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Background: Spatial differences in conduction velocity (CV) are critical for cardiac arrhythmias induction. We propose a method for an automated CV calculation to identify areas of slower conduction during cardiac arrhythmias and sinus rhythm., Methods: Color-coded representations of the isochronal activation map using data coming from the RHYTHMIA™ Mapping System were reproduced by applying a temporal isochronal window at 20 ms. Geodesic distances of the 3D mesh were calculated using an algorithm selecting the minimum distance pathway (MDP). The CV estimation was performed considering points on the boundary of two spatially and temporally adjacent isochrones. For each of the boundary points of a given isochrone, the nearest boundary point of the consecutive isochrone was chosen, the MDP was evaluated, and a map of CV was created. The proposed method has been applied to a population of 29 patients., Results: In all cases of perimitral atrial flutter (16 pts out of 29 (55%)), areas with significantly low CV (< 30 cm/s) were found. Half of the cases present regions with low CV located in the anterior wall. No case with low CV at the so-called LA isthmus was observed. Right atrial maps during common atrial flutters showed low CV areas mainly located in the inferior inter-atrial septum. No areas of low CV were observed in subjects without a history of atrial arrhythmia while pts affected by paroxysmal AF showed areas with a limited extension of low CV., Conclusions: The proposed software for automated CV estimation allows the identification of low CV areas, potentially helping electrophysiologists to plan the ablation strategy., (© 2022. The Author(s).)

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most frequent regular tachycardia in humans. In this review, we describe the most recent discoveries regarding the anatomical, physiological, and molecular biological features of the atrioventricular junction that could underlie the typical slow-fast AVNRT mechanisms, as these insights could lead to the proposal of a new theory concerning the circuit of this arrhythmia. Despite several models have been proposed over the years, the precise anatomical site of the reentrant circuit and the pathway involved in the slow-fast AVNRT have not been conclusively defined. One possible way to evaluate all the hypotheses regarding the nodal tachycardia circuit in humans is to map this circuit. Thus, we tried to identify the slow potential of nodal and inferior extension structures by using automated mapping of atrial activation during both sinus rhythm and typical slow-fast AVNRT. This constitutes a first step toward the definition of nodal area activation in sinus rhythm and during slow-fast AVNRT. Further studies and technical improvements in recording the potentials of the atrioventricular node structures are necessary to confirm our initial results., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Local impedance (LI) drop predicts acute conduction block during pulmonary vein isolation (PVI). Whether the LI drop predicts also the achievement of left atrial posterior wall isolation (LAPWI) in persistent atrial fibrillation (PersAF) patients is unknown. We evaluated the efficacy and the safety of LI drop-guided LAPW ablation by using high power (50 watts) and investigated the impact of ablation parameters on the LI drop., Methods: We included consecutive PersAF patients underwent PVI and both roof line and floor line completion to achieve LAPWI with a novel contact force (CF)- and LI-featured catheter (IntellaNAV Stablepoint™). For each radiofrequency (RF) application, we targeted a LI drop of 25 ohms., Results: Out of 30 patients, first-pass floor line block was achieved in 26 (87%) and first-pass roof line block in 17 (57%), resulting in first-pass LAPWI in 14 patients (47%). After touch-up ablations, LAPWI was achieved in 28 patients (93%) with endocardial ablation only. No procedural nor 1-month complications occurred. Overall, 877 RF applications were delivered: 787 ablation tags (89%) were associated with acute conduction block, while 90 (11%) were located at sites of acute gaps in either the roof or floor line. LI drop values were greater at segments with acute block than those with gaps (p < 0.001). At multivariable analysis, only LI drop and RF time remained independently associated with the acute block (p < 0.001; p = 0.001)., Conclusions: LI drop-guided LAPWI at a fixed power of 50 W was effective and did not lead to complications. LI drop was the most important predictor of acute conduction block., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: Unrecognized incomplete pulmonary vein (PV) isolation during the index procedure, can be a major cause of clinical recurrences of atrial fibrillation (AF) after cryoballoon (CB) ablation. We aimed to characterize the extension of the lesions produced by CB ablation and to assess the value of using an ultra-high resolution electroanatomic mapping (UHDM) system to detect incomplete CB lesions., Materials and Methods: Twenty-nine consecutive patients from the CHARISMA registry undergoing AF ablation at four Italian centers were prospectively evaluated. The Rhythmia™ mapping system and the Orion™ (Boston Scientific) mapping catheter were used to systematically map the left atrium and PVs before and after cryoablation., Results: A total of 116 PVs were targeted and isolated. Quantitative assessment of the lesions revealed a significant reduction of the antral surface area of the PV, resulting in an ablated area of 5.7 ± 0.7 cm 2 and 5.1 ± 0.8 cm 2 for the left PV pair and right PV pair, respectively ( p = 0.0068). The mean posterior wall (PW) area was 22.9 ± 2 cm 2 and, following PV isolation, 44.8 ± 6% of the PW area was ablated. After CB ablation, complete isolation of each PV was documented by the POLARMap™ catheter in all patients. By contrast, confirmatory UHDM and the Lumipoint™ tool unveiled PV signals in 1 out of 114 of the PVs (0.9%). Over 30-day follow-up, no major procedure-related adverse events were reported. After a mean follow-up of 333 days, 89.7% of patients were free from arrhythmia recurrence., Conclusion: The lesion extension achieved by the new CB ablation system involved the PV antrum, with less than 50% of the PW remaining untouched. The new system, with short tip and circular mapping catheter, failed to achieve PV isolation in only 0.9% of all PVs treated., Clinical Trial Registration: [http://clinicaltrials.gov/], identifier [NCT03793998]., Competing Interests: Authors MM and FPi were salaried Boston Scientific employees. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Spera, Narducci, Bencardino, Perna, Bisignani, Pinnacchio, Tondo, Maggio, Stabile, Iacopino, Tundo, Ferraro, De Simone, Malacrida, Pintus, Crea and Pelargonio.)

Introduction: Low-voltage activity beyond pulmonary veins (PVs) may contribute to the failure of ablation of atrial fibrillation (AF) in the long term. We aimed to assess the presence of gaps (PVG) and residual potential (residual antral potential [RAP]) within the antral scar by means of an ultra-high-density mapping (UHDM) system., Methods: We studied consecutive patients from the CHARISMA registry who were undergoing AF ablation and had complete characterization of residual PV antral activity. The Lumipoint™ (Boston Scientific) map-analysis tool was used sequentially on each PV component. The ablation endpoint was PV isolation (PVI) and electrical quiescence in the antral region., Results: Fifty-eight cases of AF ablation were analyzed. A total of 86 PVGs in 34 (58.6%) patients and 44 RAPs in 34 patients (58.6%) were found. In 16 (27.6%) cases, we found at least one RAP in patients with complete absence of PV conduction. RAPs showed a lower mean voltage than PVG (0.3 ± 0.2 mV vs. 0.7 ± 0.5 mV, p < .0001), whereas the mean number of electrogram peaks was higher (8.4 ± 1.4 vs. 3.2 ± 1.5, p < .0001). The percentage of patients in whom RAPs were detected through Lumipoint™ was higher than through propagation map analysis (58.6% vs. 36.2%, p = .025). Acute procedural success was 100%, with all PVs successfully isolated and RAPs completely abolished in all study patients. During a mean follow-up of 453 ± 133 days, 6 patients (10.3%) suffered an AF/AT recurrence., Conclusion: Local vulnerabilities in antral lesion sets were easily discernible by means of the UHDM system in both de novo and redo patients when no PV conduction was present., (© 2022 Wiley Periodicals LLC.)

Background: The antral region of pulmonary veins (PV)s seems to play a key role in a strategy aimed at preventing atrial fibrillation (AF) recurrence. Particularly, low-voltage activity in tissue such as the PV antra and residual potential within the antral scar likely represent vulnerabilities in antral lesion sets, and ablation of these targets seems to improve freedom from AF. The aim of this study is to validate a structured application of an approach that includes the complete abolition of any antral potential achieving electrical quiescence in antral regions., Methods: The improveD procEdural workfLow for cathETEr ablation of paroxysmal AF with high density mapping system and advanced technology (DELETE AF) study is a prospective, single-arm, international post-market cohort study designed to demonstrate a low rate of clinical atrial arrhythmias recurrence with an improved procedural workflow for catheter ablation of paroxysmal AF, using the most advanced point-by-point RF ablation technology in a multicenter setting. About 300 consecutive patients with standard indications for AF ablation will be enrolled in this study. Post-ablation, all patients will be monitored with ambulatory event monitoring, starting within 30 days post-ablation to proactively detect and manage any recurrences within the 90-day blanking period, as well as Holter monitoring at 3, 6, 9, and 12 months post-ablation. Healthcare resource utilization, clinical data, complications, patients' medical complaints related to the ablation procedure and patient's reported outcome measures will be prospectively traced and evaluated., Discussion: The DELETE AF trial will provide additional knowledge on long-term outcome following a structured ablation workflow, with high density mapping, advanced algorithms and local impedance technology, in an international multicentric fashion. DELETE AF is registered at ClinicalTrials.gov (NCT05005143)., (© 2022 The Authors. Clinical Cardiology published by Wiley Periodicals LLC.)

Background: Although radiofrequency (RF) catheter ablation of cavo-tricuspid isthmus (CTI) is an established treatment for typical right atrial flutter (RAFL), it remains to be established whether local tissue impedance (LI) is able to predict effective CTI ablation and what LI drop values during ablation should be used to judge a lesion as effective. We aimed to investigate the ability of LI to predict ablation efficacy in patients with RAFL., Methods: RF delivery was guided by the DirectSense™ algorithm. Successful single RF application was defined according to a defragmentation of atrial potentials (DAP), reduction of voltage (RedV) by at least 80% or changes on unipolar electrogram (UPC). The ablation endpoint was the creation of bidirectional conduction block (BDB) across the isthmus., Results: 392 point-by-point RF applications were analyzed in 48 consecutive RAFL patients. The mean baseline LI was 105.4 ± 12Ω prior to ablation and 92.0 ± 11Ω after ablation (p < 0.0001). According to validation criteria, absolute drops in impedance were larger at successful ablation sites than at ineffective ablation sites (DAP: 17.8 ± 6Ω vs. 8.7 ± 4Ω; RedV: 17.2 ± 6Ω vs. 7.8 ± 5Ω; UPC: 19.6 ± 6Ω vs. 10.1 ± 5Ω, all p < 0.0001). LI drop values significantly increased according to the number of criteria satisfied (ranging from 7.5Ω to 19.9). BDB was obtained in all cases. No procedure-related adverse events were reported., Conclusions: A LI-guided approach to CTI ablation was safe and effective in treating RAFL. The magnitude of LI drop was associated with effective lesion formation and BDB and could be used as a marker of ablation efficacy., Clinical Trial Registration: Catheter Ablation of Arrhythmias with a High-Density Mapping System in Real-World Practice (CHARISMA). URL: http://clinicaltrials.gov/ Identifier: NCT03793998., (© 2022 Wiley Periodicals LLC.)

Purpose: Highly localized impedance (LI) measurements during atrial fibrillation (AF) ablation have emerged as a viable real-time indicator of tissue characteristics and the consequent durability of the lesions created. We investigated the impact of catheter-tissue contact force (CF) on LI behavior during pulmonary vein isolation (PVI)., Methods: Forty-five consecutive patients of the CHARISMA registry undergoing de novo AF radiofrequency (RF) catheter ablation with a novel open-irrigated-tip catheter endowed with CF and LI measurement capabilities (Stablepoint™ catheter, Boston Scientific) were included., Results: A total of 2895 point-by-point RF applications were analyzed (RF delivery time (DT) = 8.7±4s, CF = 13 ±±8 g, LI drop = 23 ±±7 Ω). All PVs were successfully isolated in an overall procedure time of 118 ±±34 min (fluoroscopy time = 13 ±±8 min). The magnitude of LI drop weakly correlated with CF (r = 0.13, 95% confidence interval (CI): 0.09 to 0.16, p < 0.0001), whereas both CF and LI drop inversely correlated with DT (r = -0.26, 95%CI: -0.29 to -0.22, p < 0.0001 for CF; r = -0.36, 95%CI: -0.39 to -0.33, p < 0.0001 for LI). For each 10 g of CF, LI drop markedly increased from 22.4 ± 7 Ω to 24.0 ± 8 Ω at 5 to 25 g CF intervals (5-14 g of CF vs 15-24 g of CF, p < 0.0001), whereas it showed smooth transition over 25 g (24.8 ± 7Ω at ≥ 25 g CF intervals, p = 0.0606 vs 15-24 g of CF). No major complications occurred during the procedures or within 30 days., Conclusions: CF significantly affects LI drop and probable consequent lesion formation during RF PVI. The benefit of higher contact (> 25 g) between the catheter and the tissue appears to have less impact on LI drop., Trial Registration: Catheter Ablation of Arrhythmias With High Density Mapping System in the Real World Practice (CHARISMA). URL: http://clinicaltrials.gov/ Identifier: NCT03793998., (© 2022. The Author(s).)

Competing Interests: This research received no specific grant from any funding agency, commercial, or not‐for‐profit sectors. Maurizio Malacrida is an employee of Boston Scientific. No other conflict of interest to declare.

Background: Predicting an accessory pathway location is extremely important in pediatric patients., Aims: We designed a study to compare previously published algorithms by Arruda, Boersma, and Chiang., Methods: This multicenter study included patients who had undergone successful ablation of one accessory pathway. Analysis of resting 12-lead electrocardiograms was carried out. An aggregated prediction score was constructed on the basis of algorithm agreement, and a structured workflow approach was proposed., Results: The total population was 120 patients (mean age, 12.7 [± 3.6] years). The algorithm by Boersma had the highest accuracy (71.7%). The inter-rater agreement among the 3 reference algorithms, according to left-sided accessory pathway (AP) identification, was good between Boersma and Chiang (κ = 0.611; 95% confidence interval [CI], 0.468-0.753) but moderate between Arruda and Chiang and between Arruda and Boersma (κ = 0.566; 95% CI, 0.419-0.713 and κ = 0.582; 95% CI, 0.438-0.727, respectively). Regarding locations at risk of atrioventricular (AV) block, agreement was fair between Arruda and Chiang and between Boersma and Chiang (κ = 0.358; 95% CI, 0.195-0.520 and κ = 0.307; 95% CI, 0.192-0.422, respectively) but moderate between Arruda and Boersma (κ = 0.45; 95% CI, 0.304-0.597). On applying a first-step diagnostic evaluation, when concordance was achieved, we were able to correctly identify left-sided or non-left-sided ablation sites in 96.4% (n = 80) of cases. When concordance was achieved, correct prediction of risk/no risk of AV block was achieved in 92.2% (n = 59) of cases., Conclusions: An aggregated prediction score based on 3 reference algorithms proved able to predict an accessory pathway location very precisely and could be used to plan safely invasive procedures.

Background: An early, comprehensive rhythm-control therapy is needed in order to treat atrial fibrillation (AF) effectively and to improve ablation outcomes., Methods: A total of 153 consecutive patients from the CHARISMA registry undergoing AF ablation at eight centers were included. Patients with de novo PVI were classified as having undergone early treatment (ET) if the procedure was performed within 6 months after the first AF episode, and as having undergone delayed treatment (DT) if ablation was performed over 6 months after the first AF episode., Results: One-hundred fifty-three patients were enrolled (69.9% male, 59 ± 10 years, 61.4% paroxysmal AF, 38.6% persistent AF). The time from the first AF episode to the ablation procedure was 1034 ± 1483 days. The ET group comprised 36 patients (25.3%), the DT group 60 (39.2%) and Redo cases were 57 (37.3%). During a mean follow-up of 366 ± 130 days, 18 patients (11.8%) suffered an AF/AT recurrence. More DT patients than ET patients suffered recurrences (15.7% vs. 2.2%, p = 0.0452) and the time to AT/AF recurrence was shorter in the group of patients who received an ablation treatment after 6 months (HR = 6.19, 95% CI: 1.7 to 21.9; p = 0.0474). On multivariate Cox analysis, only hypertension (HR = 4.86, 95% CI: 1.6 to 14.98, p = 0.0062) was independently associated with recurrences. Beyond the hypertension risk factor, ET was associated with a low risk of recurrence; recurrence rate ranged from 0% (ET patients without hypertension) to 25.0% (DT patients with hypertension)., Conclusions: An early rhythm-control ablation therapy in the absence of common risk factors was associated with the lowest rate of recurrences., (© 2021 Wiley Periodicals LLC.)

Background: Atrial activation during typical atrioventricular nodal reentrant tachycardia (AVNRT) exhibits anatomic variability and spatially heterogeneous propagation inside the Koch's triangle (KT). The mechanism of the reentrant circuit has not been elucidated yet. Aim of this study is to describe the distribution of Jackman and Haïssaguerre potentials within the KT and to explore the activation mode of the KT, in sinus rhythm and during the slow-fast AVNRT., Methods: Forty-five consecutive cases of successful slow pathway (SP) ablation of typical slow-fast AVNRT from the CHARISMA registry were included., Results: The KT geometry was obtained on the basis of the electroanatomic information using the Rhythmia mapping system (Boston Scientific) (mean number of points acquired inside the KT = 277 ± 47, mean mapping time = 11.9 ± 4 min). The postero-septal regions bounded anteriorly by the tricuspid annulus and posteriorly by the lateral wall toward the crista terminalis showed a higher prevalence of Jackman potentials than mid-postero-septal regions along the tendon of Todaro and coronary sinus (CS) (98% vs. 16%, p < 0.0001). Haïssaguerre potentials seemed to have a converse distribution across the KT (0% vs. 84%, p < 0.0001). Fast pathway insertion, as located during AVNRT, was mostly recorded in an antero-septal position (n = 36, 80%), rather than in a mid-septal (n = 6, 13.3%) or even postero-septal (n = 3, 7%) location. During typical slow-fast AVNRT, two types of propagation around the CS were discernible: anterior and posterior, n = 31 (69%), or only anterior, n = 14 (31%). During the first procedure, the SP was eliminated, and acute procedural success was achieved (median of 4 [3-5] RF ablations)., Conclusion: High-density mapping of KT in AVNRT patients both during sinus rhythm and during tachycardia provides new electrophysiological insights. A better understanding and a more precise definition of the arrhythmogenic substrate in AVNRT patients may have prognostic value, especially in high-risk cases., Trial Registration: Catheter Ablation of Arrhythmias With High Density Mapping System in the Real World Practice (CHARISMA) URL: http://clinicaltrials.gov/ Identifier: NCT03793998., (© 2020. Springer Science+Business Media, LLC, part of Springer Nature.)

A 67-year-old man with history of heart failure developed dyspnea. In this report, we describe an increase in his device-detected respiratory rate. Monitoring respiratory rate is recommended for evaluating acute cardiac decompensation, but such an algorithm could also be used to diagnose episodes of pneumonia caused by severe acute respiratory syndrome-coronavirus-2 infection. ( Level of Difficulty: Intermediate. )., Competing Interests: M. Malacrida is an employee of Boston Scientific. The other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2021 The Authors.)

Background: Highly localized impedance (LI) measurements during atrial fibrillation (AF) ablation have recently emerged as a viable real-time indicator of tissue characteristics and durability of the lesions created. We report the outcomes of acute and long-term clinical evaluation of the new DirectSense algorithm in AF ablation., Methods: Consecutive patients undergoing AF ablation were included in the CHARISMA registry. RF delivery was guided by the DirectSense algorithm, which records the magnitude and time-course of the impedance drop. The ablation endpoint was pulmonary vein isolation (PVI), as assessed by the entrance and exit block., Results: 3556 point-by-point first-pass RF applications of >10 s duration were analyzed in 153 patients (mean age=59 ± 10 years, 70% men, 61% paroxysmal AF, 39% persistent AF). The mean baseline LI was 105 ± 15 Ω before ablation and 92 ± 12 Ω after ablation (p < .0001). Both absolute drops in LI and the time to LI drop (LI drop/τ) were greater at successful ablation sites (n = 3122, 88%) than at ineffective ablation sites (n = 434, 12%) (14 ± 8 Ω vs 6 ± 4 Ω, p < .0001 for LI; 0.73 [0.41-1.25] Ω/s vs. 0.35[0.22-0.59 Ω/s, p < .0001 for LI drop/τ). No major complications occurred during or after the procedures. All PVs had been successfully isolated. During a mean follow-up of 366 ± 130 days, 18 patients (11.8%) suffered an AF/atrial tachycardia recurrence after the 90-day blanking period., Conclusion: The magnitude and time-course of the LI drop during RF delivery were associated with effective lesion formation. This ablation strategy for PVI guided by LI technology proved safe and effective and resulted in a very low rate of AF recurrence over 1-year follow-up., (© 2021 Wiley Periodicals LLC.)

Background: More and more heart failure (HF) patients aged ≥ 75 years undergo cardiac resynchronization therapy (CRT) device implantation, however the data regarding the outcomes and their predictors are scant. We investigated the mid- to long-term outcomes and their predictors in CRT patients aged ≥ 75 years., Methods: Patients in the Cardiac Resynchronization Therapy Modular (CRT MORE) Registry were divided into three age-groups: <65 (group A), 65-74 (group B) and ≥75 years (group C). Mortality, hospitalization, and composite event rate were evaluated at 1 year and during long-term follow-up., Results: Patients ( n = 934) were distributed as follows: group A 242; group B 347; group C 345. On 12-month follow-up examination, 63% of patients ≥ 75 years displayed a positive clinical response. Mortality was significantly higher in patients ≥ 75 years than in the other two groups, although the rate of hospitalizations for HF worsening was similar to that of patients aged 65-74 (7 vs. 9.5%, respectively; p = 0.15). Independent predictors of death and of negative clinical response were age >80 years, chronic obstructive pulmonary disease (COPD) and chronic kidney disease (CKD). Over long-term follow-up (1020 days (IQR 680-1362)) mortality was higher in patients ≥ 75 years than in the other two groups. Hospitalization and composite event rates were similar in patients ≥ 75 years and those aged 65-74 (9 vs. 11.8%; p = 0.26, and 26.7 vs. 20.5%; p = 0.06)., Conclusion: Positive clinical response and hospitalization rates do not differ between CRT recipients ≥ 75 years and those aged 65-74. However, age > 80 years, COPD and CKD are predictors of worse outcomes.

Background: Device replacement is the ideal time to reassess health care goals regarding continuing implantable cardioverter-defibrillator (ICD) therapy. Only few data are available on the decision making at this time., Objectives: The goals of this study were to identify factors associated with poor prognosis at the time of ICD replacement and to develop a prognostic index able to stratify those patients at risk of dying early., Methods: DEtect long-term COmplications after implantable cardioverter-DEfibrillator replacement (DECODE) was a prospective, single-arm, multicenter cohort study aimed at estimating long-term complications in a large population of patients who underwent ICD/cardiac resynchronization therapy - defibrillator replacement. Potential predictors of death were investigated, and all these factors were gathered into a survival score index (SUSCI)., Results: We included 983 consecutive patients (median age 71 years (63-78)); 750 (76%) were men, 537 (55%) had ischemic cardiomyopathy; 460 (47%) were implanted with cardiac resynchronization therapy - defibrillator. During a median follow-up period of 761 days (interquartile range 628-904 days), 114 patients (12%) died. In multivariate Cox regression analysis, New York Heart Association class III/IV, ischemic cardiomyopathy, body mass index < 26 kg/m 2 , insulin administration, age ≥ 75 years, history of atrial fibrillation, and hospitalization within 30 days before ICD replacement remained associated with death. The survival score index showed a good discriminatory power with a hazard ratio of 2.6 (95% confidence interval 2.2-3.1; P < .0001). The risk of death increased according to the severity of the risk profile ranging from 0% (low risk) to 47% (high risk)., Conclusion: A simple score that includes a limited set of variables appears to be predictive of total mortality in an unselected real-world population undergoing ICD replacement. Evaluation of the patient's profile may assist in predicting vulnerability and should prompt individualized options, especially for high-risk patients., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: The aim of this study is to report heart failure hospitalization (HFH) rates and associated costs within 12 months following implantable cardioverter defibrillator (ICD)/cardiac resynchronization therapy defibrillator (CRT-D) device replacement or upgrade from ICD to CRT-D., Methods and Results: The DEtect long-term COmplications after icD rEplacement (DECODE) was a prospective, single-arm, multicentre cohort study that explored complications in ICD/CRT-D recipients. All clinical and survival data at 12 months were prospectively analysed. For each adjudicated HFH, admission and discharge dates and ICD-9-CM diagnosis and procedure codes were recorded. The reimbursement for each HFH was calculated for each diagnosis-related group code. Between 2013 and 2015, 983 patients (mean age 71 years, male 76%, mean left ventricular ejection fraction 35%, and New York Heart Association Class I/II 75.6%) were enrolled. Patients underwent device replacement (900; 91.6%, 446 ICD/454 CRT-D) or ICD upgrade to CRT-D (83; 8.4%). Post-replacement hospitalizations occurred in 220 patients, with the primary discharge diagnosis identifying cardiovascular causes in 175 patients (80%). Fifty-five (5.6%) patients experienced at least one HFH. Overall, 91 HFH events occurred (9.6% event rate, 95% confidence interval: 7.7-11.7) in 70 patients; 66 (6.7%) patients died, 40 (60.6%) of cardiovascular causes. The HFH rate was significantly higher following upgrades, and the occurrence of HFH was associated with an 11-fold increased mortality risk (95% confidence interval: 5.9-20.5, P < 0.0001). Medical diagnosis-related group accounted for 91.2% of HFH; the mean cost per HFH was €5662 ± 9497, and the mean cost per patient was €9369 ± 12 687. On multivariate analysis, predictors of HFH were atrial fibrillation, chronic kidney disease, and all-cause hospitalization within 30 days prior to the procedure., Conclusions: In the DECODE registry, HFH and mortality rates in the year following ICD/CRT-D replacement or upgrade were low. In this particular subset, underlying cardiac disease was the main driver of HFH, mortality, and higher healthcare expenditures., (© 2020 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.)

Introduction: Recently, a novel technology able to measure local impedance (LI) and tissue characteristics has been made available for clinical use. This analysis explores the relationships among LI and generator impedance (GI) parameters in atrial fibrillation (AF) patients. Characterization of LI among different ablation spots and procedural success were also evaluated., Methods and Results: Consecutive patients undergoing AF ablation from the CHARISMA registry at five Italian centers were included. A novel radiofrequency (RF) ablation catheter with a dedicated algorithm (DIRECTSENSE™) was used to measure LI and to guide ablation. The ablation endpoint was pulmonary vein (PV) isolation. We analyzed 2219 ablation spots created around PVs in 46 patients for AF ablation. The mean baseline tissue impedance was 105.8 ± 14 Ω for LI versus 91.8 ± 10 Ω for GI (p < .0001). Baseline impedance was homogenous across the PV sites and proved higher in high-voltage areas than in intermediate- and low-voltage areas and the blood pool (p < .001). Both LI and GI displayed a significant drop after RF delivery, and absolute LI drop values were significantly larger than GI drop values (14 ± 8 vs. 3.7 ± 5 Ω, p < .0001). Every 5-point increment in LI drop was associated with successful ablation (odds ratio = 3.05, 95% confidence interval: 2.3-4.1, p < .0001). Conversely, GI drops were not significantly different comparing successful versus unsuccessful sites (3.7 ± 5 vs. 2.8 ± 4 Ω, p = .1099). No steam pops or major complications occurred during or after the procedures. By the end of the procedures, all PVs had been successfully isolated in all patients., Conclusions: The magnitude of the LI drop was more closely associated with effective lesion formation than the GI drop., (© 2020 Wiley Periodicals LLC.)

Aims: We evaluated the ability of an ultrahigh mapping system to identify the most convenient Rhythmia ablation target (RAT) in intra-atrial re-entrant tachycardias (IART) in terms of the narrowest area to transect to interrupt the re-entry., Methods: A total of 24 consecutive patients were enrolled with a total of 26 IARTs. The Rhythmia mapping system was used to identify the RAT in all IARTs., Results: In 18 cases the RAT matched the mid-diastolic phase of the re-entry whereas in 8 cases the RAT differed. In these patients, the mid-diastolic tissue in the active circuit never represented the area with the slowest conduction velocity of the re-entry. The mean conduction velocity at the mid-diastolic site was significantly slower in the group of patients in which the RAT matched the mid-diastolic site (P = 0.0173) and that of the remaining circuit was significantly slower in the group in which the RAT did not match (P = 0.0068). The mean conduction velocity at the RAT was comparable between the two groups (P = 0.66)., Conclusion: Identifying the RAT in challenging IARTs by means of high-density representation of the wavefront propagation of the tachycardia seems feasible and effective. In one-third of cases this approach identifies an area that differs from the mid-diastolic corridor.

Aims: The benefit of prolonged implantable cardioverter-defibrillator (ICD)/cardiac resynchronization therapy defibrillator (CRT-D) therapy following device replacement is hindered by clinical and procedure-related adverse events (AEs). Adverse events rate is highest in more complex devices and at upgrades, as per the REPLACE registry experience, but is changing owing to the improvement in device technology and medical care. We aimed at understanding the extent and type of AEs in a contemporary Italian population., Methods and Results: Detect long-term complications after ICD replacement (DECODE) was a prospective, single-arm, multicentre cohort study aimed at estimating medium- to long-term AEs in a large population of patients undergoing ICD/cardiac resynchronization defibrillator replacement/upgrade from 2013 to 2015. We prospectively analysed all clinical and device-related AEs at 12-month follow-up (FU) of 983 consecutive patients (median age 71 years, 76% male, 55% ischaemic, 47% CRT-D) followed for 353 ± 49 days. Seven percent of the patients died (60.6% for cardiovascular reasons), whereas 104 AEs occurred; 43 (4.4%) patients needed at least one surgical action to treat the AE. Adverse events rates were 3.3/100 years lead-related, 3.4/100 years bleedings, and 1.6/100 years infective. The primary endpoint was predicted by hospitalization in the month prior to the procedure [hazard ratio (HR) = 2.23, 1.16-4.29; 0.0169] and by upgrade (HR = 1.75, 1.02-2.99, 0.0441). One hundred and twelve (11.4%) patients met the combined endpoint of death from any cause, cardiac implantable electronic device (CIED)-related infection, and surgical action/hospitalization required to treat the AE. Hospitalization within 30 days prior to the procedure (HR = 2.07, 1.13-3.81; 0.0199), anticoagulation (HR = 1.97, 1.26-3.07; 0.003), and ischaemic cardiomyopathy (HR = 1.67, 95% confidence interval 1.06-2.63; P = 0.0276) were associated with the combined endpoint during FU., Conclusions: Adverse events following CIED replacement/upgrade are lower than previously reported, possibly owing to improved patients care. Hospitalization in the month prior to the procedure, upgrade, and clinical profile (anticoagulation, ischaemic cardiomyopathy) hint to increased risk, suggesting an individualized planning of the procedure to minimize overall AEs., Clinical Trial Registration: URL: http://clinicaltrials.gov/ Identifier: NCT02076789., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Objectives: The aim of the study was to confirm the value of the VALID-cardiac resynchronization therapy (CRT) risk score in predicting outcome and to assess its association with clinical response (CR) in an unselected real-world CRT population., Methods and Results: The present analysis comprised all consecutive CRT patients (pts) enrolled in the CRT-MORE registry from 2011 to 2013. Pts were stratified into five groups (quintiles 1-5) according to the VALID-CRT risk predictor index applied to the CRT-MORE population. In the analysis of clinical outcome, adverse events comprised death from any cause and non-fatal heart failure (HF) events requiring hospitalization. CR at 12-month follow-up was also assessed. We enrolled 905 pts. During a median follow-up of 1005 [627-1361] days, 134 patients died, and 79 had at least one HF hospitalization. At 12 months, 69% of pts displayed an improvement in their CR. The mean VALID-CRT risk score derived from the CRT-MOdular Registry (MORE) population was 0.317, ranging from -0.419 in Q1 to 2.59 in Q5. The risk-stratification algorithm was able to predict total mortality after CRT (survival ranging from 93%-Q1 to 77%-Q5; hazards ratio [HR] = 1.42, 95% confidence interval [CI]: 1.25-1.61, P < .0001), and HF hospitalization (ranging from 95% to 90%; HR = 1.24, 95% CI: 1.06-1.45, P = .009). CR was significantly lower in pts with a high-to-very high risk profile (Q4-5) than in pts with a low-to-intermediate risk profile (Q1-2-3) (55% vs 79%, P < .0001)., Conclusion: The VALID-CRT risk-stratification algorithm reliably predicts outcome and CRT response after CRT in an unselected, real-world population., (© 2019 The Authors. Clinical Cardiology published by Wiley Periodicals, Inc.)

Despite the technical improvements made in recent years, the overall long-term success rate of ventricular tachycardia (VT) ablation in patients with ischemic cardiomyopathy remains disappointing. This unsatisfactory situation has persisted even though several approaches to VT substrate ablation allow mapping and ablation of noninducible/nontolerated arrhythmias. The current substrate mapping methods present some shortcomings regarding the accurate definition of the true scar, the modality of detection in sinus rhythm of abnormal electrograms that identify sites of critical channels during VT and the possibility to determine the boundaries of functional re-entrant circuits during sinus or paced rhythms. In this review, we focus on current and proposed ablation strategies for VT to provide an overview of the potential/real application (and results) of several ablation approaches and future perspectives., (© 2019 The Authors. Clinical Cardiology published by Wiley Periodicals, Inc.)

The mechanisms of atrial fibrillation (AF) induction and maintenance, including those involved in paroxysmal atrial fibrillation, are not completely known; this limits our ablation strategies and prevents us from understanding what we are actually doing when performing pulmonary vein isolation. In this report, we focus on the commonly used ablation strategies for AF and question the importance of complete pulmonary vein isolation in achieving lasting success in the ablation of AF. We also discuss in detail the absence of durable pulmonary vein isolation in patients without arrhythmic recurrences after AF ablation and the possibility to cure paroxysmal AF without concomitant pulmonary vein isolation, provocatively questioning the dogma of pulmonary vein isolation as the cornerstone of AF ablation. Finally, a prospective personalized approach in the individual patient is advocated., (© 2019 Wiley Periodicals, Inc.)

Background: The European Society of Cardiology (ESC) Guidelines published in 2016 modified indications for cardiac resynchronization therapy (CRT) in comparison with the 2013 ESC Guidelines. The aim of this analysis was to evaluate the impact of the stricter criteria suggested by the 2016 ESC Guidelines on patient outcome in a real-world population., Methods: We collected data on 930 consecutive patients with complete outcome information who had undergone CRT implantation from 2011 to 2013 from the CRT-MORE registry. Patients were classified according to 2013 (Reference) and 2016 (Current) ESC Guidelines. The primary end-point of the study was death from any cause and heart failure hospitalization., Results: According to the Reference Guidelines, 650 (69.9%) patients met Class I indications, 190 (20.4%) Class IIa, 39 (4.2%) Class IIb and 51 (5.5%) Class III. According to the Current Guidelines, 563 (60.5%) patients met Class I indications, 145 (15.6%) Class IIa, 108 (11.6%) Class IIb and 114 (12.3%) Class III. On comparing the Reference and Current Guidelines, the 538 patients who confirmed their Class I indication had a better outcome in terms of freedom from the combined end-point of heart failure (HF) hospitalization or death from any cause (hazard ratio (HR) of 0.64; 95% CI 0.42 to 0.99; p = 0.0436) when compared to the 112 patients who lost their class I indication (84 moved to class IIb and 28 moved to class III)., Conclusions: The stricter criteria for Class I CRT indication suggested by the 2016 ESC Guidelines excluded about 20% of patients with a worse prognosis., Clinical Trial Registration: CRT MORE: Cardiac Resynchronization Therapy Modular Registry URL: http://clinicaltrials.gov/Identifier:NCT01573091., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Professional guidelines are based on the best available evidence. However, patients treated in clinical practice may differ from those included in reference trials., Objective: The aim of this study was to evaluate the effects of cardiac resynchronization therapy (CRT) in a large population of patients implanted with a CRT device stratified in accordance with the 2016 European heart failure (HF) guidelines., Methods: We collected data on 930 consecutive patients from the Cardiac Resynchronization Therapy MOdular REgistry. The primary end point was a composite of death and HF hospitalization., Results: Five hundred sixty-three (60.5%) patients met class I indications, 145 (15.6%) class IIa, 108 (11.6%) class IIb, and 114 (12.3%) class III. After a median follow-up of 1001 days, 120 (14.7%) patients who had an indication to CRT had died and 71 (8.7%) had been hospitalized for HF. The time to the end point was longer in patients with a class I indication (hazard ratio 0.55; 95% confidence interval 0.39-0.76; P = .0001). After 12 months, left ventricular (LV) end-systolic volume had decreased by ≥15% in 61.5% (320/520) of patients whereas in 57.5% (389/676) of patients the absolute LV ejection fraction improvement was ≥5%. Adherence to class I was also associated with an absolute LV ejection fraction increase of >5% (P = .0142) and an LV end-systolic volume decrease of ≥15% (P = .0055)., Conclusion: In our population, ∼60% of patients underwent implantation according to the 2016 European HF guidelines class I indication. Adherence to class I was associated with a lower death and HF hospitalization rates and better LV reverse remodeling., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aim: Ventricular tachycardia (VT)/ventricular fibrillation (VF) occurrence after cardiac resynchronization therapy-defibrillator (CRT-D) replacement is unknown; hence, there is no practical guideline to recommend either CRT-D or CRT-pacemaker at the time of device replacement. We observed the 1-year VT/VF occurrence after CRT-D replacement in a subanalysis of the Detect Long-term Complications after ICD Replacement (DECODE) registry., Methods and Results: A total of 332 consecutive patients who had undergone CRT-D replacement from 2013 to 2015 were enrolled in 36 Italian centres. The primary endpoint was the number of patients with any appropriate implantable cardioverter-defibrillator (ICD) interventions during 12-month follow-up. The secondary endpoint comprised death from any cause and appropriate ICD interventions. At replacement, 214 (64.5%) patients had a left ventricular ejection fraction ≤ 35% and 138 (41.6%) patients had a secondary prevention indication for ICD. Seventy (21.1%) patients had no longer indication to ICD therapy. During a median follow-up period of 406.5 (362-533) days, VT/VF requiring therapy delivery occurred in 57 (17%) patients, specifically in 7% of those who no longer had an ICD indication. On multivariate analysis, number of criteria for ICD replacement independently predicted appropriate ICD intervention during follow-up [hazard ratio (HR) = 1.62, 95% confidence interval (CI) 1.07-2.46; log-rank P = 0.02]. The combined endpoint of death from any cause or appropriate ICD therapy occurred in 76 (23%) patients. Only NYHA class remained associated with this combined endpoint (HR = 1.97, 95% CI 1.23-3.14; P = 0.005)., Conclusions: The DECODE registry showed the 'real-world' experience of CRT-D recipients approaching device replacement, in which 7% of patients who no longer had an indication for ICD therapy experienced appropriate ICD interventions.

Background: Simultaneous cathodic-anodal capture by a bipole of a cardiac resynchronization therapy (CRT) left-ventricular (LV) catheter may depolarize a larger LV area than conventional multipoint pacing. We evaluated the feasibility of cathodic-anodal LV stimulation., Methods: In 30 patients undergoing CRT with a quadripolar LV lead, we evaluated the cathodic and anodal capture threshold for each LV pole and compared QRS on electrocardiogram (ECG) during single-point cathodic biventricular stimulation (S-BS), multipoint BS (M-BS), and cathodic-anodal BS (CA-BS)., Results: Anodal capture was obtained by three poles in 23/30 patients, by two poles in five, and was not feasible in two. The mean single-point anodal threshold was 3.93 V versus single-point cathodic threshold of 1.95 V. On comparing ECGs, M-BS and CA-BS produced similar QRS wavefront activation in 90% of patients., Conclusions: CA-BS is feasible and may be used in LV pacing to achieve a different wavefront of electrical activation. Further prospective studies are needed in order to verify the clinical impact of this kind of stimulation., (© 2018 Wiley Periodicals, Inc.)

Purpose: Latency during left ventricle (LV) pacing has been suggested as a potential cause of ineffectual biventricular pacing. We assessed the incidence, predictors, and impact on outcome of increased LV latency in 274 patients undergoing cardiac resynchronization therapy (CRT)., Methods: On implantation, the latency interval was defined as the shortest stimulus-to-QRS onset interval in any lead of the 12-lead ECG. A stimulus-to-QRS onset interval ≥ 40 ms was used to define the presence of increased LV latency., Results: Increased LV latency was observed in 55 patients (20%). On multivariate analysis, only ischemic etiology proved to be a predictor of increased LV latency. On 12-month echocardiographic evaluation, 68% patients showed a ≥ 15% decrease in LV end systolic volume (74% patients with increased LV latency, 67% patients without increased LV latency (p = 0.58). The presence of increased LV latency was not associated with a different clinical response to CRT., Conclusions: Increased LV latency occurred in almost 20% of patients undergoing CRT and was more frequent in patients with ischemic heart disease. The presence of increased LV latency does not seem to have an impact on echocardiographic or clinical response to CRT.

Aims: Some barriers seem to exist in changing implantable cardioverter defibrillator (ICD) manufacturer at the time of device replacement. We sought to understand the obstacles to changing ICD manufacturer within the cohort of patients enrolled in the Detect Long-term Complications After ICD Replacement Registry., Methods: We analyzed 784 consecutive ICD/cardiac resynchronization therapy defibrillator (CRT-D) device replacements within a 1.5-year time-frame in 36 Italian centers to evaluate potential factors associated with changing manufacturers and system-related complications., Results: Manufacturer change occurred in 191 patients (24%): 72/211 single-chamber ICDs (34%), 52/210 dual-chamber ICDs (25%) and 67/363 CRT-D (18%, P < 0.0001 vs. single-chamber). Replacement-only procedures were associated with a lower rate of manufacturer change than upgrading procedures (23 vs. 32%, P = 0.02). In the single-chamber/dual-chamber cohort, the only variables associated with manufacturer change were the number of available manufacturers (OR = 1.9; P < 0.0001) and an upgrade procedure (OR = 1.7; P = 0.035), whereas the center volume was associated with maintenance of the same manufacturer (OR = 0.5; P = 0.0172). In the CRT-D group, the number of available manufacturers [OR = 2.9; P < 0.0001, service life below the median value (OR = 2.5; P = 0.0026)], and physiological design (OR = 8.4; P = 0.0048) were associated with manufacturer change. At 6-month follow-up, 17 patients (2.2%) experienced a system complication that was lead-related in all cases; upgrade procedure was the only predictor (hazard ratio = 6.7) of complications., Conclusion: At the time of ICD replacement, a manufacturer change occurred in 24% of patients and it was less likely in CRT-D devices, which are equipped with more specific technology and less frequently require the addition of features. System-related complications are strongly associated to upgrade procedures rather than to manufacturer change.

Proper localization of the anatomical target during ablation of the accessory pathways (AP) and the ability to detect clear AP potentials on the ablation catheter are crucial for successful AP ablation. We report a case of recurring AP conduction that was finally eliminated using a novel ablation catheter equipped with high-resolution mini-electrodes. Smaller and closer electrodes result in high mapping resolution with less signal averaging and cancellation effects. Owing to improved sensitivity, the new catheter seems effective in detecting fragmented and high frequency signals, thus allowing more effective radiofrequency application and improving ablation success.

Background: Cardiac resynchronization therapy (CRT) has proved to be effective in patients with heart failure and left bundle branch block (LBBB). Recently, new electrocardiography criteria have been proposed for the diagnosis of LBBB. These criteria are stricter than the current American Heart Association (AHA) criteria. We assessed the rate of echocardiographic response to CRT in patients with traditional LBBB versus patients who met the new criteria (strict LBBB)., Methods: Consecutive patients undergoing CRT were enrolled in the CRT MORE registry. Patients with no-LBBB QRS morphology according to AHA criteria, atrial fibrillation, right bundle branch block, and right ventricular pacing were excluded. Strict LBBB was defined as: QRS ≥ 140 ms for men and ≥130 ms for women, QS or rS in V1-V2, mid-QRS notching or slurring in ≥2 contiguous leads. Patients showing a relative decrease of ≥15% in left ventricular end-systolic volume (LVESV) at 12 months were defined as responders., Results: Among 335 patients with LBBB, 131 (39%) had strict LBBB. Patients with and without strict LBBB showed comparable baseline characteristics, except for QRS duration (166 ± 20 ms vs 152 ± 25 ms, P < 0.001). On 12-month evaluation, 205 patients (61%) were responders; 85 of 131 (65%) had strict LBBB and 120 of 204 (59%) had traditional LBBB (P = 0.267). On multivariate analysis, a history of atrial fibrillation, larger LVESV, and the presence of mid-QRS notching in ≥1 lead (odds ratio 2.099; 95% confidence interval 1.061-4.152, P = 0.033) were independently associated with echocardiographic response., Conclusion: Stricter definition of LBBB did not improve response to CRT in comparison to the current AHA definition., (© 2017 Wiley Periodicals, Inc.)

Aims: The occurrence of left ventricular (LV) anodal activation during pacing with modern multipolar cardiac resynchronization therapy (CRT) systems has never been reported. The aim of our study was to demonstrate, by means of electrocardiogram (ECG) analysis, the occurrence of simultaneous cathodal-anodal LV capture with quadripolar LV leads., Methods and Results: We studied 10 first-time recipients of a CRT device equipped with a quadripolar LV lead. During follow-up, standard supine 12-lead ECGs were obtained in available cathode-to-anode LV pacing configurations with a pulse amplitude equal to twice the pacing threshold. The occurrence of simultaneous cathodal-anodal LV capture was defined as the presence of variations in electrocardiographic ventricular activation (EVA) when the distal tip (cathode)-to-device can (anode) pacing configuration was compared with the distal tip (cathode)-to-proximal ring (anode) configuration. In eight patients, we found differences in EVA when different LV sites were paced through the unipolar LV tip and unipolar LV ring configurations. In these patients, a difference in EVA was detected in 61.5% (59 of 96) of the ECG leads (marked difference in 31.3%, slight difference in 30.2%). Changes in EVA between unipolar tip-to-can and bipolar tip-to-ring pacing that were suggestive of cathodal-anodal LV capture were found in six patients. In these patients, a total of 30 (41.7%) ECG leads showed a difference in EVA (marked difference in 20.8%, slight difference in 20.8%)., Conclusion: In our experience, additional anodal capture by the proximal LV ring during LV pacing is provable in most recipients of a resynchronization device equipped with a multipolar LV lead., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)

Background: Because 20% to 40% of patients undergoing cardiac resynchronization therapy (CRT) do not respond to it, identification of potential factors predicting response is a relevant research topic., Hypothesis: There is a possible association between right ventricular function and response to CRT., Methods: We analyzed 227 patients from the Cardiac Resynchronization Therapy Modular Registry (CRT-MORE) who received CRT according to current guidelines from March to December 2013. Response to therapy was defined as a decrease of ≥15% in left ventricular end-systolic volume (LVESV) at 6 months., Results: The tricuspid annular plane systolic excursion (TAPSE) value that best predicted improvement in LVESV (sensitivity 68%, specificity 54%) was 17 mm. Stratifying patients according to TAPSE, LVESV decreased ≥15% in 78% of patients with TAPSE >17 mm (vs 59% in patients with TAPSE ≤17 mm; P = 0.006). At multivariate analysis, TAPSE >17 mm was independently associated with LVESV improvement (odds ratio: 1.97, 95% confidence interval: 1.03-3.80, P < 0.05), together with ischemic etiology (odds ratio: 0.39, 95% confidence interval: 0.20-0.75, P < 0.01). These results were confirmed for New York Heart Association class III to IV patients (79% echocardiographic response rate in patients with TAPSE >17 mm vs 55% in patients with TAPSE <17 mm; P = 0.012)., Conclusions: Baseline signs of right ventricular dysfunction suggest possible remodeling after CRT. A TAPSE value of 17 mm was identified as a good cutoff for predicting a better response to CRT in patients with both mildly symptomatic and severe heart failure., (© 2016 Wiley Periodicals, Inc.)

Background: Several studies have investigated the association between native QRS duration (QRSd) or QRS narrowing and response to biventricular pacing. However, their results have been conflicting. The aim of our study was to determine the association between the relative change in QRS narrowing index (QI) and clinical outcome and prognosis in patients who undergo cardiac resynchronization therapy (CRT) implantation., Methods and Results: We included 311 patients in whom a CRT device was implanted in accordance with current guidelines for CRT. On implantation, the native QRS, the QRSd and the QI during CRT were measured. After 6months, 220 (71%) patients showed a 10% reduction in LVESV. The median [25th-75th] QI was 14.3% [7.2-21.4] and was significantly related to reverse remodeling (r=+0.22; 95%CI: 0.11-0.32, p=0.0001). The cut-off value of QI that best predicted LV reverse remodeling after 6months of CRT was 12.5% (sensitivity=63.6%, specificity=57.1%, area under the curve=0.633, p=0.0002). The time to the event death or cardiovascular hospitalization was significantly longer among patients with QI>12.5% (log-rank test, p=0.0155), with a hazard ratio (HR) of 0.3 [95%CI: 0.11-0.78]. In the multivariate regression model adjusted for baseline parameters, a 10% increment in QI (HR=0.61[0.44-0.83], p=0.002) remained significantly associated with CRT response., Conclusions: Patients with a larger decrease in QRSd after CRT initiation showed greater echocardiographic reverse remodeling and better outcome from death or cardiovascular hospitalization. QI is an easy-to-measure variable that could be used to predict CRT response at the time of pacing site selection or pacing configuration programming., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Aims: Accurate selection of patients with left bundle branch block (LBBB) may help increasing response to cardiac resynchronization therapy (CRT). There is no agreement on LBBB definition. The aim of the study was to investigate the prevalence of 'true-LBBB' according to Strauss in patients undergoing CRT., Methods and Results: The study population included 414 consecutive patients (71.9% men; mean age 69.7 ± 9.6 years), who underwent CRT according to 2010 European Society of Cardiology (ESC) guidelines. Patients were classified into three groups: traditional LBBB according to American Heart Association, LBBB according to Strauss and intraventricular conduction delay (IVCD). Subsequently, they were re-classified into classes of recommendations, according to the current 2013 ESC Guidelines. Traditional LBBB was recorded in 229 patients (55%), an LBBB according to Strauss in 153 (37%) and an IVCD in 32 (8%). Patients with an LBBB according to Strauss showed a significantly more prolonged QRS duration (P < 0.001), greater baseline end-systolic and end-diastolic volumes (P = 0.011 and P = 0.013, respectively) compared with those with IVCD. The prevalence of mid-QRS notching in at least two contiguous leads was 100% in LBBB according to Strauss; 24% in traditional LBBB and 21.9% in IVCD (P < 0.001). At multivariate analysis, PR interval less than 200 ms and QRS of at least 150 ms were independent predictors of mid-QRS notching [odds ratio (OR) 1.78; 95% confidence interval (95% CI) 1.10-2.88; P = 0.02 and OR 2.88; 95% CI 1.80-4.62;P < 0.0001]. Applying stricter criteria for LBBB according to Strauss, a significant reduction in Class I recommendation and an increase in Class II was observed (90.1 vs. 37%; P < 0.0001 and 9.9 vs. 63%; P < 0.0001)., Conclusions: Applying stricter criteria, only 37% of patients undergoing CRT showed a true-LBBB according to Strauss. Accurate identification of true-LBBB may have a potential additional value in better selecting patients.

Background: The implantation strategy appears to play a pivotal role in determining response to cardiac resynchronization therapy (CRT)., Objective: The aim of our study was to determine the association between anatomic and electrical interlead distance and clinical outcome after CRT implantation., Methods: We included 216 first-time CRT recipients with left bundle branch block and sinus rhythm. On implantation, the electrical interlead distance (EID), defined as the time interval between spontaneous peak R waves detected at the right ventricular (RV) and left ventricular (LV) pacing sites, was measured. The anatomic distance between the RV and LV lead tips was determined on chest radiographs., Results: The mean EID was 74 ± 41 ms, and the mean horizontal corrected interlead distance (HCID) was 125 ± 73 mm. After 12 months, 87 patients (40%) displayed an improvement in their clinical composite score. The cutoff values that best predicted an improved clinical status were as follows: 84 ms for EID (area under the curve 0.59; confidence interval [CI] 0.52-0.66; P = .026) and 90 mm for HCID (area under the curve 0.62; CI 0.55-0.69; P = .004). On multivariate analysis, only EID >84 ms (hazard ratio 0.36; CI 0.14-0.89; P = .028) and HCID >90 mm (hazard ratio 0.45; CI 0.23-0.90; P = .025) were significantly associated with the composite endpoint of death or cardiovascular hospitalization. In particular, the presence of both conditions (EID <84 ms and HCID <90 mm) was associated with the highest rate of events (log-rank test P = .002)., Conclusions: The interlead anatomic and electrical distance are strongly and independently associated with patient outcome after CRT implantation. The 2 measures show an additive predictive value. (CRT MORE: Cardiac Resynchronization Therapy Modular Registry; www.clinicaltrials.gov, unique identifier: NCT01573091.), (Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

The replacement of implantable cardioverter-defibrillators (ICDs) may give rise to considerable clinical consequences, the importance of which is underrated by the medical community. Replacement-related adverse events are difficult to identify and require monitoring of both short-term complications and long-term patient outcome. The aim of this study is to perform a structured evaluation of both short- and long-term adverse events and a cost analysis of consecutive ICD replacement procedures. Detect Long-term Complications After ICD Replacement (DECODE) is a prospective, single-arm, multicenter cohort study designed to estimate long-term complication rates (at 12 months and 5 years) in patients undergoing ICD generator replacement. The study will also evaluate predictors of complications, patient management before and during the replacement procedure in clinical practice, and the costs related to use of health care resources. About 800 consecutive patients with standard indications for ICD generator replacement will be enrolled in this study. The decision to undertake generator replacement/upgrade will be made according to the investigators' own judgment (which will be recorded). Patients will be followed for 60 months through periodic in-hospital examinations or remote monitoring. Detailed data on complications related to ICD replacement in current clinical practice are still lacking. The analysis of adverse events will reveal the value of new preventive strategies, thereby yielding both clinical and economic benefits. Moreover, assessment of complication rates after ICD replacement in a real-life setting will help estimate the actual long-term cost of ICD therapy and assess the real impact of increasing ICD longevity on cost-effectiveness., (© 2015 Wiley Periodicals, Inc.)

Introduction: We evaluated the potential ability of the electrophysiological (EP) inducibility of ventricular arrhythmias to predict the likelihood of appropriate ICD intervention over the long-term in ischemic and nonischemic patients with current primary prevention indications for ICD implantation., Methods: Between 2006 and 2008, 206 consecutive heart failure patients who were candidates for ICD implantation for the primary prevention of sudden cardiac death according to standard indications underwent EP testing, usually on ICD implantation., Results: On EP testing, 15 (7%) patients had inducible monomorphic ventricular tachycardia (VT) and 14 (7%) ventricular fibrillation (VF). Over 24 months, 64 (31%) patients received appropriate ICD therapies: 51 (25%) for VT and 16 (8%) for VF. The time to the first appropriate ICD therapy trended to be shorter in the group of patients who were inducible on EP testing (p=0.072). Among patients receiving appropriate therapies, the median number of arrhythmic episodes was 2, and the proportion of patients with 2 treated arrhythmic episodes was higher in the group of inducible patients (34% versus 14%, p=0.005). On multivariate analysis, inducibility proved to be an independent predictor of frequent (2) arrhythmic episodes, as did a history of coronary artery bypass grafting. Moreover, patients with 2 treated arrhythmic episodes showed higher mortality (log-rank test, p=0.042)., Conclusion: Patients with inducibility of VT or VF are more likely to experience frequent appropriate ICD therapies during follow up.