Virtual Reality for the Management of Pain and Anxiety in Patients Undergoing Implantation of Pacemaker or Implantable Cardioverter Defibrillator: A Randomized Study.

BACKGROUND: The Virtual Reality Headset (VRH) is a device aiming at improving patient's comfort by reducing pain and anxiety during medical interventions. Its interest during cardiac implantable electronic devices (CIED) implant procedures has not been studied. METHODS: We randomized consecutive patients admitted for pacemaker or Implantable Cardioverter Defibrillator (ICD) at our center to either standard analgesia care (STD-Group), or to VRH (VRH-Group). Patients in the STD-Group received intra-venous paracetamol (1 g) 60 min before the procedure, and local anesthesia was performed with lidocaine. For patients of the VRH-Group, VRH was used on top of standard care. We monitored patients' pain and anxiety using numeric rating scales (from 0 to 10) at the time of sub-cutaneous pocket creation, and during deep axillary vein puncture. Patient comfort during the procedure was assessed using a detailed questionnaire. Morphine consumption was also assessed. RESULTS: We randomized 61 patients to STD-Group (n = 31) or VRH-Group (n = 30). Pain and anxiety were lower in the VRH-Group during deep venous puncture (3.0 ± 2.0 vs. 4.8 ± 2.2, p = 0.002 and 2.4 ± 2.2 vs. 4.1 ± 2.4, p = 0.006) but not during pocket creation (p = 0.58 and p = 0.5). Morphine consumption was lower in the VRH-Group (1.6 ± 0.7 vs. 2.1 ± 1.1 mg; p = 0.041). Patients' overall comfort during procedure was similar in both groups. CONCLUSION: VRH use improved pain and anxiety control during deep venous puncture compared to standard analgesia care, and allowed morphine consumption reduction. However, pain and anxiety were similar at the time of sub-cutaneous pocket creation.

High-density mapping of the average complex interval helps localizing atrial fibrillation drivers and predicts catheter ablation outcomes.

Background: Persistent Atrial Fibrillation (PersAF) electrogram-based ablation is complex, and appropriate identification of atrial substrate is critical. Little is known regarding the value of the Average Complex Interval (ACI) feature for PersAF ablation. Objective: Using the evolution of AF complexity by sequentially computing AF dominant frequency (DF) along the ablation procedure, we sought to evaluate the value of ACI for discriminating active drivers (AD) from bystander zones (BZ), for predicting AF termination during ablation, and for predicting AF recurrence during follow-up. Methods: We included PersAF patients undergoing radiofrequency catheter ablation by pulmonary vein isolation and ablation of atrial substrate identified by Spatiotemporal Dispersion or Complex Fractionated Atrial Electrograms (>70% of recording). Operators were blinded to ACI measurement which was sought for each documented atrial substrate area. AF DF was measured by Independent Component Analysis on 1-minute 12-lead ECGs at baseline and after ablation of each atrial zone. AD were differentiated from BZ either by a significant decrease in DF (>10%), or by AF termination. Arrhythmia recurrence was monitored during follow-up. Results: We analyzed 159 atrial areas (129 treated by radiofrequency during AF) in 29 patients. ACI was shorter in AD than BZ (76.4 ± 13.6 vs. 86.6 ± 20.3 ms; p = 0.0055), and mean ACI of all substrate zones was shorter in patients for whom radiofrequency failed to terminate AF [71.3 (67.5-77.8) vs. 82.4 (74.4-98.5) ms; p = 0.0126]. ACI predicted AD [AUC 0.728 (0.629-0.826)]. An ACI < 70 ms was specific for predicting AD (Sp 0.831, Se 0.526), whereas areas with an ACI > 100 ms had almost no chances of being active in AF maintenance. AF recurrence was associated with more ACI zones with identical shortest value [3.5 (3-4) vs. 1 (0-1) zones; p = 0.021]. In multivariate analysis, ACI < 70 ms predicted AD [OR = 4.02 (1.49-10.84), p = 0.006] and mean ACI > 75 ms predicted AF termination [OR = 9.94 (1.14-86.7), p = 0.038]. Conclusion: ACI helps in identifying AF drivers, and is correlated with AF termination and AF recurrence during follow-up. It can help in establishing an ablation plan, by prioritizing ablation from the shortest to the longest ACI zone.

Ethanol infusion in left atrial appendage vein for treating refractory left atrial appendage tachycardia.

INTRODUCTION: We describe an unusual case of atrial tachycardia (AT) emanating from the left atrial appendage body (LAA), successfully treated by chemical ablation. METHODS: A 66-year-old patient with cardiac amyloidosis and history of persistent atrial fibrillation ablation presented poorly tolerated AT with 1:1 atrioventricular nodal conduction at 135/min, despite amiodarone therapy. Three-dimensional mapping suggested a reentrant AT from the anterior aspect of the left LAA. RESULTS: The tachycardia could not be terminated with radiofrequency ablation. The LAA vein was then selectively catheterized and infused with Ethanol, resulting in immediate termination of tachycardia, without LAA isolation. No recurrence occurred at 12 months. CONCLUSION: Atrial tachycardias emanating from the LAA that are resistant to radiofrequency ablation may respond to chemical ablation of the LAA vein.

Atrial fibrillation ablation in a single atrium with inferior vena cava interruption.

Common atrium (CA), also called three-chambered heart, is one of the rare congenital anomalies, defined by a complete absence of the atrial septum, eventually associated with malformation of the atrioventricular (AV) valves. We report the case of a 57-year-old woman with CA complicated with Eisenmenger syndrome and inferior vena cava interruption, who suffered from symptomatic persistent atrial fibrillation (AF). She underwent an initial successful pulmonary vein isolation procedure. A repeat procedure for perivalvular atrial flutter was complicated with inadvertent complete AV block, due to unusual AV node location in this challenging anatomy.

Prevalence and Clinical Characteristics of Patients with Torsades de Pointes Complicating Acquired Atrioventricular Block.

BACKGROUND: Female gender, degree of QT prolongation, and genetic susceptibility are known risk factors for developing torsades de pointes (TdP) during high-grade atrioventricular block (HG-AVB). Our objective was to analyze the prevalence and clinical characteristics of patients presenting with TdP and AVB (TdP [+]) in comparison with non-TdP patients with AVB (TdP [-]). METHODS: All the ECGs from patients prospectively admitted for AVB (2 to 1, HG, and complete) at the University Hospital of Nice were analyzed. Automated corrected QT (QTc), manual measurements of QT and JT intervals, and Tpeak-to-end were performed at the time of the most severe bradycardia. RESULTS: From September 2020 to November 2021, 100 patients were admitted for HG-AVB. Among them, 17 patients with TdP were identified (8 men; 81 ± 10 years). No differences could be identified concerning automated QTc, manual QTc (Bazett correction), baseline QRS width, or mean left ventricular ejection fraction between the two groups. Potassium serum level on admission and mean number of QT-prolonging drugs per patient were not significantly different between the two groups, respectively: 4.34 ± 0.5 mmol/L in TdP [+] versus 4.52 ± 0.6 mmol/L (p = 0.33); and 0.6 ± 0.7 in TdP [+] versus 0.3 ± 0.5 (p = 0.15). In contrast, manual QTcFR (Fridericia correction), JT (Fridericia correction), Tpeak-to-end, and Tpe/QT ratio were significantly increased in the TdP [+] group, respectively: 486 ± 70 ms versus 456 ± 53 ms (p = 0.04); 433 ± 98 ms versus 381 ± 80 ms (p = 0.02); 153 ± 57 ms versus 110 ± 40 ms (p < 0.001); and 0.27 ± 0.08 versus 0.22 ± 0.06 (p < 0.001). CONCLUSIONS: The incidence of TdP complicating acquired AVB was 17%. Longer QTcFR, JT, and Tpeak-to-end were significantly increased in the case of TdP but also in the presence of permanent AVB during the hospitalization.

Additional prognostic value of echocardiographic follow-up in pulmonary hypertension-role of 3D right ventricular area strain.

AIMS: Outcomes in pulmonary hypertension (PH) are related to right ventricular (RV) function and remodelling. We hypothesized that changes in RV function and especially area strain (AS) could provide incremental prognostic information compared to the use of baseline data only. We therefore aimed to assess RV function changes between baseline and 6-month follow-up and evaluate their prognostic value for PH patients using 3D echocardiography. METHODS AND RESULTS: Ninety-five PH patients underwent a prospective longitudinal study including ESC/ERS guidelines prognostic assessment and 3D RV echocardiographic imaging at baseline and 6-month follow-up. Semi-automatic software tracked the RV along the cycle, and its output was post-processed to extract 3D deformation patterns. Over a median follow-up of 24.8 (22.1-25.7) months, 21 patients died from PH or were transplanted. Improvements in RV global AS were associated with stable or improving clinical condition as well as survival free from transplant (P < 0.001). The 3D deformation patterns confirmed that the most significant regional changes occurred within the septum. RV global AS change over 6-month by +3.5% identifies patients with a 3.7-fold increased risk of death or transplant. On multivariate COX analysis, changes in WHO class, BNP, and RV global AS were independent predictors of outcomes. Besides, the combination of these three parameters was of special interest to identify high-risk patients [HR 11.5 (1.55-86.06)]. CONCLUSION: Changes in RV function and especially changes in 3D RV AS are of prognostic importance. Our study underlines that assessing such changes from baseline to follow-up is of additional prognostic value for PH patients. CLINICAL TRIAL REGISTRATION: http://clinicaltrials.gov/ct2/show/NCT02799979.

Fibrillatory Wave Amplitude Evolution during Persistent Atrial Fibrillation Ablation: Implications for Atrial Substrate and Fibrillation Complexity Assessment.

Background. Fibrillatory Wave Amplitude (FWA) has been described as a non-invasive marker of atrial fibrillation (AF) complexity, and it predicts catheter ablation outcome. However, the actual determinants of FWA remain incompletely understood. Objective. To assess the respective implications of anatomical atrial substrate and AF spectral characteristics for FWA. Methods. Persistent AF patients undergoing radiofrequency catheter ablation were included. FWA was measured on 1-min ECG by TQ concatenation in Lead I, V1, V2, and V5 at baseline and immediately before AF termination. FWA evolution during ablation was compared to that of AF dominant frequency (DF) measured by Independent Component Analysis on 12-lead ECG. FWA was compared to the extent of endocardial low-voltage areas (LVA I < 10%; II 10-20%; III 20-30%; IV > 30%), to the surface of healthy left atrial tissue, and to P-wave amplitude in sinus rhythm. The predictive value of FWA for AF recurrence during follow-up was assessed. Results. We included 29 patients. FWA remained stable along ablation procedure with comparable values at baseline and before AF termination (Lead I p = 0.54; V1 p = 0.858; V2 p = 0.215; V5 p = 0.14), whereas DF significantly decreased (5.67 ± 0.68 vs. 4.95 ± 0.58 Hz, p < 0.001). FWA was higher in LVA-I than in LVA-II, -III, and -IV in Lead I and V5 (p = 0.02 and p = 0.01). FWA in V5 was strongly correlated with the surface of healthy left atrial tissue (R = 0.786; p < 0.001). FWA showed moderate to strong correlation to P-wave amplitude in all leads. Finally, FWA did not predict AF recurrence after a follow-up of 23.3 ± 9.8 months. Conclusions. These findings suggest that FWA is unrelated to AF complexity but is mainly determined by the amount of viable atrial myocytes. Therefore, FWA should only be referred as a marker of atrial tissue pathology.

Diuretics Versus Volume Expansion in the Initial Management of Acute Intermediate High-Risk Pulmonary Embolism.

AIMS: The very early management of pulmonary embolism (PE), a part from antithrombotic treatment, has been little studied. Our aim was to compare the effects of diuretic therapy (DT) versus volume expansion (VE) in patients hospitalized for PE with RV dysfunction. METHODS AND RESULTS: We conducted a randomized open-label multicentric study including patients with intermediate high-risk PE. Patients were randomized between diuretics or saline infusion. The primary endpoint was time to troponin (Tp) normalization. Secondary endpoints were time to normalization of B-type natriuretic peptide (BNP), changes in echocardiographic RV function parameters and treatment tolerance. Sixty patients presenting intermediate high-risk PE were randomized. Thirty received DT and 30 VE. We noted no changes in Tp kinetics between the two groups. In contrast, faster normalization of BNP was obtained in the DT group: 56 [28-120] vs 108 [48-144] h: p = 0.05, with a shorter time to 50%-decrease from peak value 36 [24-48] vs 54 [41-67] h, p = 0.003 and a higher rate of patients with a lower BNP concentration within the first 12 h (42% vs 12% p < 0.001). RV echocardiographic parameters were unchanged between the groups. One dose 40 mg furosemide was well-tolerated and not associated with any serious adverse events. CONCLUSION: In the acute management of intermediate high-risk PE, initial therapy including diuretic treatment is well-tolerated and safe. Although changes in Tp kinetics and echocardiographic RV dysfunction parameters did not differ, normalization of BNP is achieved more quickly in the DT group. This finding, which need to be confirmed in trials with clinical end points, may reflects a rapid improvement in RV function using one dose 40 mg furosemide. TRIAL REGISTRY: Clinical Trial Registration NCT02531581.

Prevalence and Clinical Characteristics of Patients with Pause-Dependent Atrioventricular Block.

BACKGROUND: In patients with complete atrioventricular block (AVB), the prevalence and clinical characteristics of patients with pause-dependent AVB (PD-AVB) is not known. Our objective was to assess the prevalence of PD-AVB in a population of patients with complete (or high-grade) AVB. METHODS: Twelve-lead electrocardiogram (ECG) and/or telemonitoring from patients admitted (from September 2020 to November 2021) for complete (or high-degree) AVB were prospectively collected at the University Hospital of Nice. The ECG tracings were analyzed by an electrophysiologist to determine the underlying mechanism of PD-AVB. RESULTS: 100 patients were admitted for complete (or high-grade) AVB (men 55%; 82 ± 12 years). Arterial hypertension was present in 68% of the patients. Baseline QRS width was 117 ± 32 ms, and mean left ventricular ejection fraction was 56 ± 7%. Fourteen patients (14%) with PD-AVB were identified, and presented similar clinical characteristics in comparison with patients without PD-AVB, except for syncope (which was present in 86% versus 51% in the non-PD-AVB patients, p = 0.01). PD-AVB sequence was induced by: Premature atrial contraction (8/14), premature ventricular contraction (5/14), His extrasystole (1/14), conduction block in a branch (1/14), and atrial tachycardia termination (1/14). All patients with PD-AVB received a dual-chamber pacemaker during hospitalization. CONCLUSION: The prevalence of PD-AVB was 14%, and may be underestimated. PD-AVB episodes were more likely associated with syncope in comparison with patients without PD-AVB.

Slow pathway elimination using antegrade conduction improvement with fast atrial pacing during AVNRT radiofrequency ablation: a proof-of-concept study.

BACKGROUND: Radiofrequency (RF) ablation of slow pathway (SP) is usually performed in sinus rhythm while monitoring the occurrence of a slow junctional rhythm (JR). JR although sensitive, is not specific for elimination of SP conduction. Our objective was to prospectively evaluate feasibility and safety of SP elimination using fast atrial rate pacing (FAP) during RF delivery. METHODS: Consecutive patients admitted for atrioventricular nodal re-rentrant tachycardia (AVNRT) ablation were included. The rate of proximal coronary sinus (CS) pacing was set to a value constantly yielding antegrade SP conduction, while carefully monitoring the AH interval. RF delivery (at the lower part of Koch's triangle) was considered successful if the AH shortened ≥ 14 ms or if transition from Wenckebach (WK) periods to a 1:1 conduction occurred. RESULTS: 24 patients were included (54 ± 20 y). Typical AVNRT was induced in all (cycle length 349 ± 83 ms). RF delivery during CS pacing (335 ± 73 ms) led to AH shortening by 51 ± 25 ms in 13 patients. In 10 patients, a transition from 3:2 or 4:3 WK periods to 1:1 conduction occurred during the successful pulse. In one patient, atrial fibrillation was systematically induced during FAP, requiring conventional ablation. Non-inducibility, and SP conduction disappearance was obtained in all patients. No patient developed AV block. After a follow-up of 12 ± 3 months, no recurrences were observed. CONCLUSION: SP ablation using FAP during RF delivery allows direct visualisation of its disappearance. In our cohort of patients, this technique was feasible without safety compromise.

Value of 3D right ventricular function over 2D assessment in acute pulmonary embolism.

BACKGROUND: Pulmonary embolism (PE) is a common life-threatening disease, with mortality related to right ventricular (RV) dysfunction. AIMS: To investigate the value of 3D global and regional RV strain in patients with acute PE and at 1 month, as compared to a control population. METHODS AND RESULTS: We conducted a longitudinal case-control prospective study, including 24 consecutive intermediate-risk PE patients. All patients underwent 2D and 3D transthoracic echocardiography within 12 hours of PE diagnosis and 1 month after hospital discharge. A control group was recruited, consisting of healthy volunteers matched on age and sex with PE patients. 3D RV echocardiographic sequences were analyzed by commercial RV-specific software and output meshes were post-processed to extract regional deformation. 3D echocardiographic 1-month follow-up was available in 18 patients. During acute PE, area strain was substantially altered in the RV free wall and within the trabecular septum. PE patients initially had RV dysfunction as assessed by 2D and 3D parameters. At follow-up, 2D parameters were restored compared to the control group, contrary to 3D RV area and circumferential strains. The McConnell's sign was identified in 83% of patients and was associated with reduced apical and global RV area strain. CONCLUSIONS: Our 3D RV strain study demonstrates an incomplete recovery of 3D strain parameters 1 month after an episode of intermediate-risk acute PE despite restored 2D parameters. Further studies are required to assess the prognostic role and implications of this residual RV strain impairment after PE.

Is pulmonary embolism recurrence linked with the severity of the first event? A French retrospective cohort study.

OBJECTIVES: Severity of a first pulmonary embolism (PE) is sometimes proposed as a criterion for prolonging anticoagulant treatment. However, little evidence supports this idea. We attempted to determine the connection between severity of first PE and the risk of recurrence. PARTICIPANTS: Patients admitted with PE between 2012 and 2018 and for whom anticoagulant treatment had been discontinued were followed. PEs were classified according to the severity into the following two groups: those with associated cardiac involvement (increased cardiac biomarker(s) and/or echocardiographic right ventricular dysfunction) and those with no cardiac involvement which were classified as non-severe. Recurrence-free survivals were estimated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: 417 patients with PEs (186 with cardiac involvement) were followed for at least 1 year after discontinuation of treatment with a mean follow-up of: 3.5±1.9 years. 72 patients (17.3%) experienced venous thromboembolism recurrence: 24 (5.8%), 44 (12 %) and 72 (28.3 %) respectively, at 1, 2 and 5 years. In 63 patients (88%), recurrence was a PE. Mean time to onset of recurrence was 24.9±19.9 months. At 5 years, the recurrence rate is higher when the first PE was associated with cardiac involvement p=0.043. In contrast, in patients with provoked PE, the recurrence rate is higher when the first PE event was associated with cardiac involvement: p=0.032. Multivariate analysis demonstrates that PE severity is an independent factor of recurrence (HR 1.634 (1.015-2.632), p=0.043). CONCLUSION: We report for the first time a possible link between a higher recurrence rate and the severity of the first PE. This result which must be confirmed in a dedicated prospective trial could become an important criterion for the duration of anticoagulant therapy after a PE. TRIAL REGISTRATION NUMBER: NCT04980924.

Does Unidirectional Block Exist after a Radiofrequency Line Creation? Insights from Ultra-High-Density Mapping (The UNIBLOCK Study).

BACKGROUND: Whether unidirectional conduction block (UB) can be observed after creation of a radiofrequency (RF) line is still debated. Previous studies reported a prevalence of 9 to 33% of UB, but the assessment was performed using a point-by-point recording across the line. Ultra-high-density (UHD) system may bring some new insights on the exact prevalence of UB. PURPOSE: A prospective study was conducted to assess the prevalence of UB and bidirectional block (BB) using UHD system after RF line creation. METHODS: Patients referred for atrial RF ablation procedure were included in this multicenter prospective study. UHD maps were performed by pacing both sides of the created line. RESULTS: A total of 80 maps were created in 40 patients (67 ± 12 years, 70% male) by pacing (mean cycle length 600 ± 57 ms) from both sides of the cavotricuspid isthmus line. After a 47 ± 17 min waiting time after the last RF application, UHD maps (mean number of 4842 ± 5010 electrograms, acquired during 6 ± 5 min) showed that BB was unambiguously confirmed on all of them. UB was not observed in any map. After a mean follow-up of 12 ± 4 months, 6 (14%) patients experienced an arrhythmia recurrence. CONCLUSION: After creation of an RF line, no case of UB was observed using UHD mapping, suggesting that the presence of a conduction block along a RF line is always associated with a block in the opposite direction.

Cardiac anatomical axes by CT scan and confirmation of the accuracy of fluoroscopic individualized left anterior oblique projection for right ventricular lead implantation.

BACKGROUND: The fluoroscopic individualized LAO (i-LAO) projection has demonstrated high accuracy for identifying right ventricular (RV) lead positioning, likely by approximating a view along the septal or RV long axes. However, RV and septal anatomical axes have not been studied, and their relation with i-LAO is unknown. We sought to determine RV, septal, and left ventricular (LV) long-axis orientations by CT scan and to compare them to the i-LAO angle, to confirm the anatomical relevance of i-LAO. METHODS: We prospectively included patients (pts) for whom i-LAO angle was determined during pacemaker or defibrillator implant. Then, RV, septal, and LV long-axis orientations were determined by CT scan by a physician blinded to i-LAO data. The horizontal components of the cardiac axes were compared with those of the i-LAO angle. RESULTS: We included 26 pts. Median values were 57.5° for i-LAO angle (range 47.5-70), 64.5° for RV axis (range 48-90), 51.5° for septal axis (range 39-74), and 37° for LV axis (range 25-67). i-LAO angle best correlated with septal axis (r = 0.91 and ρc = 0.71). Up to an angle of 70° (maximal measurable i-LAO value; 23/26 pts), the i-LAO angle was comprised between the septal and the RV axes (21/23 pts, 91.3%), or within 2° of this interval (2/23 pts, 8.7%). CONCLUSIONS: RV and septal anatomical axes present major interindividual variations, prompting the use of individualized fluoroscopy criteria for lead implantation. i-LAO angle demonstrated to be almost constantly between the septal and RV long axes, thus confirming its anatomical relevance for RV lead implantation.

Three-dimensional right ventricular shape and strain in congenital heart disease patients with right ventricular chronic volume loading.

AIMS: Right ventricular (RV) function assessment is crucial in congenital heart disease patients, especially in atrial septal defect (ASD) and repaired Tetralogy of Fallot (TOF) patients with pulmonary regurgitation (PR). In this study, we aimed to analyse both 3D RV shape and deformation to better characterize RV function in ASD and TOF-PR. METHODS AND RESULTS: We prospectively included 110 patients (≥16 years old) into this case-control study: 27 ASD patients, 28 with TOF, and 55 sex- and age-matched healthy controls. Endocardial tracking was performed on 3D transthoracic RV echocardiographic sequences and output RV meshes were post-processed to extract local curvature and deformation. Differences in shape and deformation patterns between subgroups were quantified both globally and locally. Curvature highlights differences in RV shape between controls and patients while ASD and TOF-PR patients are similar. Conversely, strain highlights differences between controls and TOF-PR patients while ASD and controls are similar [global area strain: -31.5 ± 5.8% (controls), -34.1 ± 7.9% (ASD), -24.8 ± 5.7% (TOF-PR), P < 0.001, similar significance for longitudinal and circumferential strains]. The regional and local analysis highlighted differences in particular in the RV free wall and the apical septum. CONCLUSION: Chronic RV volume loading results in similar RV shape remodelling in both ASD and TOF patients while strain analysis demonstrated that RV strain is only reduced in the TOF group. This suggests a fundamentally different RV remodelling process between both conditions.

Active compression versus standard anterior-posterior defibrillation for external cardioversion of atrial fibrillation: A prospective randomized study.

BACKGROUND: Electrical cardioversion is the first-line rhythm control therapy for symptomatic persistent atrial fibrillation (AF). Contemporary use of biphasic shock waveforms and anterior-posterior positioning of defibrillation electrodes have improved cardioversion efficacy; however, it remains unsuccessful in >10% of patients. OBJECTIVE: The purpose of this study was to assess the efficacy of applying active compression on defibrillation electrodes during AF cardioversion. METHODS: We performed a bicenter randomized study including patients referred for persistent AF cardioversion. Elective external cardioversion was performed by a standardized step-up protocol with increasing biphasic shock energy (50-100-150-200 J). Patients were randomly assigned to standard anterior-posterior defibrillation or to defibrillation with active compression applied over the anterior electrode. If sinus rhythm was not achieved at 200 J, a single crossover shock (200 J) was applied. Defibrillation threshold, total delivered energy, number of shocks, and success rate were compared between groups. RESULTS: We included 100 patients, 50 in each group. In the active compression group, defibrillation threshold was lower (103.1 ± 49.9 J vs 130.4 ± 47.7 J; P = .008), as well as total delivered energy (203 ± 173.3 J vs 309 ± 213.5 J; P = .0076) and number of shocks (2.2 ± 1.1 vs 2.9 ± 1.2; P = .0033), and cardioversion was more often successful (48 of 50 patients [96%] vs 42 of 50 patients [84%]; P = .0455) than that in the standard anterior-posterior group. Crossover from the compression group to the standard group was not successful (0 of 2 patients), whereas crossover from the standard group to the compression group was successful in 50% of patients (4 of 8). CONCLUSION: Active compression applied to the anterior defibrillation electrode is more effective for persistent AF cardioversion than standard anterior-posterior cardioversion, with lower defibrillation threshold and higher success rate.

Data Augmentation for Automatic Identification of Spatiotemporal Dispersion Electrograms in Persistent Atrial Fibrillation Ablation Using Machine Learning.

Catheter ablation is increasingly used to treat atrial fibrillation (AF), the most common sustained cardiac arrhythmia encountered in clinical practice. A recent breakthrough finding in AF ablation consists in identifying ablation sites based on their spatiotemporal dispersion (STD). STD stands for a delay of the cardiac activation observed in intracardiac electrograms (EGMs) across contiguous leads. In practice, interventional cardiologists localize STD sites visually using the PentaRay multipolar mapping catheter. This work aims at automatically characterizing STD by classifying EGM data into STD vs. non STD groups using machine learning (ML) techniques. A dataset of 23082 multichannel EGM recordings acquired by the PentaRay coming from 16 persistent AF patients is included in this study. A major problem hampering the classification performance lies in the highly imbalanced dataset ratio. We suggest to tackle data imbalance using adapted data augmentation techniques including 1) undersampling 2) oversampling 3) lead shift 4) time reversing and 5) time shift. These tools are designed to preserve the integrity of the cardiac data and are validated by a partner cardiologist. They provide enhancement in classification performance in terms of sensitivity, which increases from 50% to 80% while maintaining accuracy and AUC around 90% with oversampling. Bootstrapping is applied to check the variability of the trained classifiers.Clinical relevance-The machine learning techniques developed in this contribution are expected to aid cardiologists in performing patient-tailored catheter ablation procedures for treating persistent AF.