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Aims To non-invasively characterize, by means of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR), scar differences, and potential variables associated with ventricular tachycardia (VT) occurrence in chronic post-myocardial infarction (MI) patients. Methods and results A case–control study was designed through retrospective LGE-CMR data analysis of chronic post-MI patients (i) consecutively referred for VT substrate ablation after a first VT episode (n = 66) and (ii) from a control group (n = 84) with no arrhythmia evidence. The myocardium was characterized differentiating core, border zone (BZ), and BZ channels (BZCs) using the ADAS 3D post-processing imaging platform. Clinical and scar characteristics, including a novel parameter, the BZC mass, were compared between both groups. One hundred and fifty post-MI patients were included. Four multivariable Cox proportional hazards regression models were created for total scar mass, BZ mass, core mass, and BZC mass, adjusting them by age, sex, and left ventricular ejection fraction (LVEF). A cut-off of 5.15 g of BZC mass identified the cases with 92.4% sensitivity and 86.9% specificity [area under the ROC curve (AUC) 0.93 (0.89–0.97); P Conclusions The mass of BZC is the strongest independent variable associated with the occurrence of sustained monomorphic ventricular tachycardia in post-MI patients after adjustment for age, sex, and LVEF. Border zone channel mass measurement could permit a more accurate VT risk stratification than LVEF in chronic post-MI patients.

Background Pacemapping (PM) is a useful maneuver for aiding premature ventricular complex (PVC) ablation. Its standalone clinical value is still to be defined. Objectives The purpose of this study was to analyze the efficacy of a predefined PM protocol for low-burden PVC ablation, regardless of their site of origin (SOO) and the presence of structural heart disease. Methods This was a prospective, nonrandomized, multicenter study. The PM protocol was performed when 94% correlation, and 3 radiofreqency (RF) applications were delivered. Results Of 185 patients, 105 (57%) underwent activation mapping, 60 (32%) were PM-guided, and 20 (11%) were canceled due to absence of PVCs. Baseline QRS, PVC burden, and outflow tract origin were independent predictors of PM-guided ablation. A higher proportion of right ventricular outflow tract SOO in the PM group (52% vs 40%; P = .03) was observed. Mean target area was 0.6 ± 0.9 cm2. Mean 10-ms isochronal area in local activation time (LAT)-guided procedures was higher (1.7 ± 2.3 cm2; P Conclusion When LAT mapping is precluded, application of a PM-guided ablation protocol directed to >94% matching correlation target area is a more efficient alternative with comparable clinical results.

A 38-year-old woman with a structurally normal heart was referred for catheter ablation due to symptomatic, monomorphic, high burden (12%) premature ventricular complexes (PVC) refractory to medical therapy. The PVC's ECG morphology suggested an origin in the proximal left anterior fascicle (LAF). During procedure PVCs were mechanically suppressed. Consequently, selection of the ablation target site was based on pace-mapping. This case illustrates how ablation from the right coronary cusp (RCC) for PVC arising from the proximal LAF could be accurately guided by pace-mapping. At this location, pacing can result in both a selective and a non-selective capture of the proximal LAF.

Objectives This study sought to analyze safety and outcomes of ventricular tachycardia (VT) substrate ablation during sinus rhythm (SR), without baseline VT induction. Background Safety and outcomes after scar-related VT ablation during SR are not well known. Hemodynamic instability and need for electrical cardioversion can compromise safety of VT ablation procedures. Methods Four hundred twelve consecutive patients with structural heart disease undergoing VT ablation were included in a prospective multicenter registry. Substrate ablation during SR, without baseline VT induction, was the first step of the ablation procedure and the standard protocol. Scar dechanneling was the substrate ablation technique used. VT inducibility was tested after substrate ablation. Results VT induction protocol was negative after substrate ablation in 289 patients (70.1%), completing the procedure in SR. Procedure-related complication rate was 6.5%, including 1 death (0.2%). Thirty-day mortality after first VT ablation procedure was 1.7%. Overall survival was 95.8% and 88.6% at 1 and 3 years of follow-up, respectively. In a multivariable proportional hazards regression model, age ≥70 years (hazard ratio [HR]: 4.95 [2.59 to 9.47]; p Conclusions Substrate ablation during SR avoiding multiple VT induction has low procedure-related complications and low early mortality. Age, chronic obstructive pulmonary disease, and reduced left ventricular ejection fraction, but also incomplete substrate elimination, are predictors of mortality.

[Background]: Ventricular tachycardia substrate ablation (VTSA) incorporating hidden slow conduction (HSC) analysis allows further arrhythmic substrate identification., [Objective]: The purpose of this study was to analyze whether the elimination of HSC electrograms (HSC-EGMs) during VTSA results in better short- and long-term outcomes., [Methods]: Consecutive patients (N = 70; 63% ischemic; mean age 64 ± 14.6 years) undergoing VTSA were prospectively included. Bipolar EGMs with >3 deflections and duration, [Results]: A total of 5076 EGMs were analyzed; 1029 (20.2%) qualified as potential HSC-EGMs, and 475 of them were tagged as HSC-EGMs. Scars in patients with HSC-EGMs (n = 43 [61.4%]) were smaller (32.2 [17–58] cm2 vs 85 [41–92.4] cm2; P = .006) and more heterogeneous (core/scar area ratio 0.15 [0.05–0.44] vs 0.44 [0.33–0.57]; P = .017); 32.4% of HSC-EGMs were located in normal voltage tissue. Patients undergoing VTSA incorporating HSC analysis required less radiofrequency time (15.6 [8–23.1] vs 23.9 [14.9–30.8]; P < .001) and had a lower rate of VT inducibility after VTSA (28.6% vs 52.9%; P = .003) than did the historical controls. Patients undergoing VTSA incorporating HSC analysis showed a higher 2-year VT/ventricular fibrillation–free survival (75.7% vs 58.8%; log-rank, P = .046) after VTSA., [Conclusion]: VTSA incorporating HSC analysis allowed further arrhythmic substrate identification (especially in the border zone and normal voltage areas) and was associated with increased VTSA efficiency and better short- and long-term outcomes.

Objectives This study aimed to characterize the long-term scar remodeling process after an acute myocardial infarction (AMI) and the underlying scar-related arrhythmogenic substrate using serial late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Background Little is known about the time course needed for completion of the scar healing process after an AMI, which can be assessed by noninvasive cardiac imaging techniques such as LGE-CMR. Methods Fifty-six patients with revascularized ST-segment elevation AMI (STEMI) were consecutively included. LGE-CMR (3-T) was obtained at 7 days, 6 months, and 4 years after STEMI. The myocardium was segmented into 10 layers from the endocardium to epicardium, characterizing the core, border zone (BZ), and BZ channels (BZCs) using a dedicated post-processing software. Results Mean age of the patients was 57 ± 11 years; 77% were men. Left ventricular ejection fraction improved at 6 months from 47% to 51% (p Conclusions CMR data post-processing permitted a dynamic assessment of quantitative and qualitative post-AMI scar characteristics. Scar size and number of BZCs steadily decreased 4 years after AMI. BZC distribution was significantly modified during this time. These dynamic parameters could be reliably assessed with CMR; their evaluation might be of prognostic value.

To investigate the role of classical (CLM, CD14++CD16−), intermediate (INTM, CD14++CD16+), and non-classical (Non-CLM, CD14+CD16++) monocytes in scar formation after ST-elevation myocardial infarction (STEMI), evaluated with cardiac magnetic resonance (CMR). One hundred two patients with a first STEMI had serial blood analyses after 1, 3, and 7 days. A CMR was performed at 7 days and 6 months, depicting scar core (CO), border zone (BZ), and the presence of BZ channels. CLM and INTM levels progressively decreased, correlated with the scar mass, CO, and BZ at 7 days and 6 months (p

Frequent premature ventricular contractions (PVCs) associated left ventricular systolic dysfunction (LVSD) is a well-known clinical scenario and numerous predictors for cardiomyopathy (CMP) development have been already thoroughly described. It may present as a "pure" form of dissynchrony-induced cardiomyopathy or it may be an aggravating component of a multifactorial structural heart disease. However, the precise risk to develop PVC-induced CMP (which would allow for tailored-patient monitoring and/or early treatment) and the degree of CMP reversibility after PVC suppression/elimination (which may permit appropriate candidate selection for therapy) are unclear. Moreover, there is limited data regarding the time course of CMP development and resolution after arrhythmia suppression. Even less known are the other components of PVC-induced CMP, such as right ventricular (RV) and atrial myopathies. This review targets to synthetize the most recent information in this regard and bring a deeper understanding of this heart failure scenario. The mechanisms, time course (both in experimental models and clinical experiences) and predictors of reverse-remodelling after arrhythmia suppression are described. The novel experience hereby presented may aid everyday clinical practice, promoting a new paradigm involving more complex, multi-level and multi-modality evaluation and possible earlier intervention at least in some patient subsets.

Atrial fibrillation (AF) and hypertrophic cardiomyopathy (HCM) are two very common clinical entities, which often occur simultaneously, giving a hard time to both patients and cardiologists. Myocyte hypertrophy, myocyte disarray and interstitial fibrosis in the left atrium (LA) predisposes to atrial arrhythmias due to modifications of the substrate that promote re-entry. AF is usually poorly tolerated due to the shortening of the diastolic time with rapid heart rates and the lack of the atrial contribution to the diastolic filling in patients who often have a previous diastolic dysfunction. AF onset frequently results in exercise intolerance and recurrent heart failure admissions and also has prognostic implications. Early maintenance of sinus rhythm appears as a worthy approach in these patients, especially when started early in the course of the disease. However, treatment with antiarrhythmic (AA) agents in HCM patients is less effective than in patients without the disease, and concerns regarding safety frequently limit the long-term adherence. Catheter ablation has limited efficacy in patients with persistent AF but can play an important role in patients with paroxysmal AF, emphasizing the importance of an accurate patient selection. The aim of this review is to provide an overview of the pathophysiology of combined HCM and AF and the principal pharmacological and non-pharmacological treatments recommended in this complex clinical scenario.

Atrial fibrillation (AF) is the most prevalent form of cardiac arrhythmia. It is often related to diverse pathological conditions affecting the atria and leading to remodeling processes including collagen accumulation, fatty infiltration, and amyloid deposition. All these events generate atrial fibrosis, which contribute to beget AF. In this scenario, cardiac imaging appears as a promising noninvasive tool for monitoring the presence and degree of LA fibrosis and remodeling. The aim of this review is to comprehensively examine the bench mechanisms of atrial fibrosis moving, then to describe the principal imaging techniques that characterize it, such as cardiac magnetic resonance (CMR) and multidetector cardiac computed tomography (MDCT), in order to tailor atrial fibrillation ablation to each individual.

Funding Acknowledgements Type of funding sources: None. Background Pacemapping (PM) is a useful maneuver for aiding PVC ablation procedures, but its stand-alone clinical value when activation mapping is precluded is still to be defined. Objectives To analyze the clinical efficacy of a predefined PM protocol to be applied during low-burden premature ventricular complex (PVC) ablation procedures, regardless of their site of origin (SOO) and the presence of prior structural heart disease (SHD). Methods Prospective, non-randomized, multicenter study including 185 consecutive patients referred for a first PVC ablation. A predefined PM protocol was performed to guide ablation whenever a burden < 1 PVC/min was found after a 15-min waiting period, which precluded activation mapping. PM was performed using the PASO module of CARTO3 navigation system, obtaining a correlation grading, color-coded map. A minimum correlation of 94% was required for classifying an area as the PVC-SOO. After identifying the SOO, a high-density PM map with a fill threshold set to 6 was performed and ablation was delivered to the ‘target area’, defined as the area delimited by the 3 best matching points above the minimum correlation of 94%. Three RF applications were systematically applied in the target area with appropriate parameters: 40 W for the RVOT and aortic root, 50 W for the subvalvular LVOT, 20-30 W in the distal coronary sinus, at operator’s discretion in other locations. Clinical success was defined as a PVC-burden reduction of ≥ 80% in the 24-h Holter after 6 months. Results 105/185 patients (57%) could undergo activation mapping, while 60/185 (32%) had to be PM-guided. Only 20 patients (11%) had to be canceled due to complete absence of PVCs. Baseline QRS, PVC burden and an OT origin were independent predictors of the need to undergo a PM-guided ablation. The most frequent SOO locations were RVOT (44%), LV (23%), and LVOT (16%), with a significantly higher proportion of RVOT-SOO in the PM group (52% vs. 40%, p = 0.03). The mean target area was 0.6 ± 0.9 cm2, with a mean smallest PM correlation within that area of 95 ± 4%. The mean 10-ms isochronal area in LAT-guided procedures was significantly higher than the PM target area (1.7 ± 2.3 cm2; p < 0.001). The mean number of PM matching points acquired was 39 ± 21 (range 6 – 98). Mean mapping (29 ± 22 min) and RF (135 ± 124 sec) times were similar both for LAT and PM-guided procedures, with significantly shorter procedure times in the PM group (53 ± 24 vs. 61 ± 26 min; p = 0.04). Clinical success after a 6-month follow-up reached 87% for the PM approach, similar to that of LAT mapping-based ablation procedures (90%; p = 0.58). Conclusions When LAT mapping is precluded by a very low PVC burden in unselected patients referred for PVC ablation procedures, a first-line, stepwise PM and ablation protocol directed to a target area with > 94% matching correlation is a feasible alternative, reaching comparable clinical results regardless of the PVC-SOO and the presence of SHD. Abstract Figure. Example of a predefined PM protocol

Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Beca de la Asociación del Ritmo Cardiaco para Formación en Investigación Post-Residencia en centros españoles. Background To predict the premature ventricular complex (PVC) site of origin (SOO) before the ablation procedure has important implications. 12 lead ECG information as well clinical characteristics are related with the PVC-SOO, but there is no prospective data validation. Purpose This prospective multicenter study sought to analyze the applicability and accuracy of a simple hybrid algorithm that includes electrocardiographic and clinical information in a consecutive patient population with outflow tract (OT) PVCs undergoing catheter ablation. Methods Consecutive patients with frequent OT-PVCs and indication for catheter ablation were prospectively included in 4 centers. The vascular access (femoral vein vs femoral artery) and the first outflow tract to be mapped were decided based on a two-steps hybrid algorithm (see Figure 1) including ECG information [R/S PVC precordial transition (PT): early PT if it occurs before V3; late PT if beyond V3) and clinical information [the following variables compute 1 point in a clinical score: age (>59 y.o); presence of hypertension; and gender (man)]. Results 115 consecutive patients [42 (37%) man, 52 + 15 y.o] were included. Mean PVC burden at baseline was 20 ± 13% and mean LVEF was 59 ± 8%. Mean procedure time was 55 ± 26 min. Complete acute abolition of the PVC was achieved in 110 (96%) patients. 84 (73%) patients had the PVC’s SOO in the right ventricle OT (RVOT) whereas 31 (27%) in the left ventricular OT (LVOT). Compared with patients with a RVOT-SOO, those with a LVOT-SOO were more frequently man [18 (58%) vs 24 (29%), p = 0.004], more frequently suffered from hypertension [18 (58%) vs 15 (18%), p Conclusions The hybrid algorithm, prospectively evaluated in an international multicenter study, has proved to permit to accurately anticipate the PVC’s SOO (right vs left) in a consultive population of patients with OT PVCs. Abstract Figure 1

Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Dr Teres is funded by the research fellowship grant from the Swiss Heart Rhythm Foundation, Dr Carreno was funded was funded by a Scholarship from Sociedad Española de Cardiología (SEC). Introduction Left atrial wall thickness (LAWT) is a determinant of transmural lesion formation during atrial fibrillation (AF) ablation. The utility of ablation index (AI) to dose radiofrequency (RF) delivery for the reduction of AF recurrences has already been proven with a target AI ≥ 400 at the posterior wall and ≥550 at the anterior wall. Objective To determine if adapting AI to atrial wall thickness (AWT) is feasible, effective and safe during AF ablation. Methods Consecutive patients referred for a first PAF ablation. LAWT 3D-maps were obtained from multidetector computed tomography (MDCT) and integrated into the CARTO navigation system. LAWT maps were semi-automatically computed from the MDCT as the local distance between the LA endo and epicardium and categorized into 1mm-layers and AI was titrated to the LAWT, as follows: Thickness < 1 mm (red): 300; 1-2 mm (yellow): 350; 2-3 mm (green): 400; 3-4 mm (blue): 450; > 4 mm (purple): 450 (Figure). The ablation line was designed in a personalized fashion to avoid thicker regions. All ablation procedures were performed under general anesthesia with a high frequency low-volume ventilation. Primary endpoints were acute efficacy and safety, and freedom from AF recurrences. Follow-up (FU) was scheduled at 1, 3, 6, and every 6 months thereafter. Results 90 patients [60 (67 %) male, age 58 ± 13 years] were included. Mean LAWT was 1.25 ± 0.62 mm. Mean AI was 366 ± 26 on the right pulmonary veins (RPVs) with a first-pass isolation in 84 (93%) patients and 380 ± 42 on the left pulmonary veins (LPVs) with first-pass in 87 (97%). Procedure time was 59 min [49-66]; RF time 14 min [12,5-16]; fluoroscopy time 0.7 min [0.5-1.4]. No major complication occurred. Eighty-six out of 90 (95.5%) patients were free of recurrence after a mean FU of 11 ± 4 months. Conclusions Personalized AF ablation, adapting the AI to LAWT allowed decreasing RF delivery, fluoroscopy and procedure time while obtaining a high rate of first-pass isolation. Lesion durability as estimated by freedom from AF recurrences was as high as in more demanding ablation protocols. Abstract Figure. Personalized protocol and results

Funding Acknowledgements Type of funding sources: None. Background Epidemiological studies suggested that premature ventricular complexes (PVCs) are associated with cardiac mortality. But data are still inconclusive. Aim This study sought to analyze predictors of adverse outcomes in a population of patients with left ventricular (LV) systolic dysfunction who underwent PVC ablation. Methods 135 consecutive patients [100 (74%) men, 59 +12 y.o.] with LV systolic dysfunction [LV ejection fraction (LVEF) Results 82 (61%) patients had a left-sided PVC’s site of origin (LS-SOO), 51 (38%) had a right-sided SOO (RS-SOO) whereas SOO could not be determined in 2 (1%) patients. LS-SOO patients were older (61 ± 11 vs 52 ± 10, p After a mean follow-up of 39 ± 21 months (range 24-94 months) there was a significant reduction in the PVC burden from 24 ± 13% at baseline to 4 ± 6% at LTFUP, p Conclusions Among patients with LV dysfunction who underwent PVC ablation, those with LS-SOO were older and more frequently had AF and SHD. LS-SOO was associated with adverse cardiovascular outcomes. These findings suggest that PVCs with LS and RS-SOO should be considered as two different clinicals entities, with different prognostic values. Abstract Figure 1

Aims To assess potential benefits of a local activation time (LAT) automatic acquisition protocol using wavefront annotation plus an ECG pattern matching algorithm [automatic (AUT)-arm] during premature ventricular complex (PVC) ablation procedures. Methods and results Prospective, randomized, controlled, and international multicentre study (NCT03340922). One hundred consecutive patients with indication for PVC ablation were enrolled and randomized to AUT (n = 50) or manual (MAN, n = 50) annotation protocols using the CARTO3 navigation system. The primary endpoint was mapping success. Clinical success was defined as a PVC-burden reduction of ≥80% in the 24-h Holter within 6 months after the procedure. Mean age was 56 ± 14 years, 54% men. The mean baseline PVC burden was 25 ± 13%, and mean left ventricular ejection fraction (LVEF) 55 ± 11%. Baseline characteristics were similar between the groups. The most frequent PVC-site of origin were right ventricular outflow tract (41%), LV (25%), and left ventricular outflow tract (17%), without differences between groups. Radiofrequency (RF) time and number of RF applications were similar for both groups. Mapping and procedure times were significantly shorter in the AUT-arm (25.5 ± 14.3 vs. 32.8 ± 12.6 min, P = 0.009; and 54.8 ± 24.8 vs. 67.4 ± 25.2, P = 0.014, respectively), while more mapping points were acquired [136 (94–222) AUT vs. 79 (52–111) MAN; P Conclusion The use of a complete automatic protocol for LAT annotation during PVC ablation procedures allows to achieve similar clinical endpoints with higher procedural efficiency when compared with conventional, manual annotation carried out by expert operators.

Funding Acknowledgements Dr Teres was funded by Swiss Heartrhythm Foundation Introduction pulmonary vein (PV) reconnections due to gaps on circumferential ablation lines are responsible for atrial fibrillation recurrences after catheter ablation. We sought to analyze the local left atrial wall thickness (LAWT) of PV line gaps at AF redo ablation during real-time catheter positioning. LAWT was measured on the MDCT 3D reconstruction and fused with the LA anatomy using CARTO-merge. Objective To analyze the relationship between local reconnection gaps and the LAWT during AF redo procedures. Methods Single-Center cohort study that included 41 consecutive patients referred for AF redo procedure. All patients had a MDCT prior to the ablation procedure. LAWT maps were semi-automatically computed from the MDCT as the local distance between the LA endo and epicardium. Each PV line was subdivided into 8 segments and mean LAWT was computed. During the procedure, the local gap was defined as the earliest activation site at the reconnected segment of the circumferential PV line (Figure 1A & 1B). Results 41 patients [31 (75.6%) male, age 60 ± 10 years] were included. Mean LAWT was 1.36 ± 0.20 mm. Mean PV circumferential line WT was higher in left PVs than in the right PVs 1.68 ± 0.57 vs. 1.31 ± 0.39 mm p Conclusions Reconnection points were more frequently present in the thicker segments of the PV circumferential line. The most frequently reconnected segment was the anterior carina in both right and left PVs. Atrial wall thickness maps derived from MDCT are useful to guide AF redo procedures. Abstract Figure. 1) Activation & WT map; 2) Segment WT

Introduction Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) permits to identify the arrhythmogenic substrate (AS) in ischemic patients. However, it is unknown why the majority of them never develop ventricular tachycardias (VT), irrespectively of their left ventricular ejection fraction (LVEF). Purpose To characterize the fundamental differences and potential predictors of scar arrhythmogenicity in post-myocardial infarction (MI) patients with and without VT. Methods 36 consecutive ischemic patients with no arrhythmia evidence underwent a LGE-CMR study 4 years after the MI (controls). Scar data were compared with those obtained from 49 ischemic patients referred for VT substrate ablation (cases). Propensity score matching (PSM) was performed to adjust for age, LVEF, scar mass, and time from MI. The myocardium was segmented in 10 layers (endo- to epicardium), characterizing the core, border zone (BZ) and BZ channels (BZCs) using a dedicated post-processing software. Results Compared to controls, cases were significantly older (67.3 ± 9.1 vs. 56.5 ± 11), had lower LVEF (33.1 ± 10.1 vs. 51 ± 9.4), greater scar mass (33.9 ± 17.2 vs. 14.2 ± 11.6 g), BZ mass (21.1 ± 9.9 vs. 9.6 ± 7.6 g), core mas (12.6 ± 8.8 vs. ± g), number of BZC (2.9 ± 1.4 vs. 1.1 ± 1.1) and BZC mass (10.5 ± 4.2 vs. 2.3 ± 2.4 g) (p 4.28 g (AUC 0.98; p Conclusions Compared with the cases, an otherwise similar control group (PS-matched for age, LVEF, scar mass, and time from MI) showed fewer BZC and a reduced BZC mass. BZC mass was the only independent predictor of being a case. A BZC mass cut-off point of > 4.28 g showed a 100% sensitivity and 91% specificity for the identification of ischemic patients with documented VT. Abstract Figure. Mean BZC mass and ROC curve analysis

Funding Acknowledgements Dr Teres was funded by Swiss Heartrhythm Foundation Introduction Circumferential pulmonary vein isolation (PVI) has become a mainstay in the treatment of atrial fibrillation (AF). The utility of ablation index (AI) to dose radiofrequency delivery for the reduction of AF recurrences has already been proven with a target AI ≥ 400 at the posterior wall and ≥550 at the anterior Wall. Nevertheless, the left atrial wall is a thin, heterogeneous structure with an important inter and intra-patient variability of LAWT. Objective To determine if adapting AI to atrial wall thickness (AWT) is feasible, effective and safe during AF ablation. Methods Single-Center study that included 80 consecutive patients referred for a first paroxysmal AF ablation that was performed with a single catheter approach with the intention to reduce vascular access complication rate. All patients had a MDCT prior to the ablation procedure. LAWT maps were semi-automatically computed from the MDCT as the local distance between the LA endo and epicardium. All procedures were performed under general anesthesia with a high-rate low-volume ventilation protocol for obtaining higher catheter stability. The transeptal puncture was TEE-guided. During the procedure, the WT map was fused with the LA anatomy using CARTO-merge. LAWT was categorized into 1mm-layers and the AI was titrated to the local atrial WT as follows: Thickness < 1 mm (red): 300; 1-2 mm (yellow): 350; 2-3 mm (green): 400; 3-4 mm (blue): 450; > 4 mm (purple): 450 (Figure). Maximal inter-lesion distance was set at 6 mm. VisiTag settings were: catheter position stability: minimum time 3 s, maximum range 4 mm; force over time: 25%, minimum force 3 g; lesion tag size: 3 mm. Respiration training was not possible due to the high catheter stability. The circumferential ablation line was designed in a personalized fashion to avoid thicker regions. Results 80 patients [41 (51,2 %) male, age 60± 11 years] were included. Mean LVEF was 59 ± 5 %, Mean LA diameter 39,1 ± 5,8 mm, Mean LAWT was 1.36 ± 0.63 mm. Mean AI was 352 ± 36 on the RPVs and 356 ± 36 on the LPVs. Procedure time was 60,0 min (IQR 51-70). Fluoroscopy time was 58,5 s (35-97,5). First pass isolation was obtained in 72 (90%) of the RPVs and 75 (93,8%) of the LPVs. Conclusions the present study, assessing a novel, personalized protocol for radiofrequency titration during atrial fibrillation ablation, shows a high rate of first pass isolation with a lower need for RF energy delivery and lower procedure requirements, as compared to previous PV ablation protocols. Further studies are needed to evaluate the long-term results of this approach. Abstract Figure. LAWT-map Visitag points with tailored AI

BACKGROUND Frequent premature ventricular complexes (PVCs) are common after a myocardial infarction (MI), but data on PVC ablation in this population are limited. OBJECTIVE The purpose of this study was to analyze data on PVC ablation in post-MI patients. METHODS Three hundred thirty-two patients with frequent PVCs and left ventricular (LV) dysfunction were prospectively studied. Data from 67 patients (20%; age 63 +/- 10 years; 65 men [93%]) with previous MI were compared with the remaining 265 patients. RESULTS PVCs in post-MI patients originate predominantly from the LV (92% LV vs 6% right ventricle [RV]; P

Aims A pre-operative non-invasive identification of the site of origin (SOO) of outflow tract ventricular arrhythmias (OTVAs) is important to properly plan radiofrequency ablation procedures. Although some algorithms based on electrocardiograms (ECGs) have been developed to predict left vs. right ventricular origins, their accuracy is still limited, especially in complex anatomies. The aim of this work is to use patient-specific electrophysiological simulations of the heart to predict the SOO in OTVA patients. Methods and results An in silico pace-mapping procedure was designed and used on 11 heart geometries, generating for each case simulated ECGs from 12 clinically plausible SOO. Subsequently, the simulated ECGs were compared with patient ECG data obtained during the clinical tachycardia using the 12-lead correlation coefficient (12-lead ρ). Left ventricle (LV) vs. right ventricle (RV) SOO was estimated by computing the LV/RV ratio for each patient, obtained by dividing the average 12-lead ρ value of the LV- and RV-SOO simulated ECGs, respectively. Simulated ECGs that had virtual sites close to the ablation points that stopped the arrhythmia presented higher correlation coefficients. The LV/RV ratio correctly predicted LV vs. RV SOO in 10/11 cases; 1.07 vs. 0.93 P Conclusion The obtained results demonstrate the potential of the developed in silico pace-mapping technique to complement standard ECG for the pre-operative planning of complex ventricular arrhythmias.

Aims Frequent premature ventricular complexes (PVCs) can induce or worsen left ventricular systolic dysfunction. We aimed to investigate the influence of the baseline QRS in the response after PVC ablation in patients with depressed left ventricular ejection fraction (LVEF). Methods and results Two hundred and fifteen [59 ± 13 years old, 152 (71%) men] consecutive patients with left ventricular (LV) systolic dysfunction and frequent PVCs referred for ablation were included and followed-up for 12 months. Echocardiographic response was defined as an improvement of at least five absolute points in LVEF. Clinical, electrocardiogram, and electrophysiological characteristics were analysed. Mean baseline QRS duration was 110 ms [97–140]. Premature ventricular complex burden significantly decreased after ablation from 23% [16–33] at baseline to 1% [0–8] at 12 months, P 130 ms. Conclusions In patients with LV systolic dysfunction, intrinsic QRS duration is inversely related to the probability and the degree of echocardiographic response after frequent PVC ablation. Patients with a QRS duration >130 ms at baseline have the poorer response after ablation.

Aims Sudden cardiac death (SCD) risk estimation in patients referred for cardiac resynchronization therapy (CRT) remains a challenge. By CRT-mediated improvement of left ventricular ejection fraction (LVEF), many patients loose indication for primary prevention implantable cardioverter-defibrillator (ICD). Increasing evidence shows the importance of myocardial scar for risk prediction. The aim of this study was to investigate the prognostic impact of myocardial scar depending on the echocardiographic response in patients undergoing CRT. Methods and results Patients with indication for CRT were prospectively enrolled. Decision about ICD or pacemaker implantation was based on clinical criteria. All patients underwent delayed-enhancement cardiac magnetic resonance imaging. Median follow-up duration was 45 (24–75) months. Primary outcome was a composite of sustained ventricular arrhythmia, appropriate ICD therapy, or SCD. A total of 218 patients with LVEF 25.5 ± 6.6% were analysed [158 (73%) male, 64.9 ± 10.7 years]. Myocardial scar was observed in 73 patients with ischaemic cardiomyopathy (ICM) (95% of ICM patients); in 62 with non-ischaemic cardiomyopathy (45% of these patients); and in all but 1 of 36 (17%) patients who reached the primary outcome. Myocardial scar was the only significant predictor of primary outcome [odds ratio 27.7 (3.8–202.7)], independent of echocardiographic CRT response. A total of 55 (25%) patients died from any cause or received heart transplant. For overall survival, only a combination of the absence of myocardial scar with CRT response was associated with favourable outcome. Conclusion Malignant arrhythmic events and SCD depend on the presence of myocardial scar but not on CRT response. All-cause mortality improved only with the combined absence of myocardial scar and CRT response.

Aims Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) permits characterizing ischaemic scars, detecting heterogeneous tissue channels (HTCs) which constitute the arrhythmogenic substrate (AS). Late gadolinium enhancement cardiac magnetic resonance also improves the arrhythmia-free survival when used to guide ventricular tachycardia (VT) substrate ablation. However, its availability may be limited. We sought to evaluate the performance of multidetector cardiac computed tomography (MDCT) imaging in identifying HTCs detected by LGE-CMR in ischaemic patients undergoing VT substrate ablation. Methods and results Thirty ischaemic patients undergoing both LGE-CMR and MDCT before VT substrate ablation were included. Using a dedicated post-processing software, two blinded operators, assigned either to LGE-CMR or MDCT analysis, characterized the presence of CMR and computed tomography (CT) channels, respectively. Cardiac magnetic resonance channels were classified as endocardial (layers < 50%), epicardial (layers ≥ 50%), or transmural. Cardiac magnetic resonance- vs. CT-channel concordance was considered when showing the same orientation and American Heart Association (AHA) segment. Mean age was 69 ± 10 years; 90% were male. Mean left ventricular ejection fraction was 35 ± 10%. All patients had CMR channels (n = 76), whereas only 26/30 (86.7%) had CT channels (n = 91). Global sensitivity (Se) and positive predictive values for detecting CMR channels were 61.8% and 51.6%, respectively. MDCT performance improved in patients with epicardial CMR channels (Se 80.5%) and transmural scars (Se 72.2%). In 4/11 (36%) patients with subendocardial myocardial infarction (MI), MDCT was unable to identify the AS. Conclusions Compared to LGE-CMR, myocardial wall thickness assessment using MDCT fails to detect the presence of AS in 36% of patients with subendocardial MI, showing modest sensitivity identifying HTCs but a better performance in patients with transmural scars.

Aims Left ventricular (LV) outflow tract ventricular arrhythmias (OTVA) are associated with hypertension (HT), older age, and LV dysfunction, suggesting that LV overload plays a role in the aetiopathogenesis. We hypothesized that anatomical modifications of the LV outflow tract (LVOT) could predict left vs. right OTVA site of origin (SOO). Methods and results Fifty-six (32 men, 53 ± 18 years old) consecutive patients referred for OTVA ablation were included. Cardiac multidetector computed tomography was performed before ablation and then imported to the CARTO system to aid the mapping and ablation procedure. Anatomical characteristics of the aortic root as well as aortopulmonary valvular planar angulation (APVPA) were analysed. The LV was the OTVA SOO (LVOT-VA) in 32 (57%) patients. These patients were more frequently male (78% vs. 22%, P = 0.001), older (57 ± 18 vs. 47 ± 18 years, P = 0.055), and more likely to have HT (59% vs. 21%, P = 0.004), compared to right OTVA patients. Aortopulmonary valvular planar angulation was higher in LVOT-VA patients (68 ± 5° vs. 55 ± 6°, respectively; P

Background Patients with transmural myocardial infarction (MI) who undergo endocardial-only substrate ablation are at increased risk for ventricular tachycardia recurrence. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) can be used to assess infarct transmurality (IT). However, the degree of IT associated with an epicardial arrhythmogenic substrate (AS) has not been determined. Objective The purpose of this study was to determine the degree of IT observed by LGE-CMR and multidetector computed tomography (MDCT) that predicts the presence of epicardial AS. Methods The study included 38 post-MI patients. Ten patients with a subendocardial infarction underwent endocardial-only mapping, and 28 with a classic transmural MI (C-TMI), defined as hyperenhancement ≥75% of myocardial wall thickness (WT), underwent endo–epicardial mapping. LGE-CMR/MDCT data were registered to high-density endocardial or epicardial maps to be analyzed for the presence of AS. Results Of the 28 post-MI patients with C-TMI, 18 had epicardial AS (64%) and 10 (36%) did not. An epicardial scar area ≥14 cm2 on LGE-CMR identified patients with epicardial AS (sensitivity 1, specificity 1). Mean WT in the epicardial scar area in these patients was lower than in patients without epicardial AS (3.14 ± 1.16 mm vs 5.54 ± 1.78 mm; P = .008). A mean WT cutoff value ≤3.59 mm identified patients with epicardial AS (sensitivity 0.91, specificity 0.93). Conclusion An epicardial scar area ≥14 cm2 on LGE-CMR and mean CT-WT ≤3.59 mm predict epicardial AS in post-MI patients.

Objectives The aim of this study was to analyze whether scar characterization could improve the risk stratification for life-threatening ventricular arrhythmias and sudden cardiac death (SCD). Background Among patients with a cardiac resynchronization therapy (CRT) indication, appropriate defibrillator (CRT-D) therapy rates are low. Methods Primary prevention patients with a class I indication for CRT were prospectively enrolled and assigned to CRT-D or CRT pacemaker according to physician’s criteria. Pre-procedure contrast-enhanced cardiac magnetic resonance was obtained and analyzed to identify scar presence or absence, quantify the amount of core and border zone (BZ), and depict BZ distribution. The presence, mass, and characteristics of BZ channels in the scar were recorded. The primary endpoint was appropriate defibrillator therapy or SCD. Results 217 patients (39.6% ischemic) were included. During a median follow-up of 35.5 months (12 to 62 months), the primary endpoint occurred in 25 patients (11.5%) and did not occur in patients without myocardial scar. Among patients with scar (n = 125, 57.6%), those with implantable cardioverter-defibrillator (ICD) therapies or SCD exhibited greater scar mass (38.7 ± 34.2 g vs. 17.9 ± 17.2 g; p Conclusions The presence, extension, heterogeneity, and qualitative distribution of BZ tissue of myocardial scar independently predict appropriate ICD therapies and SCD in CRT patients.

Purpose: Activation mapping is used to guide ablation of idiopathic outflow tract ventricular arrhythmias (OTVAs). Isochronal activation maps help to predict the site of origin (SOO): left vs right outflow tract (OT). We evaluate an algorithm for automatic activation mapping based on the onset of the bipolar electrogram (EGM) signal for predicting the SOO and the effective ablation site in OTVAs. Methods: Eighteen patients undergoing ablation due to idiopathic OTVAs were studied (12 with left ventricle OT origin). Right ventricle activation maps were obtained offline with an automatic algorithm and compared with manual annotation maps obtained during the intervention. Local activation time (LAT) accuracy was assessed, as well as the performance of the 10 ms earliest activation site (EAS) isochronal area in predicting the SOO. Results: High correlation was observed between manual and automatic LATs (Spearman's: 0.86 and Lin's: 0.85, both p < 0.01). The EAS isochronal area were closely located in both map modalities (5.55 ± 3.56 mm) and at a similar distance from the effective ablation site (0.15 ± 2.08 mm difference, p = 0.859). The 10 ms isochronal area longitudinal/perpendicular diameter ratio measured from automatic maps showed slightly superior SOO identification (67% sensitivity, 100% specificity) compared with manual maps (67% sensitivity, 83% specificity). Conclusions: Automatic activation mapping based on the bipolar EGM onset allows fast, accurate and observer-independent identification of the SOO and characterization of the spreading of the activation wavefront in OTVAs. This study was supported by personal grants to A.A. refs.: BES-2011-046644 and EEBB-I-15-09466, by projects TEC2013-42140-R, DPI2016-75458-R and TIN2011-28067 from Ministerio de Economía y Competitividad. Also by Gobierno de Aragón (Spain) and European Social Fund (EU) through Grupo Consolidado BSICoS ref.: T 96. The CIBER-BBN is an initiative of Instituto de Salud Carlos III. This work was also supported in part by the project PI14/00759, integrated in the Plan Nacional de I + D + i and co-funded by the ISCIII-Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER).

Predicting sudden cardiac death risk in the first months after ST-segment elevation myocardial infarction (STEMI) remains challenging.The purpose of this study was to investigate the ability of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) to identify the potentially arrhythmogenic substrate and its temporal evolution after STEMI.One hundred consecutive patients with a first STEMI were included. Three-dimensional high-resolution LGE-CMR was obtained at 3 T on days 7 and 180. Left ventricular wall was segmented and characterized by pixel signal intensity algorithm in 5 layers from endocardium to epicardium. A 3-dimensional color-coded shell map was obtained for each layer, depicting scar core and border zone (BZ) distribution. Presence and characteristics of BZ channels were registered for each layer.At 180 days, left ventricular ejection fraction had improved significantly (from 46.7% ± 10% to 51.5% ± 10%; P.001) and scar mass was reduced (from 22.6 ± 20 g to 13.8 ± 12 g; P.001). Most BZ channels (89%) were identified in the same myocardial layer and American Heart Association (AHA) segment, with the same orientation and morphology in both studies. Early LGE-CMR had 96% sensitivity and 90% specificity for predicting presence of BZ channels at 180 days. Greater presence was observed in patients with no-reflow phenomenon at baseline (P = .01).Most BZ channels can be identified by LGE-CMR at day 7 post-STEMI and, despite scar mass reduction, remain unaltered at 6 months, suggesting that the potentially arrhythmogenic substrate is established within the first week post-STEMI.

We have read with interest the paper by Friedman et al. in a previous issue of this journal entitled “Predictors of Cardiac Perforation With Catheter Ablation of Atrial Fibrillation” ([1][1]). The authors analyzed predictors of cardiac perforation in a nationwide registry of 102,398 patients

Aims Identification of local abnormal electrograms (EGMs) during ventricular tachycardia substrate ablation (VTSA) is challenging when they are hidden within the far-field signal. This study analyses whether the response to a double ventricular extrastimulus during substrate mapping could identify slow conducting areas that are hidden during sinus rhythm. Methods and results Consecutive patients ( n = 37) undergoing VTSA were prospectively included. Bipolar EGMs with >3 deflections and duration

Aims ST-segment elevation myocardial infarction (STEMI) triggers remote extracellular matrix expansion. Myocardial extracellular volume fraction (ECV), determined by cardiovascular magnetic resonance, permits quantification of interstitial space expansion. Our aim was to determine the relationship between early serum fibrosis biomarkers and 180-day post-infarct remote myocardium remodeling using ECV. Methods and results In 26 patients with STEMI, functional imaging, T1-mapping, and late-gadolinium-enhancement were performed on a 3-T CMR scanner at baseline (days 3 to 5) and 180days. Biomarkers were measured at days 1, 3, and 7 after STEMI. The mean initial and follow-up left ventricular ejection fraction (LVEF) were 48.3±18.1% and 52.6±12.3%, respectively. Initial infarct size was 11.6±16.8% of LV mass. ECV in the remote myocardium at 180days correlated with indexed end-systolic volume (r=0.4, p=0.045). A significant correlation was observed between galectin-3 at day 7 and ECV at 6months (r=0.428, p=0.037). A trend towards a direct correlation was found for BNP (r=0.380, p=0.059). Multivariate analysis revealed that BNP and galectin-3 were independent predictors of long-term changes in ECV and explained nearly 30% of the variance in this parameter (r 2 =0.34; p=0.01). A galectin-3 cutoff value of 10.15ng/mL was the most powerful predictor of high ECV values (≥28.5%) at follow-up. Galectin-3 at day 7 was an independent predictor of high ECV values at follow-up (OR=22.51; CI 95%: 2.1–240.72; p=0.01) with 0.76 AUC (CI: 0.574–0.964; p=0.03). Conclusions Galectin-3 measured acutely after STEMI is an independent predictor of increased ECV at 6-month follow-up that might be useful for long-term risk stratification.

Aims Ablation of frequent premature ventricular complexes (PVCs) improves left ventricular ejection fraction in patients with left ventricular (LV) systolic dysfunction. This study aims to evaluate the long-term hard outcomes and potential prognostic variables in this population. Methods and results Prospective multicentre study including 101 consecutive patients [56 ± 12 years old, 62 (61%) men] with LV systolic dysfunction and frequent PVCs who underwent PVC ablation before November 2015. The last evaluation performed was considered the long-term follow-up (LTFUP) evaluation. Mean follow-up was 34 ± 16 months (range 24–84 months). Ablation was successful in 95 (94%) patients. There was a significant reduction in the PVC burden from 21 ± 12% at baseline to 3.8 ± 6% at LTFUP, P Conclusion In patients with LV systolic dysfunction, ablation of frequent PVCs induces a significant improvement in functional, structural, and neurohormonal status, which persists at LTFUP. A sustained reduction in the baseline PVC burden is associated with a lower risk of cardiac mortality, cardiac transplantation, or hospitalization for heart failure during follow-up.

Risk stratification for sudden cardiac death (SCD) is one of the main objectives of clinical arrhythmology. Despite increased knowledge of the fundamental basis and predictors of SCD, the estimation of individual risk remains challenging. To date, symptomatic heart failure and reduced left ventricular ejection fraction are the main variables used to identify patients at high risk of SCD who could potentially benefit from preventive therapies. Beyond left ventricular ejection fraction, new diagnostic tools have been proposed to better stratify patients at risk of SCD. Among them, cardiovascular magnetic resonance imaging, which allows direct visualization of the arrhythmogenic substrate, is considered particularly promising. Genetic testing and serum biomarkers may also have a role in SCD risk assessment.

Mild therapeutic hypothermia (MTH) is associated with an increased risk of both thrombotic and bleeding events. Although little is known about the use of Glycoprotein IIb-IIIa inhibitors (GPi) in this setting, the early action and the intravenous administration of these agents in patients who cannot swallow might potentially translate into clinical benefits in patients with acute coronary syndromes (ACS).To assess the incidence of bleeding/thrombotic events in patients with ACS under MTH after an Out-of-hospital cardiac arrest (OHCA) who received GPi or not.From January 2010 to September 2015, 110 patients were treated with MTH after an OHCA. Among them, 88 (80%) had an ACS and 71 patients (80.6%) underwent percutaneous coronary intervention (PCI). In 17 (24%) GPi were administered in the cath-lab. During hospitalization, 11.7% in the GPi and 9.25%in the non GPi group presented thrombotic events (stent thrombosis, deep vein thrombosis, pulmonary embolism) without significant differences between groups (p= 0.762). The incidence of any bleeding (64.7% vs. 14.8%; p0.0001), and major bleeding (41.1% vs. 3.7; p0.0001) was significantly higher in patients receiving GPi. Finally, in-hospital mortality did not differ between groups (24% vs. 35, 2%; p=0.385).In this study, the use of GPi in patients with ACS undergoing PCI under MTH was associated with an increased bleeding risk without reduction of thrombotic events. According to these results, the use of GPi should be carefully considered in this setting.

Background There is no consensus on the appropriate indications for the epicardial approach in substrate ablation of post–myocardial infarction (MI) ventricular tachycardia (VT). Objective The purpose of this study was to investigate whether infarct transmurality (IT) could identify patients who would benefit from a combined first-line endo-epicardial approach. Methods Before ablation, IT was assessed by contrast-enhanced cardiac magnetic resonance imaging (hyperenhancement ≥75% of the wall thickness in ≥1 segment), echocardiography (dyskinesia/akinesia + hyperrefringency + wall thinning), computed tomography (wall thinning), or scintigraphy (transmural necrosis). Prospectively from January 2011, an endocardial approach was used in patients with subendocardial MI (group 1) and a combined endo-epicardial approach in patients with transmural MI (group 2). Outcomes in both groups were compared with those in patients with transmural MI and only endocardial approach due to previous cardiac surgery or procedure performed before January 2011 (group 3). The primary end point was VT/ventricular fibrillation recurrence-free survival. Results Ninety patients (92.2% men; mean age 67.4 ± 9.8 years) undergoing VT substrate ablation were included: group 1, n=34; group 2, n=24; group 3, n=32. During a mean follow-up duration of 22.5 ± 13.7 months, 5 patients in group 1 (14.7%), 3 patients in group 2 (12.5%), and 13 patients in group 3 (40.6%) had VT recurrences ( P = .011). Time to recurrence was the shortest in group 3 (log-rank, P = .018). The endocardial approach in patients with transmural MI was associated with an increased risk of recurrence (hazard ratio 4.01; 95% confidence interval 1.41–11.3; P = .009). Conclusion The endocardial approach in patients with transmural MI undergoing VT substrate ablation is associated with an increased risk of recurrence. IT may be a useful criterion for the selection of a first-line combined endo-epicardial approach.

Premature ventricular complex (PVC) ablation has been shown to improve left ventricular ejection fraction (LVEF) and New York Heart Association functional class in patients with left ventricular dysfunction. Both are considered key variables in predicting risk of sudden cardiac death.The objective of this study was to assess whether ablation might remove the primary prevention (PP) implantable cardioverter-defibrillator (ICD) indication in patients with frequent PVC.Sixty-six consecutive patients with PP-ICD indication and frequent PVC [33 (50%) men; mean age 53 ± 13 years; 11 (17%) with ischemic heart disease] underwent PVC ablation. The ICD was withheld and the indication was reevaluated at 6 and 12 months.LVEF progressively improved from 28% ± 4% at baseline to 42% ± 12% at 12 months (P.001). New York Heart Association functional class improved from 2 patients with NYHA functional class I (3%) at baseline to 35 (53%) at 12 months (P.001). The brain natriuretic peptide level decreased from 246 ± 187 to 176 ± 380 pg/mL (P = .004). The PP-ICD indication was removed in 42 patients (64%) during follow-up, from 38 (92%) of them at 6 months, showing an independent association with baseline PVC burden and successful sustained ablation. In patients with successful sustained ablation, a cutoff value of 13% PVC burden had a sensitivity of 100% and a specificity of 93% (area under the curve 99%) for removing ICD indication postablation. No sudden cardiac deaths or malignant ventricular arrhythmias were observed.In patients with frequent PVC and PP-ICD indication, ablation improves LVEF and, in most cases, allows removal of the indication. Withholding the ICD and reevaluating within 6 months of ablation seems to be a safe and appropriate strategy.

Background The earliest activation site (EAS) location in the septal right ventricular outflow tract (RVOT) could be an additional mapping data predictor of left ventricular outflow tract (LVOT) vs RVOT origin of idiopathic ventricular arrhythmias (VAs). Objective The purpose of this study was to assess the impact of EAS location in predicting LVOT vs RVOT origin. Methods Macroscopic and histologic study was performed in 12 postmortem hearts. Electroanatomic maps (EAMs) from 37 patients with outflow tract (OT) VA with the EAS in the septal RVOT were analyzed. Pulmonary valve (PV) was defined by voltage scanning after validation of voltage thresholds by image integration. EAM measurements were correlated with those of macroscopic/histologic study. Results A cutoff value of 1.9 mV discriminated between subvalvular and supravalvular positions (90% sensitivity, 96% specificity). EAS ≥1 cm below PV excluded RVOT site of origin (SOO). According to anatomic findings (distance PV–left coronary cusp=5 ± 3 vs PV–right coronary cusp=11 ± 5 mm), EAS–PV distance was significantly shorter in VAs arising from left coronary cusp than from the other LVOT locations (4.2 ± 5.4 mm vs 9.2 ± 7 mm; P = .034). The 10-ms isochronal longitudinal/perpendicular diameter ratio was higher in the RVOT vs the LVOT SOO group (1.97 ± 1.2 vs 0.79 ± 0.49; P = .001). An algorithm based on EAS–PV distance and the 10-ms isochronal longitudinal/perpendicular diameter ratio predicted LVOT SOO with 91% sensitivity and 100% specificity. Conclusion An algorithm based on the EAS–PV distance and the 10-ms isochronal longitudinal/perpendicular diameter ratio accurately predicts LVOT vs RVOT SOO in outflow tract VAs with EAS in the septal RVOT.

Background— Ventricular tachycardia (VT) substrate ablation usually requires extensive ablation. Scar dechanneling technique may limit the extent of ablation needed. Methods and Results— The study included 101 consecutive patients with left ventricular scar–related VT (75 ischemic patients; left ventricular ejection fraction, 36±13%). Procedural end point was the elimination of all identified conducting channels (CCs) by ablation at the CC entrance followed by abolition of residual inducible VTs. By itself, scar dechanneling rendered noninducibility in 54.5% of patients; ablation of residual inducible VT increased noninducibility to 78.2%. Patients needing only scar dechanneling had a shorter procedure (213±64 versus 244±71 minutes; P =0.027), fewer radiofrequency applications (19±11% versus 27±18%; P =0.01), and external cardioversion/defibrillation shocks (20% versus 65.2%; P P =0.013) and those with complete CC-electrogram elimination (log-rank P =0.013). The complications rate was 6.9%, with no deaths. Conclusions— Scar dechanneling alone results in low recurrence and mortality rates in more than half of patients despite the limited ablation extent required. Residual inducible VT ablation improves acute results, but patients who require it have worse outcomes. Recurrences are mainly related to incomplete CC-electrogram elimination.

Item does not contain fulltext Time-to-peak measurements and single-parameter observations are cumbersome and often confusing for quantifying local changes in myocardial function. Recent spatiotemporal normalization techniques can provide a global picture of myocardial motion and strain patterns and overcome some of these limitations. Despite these advances, the quantification of pattern changes remains descriptive, which limits their relevance for longitudinal studies. Our paper provides a new perspective to the longitudinal analysis of myocardial motion. Non-rigid registration (diffeomorphic registration via currents) is used to match pairs of patterns, and pattern changes are inferred from the registration output. Scalability is added to the different components of the input patterns in order to tune up the contributions of the spatial, temporal and magnitude dimensions to data changes, which are of interest for our application. The technique is illustrated on 2D echocardiographic sequences from 15 patients with hypertrophic obstructive cardiomyopathy. These patients underwent biventricular pacing, which aims at provoking mechanical dyssynchrony to reduce left ventricular outflow tract (LVOT) obstruction. We demonstrate that our method can automatically quantify timing and magnitude changes in myocardial motion between baseline (non-paced) and 1 year follow-up (pacing on), resulting in a more robust analysis of complex patterns and subtle changes. Our method helps confirming that the reduction of LVOT pressure gradient actually comes from the induction of the type of dyssynchrony that was expected.

Aims Current navigation systems incorporate algorithms for automatic identification of local activation time (LAT). However, data about their utility and accuracy in premature ventricular complex (PVC) ablation procedures are scarce. This study analyses the accuracy of an algorithmic method based on automatic annotation of the maximal negative slope of the unipolar electrogram within the window demarcated by the bipolar electrogram compared with conventional manual annotation during PVC ablation procedures. Methods and results Forty patients with successful ablation of focal PVC in three centres were included. Electroanatomical activation maps obtained with the automatic system (WF-map) were compared with manual annotation maps (M-map). Correlation and concordance of LAT obtained with both methods were assessed at 3536 points. The distance between the earliest activation site (EAS) and the effective radiofrequency application point (e-RFp) were determined in M-map and WF-map. The distance between WF-EAS and M-EAS was assessed. Successful ablation sites included left ventricular outflow tract (LVOT; 55%), right ventricular outflow tract (40%), and tricuspid annulus (5%). Good correlation was observed between the two annotation approaches (r = 0.655; P