Publications by authors named "Philippe Ritter"

128 Publications

Exploring a New Systematic Route for Left Ventricular Pacing in Cardiac Resynchronization Therapy.

Circ J 2021 Feb 27;85(3):283-290. Epub 2021 Jan 27.

MicroPort CRM.

Background: Frequency and distribution of left ventricular (LV) venous collaterals were studied in vivo to evaluate the ease and feasibility of implanting a new ultra-thin LV quadripolar microlead for cardiac resynchronization therapy (CRT).Methods and Results:Evaluable venograms were analyzed to define the prevalence of venous collaterals (>0.5 mm diameter) between: (1) different LV segments; and (2) different major LV veins in: unselected patients who underwent CRT from 2008 to 2012 at Rouen Hospital, France (retrospective); and CRT patients from the Axone Acute pilot study in 2018 (prospective). In prospective patients with evaluable venograms, LV microlead implantation was attempted. Thirty-six (21/65 retrospective, 15/20 prospective) patients had evaluable venograms with ≥1 visible venous collaterals. Collaterals were found between LV veins in all CRT patients with evaluable venograms. Regionally, prevalence was highest between: the apical inferior and apical lateral (42%); and mid inferior and mid inferolateral (42%) segments. Collateral connections were most prevalent between: the inferior interventricular vein (IIV) and lateral vein (64% [23/36]); and IIV and infero-lateral vein (36% [13/36]). Cross-vein microlead implantation was possible in 18 patients (90%), and single-vein implantation was conducted in the other 2 patients (10%).

Conclusions: Venous collaterals were found in vivo between LV veins in all CRT patients with evaluable venograms, making this network an option for accessing multiple LV sites using a single LV microlead.
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http://dx.doi.org/10.1253/circj.CJ-20-0266DOI Listing
February 2021

Wearable cardioverter-defibrillator in patients with a transient risk of sudden cardiac death: the WEARIT-France cohort study.

Europace 2021 Jan;23(1):73-81

Department of Cardiology, European Georges Pompidou Hospital, 75015 Paris, France.

Aims : We aimed to provide contemporary real-world data on wearable cardioverter-defibrillator (WCD) use, not only in terms of effectiveness and safety but also compliance and acceptability.

Methods And Results : Across 88 French centres, the WEARIT-France study enrolled retrospectively patients who used the WCD between May 2014 and December 2016, and prospectively all patients equipped for WCD therapy between January 2017 and March 2018. All patients received systematic education session through a standardized programme across France at the time of initiation of WCD therapy and were systematically enrolled in the LifeVest Network remote services. Overall, 1157 patients were included (mean age 60 ± 12 years, 16% women; 46% prospectively): 82.1% with ischaemic cardiomyopathy, 10.3% after implantable cardioverter-defibrillator explant, and 7.6% before heart transplantation. Median WCD usage period was 62 (37-97) days. Median daily wear time of WCD was 23.4 (22.2-23.8) h. In multivariate analysis, younger age was associated with lower compliance [adjusted odds ratio (OR) 0.97, 95% confidence interval (CI) 0.95-0.99, P < 0.01]. A total of 18 participants (1.6%) received at least one appropriate shock, giving an incidence of appropriate therapy of 7.2 per 100 patient-years. Patient-response button allowed the shock to be aborted in 35.7% of well-tolerated sustained ventricular arrhythmias and in 95.4% of inappropriate ventricular arrhythmia detection, finally resulting in an inappropriate therapy in eight patients (0.7%).

Conclusion: Our real-life findings reinforce previous studies on the efficacy and safety of the WCD in the setting of transient high-risk group in selected patients. Moreover, they emphasize the fact that when prescribed appropriately, in concert with adequate patient education and dedicated follow-up using specific remote monitoring system, compliance with WCD is high and the device well-tolerated by the patient.
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http://dx.doi.org/10.1093/europace/euaa268DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7842091PMC
January 2021

Progressive implantable cardioverter-defibrillator therapies for ventricular tachycardia: The efficacy and safety of multiple bursts, ramps, and low-energy shocks.

Heart Rhythm 2020 12 30;17(12):2072-2077. Epub 2020 Jul 30.

Cardio-Thoracic Unit, Bordeaux University Hospital (CHU), Pessac, France; IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France.

Background: The Heart Rhythm Society, the European Heart Rhythm Association, the Asia Pacific Heart Rhythm Society, the Latin American Heart Rhythm Society expert consensus statement on optimal implantable cardioverter-defibrillator programming recommends burst antitachycardia pacing (ATP) for the treatment of ventricular tachycardia (VT) up to high rates. The number of bursts is not specified, and treatment by ramps or low-energy shocks is not recommended.

Objectives: We investigated the efficacy and safety of progressive therapies for VTs between 150 and 200 beats/min. After 3 failed bursts, we compared 3 ramps vs 3 bursts followed by a low-energy shock vs high-energy shock.

Methods: Using remote monitoring, we included monomorphic VT episodes treated with ≥1 burst.

Results: A total of 1126 VT episodes were included. A single burst was as likely to terminate VT between 150 and 200 beats/min as VT between 200 and 230 beats/min (63% vs 64%; P=.41), but was more likely to accelerate the latter (3.2% vs 0.25%; P<.01). For VT <200 beats/min, the likelihood of ATP success increased progressively (73% with 2 bursts, 78% with 3 bursts). Three additional bursts further increased VT termination to 89%, similar to the success rate with 3 additional ramps (88%; P=.17). Programming 6 bursts is associated with the probability of acceleration requiring shock of 6.6%. A low-energy first shock was less successful than a high-energy shock (66% vs 86%; P<.01) and more likely to accelerate VT (17% vs 0%; P<.01).

Conclusion: Programming up to 6 burst ATP therapies for VTs 150-200 beats/min can avoid implantable cardioverter-defibrillator shocks in most patients. Ramp ATP after failed bursts were similarly effective. Low-energy shocks are less effective and more arrhythmogenic than high-energy shocks.
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http://dx.doi.org/10.1016/j.hrthm.2020.07.032DOI Listing
December 2020

Predictors of atrial mechanical sensing and atrioventricular synchrony with a leadless ventricular pacemaker: Results from the MARVEL 2 Study.

Heart Rhythm 2020 12 24;17(12):2037-2045. Epub 2020 Jul 24.

NYU Langone Medical Center, New York, New York.

Background: The MARVEL (Micra Atrial TRacking Using a Ventricular AccELerometer) 2 study assessed the efficacy of atrioventricular (AV) synchronous pacing with a Micra leadless pacemaker. Average atrioventricular synchrony (AVS) was 89.2%. Previously, low amplitude of the Micra-sensed atrial signal (A4) was observed to be a factor of low AVS.

Objective: The purpose of this study was to identify predictors of A4 amplitude and high AVS.

Methods: We analyzed 64 patients enrolled in MARVEL 2 who had visible P waves on electrocardiogram for assessing A4 amplitude and 40 patients with third-degree AV block for assessing AVS at rest. High AVS was defined as >90% correct atrial-triggered ventricular pacing. The association between clinical factors and echocardiographic parameters with A4 amplitude was investigated using a multivariable model with lasso variable selection. Variables associated with A4 amplitude together with premature ventricular contraction burden, sinus rate, and sinus rate variability (standard deviation of successive differences of P-P intervals [SDSD]) were assessed for association with AVS.

Results: In univariate analysis, low A4 amplitude was inversely related to atrial function assessed by E/A ratio and e'/a' ratio, and was directly related to atrial contraction excursion (ACE) and atrial strain (Ɛa) on echocardiography (all P ≤.05). The multivariable lasso regression model found coronary artery bypass graft history, E/A ratio, ACE, and Ɛa were associated with low A4 amplitude. E/A ratio and SDSD were multivariable predictors of high AVS, with >90% probability if E/A <0.94 and SDSD <5 bpm.

Conclusion: Clinical parameters and echocardiographic markers of atrial function are associated with A4 signal amplitude. High AVS can be predicted by E/A ratio <0.94 and low sinus rate variability at rest.
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http://dx.doi.org/10.1016/j.hrthm.2020.07.024DOI Listing
December 2020

Validating QT-Interval Measurement Using the Apple Watch ECG to Enable Remote Monitoring During the COVID-19 Pandemic.

Circulation 2020 07 1;142(4):416-418. Epub 2020 Jun 1.

Bordeaux University Hospital (CHU), Cardio-Thoracic Unit, Pessac, France (M.S., T.C., F.D.R., S.A.-A., H.M., N.W., P.R., M.H., S.P., P.B.).

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http://dx.doi.org/10.1161/CIRCULATIONAHA.120.048253DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7382529PMC
July 2020

Electrogram morphology discriminators in implantable cardioverter defibrillators: A comparative evaluation.

J Cardiovasc Electrophysiol 2020 06 7;31(6):1493-1506. Epub 2020 May 7.

Cardio-Thoracic Unit, Bordeaux University Hospital (CHU), Pessac, France.

Background: Morphology algorithms are currently recommended as a standalone discriminator in single-chamber implantable cardioverter defibrillators (ICDs). However, these proprietary algorithms differ in both design and nominal programming.

Objective: To compare three different algorithms with nominal versus advanced programming in their ability to discriminate between ventricular (VT) and supraventricular tachycardia (SVT).

Methods: In nine European centers, VT and SVTs were collected from Abbott, Boston Scientific, and Medtronic dual- and triple-chamber ICDs via their respective remote monitoring portals. Percentage morphology matches were recorded for selected episodes which were classified as VT or SVT by means of atrioventricular comparison. The sensitivity and related specificity of each manufacturer discriminator was determined at various values of template match percentage from receiving operating characteristics (ROC) curve analysis.

Results: A total of 534 episodes were retained for the analysis. In ROC analyses, Abbott Far Field MD (area under the curve [AUC]: 0.91; P < .001) and Boston Scientific RhythmID (AUC: 0.95; P < .001) show higher AUC than Medtronic Wavelet (AUC: 0.81; P < .001) when tested for their ability to discriminate VT from SVT. At nominal % match threshold all devices provided high sensitivity in VT identification, (91%, 100%, and 90%, respectively, for Abbott, Boston Scientific, and Medtronic) but contrasted specificities in SVT discrimination (85%, 41%, and 62%, respectively). Abbott and Medtronic's nominal thresholds were similar to the optimal thresholds. Optimization of the % match threshold improved the Boston Scientific specificity to 79% without compromising the sensitivity.

Conclusion: Proprietary morphology discriminators show important differences in their ability to discriminate SVT. How much this impact the overall discrimination process remains to be investigated.
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http://dx.doi.org/10.1111/jce.14518DOI Listing
June 2020

Causes of impaired biventricular pacing in cardiac resynchronization devices with left ventricular sensing.

Pacing Clin Electrophysiol 2020 03 17;43(3):332-340. Epub 2020 Feb 17.

Bordeaux University Hospital (CHU), Cardio-Thoracic Unit, Pessac, France.

Background: Loss of biventricular stimulation can result in nonresponse to cardiac resynchronization therapy (CRT). Problems associated with the left ventricular (LV) lead and LV sensing can be challenging to detect and their incidence is unclear. The purpose of this study was to investigate mechanisms of loss of biventricular pacing due to LV lead- and LV sensing-associated problems.

Methods: In this bicentric study, CRT patients were surveilled using a novel remote monitoring algorithm from Biotronik (Germany) that registers LV electrograms (EGMs) during intermittent loss of resynchronization. The episodes were analyzed to assess the mechanisms of resynchronization interruptions.

Results: We analyzed 582 EGMs from 61 patients. During a median follow-up of 6 months, 59% of the patients had such episodes. The majority of the episodes (61%) were related to inappropriate inhibition of LV pacing, mostly due to upper rate lock-in caused by LV sensing (58%). In contrast, 8% of episodes showed intermittent loss of LV capture, which was identified thanks to LV sensing. The remaining 31% of episodes were due to physiological reasons for resynchronization interruptions (eg, supraventricular tachycardia [18%], premature beats [8%], and others [5%]). Patients with CRT interruption episodes had lower resynchronization rates (median: 98.5% vs 100%, P = .044).

Conclusions: Inadequate programming (active LV sensing with T-wave protection) is the main cause of impaired resynchronization in devices with LV sensing. In general, we recommend the deactivation of the LV T-wave protection function.
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http://dx.doi.org/10.1111/pace.13883DOI Listing
March 2020

Impact of paced left ventricular dyssynchrony on left ventricular reverse remodeling after cardiac resynchronization therapy.

J Cardiovasc Electrophysiol 2020 02 15;31(2):494-502. Epub 2020 Jan 15.

Division of Cardiology, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium.

Introduction: We investigated whether pacing-induced electrical dyssynchrony at the time of cardiac resynchronization therapy (CRT) device implantation was associated with chronic CRT response.

Methods And Results: We included a total of 69 consecutive heart failure patients who received a CRT device. Left (LVp-RVs) and right (RVp-LVs) pacing-induced interlead delays were measured intraoperatively and used to determine if there was paced left ventricular (LV) dyssynchrony, defined as present when LVp-RVs is larger than RVp-LVs. CRT response was defined as a reduction in LV end-systolic volume ≥15%, 6 months after implantation. Paced left ventricular dyssynchrony (PLVD) was associated with ischemic cardiomyopathy (ICM) (χ : 8; P = .005) but not with QRS morphology nor with pacing lead positions. In a univariate analysis, PLVD (odds ratio [OR], 6.53; 95% confidence interval [CI], 2.2-18.9; P = .001), atypical left bundle branch block (LBBB) (OR, 3.3; 95% CI, 1.2-9.4; P = .022), and ICM (OR, 5.2; 95% CI, 1.6-17; P = .006) were associated with nonresponse. In a multivariate analysis, both PLVD (OR, 9.74; 95% CI, 2.8-33.9; P < .0001) and atypical LBBB (OR, 5.6; 95% CI, 1.5-20.3; P = .009) were independently associated with nonresponse. Adding PLVD to a model based on QRS morphology provided a significant and meaningful incremental value to predict LV reverse remodeling after CRT (χ to enter: 8; P < .005). Computer simulations corroborate these findings by showing that, while intrinsic electrical dyssynchrony is a prerequisite, the level of pacing-induced dyssynchrony modulates acute CRT response.

Conclusion: In addition to the intrinsic electrical substrate, PLVD is strongly associated with less LV reverse remodeling, demonstrating that measuring the electrical substrate during pacing has additional value for prediction of CRT response in an already well-selected patient population.
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http://dx.doi.org/10.1111/jce.14330DOI Listing
February 2020

Atrioventricular Synchronous Pacing Using a Leadless Ventricular Pacemaker: Results From the MARVEL 2 Study.

JACC Clin Electrophysiol 2020 01 11;6(1):94-106. Epub 2019 Nov 11.

Leon H. Charney Division of Cardiology, NYU Langone Medical Center, New York, New York, USA.

Objectives: This study reports on the performance of a leadless ventricular pacemaker with automated, enhanced accelerometer-based algorithms that provide atrioventricular (AV) synchronous pacing.

Background: Despite many advantages, leadless pacemakers are currently only capable of single-chamber ventricular pacing.

Methods: The prospective MARVEL 2 (Micra Atrial tRacking using a Ventricular accELerometer 2) study assessed the performance of an automated, enhanced accelerometer-based algorithm downloaded to the Micra leadless pacemaker for up to 5 h in patients with AV block. The primary efficacy objective was to demonstrate the superiority of the algorithm to provide AV synchronous (VDD) pacing versus VVI-50 pacing in patients with sinus rhythm and complete AV block. The primary safety objective was to demonstrate that the algorithm did not result in pauses or heart rates of >100 beats/min.

Results: Overall, 75 patients from 12 centers were enrolled; an accelerometer-based algorithm was downloaded to their leadless pacemakers. Among the 40 patients with sinus rhythm and complete AV block included in the primary efficacy objective analysis, the proportion of patients with ≥70% AV synchrony at rest was significantly greater with VDD pacing than with VVI pacing (95% vs. 0%; p < 0.001). The mean percentage of AV synchrony increased from 26.8% (median: 26.9%) during VVI pacing to 89.2% (median: 94.3%) during VDD pacing. There were no pauses or episodes of oversensing-induced tachycardia reported during VDD pacing in all 75 patients.

Conclusions: Accelerometer-based atrial sensing with an automated, enhanced algorithm significantly improved AV synchrony in patients with sinus rhythm and AV block who were implanted with a leadless ventricular pacemaker. (Micra Atrial Tracking Using a Ventricular Accelerometer 2 [MARVEL 2]; NCT03752151).
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http://dx.doi.org/10.1016/j.jacep.2019.10.017DOI Listing
January 2020

Patient selection, pacing indications, and subsequent outcomes with de novo leadless single-chamber VVI pacing.

Europace 2019 Nov;21(11):1686-1693

New York University, New York, NY, USA.

Aims: Patient selection is a key component of securing optimal patient outcomes with leadless pacing. We sought to describe and compare patient characteristics and outcomes of Micra patients with and without a primary pacing indication associated with atrial fibrillation (AF) in the Micra IDE trial.

Methods And Results: The primary outcome (risk of cardiac failure, pacemaker syndrome, or syncope related to the Micra system or procedure) was compared between successfully implanted patients from the Micra IDE trial with a primary pacing indication associated with AF or history of AF (AF group) and those without (non-AF group). Among 720 patients successfully implanted with Micra, 228 (31.7%) were in the non-AF group. Reasons for selecting VVI pacing in non-AF patients included an expectation for infrequent pacing (66.2%) and advanced age (27.2%). More patients in the non-AF group had a condition that precluded the use of a transvenous pacemaker (9.6% vs. 4.7%, P = 0.013). Atrial fibrillation patients programmed to VVI received significantly more ventricular pacing compared to non-AF patients (median 67.8% vs. 12.6%; P < 0.001). The overall occurrence of the composite outcome at 24 months was 1.8% with no difference between the AF and non-AF groups (hazard ratio 1.36, 95% confidence interval 0.45-4.2; P = 0.59).

Conclusion: Nearly one-third of patients selected to receive Micra VVI therapy were for indications not associated with AF. Non-AF VVI patients required less frequent pacing compared to patients with AF. Risks associated with VVI therapy were low and did not differ in those with and without AF.
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http://dx.doi.org/10.1093/europace/euz230DOI Listing
November 2019

Dynamic atrioventricular delay programming improves ventricular electrical synchronization as evaluated by 3D vectorcardiography.

J Electrocardiol 2020 Jan - Feb;58:1-6. Epub 2019 Oct 20.

Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands. Electronic address:

Background: Optimal timing of the atrioventricular delay in cardiac resynchronization therapy (CRT) can improve synchrony in patients suffering from heart failure. The purpose of this study was to evaluate the impact of SyncAV™ on electrical synchrony as measured by vectorcardiography (VCG) derived QRS metrics during bi-ventricular (BiV) pacing.

Methods: Patients implanted with a cardiac resynchronization therapy (CRT) device and quadripolar left ventricular (LV) lead underwent 12‑lead ECG recordings. VCG metrics, including QRS duration (QRSd) and area, were derived from the ECG by a blinded observer during: intrinsic conduction, BiV with nominal atrioventricular delays (BiV Nominal), and BiV with SyncAV programmed to the optimal offset achieving maximal synchronization (BiV + SyncAV Opt).

Results: One hundred patients (71% male, 40% ischemic, 65% LBBB, 32 ± 9% ejection fraction) completed VCG assessment. QRSd during intrinsic conduction (166 ± 25 ms) was narrowed successively by BiV Nominal (137 ± 23 ms, p < .05 vs. intrinsic) and BiV + SyncAV Opt (122 ± 22 ms, p < .05 vs. BiV Nominal). Likewise, 3D QRS area during intrinsic conduction (90 ± 42 mV ∗ ms) was reduced by BiV Nominal (65 ± 39 mV ∗ ms, p < .05 vs. intrinsic) and further by BiV + SyncAV Opt (53 ± 30 mV ∗ ms, p = .06 vs. BiV Nominal).

Conclusion: With VCG-based, patient-specific optimization of the programmable offset, SyncAV reduced electrical dyssynchrony beyond conventional CRT.
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http://dx.doi.org/10.1016/j.jelectrocard.2019.09.026DOI Listing
October 2019

Prognostic value of the 12-lead surface electrocardiogram in sarcomeric hypertrophic cardiomyopathy: data from the REMY French register.

Europace 2020 01;22(1):139-148

Département de Cardiologie et Maladies Vasculaires, INSERM CMR970, Paris Cardiovascular Research Center - PARCC, Paris, France.

Aims: To identify independent electrocardiogram (ECG) predictors of long-term clinical outcome based on standardized analysis of the surface ECG in a large multicentre cohort of patients with sarcomeric hypertrophic cardiomyopathy (HCM).

Methods And Results: Retrospective observational study from the REMY French HCM clinical research observatory. Primary endpoint was a composite of all-cause mortality, major non-fatal arrhythmic events, hospitalization for heart failure (HF), and stroke. Secondary endpoints were components of the primary endpoint. Uni- and multivariable Cox proportional hazard regression analysis was performed to identify independent predictors. Among 994 patients with HCM, only 1.8% had a strictly normal baseline ECG. The most prevalent abnormalities were inverted T waves (63.7%), P-wave abnormalities (30.4%), and abnormal Q waves (25.5%). During a mean follow-up of 4.0 ± 2.0 years, a total of 272 major cardiovascular events occurred in 217 patients (21.8%): death or heart transplant in 98 (9.8%), major arrhythmic events in 40 (4.0%), HF hospitalization in 115 (11.6%), and stroke in 23 (2.3%). At multivariable analysis using ECG covariates, prolonged QTc interval, low QRS voltage, and PVCs of right bundle branch block pattern predicted worse outcome, but none remained independently associated with the primary endpoint after adjustment on main demographic and clinical variables. For secondary endpoints, abnormal Q waves independently predicted all-cause death [hazard ratio (HR) 2.35, 95% confidence interval (CI) 1.23-4.47; P = 0.009] and prolonged QTc the risk of HF hospitalization (HR 1.006, 95% CI 1.001-1.011; P = 0.024).

Conclusion: The 12-lead surface ECG has no independent value to predict the primary outcome measure in patients with HCM. The 12-lead surface ECG has been widely used as a screening tool in HCM but its prognostic value remains poorly known. The value of baseline surface ECG to predict long-term clinical outcomes was studied in a cohort of 994 patients with sarcomeric HCM. The surface ECG has no significant additional value to predict outcome in this patient population.
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http://dx.doi.org/10.1093/europace/euz272DOI Listing
January 2020

Very-late onset twiddler syndrome as an unusual cause of syncope.

J Interv Card Electrophysiol 2019 Dec 24;56(3):359-360. Epub 2019 Aug 24.

Cardio-Thoracic Unit, Bordeaux University Hospital (CHU), Pessac, France.

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http://dx.doi.org/10.1007/s10840-019-00613-zDOI Listing
December 2019

Oversensing issues leading to device extraction: When subcutaneous implantable cardioverter-defibrillator reached a dead-end.

Heart Rhythm 2020 01 8;17(1):66-74. Epub 2019 Jul 8.

Bordeaux University Hospital, Cardio-Thoracic Unit, Pessac, France; IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac - Bordeaux, France.

Background: Subcutaneous implantable cardioverter-defibrillator (S-ICD) implantations are rapidly expanding. However, the subcutaneous detection and interpretation of cardiac signals in S-ICDs is much more challenging than by conventional devices. There is a complete paradigm shift in cardiac signal sensing with subcutaneous signal detection, leading in some cases to oversensing with restricted programming options.

Objectives: The aim of this single-center study was to quantify and describe cases where recurring oversensing made the extraction of the device necessary.

Methods: Consecutive patients (n = 108) implanted with an S-ICD in our tertiary referral hospital were considered for analysis. Clinical and remote monitoring data were analyzed.

Results: The S-ICD had to be explanted in 6 of 108 implanted patients (5.6%) because of refractory oversensing issues: myopotential oversensing, P- or T-wave oversensing, rate-dependent left bundle branch block aberrancy during exercise with R-wave double counting, and R-wave amplitude decrease after ventricular tachycardia ablation leading to noise detection. Seventeen of 108 patients experienced oversensing (15.7%): 9 patients had at least 1 inappropriate charge without a shock (8.3%), 3 patients had at least 1 inappropriate shock (2.8%), and 5 patients had both episodes (4.6%).

Conclusion: So far, cardiologists have had to deal with transvenous ICD lead fractures, but signal oversensing without correcting programming option could be the equivalent weakness of S-ICDs, despite an adequate screening.
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http://dx.doi.org/10.1016/j.hrthm.2019.07.004DOI Listing
January 2020

Incidence and outcomes of systemic infections in patients with leadless pacemakers: Data from the Micra IDE study.

Pacing Clin Electrophysiol 2019 08 2;42(8):1105-1110. Epub 2019 Jul 2.

University Hospital Southampton, NHS Foundation Trust, Southampton, UK.

Background: The Micra clinical trials have enrolled more than 2500 patients without any reported device-related infections that required removal during follow-up. Leadless pacemakers might be more resistant to bacterial seeding due to smaller surface area and a greater tendency for encapsulation.

Objective: To analyze the incidence and outcomes of serious infectious events (SIEs: bacteremia or endocarditis) that developed during follow-up in patients with history of Micra leadless pacemaker implantation.

Methods: SIE and outcomes were characterized based upon adverse event reports. Among 720 patients implanted with Micra in the investigational device exemption trial, we identified 16 patients who had documented 21 SIEs during follow-up.

Results: Among patients with SIEs, mean age was 71.9 ± 11.7 years. SIEs occurred at a mean 4.8 ± 4.5 months after implant and patients were followed for 13.1 ± 9.1 months after documentation of SIE. All events were adjudicated as unrelated to the Micra device or procedure. Bacteremia was documented to be related to a gram-positive organism in 13 events (seven Staphylococcus, three Streptococcus, two Enterococcus, and one uncharacterized gram-positive bacteria), and gram-negative organisms in three events. In five events, the type of organism was not characterized (two patients with endocarditis). No persistent cases of bacteremia after antibiotic cessation were seen over the duration of follow-up CONCLUSION: In this small series of Micra patients who developed SIEs postimplant, the occurrence of bacteremia and/or endocarditis did not appear to lead to persistent bacteremia off antibiotics; most events resolved with antibiotic treatment.
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http://dx.doi.org/10.1111/pace.13752DOI Listing
August 2019

Left ventricular sensing in cardiac resynchronization devices-opportunities and pitfalls for device programming.

J Cardiovasc Electrophysiol 2019 08 4;30(8):1352-1361. Epub 2019 Jul 4.

Dept. of Cardiology, Cardiothoracic Unit, Bordeaux University Hospital (CHU), Pessac, France.

Introduction: Some cardiac resynchronization therapy (CRT) device manufacturers (Biotronik, Germany; Boston Scientific, United States) have implemented left ventricular (LV) sensing functionality to prevent pacing into the vulnerable phase. Physicians are only partially aware of programming pitfalls related to LV sensing and general programming advice is lacking.

Methods And Results: We provide an illustrative case-series-based review of the variety of potential problems with LV sensing. LV sensing may inappropriately impair CRT delivery due to LV-sensing issues or improper device programming. This can cause beat-wise loss of resynchronization but also ongoing desynchronization. On the other hand, LV sensing provides additional diagnostic information, which may reveal intermittent problems of the LV lead such as capture loss. We summarize the available evidence to provide manufacturer-specific recommendations on device programming and troubleshooting for daily clinical practice.

Conclusion: CRT devices with LV sensing may suffer from impaired resynchronization due to programming pitfalls. If LV sensing is active (nominal setting in Biotronik and Boston Scientific devices), careful lookout for related problems and resynchronization percentage is required. Optimization is mandatory and even deactivation of LV sensing may have to be considered.
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http://dx.doi.org/10.1111/jce.14039DOI Listing
August 2019

Long-Term Follow-Up of Idiopathic Ventricular Fibrillation in a Pediatric Population: Clinical Characteristics, Management, and Complications.

J Am Heart Assoc 2019 05;8(9):e011172

1 Electrophysiology Department, Hopital Haut Lévêque Bordeaux France.

Background The natural history and long-term outcome in pediatric patients with idiopathic ventricular fibrillation ( IVF ) are poorly characterized. We sought to define the clinical characteristics and long-term outcomes of a pediatric cohort with an initial diagnosis of IVF . Methods and Results Patients were included from an International Registry of IVF (consisting of 496 patients). Inclusion criteria were: (1) VF with no identifiable cause following comprehensive analysis for ischemic, electrical or structural heart disease and (2) age ≤16 years. These included 54 pediatric IVF cases (age 12.7±3.7 years, 59% male) among whom 28 (52%) had a previous history of syncope (median 2 syncopal episodes [interquartile range 1]). Thirty-six (67%) had VF in situations associated with high adrenergic tone. During a median 109±12 months of follow-up, 31 patients (57%) had recurrence of ventricular arrhythmias, mainly VF . Two patients developed phenotypic expression of an inherited arrhythmia syndrome during follow-up (hypertrophic cardiomyopathy and long QT syndrome, respectively). A total of 15 patients had positive genetic testing for inherited arrhythmia syndromes. Ten patients (18%) experienced device-related complications. Three patients (6%) died, 2 due to VF storm. Conclusions In pediatric patients with IVF , a minority develop a definite clinical phenotype during long-term follow-up. Recurrent VF is common in this patient group.
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http://dx.doi.org/10.1161/JAHA.118.011172DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6512137PMC
May 2019

Algorithm-based reduction of inappropriate defibrillator shock: Results of the Inappropriate Shock Reduction wIth PARAD+ Rhythm DiScrimination-Implantable Cardioverter Defibrillator Study.

Heart Rhythm 2019 09 22;16(9):1429-1435. Epub 2019 Mar 22.

CHU Bordeaux, Groupe hospitalier Sud, Hôpital Haut-Lévêque, Bordeaux, France.

Background: Inappropriate shocks (IS) continue to have a major negative impact on patients implanted with defibrillators.

Objective: The purpose of this study was to assess IS reduction with the PARAD+ discrimination algorithm in a general population implanted for primary or secondary prevention.

Methods: ISIS-ICD (Inappropriate Shock Reduction wIth PARAD+ Rhythm DiScrimination-Implantable Cardioverter Defibrillator) was a 2-year international, interventional study in patients implanted with a dual implantable cardioverter-defibrillator (ICD) or triple-chamber defibrillator (cardiac resynchronization therapy-defibrillator [CRT-D]) featuring PARAD+. IS (shocks not delivered for ventricular tachycardia or fibrillation) were independently adjudicated. The primary endpoint was percentage of IS-free patients at 24 months. Primary and worst-case analyses of annual incidence rates of patients with ≥1 IS, overall and per defibrillator type, were conducted.

Results: In total, 1013 patients (80.7% male; age 67.1 ± 11.4 years; 68%/30%/2% primary/secondary/other indication) were enrolled and followed for a median of 552 days (interquartile range 354; 725). Of 993 analyzed patients programmed with PARAD+, 14 had ≥1 IS, corresponding to a percentage free from IS of 98.1% (95% confidence interval [CI] 96.8%- 98.9%). Annual incidence rates (per 100 person-years) of patients with IS were 1.0 (95% CI 0.59-1.69) and 2.1 (95% CI 1.46-3.02) in the primary and worst-case analyses, respectively. In ICD patients, rates were 1.2 (95% CI 0.68-2.23) and 2.3 (95% CI 1.47-3.53), and in CRT-D patients 0.59 (95% CI 0.19-1.83) and 1.8 (95% CI 0.93-3.44) per 100 person-years.

Conclusion: The annual rate of defibrillator patients with IS using the enhanced PARAD+ discrimination algorithm alone ranged from 1.0 to 2.1 per 100 person-years in a general population implanted for primary or secondary prevention.
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http://dx.doi.org/10.1016/j.hrthm.2019.03.016DOI Listing
September 2019

Statistical ranking of electromechanical dyssynchrony parameters for CRT.

Open Heart 2019;6(1):e000933. Epub 2019 Jan 21.

Center for Training and Research in MathematIcs and Scientific Computing (CERMICS), Université Paris-Est, ENPC, Marne-la-Vallée, France.

Objective: Mechanical evaluation of dyssynchrony by echocardiography has not replaced ECG in routine cardiac resynchronisation therapy (CRT) evaluation because of its complexity and lack of reproducibility. The objective of this study was to evaluate the potential correlations between electromechanical parameters (atrioventricular, interventricular and intraventricular from the dyssynchrony model presented in 2000), their ability to describe dyssynchrony and their potential use in resynchrony.

Methods: 455 sets of the 18 parameters of the model obtained in 91 patients submitted to various pacing configurations were evaluated two by two using a Pearson correlation test and then by groups according to their ability to describe dyssynchrony, using the Column selection method of machine learning.

Results: The best parameter is duration of septal contraction, which alone describes 25% of dyssynchrony. The best groups of 3, 4 and ≥8 variables describe 59%, 73% and almost 100% of dyssynchrony, respectively. Left pre-ejection interval is highly and significantly correlated to a maximum of other variables, and its decrease is associated with the favourable evolution of all other correlated parameters. Increase in filling duration and decrease in duration of septum to lateral wall contraction difference are not associated with the favourable evolution of other parameters.

Conclusions: No single electromechanical parameter alone can fully describe dyssynchrony. The 18-parameter model can be simplified, but still requires at least 4-8 parameters. Decrease in left pre-ejection interval favourably drives resynchrony in a maximum of other parameters. Increase in filling duration and decrease in septum-lateral wall difference do not appear to be good CRT targets.
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http://dx.doi.org/10.1136/openhrt-2018-000933DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6347881PMC
February 2021

Behavior of leadless AV synchronous pacing during atrial arrhythmias and stability of the atrial signals over time-Results of the MARVEL Evolve subanalysis.

Pacing Clin Electrophysiol 2019 Mar 12;42(3):381-387. Epub 2019 Feb 12.

Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium.

Introduction: The MARVEL study demonstrated at a single time point that accelerometer (ACC)-based atrial sensing improves atrioventricular (AV) synchrony (AVS) in patients with AV block and a Micra pacemaker (Medtronic, Minneapolis, MN, USA). The purpose of the MARVEL Evolve substudy was to assess the performance over time.

Methods: This prospective single-center study compared AVS and ACC signals at two visits ≥6 months apart. Custom software was temporarily downloaded into the Micra at each visit and AVS was measured during 30 min at rest.

Results: Nine patients from the MARVEL study were enrolled. The mean (±standard deviation) age was 82.3 ± 6.0 years old, 67% were male, and a Micra was implanted for 6.0 ± 6.4 months. High-degree AV block was present in four patients, whereas five with predominantly intrinsic conduction required intermittent pacing for bradycardia. The mean interval between visits was 7.1 ± 0.6 months. Seven patients had normal sinus node function at both visits and were included in a paired analysis. Both ACC signal amplitude (visit 2-visit 1 = 1.4 mG; 95% confidence interval [CI] [-25.8 to 28.4 mG]; P = 0.933) and AVS (visit 1: 90.8%, 95% CI [72.4, 97.4] and visit 2: 91.4%, 95% CI [63.8, 98.5]; P = 0.740) remained stable. Three patients had spontaneous atrial tachycardia. During atrial fibrillation, no atrial contraction was detected or tracked. During atrial flutter, intermittent tracking resulted in a ventricular rate of 60 ± 8 beats per minute (bpm); there was no ventricular pacing >100 bpm.

Conclusion: ACC signals amplitude and performance of AVS pacing were stable over time. During atrial arrhythmias, the AV synchronous pacing mode behaved safely.
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http://dx.doi.org/10.1111/pace.13615DOI Listing
March 2019

Dynamic programming of atrioventricular delay improves electrical synchrony in a multicenter cardiac resynchronization therapy study.

Heart Rhythm 2019 07 23;16(7):1047-1056. Epub 2019 Jan 23.

Section of Cardiac Electrophysiology, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio.

Background: Patient-specific programming of cardiac resynchronization therapy (CRT) is often neglected, despite significant nonresponse rates. The device-based SyncAV CRT algorithm dynamically adjusts atrioventricular delays to the intrinsic AV interval, reduced by a programmable offset, to accommodate each patient's changing needs.

Objective: The purpose of this study was to evaluate the acute effect of biventricular (BiV) pacing enhanced by SyncAV on electrical synchrony in a broad patient population.

Methods: Patients with existing CRT implants were prospectively evaluated at 5 international centers. Blinded 12-lead electrocardiographic QRS duration (QRSd) measurements were used to compare intrinsic conduction with nominal BiV pacing, BiV + SyncAV (default 50 ms offset), and BiV + SyncAV (optimized, patient-specific offset). BiV configurations were tested twice using the latest activating and earliest activating left ventricular (LV) electrodes as cathodes.

Results: Ninety patients (mean age 67.1 ± 9.5 years; 67 (74%) men; 55 (63%) with left bundle branch block; 37 (43%) with ischemic cardiomyopathy; LV ejection fraction 32% ± 9%) with intact atrioventricular conduction (PR interval 195 ± 45 ms) were enrolled. With BiV pacing from the latest activating LV electrode, the intrinsic QRSd of 155 ± 29 ms was reduced by 9% ± 20% to 138 ± 27 ms using traditional BiV pacing and by 13% ± 14% to 133 ± 25 ms using BiV + SyncAV (50 ms offset). The maximal QRSd reduction by 20% ± 10% to 123 ± 22 ms was achieved by BiV + SyncAV with an optimized offset. Similar QRSd reductions were observed with BiV pacing from the earliest activating LV electrode across all settings. Of all baseline characteristics, intrinsic QRSd was the only significant predictor of QRSd reduction magnitude.

Conclusion: SyncAV improved acute electrical synchrony beyond conventional CRT, particularly with patient-specific optimization. The degree of synchrony restored was contingent on intrinsic QRSd, but not limited by other baseline characteristics or by the LV pacing electrode used.
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http://dx.doi.org/10.1016/j.hrthm.2019.01.020DOI Listing
July 2019

Role of medical reaction in management of inappropriate ventricular arrhythmia diagnosis: the inappropriate Therapy and HOme monitoRiNg (THORN) registry.

Europace 2019 Apr;21(4):607-615

Department of Cardiology, Centre Hospitalier Universitaire La Timone, Marseille, France.

Aims: Implantable cardioverter-defibrillators (ICDs) reduce sudden cardiac death in selected patients but inappropriate ICD shocks have been associated with increased mortality. The THORN registry aims to describe the rate of inappropriate ventricular arrhythmia diagnoses and therapies in patients followed by remote monitoring, as well as the following delay to next patient contact (DNPC).

Methods And Results: One thousand eight hundred and eighty-two patients issued from a large remote monitoring database first implanted with an ICD for primary or secondary prevention in 110 French hospitals from 2007 to 2014 constitute the THORN population. Among them, 504 patients were additionally followed prospectively for evaluation of the DNPC. Eight hundred and ninety-five out of 1551 (58%) patients had ischaemic heart disease and 358/771 (46%) were implanted for secondary prevention. During 13.7 ± 3.4 months of follow-up, the prevalence of first inappropriate diagnosis in a ventricular arrhythmia zone with enabled therapy was 162/1882 (9%). Among those patients, 122/162 (75%) suffered at least one inappropriate therapy and 58/162 (36%) at least one inappropriate shock. Eighty-three out of 162 (51%) of first inappropriate diagnosis occurred during the first 4 months following implantation. The median DNPC was 8 days (interquartile range 1-26). At least one other day with recording of an inappropriate diagnosis of the same cause occurred in 13/43 (30%) of available DNPC periods, with an inappropriate therapy in 7/13 (54%).

Conclusion: Inappropriate diagnoses occurred in 9% of patients implanted with an ICD during the first 14 months. The DNPC after inadequate ventricular arrhythmia diagnoses remains long in daily practice and should be optimized.

Clinicaltrials.gov Identifier: NCT01594112.
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http://dx.doi.org/10.1093/europace/euy284DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6452297PMC
April 2019

Health-related quality of life impact of a transcatheter pacing system.

J Cardiovasc Electrophysiol 2018 12 15;29(12):1697-1704. Epub 2018 Oct 15.

Department of Cardiology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands.

Background: Transcatheter pacing systems (TPS) provide a novel, minimally invasive approach in which a miniaturized, leadless pacemaker (PM) is transfemorally implanted in the right ventricle. We evaluated the health-related quality of life (HRQoL) impact, patient satisfaction, and activity restrictions following TPS in a large prospective multicenter clinical trial.

Methods And Results: Patients who underwent a Micra TPS implantation between December 2013 and May 2015 were included. HRQoL impact was evaluated using the Short-Form-36 (SF-36) questionnaire at baseline, 3, and 12 months. Patient satisfaction was assessed using a three-item questionnaire determining recovery, activity level, and esthetic appearance at 3 months. Implanting physicians compared the patient activity restrictions for TPS to traditional PM therapy. A total of 720 patients were implanted with a TPS (76 ± 11 years; 59% male). Of these patients, 702 (98%), 681 (95%), and 635 (88%) completed the SF-36 at baseline, 3 and 12 months, respectively. Improvements were observed at 3 and 12 months in all SF-36 domains and all attained statistical significance. Of 693 patients who completed the patient satisfaction questionnaire, 96%, 91%, 74% were (very) satisfied with their esthetic appearance, recovery, and level of activity, respectively. TPS discharge instructions were rated less restrictive in 49%, equally restrictive in 47%, and more restrictive in 4% of cases compared with traditional PM systems.

Conclusions: TPS resulted in postimplant HRQoL improvements at 3 and 12 months, and high levels of patient satisfaction at 3 months. Further, TPS was associated with less activity restrictions compared with traditional PM systems.
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http://dx.doi.org/10.1111/jce.13726DOI Listing
December 2018

Updated performance of the Micra transcatheter pacemaker in the real-world setting: A comparison to the investigational study and a transvenous historical control.

Heart Rhythm 2018 12 10;15(12):1800-1807. Epub 2018 Aug 10.

University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.

Background: Early results of the Micra Investigational Device Exemption (IDE) study and Micra Post-Approval Registry (PAR) demonstrated excellent safety and efficacy performance; however, intermediate-term results across a large patient population in the real-world setting have not been evaluated.

Objectives: We report updated performance of the Micra transcatheter pacemaker from a worldwide PAR and compare it with the IDE study as well as a transvenous historical control.

Methods: The safety objective of the analysis was system- or procedure-related major complications through 12 months postimplantation. We compared the major complication rate with that of the 726 patients from the IDE and with a reference data set of 2667 patients with transvenous pacemakers by using a Fine-Gray competing risk model.

Results: The Micra device was successfully implanted in 1801 of 1817 patients (99.1%). The mean follow-up period was 6.8 ± 6.9 months. Through 12 months, the major complication rate was 2.7% (95% confidence interval [CI] 2.0%-3.7%). The risk of major complications for Micra PAR patients was 63% lower than that for patients with transvenous pacemakers through 12 months postimplantation (hazard ratio 0.37; 95% CI 0.27-0.52; P < .001). The major complication rate trended lower in the PAR than in the IDE study (hazard ratio 0.71; 95% CI 0.44-1.1; P = .160), driven by the lower pericardial effusion rate in the PAR. There were 3 cases of infection associated with the procedure, but none required device removal and there were no battery or telemetry issues. Pacing thresholds were low and stable through 12 months postimplantation.

Conclusion: Performance of the Micra transcatheter pacemaker in international clinical practice remains consistent with previously reported data. Major complications were infrequent and occurred 63% less often compared to transvenous systems.

Clinical Trial Registration: Micra Transcatheter Pacing System Post-Approval Registry ClinicalTrials.gov identifier: NCT02536118; Micra Transcatheter Pacing Study ClinicalTrials.gov identifier: NCT02004873.
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http://dx.doi.org/10.1016/j.hrthm.2018.08.005DOI Listing
December 2018

Cardiac Rhythm Disturbances in Hemodialysis Patients: Early Detection Using an Implantable Loop Recorder and Correlation With Biological and Dialysis Parameters.

JACC Clin Electrophysiol 2018 03 27;4(3):397-408. Epub 2017 Sep 27.

Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France; Unité INSERM 1026, Universite de Bordeaux, Bordeaux, France.

Objectives: The aim of this study was to identify using implantable loop recorder (ILR) monitoring the mechanisms leading to sudden death (SD) in patients undergoing hemodialysis (HD).

Background: SD accounts for 11% to 25% of death in HD patients.

Methods: Continuous rhythm monitoring was performed using the remote monitoring capability of the ILR device in patients undergoing HD at 8 centers. Clinical, biological, and technical HD parameters were recorded and analyzed.

Results: Seventy-one patients (mean age 65 ± 9 years, 73% men) were included. Left ventricular ejection fraction was <50% in 16%. Twelve patients (17%) had histories of atrial fibrillation or flutter at inclusion. During a mean follow-up period of 21.3 ± 6.9 months, 16 patients died (14% patient-years), 7 (44%) of cardiovascular causes. Four SDs occurred, with progressive bradycardia followed by asystole. The incidence of patients presenting with significant conduction disorder and with ventricular arrhythmia was 14% and 9% patient-years, respectively. In multivariate survival frailty analyses, a higher risk for conduction disorder was associated with plasma potassium >5.0 mmol/l, bicarbonate <22 mmol/l, hemoglobin >11.5 g/dl, pre-HD systolic blood pressure >140 mm Hg, the longer interdialytic period, history of coronary artery disease, previous other arrhythmias, and diabetes mellitus. A higher risk for ventricular arrhythmia was associated with potassium <4.0 mmol/l, no antiarrhythmic drugs, and previous other arrhythmias. With ILR monitoring, de novo atrial fibrillation or flutter was diagnosed in 14 patients (20%).

Conclusions: ILR may be considered in HD patients prone to significant conduction disorders, ventricular arrhythmia, or atrial fibrillation or flutter to allow early identification and initiation of adequate treatment. Therapeutic strategies reducing serum potassium variability could decrease the rate of SD in these patients. (Implantable Loop Recorder in Hemodialysis Patients [RYTHMODIAL]; NCT01252823).
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http://dx.doi.org/10.1016/j.jacep.2017.08.002DOI Listing
March 2018

Localized Structural Alterations Underlying a Subset of Unexplained Sudden Cardiac Death.

Circ Arrhythm Electrophysiol 2018 07;11(7):e006120

IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, France (M. Haïssaguerre, M. Hocini, G.C., J.D., F.S., S.P., H.C., M.T., A.D., R.M., N.D., P.B., P.R., S.P., T.P., N.K., G.M., X.P., C.D., L.L., R.C., P.J., D.B., E.V., M.P., R.W., O.B., R.D.).

Background: Sudden cardiac death because of ventricular fibrillation (VF) is commonly unexplained in younger victims. Detailed electrophysiological mapping in such patients has not been reported.

Methods: We evaluated 24 patients (29±13 years) who survived idiopathic VF. First, we used multielectrode body surface recordings to identify the drivers maintaining VF. Then, we analyzed electrograms in the driver regions using endocardial and epicardial catheter mapping during sinus rhythm. Established electrogram criteria were used to identify the presence of structural alterations.

Results: VF occurred spontaneously in 3 patients and was induced in 16, whereas VF was noninducible in 5. VF mapping demonstrated reentrant and focal activities (87% versus 13%, respectively) in all. The activities were dominant in one ventricle in 9 patients, whereas they had biventricular distribution in others. During sinus rhythm areas of abnormal electrograms were identified in 15/24 patients (62.5%) revealing localized structural alterations: in the right ventricle in 11, the left ventricle in 1, and both in 3. They covered a limited surface (13±6 cm) representing 5±3% of the total surface and were recorded predominantly on the epicardium. Seventy-six percent of these areas were colocated with VF drivers (<0.001). In the 9 patients without structural alteration, we observed a high incidence of Purkinje triggers (7/9 versus 4/15, =0.033). Catheter ablation resulted in arrhythmia-free outcome in 15/18 patients at 17±11 months follow-up.

Conclusions: This study shows that localized structural alterations underlie a significant subset of previously unexplained sudden cardiac death. In the other subset, Purkinje electrical pathology seems as a dominant mechanism.
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http://dx.doi.org/10.1161/CIRCEP.117.006120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7661047PMC
July 2018

Response to cardiac resynchronization therapy is determined by intrinsic electrical substrate rather than by its modification.

Int J Cardiol 2018 Nov 6;270:143-148. Epub 2018 Jun 6.

IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, F-33600 Pessac, Bordeaux, France; Bordeaux University Hospital (CHU), Cardio-Thoracic Unit, F-33600 Pessac, France.

Background: Electrocardiographic mapping (ECM) expresses electrical substrate through magnitude and direction of the activation delay vector (ADV). We investigated to what extent the response to cardiac resynchronization therapy (CRT) is determined by baseline ADV and by ADV modification through CRT and optimization of left ventricular (LV) pacing site.

Methods: ECM was performed in 79 heart failure patients (4 RBBB, 12 QRS < 120 ms, 23 non-specific conduction delay [NICD] and 40 left bundle branch block [LBBB]). 67 patients (QRS ≥ 120 ms) underwent CRT implantation and in 26 patients multiple LV pacing site optimization was performed. ADV was calculated from locations/depolarization times of 2000 virtual epicardial electrodes derived from ECM. Acute response was defined as ≥10% LVdP/dt increase, chronic response by composite clinical score at 6 months.

Results: During intrinsic conduction, ADV direction was similar in patients with QRS < 120 ms, NICD and LBBB, pointing towards the LV free wall, while ADV magnitude was larger in LBBB (117 ± 25 ms) than in NICD (70 ± 29 ms, P < 0.05) and QRS < 120 ms (52 ± 14 ms, P < 0.05). Intrinsic ADV accurately predicted the acute (AUC = 0.93) and chronic (AUC = 0.90) response to CRT. ADV change by CRT only moderately predicted response (highest AUC = 0.76). LV pacing site optimization had limited effects: +3 ± 4% LVdP/dt when compared to conventional basolateral LV pacing.

Conclusion: The baseline electrical substrate, adequately measured by ADV amplitude, strongly determines acute and chronic CRT response, while the extent of its modification by conventional CRT or by varying LV pacing sites has limited effects.
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http://dx.doi.org/10.1016/j.ijcard.2018.06.005DOI Listing
November 2018

Predictors of future onset of atrial fibrillation in hypertrophic cardiomyopathy.

Arch Cardiovasc Dis 2018 Oct 6;111(10):591-600. Epub 2018 Jun 6.

Inserm U1045, l'institut de rythmologie et modélisation cardiaque, Bordeaux University, 33604 Pessac, France; Department of echocardiography and cardiomyopathies competence centre, Bordeaux University Hospital, 33000 Bordeaux, France. Electronic address:

Background: Novel predictors of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) are desirable.

Aim: To detect new multimodality imaging variables predictive of de novo AF in HCM.

Methods: Consecutive patients with HCM underwent clinical assessment and 48-hour Holter electrocardiography to detect AF episodes. Left ventricular (LV) morphology, function and fibrosis, and the left atrium (LA) were characterized by cardiac magnetic resonance. Mitral valve, systolic pulmonary artery pressure, LV filling and maximum gradients were assessed by echocardiography. Patients with no previous history of AF were followed with Holter recordings.

Results: Two hundred and nine patients were included (mean age 53±16 years; 140 men), 46 (22%) of whom had a history of AF and a longer duration from HCM diagnosis, more frequent use of heart failure medication, a higher systolic pulmonary artery pressure, a lower LV ejection fraction, a higher extent of LV fibrosis and prevalence of fibrosis on right ventricular (RV)-LV insertions, a higher LA volume and lower LA phasic function. Patients with no AF at inclusion were followed for 26 (17-42) months, and 15 (9%) developed de novo AF. Among clinical characteristics, New York Heart Association class was the only significant AF predictor in the multivariable analysis (hazard ratio 2.65 per class, 95% confidence interval [CI] 1.15-6.10; P=0.02). Among imaging characteristics, two independent predictors were identified: myocardial fibrosis on RV insertions (hazard ratio 2.8, 95% CI 1.3-5.9; P=0.008); and LA volume (hazard ratio 1.03 per mL/m, 95% CI 1.01-1.06; P=0.006).

Conclusions: AF in HCM is predicted by New York Heart Association class, LA volume and LV fibrosis on RV-LV insertions on cardiac magnetic resonance imaging. The mechanisms relating the ventricular phenotype to AF should be clarified in future studies.
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http://dx.doi.org/10.1016/j.acvd.2018.03.007DOI Listing
October 2018