Prognostic value of ventricular arrhythmia in early post-infarction left ventricular dysfunction: the French nationwide WICD-MI study.

BACKGROUND AND AIMS: Prophylactic implantable cardioverter-defibrillators (ICDs) are not recommended until left ventricular ejection fraction (LVEF) has been reassessed 40 to 90 days after an acute myocardial infarction. In the current therapeutic era, the prognosis of sustained ventricular arrhythmias (VAs) occurring during this early post-infarction phase (i.e. within 3 months of hospital discharge) has not yet been specifically evaluated in post-myocardial infarction patients with impaired LVEF. Such was the aim of this retrospective study. METHODS: Data analysis was based on a nationwide registry of 1032 consecutive patients with LVEF ≤ 35% after acute myocardial infarction who were implanted with an ICD after being prescribed a wearable cardioverter-defibrillator (WCD) for a period of 3 months upon discharge from hospital after the index infarction. RESULTS: ICDs were implanted either because a sustained VA occurred while on WCD (VA+/WCD, n = 72) or because LVEF remained ≤35% at the end of the early post-infarction phase (VA-/WCD, n = 960). The median follow-up was 30.9 months. Sustained VAs occurred within 1 year after ICD implantation in 22.2% and 3.5% of VA+/WCD and VA-/WCD patients, respectively (P < .0001). The adjusted multivariable analysis showed that sustained VAs while on WCD independently predicted recurrence of sustained VAs at 1 year (adjusted hazard ratio [HR] 6.91; 95% confidence interval [CI] 3.73-12.81; P < .0001) and at the end of follow-up (adjusted HR 3.86; 95% CI 2.37-6.30; P < .0001) as well as 1-year mortality (adjusted HR 2.86; 95% CI 1.28-6.39; P = .012). CONCLUSIONS: In patients with LVEF ≤ 35%, sustained VA during the early post-infarction phase is predictive of recurrent sustained VAs and 1-year mortality.

Cardiac stereotactic radiation therapy for refractory ventricular arrhythmias in patients with left ventricular assist devices.

Left ventricular assist device (LVAD) implantation is an established treatment for patients with advanced heart failure refractory to medical therapy. However, the incidence of ventricular arrhythmias (VAs) is high in this population, both in the acute and delayed phases after implantation. About one-third of patients implanted with an LVAD will experience sustained VAs, predisposing these patients to worse outcomes and complicating patient management. The combination of pre-existing myocardial substrate and complex electrical remodeling after LVAD implantation account for the high incidence of VAs observed in this population. LVAD patients presenting VAs refractory to antiarrhythmic therapy and catheter ablation procedures are not rare. In such patients, treatment options are extremely limited. Stereotactic body radiation therapy (SBRT) is a technique that delivers precise and high doses of radiation to highly defined targets, reducing exposure to adjacent normal tissue. Cardiac SBRT has recently emerged as a promising alternative with a growing number of case series reporting the effectiveness of the technique in reducing the VA burden in patients with arrhythmias refractory to conventional therapies. The safety profile of cardiac SBRT also appears favorable, even though the current clinical experience remains limited. The use of cardiac SBRT for the treatment of refractory VAs in patients implanted with an LVAD are even more scarce. This review summarizes the clinical experience of cardiac SBRT in LVAD patients and describes technical considerations related to the implementation of the SBRT procedure in the presence of an LVAD.

Value of HAVOC and Brown ESUS-AF scores for atrial fibrillation on implantable cardiac monitors after embolic stroke of undetermined source.

OBJECTIVES: Up to 20 % of ischemic strokes are associated with overt atrial fibrillation (AF). Furthermore, silent AF was detected by an implantable cardiac monitor (ICM) in 1 in 3 cryptogenic strokes in the CRYSTAL AF study. An ESC position paper has suggested a HAVOC score ≥ 4 or a Brown ESUS-AF score ≥ 2 as criteria for ICM implantation after cryptogenic stroke, but neither of these criteria has been developed or validated in ICM populations. We assessed the performance of HAVOC and Brown ESUS-AF scores in a cohort of ICM patients implanted after embolic stroke of undetermined source (ESUS). METHODS: All patients implanted with an ICM for ESUS between February 2016 and February 2022 at two French University Hospitals were retrospectively included. Demographic data, cardiovascular risk factors, and clinical and biological data were collected after a review of electronic medical records. HAVOC and Brown ESUS-AF scores were calculated for all patients. FINDINGS: Among the 384 patients included, 106 (27 %) developed AF during a mean follow-up of 33 months. The scores performances for predicting AF during follow-up were: HAVOC= AUC: 68.5 %, C-Index: 0.662, and Brown ESUS-AF=AUC: 72.9 %, C-index 0.712. Compared with the CHA2DS2-VASc score, only the Brown ESUS-AF score showed significant improvement in NRI/IDI. Furthermore, classifying patients according to the suggested HAVOC and Brown ESUS-AF thresholds, only 24 % and 31 % of the cohort, respectively, would have received an ICM, and 58 (55 %) and 47 (44 %) of the AF patients, respectively, would not have been implanted with an ICM. CONCLUSION: HAVOC and Brown ESUS-AF scores showed close and moderate performance in predicting AF on ICM after cryptogenic stroke, with a significant lack of sensitivity. Specific risk scores should be developed and validated in large ICM cohorts.

Catheter knot around the mitral valve apparatus: An exceptional complication of remote magnetic navigation.

Remote magnetic navigation (RMN) is as safe and effective as manual navigation for catheter ablation of ventricular arrhythmias. This case is the first description of a soft-tip ablation catheter entrapment in the mitral valve apparatus during an RMN ablation procedure. The tight knot created by the catheter around a mitral valve chordae required surgical removal. This complication, which has never been reported before, highlights the need for closer fluoroscopic monitoring when performing catheter loops inside the ventricles when using the RMN system.

How to use pace mapping for ventricular tachycardia ablation in postinfarct patients.

We aim to describe the technical aspects of pace mapping (PM), as well as the two typical patterns of pacing correlation maps during ventricular tachycardia (VT) ablation. The first main pattern is focal, with a gradual and eccentric decrease of the QRS correlation from the area with the best PM correlation. This focal pattern may be associated with two clinical situations: (1) with some endocardial points showing a good correlation compared to VT morphology: true endocardial exit of VT or endocardial breakthrough of either an intramural or an epicardial circuit; (2) without any endocardial points showing a good correlation compared to VT morphology: the VT may originate from the other ventricle, but the presence of an intramural or an epicardial circuit should be considered in patients with a structural heart disease. The second pattern is the presence of PM points exhibiting a good correlation close to other PM points showing a poor correlation compared to VT morphology: this abrupt change in paced QRS morphology over a short distance indicates divergence of activation wavefronts between these sites and suggests the presence of a slow conduction channel: the VT isthmus.

Mechanism of ventricular tachycardia in a patient with double-outlet left ventricle.

We report the case of ventricular tachycardia (VT) ablation procedure in a patient with history of surgically repaired double-outlet left ventricle. The electrophysiology procedure revealed a re-entry pattern between the right-ventricle to main-pulmonary-artery conduit and the tricuspid annulus. The re-entrant mechanism was most likely promoted by a fibrous remodeling of this area, related to the surgical repair. This case is the first to describe a re-entry mechanism between fixed anatomical barriers in a repaired right ventricle of a double-outlet left ventricle. A pace mapping technique was used to highlight the VT isthmus.

Distance between the descending aorta and the left inferior pulmonary vein as a determinant of biophysical parameters during paroxysmal atrial fibrillation cryoablation.

INTRODUCTION: The distance from the descending aorta (DA) to the posterior wall of the left atrium (LA) is variable. We aimed to determine whether the proximity between the DA and the left inferior pulmonary vein (LIPV) ostium has an impact on biophysical parameters and cryoballoon (CB) ablation efficacy during LIPV freezing. METHODS: Patients referred for CB-ablation of atrial fibrillation (AF) in two high-volume centers were included. Cryoablation data were collected prospectively for each patient. The anatomical relationships between the LIPV and the DA (distance LIPV ostium-DA, presence of an aortic imprint on the posterior aspect of the LIPV) were then retrospectively analysed on the LA computed tomography scans realized before AF ablation. RESULTS: A total of 350 patients were included (70% men, 59.7 ± 11.5 years). The decrease in the Ostium-DA distance was significantly correlated to the increase in the time-to-isolation (TTI) (r = -.31; p = .036), with less negative temperature (r = -.11; p = .045). Similarly, the presence of an aortic imprint on the LIPV was associated with a longer TTI (p < .001). The analysis of redo procedures data shows a trend toward the presence of shorter ostium-DA distances (15.3 ± 3.29 vs. 18.1 ± 4.99, p = .15) and more frequent aortic imprints (63.6% vs. 47.5%, p = .34) in patients with LIPV reconnection as opposed to patients without reconnection in the LIPV. CONCLUSION: Our findings indicated that the DA seems to have a "radiator" effect influencing LIPV cryoablation parameters during CB-ablation. Additional studies will be needed to elucidate whether this biophysical influence has a clinical impact in LIPVs reconnections.

Comparison of clockwise and counterclockwise right atrial flutter using high-resolution mapping and automated velocity measurements.

BACKGROUND: Only few studies have been performed that explore the electrophysiological differences between clockwise (CW) and counterclockwise (CCW) right atrial (RA) cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) using the high-resolution Rhythmia mapping system. OBJECTIVES: We sought to compare CW and CCW CTI-dependent AFL in pure right AFL patients (pts) using the ultra-high-definition (ultra-HD) Rhythmia mapping system and we mathematically developed a cartography model based on automatic velocity RA measurements to identify electrophysiological AFL specificities. METHODS AND RESULTS: Thirty-three pts were recruited. The mean age was 71 ± 13 years old. The sinus venosus (SV) block line was present in 32/33 of cases (97%) and no significant difference was found between CCW and CW CTI AFL (100% vs. 91%; p = .7). No line was localized in the region of the crista terminalis (CT). A superior gap was present in the posterior line in 14/31 (45.2%) but this was similarly present in CCW AFL, when compared to CW AFL (10/22 [45.5%] vs. 4/10 [40%]; p = .9). When present, the extension of the posterior line of block was observed in 18/31 pts (58%) without significant differences between CCW and CW CI AFL (12/22 [54.5%] vs. 6/10 [60%]; p = .9) The Eustachian ridge line of block was similarly present in both groups (82% [18/22] vs. 45.5% [5/11]; p = .2). The absence of the Eustachian ridge line of block led to significantly slowed velocity in this area (28 ± 10 cm/s; n = 8), and the velocities were similarly altered between both groups (26 ± 10 [4/22] vs. 29.8 ± 11 cm/s [4/11]; p = .6). We created mathematical, three-dimensional RA reconstruction-velocity model measurements. In each block localization, when the block line was absent, velocity was significantly slowed (≤20 cm/s). A systematic slowdown in conduction velocity was observed at the entrance and exit of the CTI in 100% of cases. This alteration to the conduction entrance was localized at the lateral side of the CTI for the CCW AFL and at the septal side of the CTI for CW AFL. The exit-conduction alteration was localized at the CTI septal side for the CCW AFL and at the CTI lateral side for the CW AFL. CONCLUSION: The ultra-HD Rhythmia mapping system confirmed the absence of significant electrophysiological differences between CCW and CW AFL. The mechanistic posterior SV and Eustachian ridge block lines were confirmed in each arrhythmia. A systematic slowing down at the entrance and exit of the CTI was demonstrated in both CCW and CW AFL, but in reverse positions.

Multimodal fusion workflow for target delineation in cardiac radioablation of ventricular tachycardia.

BACKGROUND: Cardiac radioablation (CR) is an innovative treatment to ablate cardiac arrythmia sources by radiation therapy. CR target delineation is a challenging task requiring the exploitation of highly different imaging modalities, including cardiac electro-anatomical mapping (EAM). PURPOSE: In this work, a data integration process is proposed to alleviate the tediousness of CR target delineation by generating a fused representation of the heart, including all the information of interest resulting from the analysis and registration of electro-anatomical data, PET scan and planning computed tomography (CT) scan. The proposed process was evaluated by cardiologists during delineation trials. METHODS: The data processing pipeline was composed of the following steps. The cardiac structures of interest were segmented from cardiac CT scans using a deep learning method. The EAM data was registered to the cardiac CT scan using a point cloud based registration method. The PET scan was registered using rigid image registration. The EAM and PET information, as well as the myocardium thickness, were projected on the surface of the 3D mesh of the left ventricle. The target was identified by delineating a path on this surface that was further projected to the thickness of the myocardium to create the target volume. This process was evaluated by comparison with a standard slice-by-slice delineation with mental EAM registration. Four cardiologists delineated targets for three patients using both methods. The variability of target volumes, and the ease of use of the proposed method, were evaluated. RESULTS: All cardiologists reported being more confident and efficient using the proposed method. The inter-clinician variability in delineated target volume was systematically lower with the proposed method (average dice score of 0.62 vs. 0.32 with a classical method). Delineation times were also improved. CONCLUSIONS: A data integration process was proposed and evaluated to fuse images of interest for CR target delineation. It effectively reduces the tediousness of CR target delineation, while improving inter-clinician agreement on target volumes. This study is still to be confirmed by including more clinicians and patient data to the experiments.

Analysis of the effectiveness of the latest 4th-generation cryoballoon catheters in pulmonary vein isolation using high-resolution mapping.

BACKGROUND: Long-term data showed that up to 27% of pulmonary veins are reconnected using cryoballoon ablation. This study aimed to evaluate the efficacy of the latest 4th-generation cryoballoon catheters using ultra high-resolution mapping. METHODS: In patients with atrial fibrillation, a standard pulmonary vein isolation (PVI) with the latest 4th-generation cryoballoon catheter (Arctic Front Advance PRO, Medtronic Minneapolis, USA) and the spiral mapping catheter (Achieve Advance, Medtronic, Minneapolis, MN, USA) was performed. Subsequently, high-resolution mapping was achieved using the novel multipolar grid mapping catheter (Advisor HD Grid SE, Abbott Laboratories, USA). Follow-up was obtained after 6 months by means of a 7-day Holter electrocardiogram. RESULTS: In our study, acute PVI was successfully achieved in all 31 patients. The latest 4th-generation cryoballoon catheter is safe in the acute phase of PVI. Additional high-resolution mapping (mean points per map 21,001 ± 4911) using the multipolar grid mapping catheter enabled us to identify residual gaps only in the carina pulmonary vein region; therefore, no additional ablation was performed. Three of 31 patients (10%) presented with atrial arrhythmia recurrence always related with pulmonary vein reconnection; using high-resolution mapping had no additional benefit in identifying pulmonary veins in which reconnection will occur. CONCLUSION: The utility of additional high-density mapping, facilitated by the HD Grid catheter after PVI with the 4th-generation cryoballoon catheter do not substantiate a discernible advantage over conventional mapping methodologies, particularly, the spiral mapping catheter. Residual carinal conduction was observed in a substantial cohort of patients (48%), highlighting a persistent challenge in achieving complete electrical isolation.

Patient-specific quantification of cardiorespiratory motion for cardiac stereotactic radioablation treatment planning.

Background: Cardiac radioablation is a new treatment for patients with refractory ventricular tachycardia (VT). The target for cardiac radioablation is subject to cardiorespiratory motion (CRM), the heart's movement with breathing and cardiac contraction. Data regarding the magnitude of target CRM are limited but are highly important for treatment planning. Objectives: The study sought to assess CRM amplitude by using ablation catheter geometrical data. Methods: Electroanatomic mapping data of patients undergoing catheter ablation for VT at 3 academic centers were exported. The spatial position of the ablation catheter as a function of time while in contact with endocardium was analyzed and used to quantify CRM. Results: Forty-four patients with ischemic and nonischemic cardiomyopathy and VT contributed 1364 ablation lesions to the analysis. Average cardiac and respiratory excursion were 1.62 ± 1.21 mm and 12.12 ± 4.10 mm, respectively. The average ratio of respiratory to cardiac motion was approximately 11:1. CRM was greatest along the craniocaudal axis (9.66 ± 4.00 mm). Regional variations with respect to respiratory and cardiac motion were observed: basal segments had smaller displacements vs midventricular and apical segments. Patient characteristics (previous cardiac surgery, height, weight, body mass index, and left ventricular ejection fraction) had a statistically significant, albeit clinically moderate, impact on CRM. Conclusion: CRM is primarily determined by respiratory displacement and is modulated by the location of the target and the patient's biometric characteristics. The patient-specific quantification of CRM may allow to decrease treatment volume and reduce radiation exposure of surrounding organs at risk while delivering the therapeutic dose to the target.

Quinidine for ventricular arrhythmias: A comprehensive review.

Quinidine, the first antiarrhythmic drug, was widely used during the 20th century. Multiple studies have been conducted to provide insights into the pharmacokinetics and pleiotropic effects of Class Ia antiarrhythmic drugs. However, safety concerns and the emergence of new drugs led to a decline in their use during the 1990s. Despite this, recent studies have reignited the interest in quinidine, particularly for ventricular arrhythmias, where other antiarrhythmics have failed. In conditions such as Brugada syndrome, idiopathic ventricular fibrillation, early repolarization syndrome, short QT syndrome, and electrical storms, quinidine remains a valuable asset. Starting from the European and American recommendations, this comprehensive review aimed to explore the various indications for quinidine and the studies that support its use. We also discuss the potential future of quinidine, including the necessary research to optimize its use and patient selection. Additionally, it addresses the imperative task of mitigating the iatrogenic burden associated with quinidine usage and confronts the challenge of ensuring drug accessibility.

Efficacy and clinical implications of a stepwise screening strategy for atrial fibrillation after stroke: Insights from the SAFAS study.

BACKGROUND: Although guidelines recommend screening patients for atrial fibrillation (AF) after stroke, the optimal timing and combination of screening tools remain unclear. AIMS: We evaluated the suitability of a sequential combination of screening techniques for AF detected after stroke (AFDAS). We also compared patient characteristics according to the timing of AFDAS. METHODS: Patients without previous AF admitted for acute ischaemic stroke were prospectively enrolled. After a stepwise screening approach for AFDAS based on electrocardiogram, telemetry monitoring and in-hospital long-term Holter, patients with cryptogenic stroke underwent implantation of an implantable cardiac monitor (ICM). Early AFDAS was defined as AF diagnosed during hospitalization and late AFDAS as AF diagnosed on an ICM. RESULTS: Of the 240 patients included, 104 (43.3%) had a documented cause of stroke not related to AF. Among the 136 remaining patients, AFDAS was detected in 82 (60.3%) during the acute screening phase or during the 3-year follow-up by ICM. Early AFDAS was diagnosed by ECG, telemetry and in-hospital long-term Holter monitoring in 17 (20.7%), 25 (30.5%) and 18 (22.0%) patients, respectively. Among 76 patients who had an ICM implanted for cryptogenic stroke, AF was detected in 22 patients (28.9%). Except for age and stroke location, patients with early AFDAS did not differ from those with late AFDAS, particularly with regard to the prevalence of atrial cardiomyopathy markers. CONCLUSION: A stepwise approach to AFDAS screening allows early detection of AF in a considerable number of patients during their hospitalization. ICMs remain complementary to non-invasive screening tools for the detection of remote episodes of AF.

One-year mortality and causes of death after stereotactic radiation therapy for refractory ventricular arrhythmias: A systematic review and pooled analysis.

Patients treated with cardiac stereotactic body radiation therapy (radioablation) for refractory ventricular arrhythmias are patients with advanced structural heart disease and significant comorbidities. However, data regarding 1-year mortality after the procedure are scarce. This systematic review and pooled analysis aimed at determining 1-year mortality after cardiac radioablation for refractory ventricular arrhythmias and investigating leading causes of death in this population. MEDLINE/EMBASE databases were searched up to January 2023 for studies including patients undergoing cardiac radioablation for the treatment of refractory ventricular arrhythmias. Quality of included trials was assessed using the NIH Tool for Case Series Studies (PROSPERO CRD42022379713). A total of 1,151 references were retrieved and evaluated for relevance. Data were extracted from 16 studies, with a total of 157 patients undergoing cardiac radioablation for refractory ventricular arrhythmias. Pooled 1-year mortality was 32 % (95 %CI: 23-41), with almost half of the deaths occurring within three months after treatment. Among the 157 patients, 46 died within the year following cardiac radioablation. Worsening heart failure appeared to be the leading cause of death (52 %), although non-cardiac mortality remained substantial (41 %) in this population. Age≥70yo was associated with a significantly higher 12-month all-cause mortality (p<0.022). Neither target volume size nor radiotherapy device appeared to be associated with 1-year mortality (p = 0.465 and p = 0.199, respectively). About one-third of patients undergoing cardiac stereotactic body radiation therapy for refractory ventricular arrhythmias die within the first year after the procedure. Worsening heart failure appears to be the leading cause of death in this population.

Triggers of Ventricular Fibrillation in Patients With Inferolateral J-Wave Syndrome.

BACKGROUND: There are few data on ventricular fibrillation (VF) initiation in patients with inferolateral J waves. OBJECTIVES: This multicenter study investigated the characteristics of triggers initiating spontaneous VF in inferolateral J-wave syndrome. METHODS: A total of 31 patients (age 37 ± 14 years, 24 male) with spontaneous VF episodes associated with inferolateral J waves were evaluated to determine the origin and characteristics of triggers. The J-wave pattern was recorded in inferior leads in 11 patients, lateral leads in 3, and inferolateral leads in 17. RESULTS: The VF triggers (n = 37) exhibited varying QRS durations (176 ± 21 milliseconds, range 119-219 milliseconds) and coupling intervals (339 ± 46 milliseconds, range 250-508 milliseconds) with a right (70%) or left (30%) bundle branch block (BBB) pattern. Trigger patterns were associated with J-wave location: left BBB triggers with inferior J waves and right BBB triggers with lateral J waves. Electrophysiologic study was performed for 22 VF triggers in 19 patients. They originated from the left or right Purkinje system in 6 and from the ventricular myocardium in 10 and were undetermined in 6. Purkinje vs myocardial triggers showed distinct electrocardiographic characteristics in coupling interval and QRS-complex duration and morphology. Abnormal epicardial substrate associated with fragmented electrograms was identified in 9 patients, with triggers originating from the same region in 7 patients. Catheter ablation resulted in VF suppression in 15 patients (79%). CONCLUSIONS: VF initiation in inferolateral J-wave syndrome is associated with significant individual heterogeneity in trigger characteristics. Myocardial triggers have electrocardiographic features distinct from Purkinje triggers, and their origin often colocalizes with an abnormal epicardial substrate.

Impact of Catheter Ablation of Electrical Storm on Survival: A Propensity Score-Matched Analysis.

BACKGROUND: Electrical storm (ES) is a life-threatening condition, associated with substantial early and subacute mortality. Catheter ablation (CA) is a well-established therapy for ES. However, data regarding the impact of CA on the short-term and midterm survival of patients admitted for ES remain unclear. OBJECTIVES: This multicenter study aimed to investigate the impact of CA of ES on survival outcomes, while accounting for key patient characteristics associated with treatment selection. METHODS: A propensity score-matching (PSM) analysis was performed on 780 consecutive patients admitted for ES in 4 tertiary centers. PSM (1:1) based on the main characteristics associated with the use of CA or medical therapy alone was performed, resulting in 2 groups of 288 patients. RESULTS: After PSM, patients who underwent CA (n = 288) and those treated with medical therapy alone (n = 288) did not present any significant differences in the main demographic characteristics, ES presentation, and management. Compared with medical therapy alone, CA was associated with a significantly lower rate of ES recurrence at 1 year (5% vs 26%; P < 0.001). Similarly, CA was associated with a higher 1-year (91% vs 81%; P < 0.001) and 3-year (78% vs 71%; P = 0.017) survival after discharge. In subgroup analyses, effect of ablation therapy remained consistent in patients older than 70 years of age (HR: 0.39; 95% CI: 0.24-0.66), with substantial efficacy in patients with a LVEF <35% (HR: 0.39; 95% CI: 0.27-0.59). CONCLUSIONS: In propensity-matched analyses, this large study shows that CA-based management of patients admitted for ES is associated with a reduction in mortality compared with medical treatment, particularly in patients with a low ejection fraction.

Distinct Substrates of Idiopathic Ventricular Fibrillation Revealed by Arrhythmia Characteristics on Implantable Cardioverter-Defibrillator.

BACKGROUND: Idiopathic ventricular fibrillation (IVF) can be associated with undetected distinct conditions such as microstructural cardiomyopathic alterations (MiCM) or Purkinje (Purk) activities with structurally normal hearts. OBJECTIVE: This study sought to evaluate the characteristics of recurrent VF recorded on implantable defibrillator electrograms, associated with these substrates. METHODS: This was a multicenter collaboration study. At 32 centers, we selected patients with an initial diagnosis of IVF and recurrent arrhythmia at follow-up without antiarrhythmic drugs, in whom mapping demonstrated Purk or MiCM substrate. We analyzed variables related to previous ectopy, sinus rate preceding VF, trigger, and initial VF cycle lengths. Logistic regression with cross validation was used to evaluate the performance of criteria to discriminate Purk or MiCM substrates. RESULTS: Among 95 patients (35 women, age 35 ± 11 years) meeting the inclusion criteria, IVF was associated with MiCM in 41 and Purk in 54 patients. A total of 117 arrhythmia recurrences including 91% VF were recorded on defibrillator. Three variables were mostly discriminant. Sinus tachycardia (≤570 ms) was more frequent in MiCM (35.9% vs 13.4%, P = 0.014) whereas short-coupled (<350 ms) triggers were most frequent in Purk-related VF (95.5% vs 23.1%, P = 0.001), which also had shorter VFCLs (182 ± 15 ms vs 215 ± 24 ms, P < 0.001).The multivariable combination provided the highest prediction (accuracy = 0.93 ± 0.05, range 0.833-1.000), discriminating 81% of IVF substrates with a high probability (>80%). Ectopy were inconsistently present before VF. CONCLUSIONS: Characteristics of arrhythmia recurrences on implantable cardioverter- defibrillator provide phenotypic markers of the distinct and hidden substrates underlying IVF. These findings have significant clinical and genetic implications.

Impact of pulmonary veins anatomy on the outcomes of radiofrequency ablation for paroxysmal atrial fibrillation in the era of contact force-sensing ablation catheters.

BACKGROUND: Pulmonary vein (PV) isolation (PVI) has become the cornerstone of atrial fibrillation (AF) ablation in patients with paroxysmal AF (PAF). PVI durability is influenced by many factors including PVs anatomy. Data regarding the influence of PVs anatomical variations on the outcomes of PAF ablation in the era of contact force-sensing ablation catheters are scarce and contradictory. METHODS: Consecutive patients referred to our center for a first ablation of PAF using radiofrequency (RF) were included. PVs anatomy was classified into 3 groups: typical anatomy (4 distinct veins), left common ostium (LCO), and right accessory PV (RAPV). The primary outcome was recurrence of atrial arrhythmia episode during a 12-month follow-up after ablation. RESULTS: Two hundred twenty-three patients were included (mean age 58.4 ± 10.8 years and 70.9% male). Among this cohort, 141 patients (63.2%) had typical PV anatomy, 53 (23.8%) had a LCO, and 29 (13.0%) had a RAPV. The existence of a RAPV was not associated with a higher rate of AF recurrences (22 (14.3%) vs. 7 (10.1%), p = 0.519). After multivariate analysis, the presence of an LCO did not appear to be associated with the AF recurrence rate at 12 months (OR = 1.69, 95%CI 0.95-2.49, p = 0.098). Maintenance of antiarrhythmic drugs after ablation was the only factor independently associated with a decreased risk of AF recurrence at 12 months (OR = 0.76, 95%CI 0.60-0.97, p = 0.046). CONCLUSION: This study suggests that the presence of an LCO or a RAPV is not associated with a higher rate of AF recurrence at 12 months after radiofrequency PVI using contact force-sensing catheters in PAF patients.

Robotic magnetic-guided catheter ablation in patients with congenital heart disease: a systematic review and pooled analysis.

BACKGROUND: Robotic magnetic navigation (RMN) has emerged as a potential solution to overcome challenges associated with catheter ablation of arrhythmias in patients with congenital heart disease (CHD). OBJECTIVES: To assess safety and efficacy of RMNguided catheter ablation in patients with CHD. DESIGN AND METHODS: A systematic review and pooled analysis was conducted on patients with CHD who underwent RMNguided catheter ablation. Random effects models were used to generate pooled estimates with the inverse variance method used for weighting studies. RESULTS: Twentyfour nonoverlapping records included 167 patients with CHD, mean age 36.5 years, 44.6% female. Type of CHD was simple in 27 (16.2%), moderate in 32 (19.2%), and complex in 106 (63.5%). A total of 202 procedures targeted 260 arrhythmias, the most common being macroreentrant atrial circuits. The mean procedural duration was 207.5 minutes, with a mean fluoroscopy time of 12.1 minutes. The pooled acute success rate was 89.2% [95% CI (77.8%, 97.4%)]. Freedom from arrhythmia recurrence was 84.5% [95% CI (72.5%, 94.0%)] over a mean follow-up of 24.3 months. The procedural complication rate was 3.5% with no complication attributable to RMN technology. CONCLUSION: RMN-guided ablation appears to be safe and effective across a variety of arrhythmia substrates and types of CHD.