0.05-mV decrease), decreased, and normalized J waves (residual J wave ≤0.05 mV) were 20%, 80%, and 0% for Br group patients and 29%, 8%, and 63% for ER group patients, respectively (P <.001). Within the ER group, inferior J waves persisted in 34% of the cases, decreased in 9%, and normalized in 56% whereas lateral J waves always normalized (P <.001). Baseline QRS width was broader in ER group patients with persistent J waves (90 ms vs 80 ms; P = .003) and was unchanged with isoproterenol (90 ms; P = .19), whereas it decreased in the remaining patients (75 ms; P <.001). CONCLUSIONS: J-wave syndromes have distinct regional sensitivity to beta-adrenergic stimulation. J waves may persist in a subset of patients with precordial and inferior J waves but never in lateral location. This heterogeneous response to isoproterenol may indicate distinctive mechanisms for Brugada and ER patterns, including depolarization abnormalities or ion channel sensitivity.
    Heart rhythm: the official journal of the Heart Rhythm Society 08/2012; · 4.56 Impact Factor
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    ABSTRACT: Comparison of Ventricular Radiofrequency Lesions in Sheep. Introduction: In vivo assessment of RF ablation lesions is limited. Improved feedback could affect procedural outcome. A novel catheter, IRIS™ Cardiac Ablation Catheter (IRIS), enabling direct tissue visualization during ablation, was compared to a 3.5 mm open-irrigated tip ThermoCool™ Catheter (THERM) for endocardial ventricular RF ablation in sheep. Methods: Sixteen anesthetized sheep (6 ± 1 years old, 60 ± 10 kg) underwent ventricular RF applications with either the THERM (Biosense Webster) or IRIS (Voyage Medical) ablation catheter. In the THERM group, RF was delivered (30 W, 60 seconds) when electrode contact was achieved as assessed by recording high-amplitude electrogram, tactile feedback, and x-ray. In the IRIS group, direct visualization was used to confirm tissue contact and to guide energy delivery (10-25 W for 60 seconds) depending on visual feedback during lesion formation. Results: A total of 160 RF applications were delivered (80 with THERM; 80 with IRIS). Average power delivery was significantly higher in the THERM group than in the IRIS group (30 ± 2 W [25-30 W] for 57 ± 14 seconds vs 21 ± 4 W [10-25 W] for 57 ± 27 seconds; P<0.001). At necropsy, 62/80 (78%) lesions created with THERM were identified versus 79/80 (99%) with IRIS (P<0.001). The lesion dimensions were not significantly different between THERM and IRIS. Conclusion: Despite best efforts using standard clinical assessments of catheter contact, 22% of RF applications in the ventricles using a standard open-irrigated catheter could not be identified on necropsy. In vivo assessment of catheter contact by direct visualization of the tissue undergoing RF ablation with the IRIS™ catheter was more reliable by allowing creation of 99% prescribed target lesions without significant complications. (J Cardiovasc Electrophysiol, Vol. 23, pp. 869-873, August 2012).
    Journal of Cardiovascular Electrophysiology 05/2012; 23(8):869-73. · 3.48 Impact Factor
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    ABSTRACT: This is a case of atrial tachycardia 2 years after pulmonary transplantation. After excluding right atrial involvement, tachycardia origin was located in a scar region medial to the anastomosis of the left inferior pulmonary donor vein. Tachycardia mechanism was microreentry. Noninvasive electrocardiographic mapping performed before the ablation procedure matched with results of invasive Carto mapping and predicted both tachycardia mechanism and origin. We discuss arrhythmia mechanism found after pulmonary transplantation and benefit of noninvasive electrocardiographic mapping for procedure planning.
    Journal of Cardiovascular Electrophysiology 04/2012; 23(5):553-5. · 3.48 Impact Factor
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    ABSTRACT: Catheter ablation of ventricular tachycardia (VT) is effective and particularly useful in patients with frequent defibrillator interventions. Various substrate modification techniques have been described for unmappable or hemodynamically intolerable VT. Noninducibility is the most frequently used end point but is associated with significant limitations, so the optimal end point remains unclear. We hypothesized that elimination of local abnormal ventricular activities (LAVAs) during sinus rhythm or ventricular pacing would be a useful and effective end point for substrate-based VT ablation. As an adjunct to this strategy, we used a new high-density mapping catheter and frequently used epicardial mapping. Seventy patients (age, 67±11 years; 7 female) with VT and structurally abnormal ventricle(s) were prospectively enrolled. Conventional mapping was performed in sinus rhythm in all, and a high-density Pentaray mapping catheter was used in the endocardium (n=35) and epicardially. LAVAs were recorded in 67 patients (95.7%; 95% confidence interval, 89.2-98.9). Catheter ablation was performed targeting LAVA with an irrigated-tip catheter placed endocardially via a transseptal or retrograde aortic approach or epicardially via the subxiphoid approach. LAVAs were successfully abolished or dissociated in 47 of 67 patients (70.1%; 95% confidence interval, 58.7-80.1). In multivariate analysis, LAVA elimination was independently associated with a reduction in recurrent VT or death (hazard ratio, 0.49; 95% confidence interval, 0.26-0.95; P=0.035) during long-term follow-up (median, 22 months). LAVAs can be identified in most patients with scar-related VT. Elimination of LAVAs is feasible and safe and is associated with superior survival free from recurrent VT.
    Circulation 04/2012; 125(18):2184-96. · 15.20 Impact Factor

Publication Stats

478 Citations
225.71 Total Impact Points


  • 2011–2014
    • Université Victor Segalen Bordeaux 2
      Burdeos, Aquitaine, France
    • The University of Calgary
      Calgary, Alberta, Canada
    • Inselspital, Universitätsspital Bern
      Berna, Bern, Switzerland
  • 2008–2014
    • Medical University of Graz
      • Department of Medicine
      Gratz, Styria, Austria
  • 2013
    • Universitäts-Herzzentrum Freiburg - Bad Krozingen
      باد کروزینگن, Baden-Württemberg, Germany
    • Johns Hopkins Medicine
      • Department of Medicine
      Baltimore, Maryland, United States
  • 2012
    • King's College London
      Londinium, England, United Kingdom
    • Centre Hospitalier Universitaire de Bordeaux
      Burdeos, Aquitaine, France
    • University of Bordeaux
      Burdeos, Aquitaine, France
  • 2007–2011
    • Johns Hopkins University
      • Department of Medicine
      Baltimore, MD, United States
  • 2009
    • University Medical Center Utrecht
      • Department of Cardiology
      Utrecht, Provincie Utrecht, Netherlands