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Background: Brugada syndrome (BrS) is associated with mutations in the cardiac sodium channel gene, SCN5A. However, genetic studies of patients with BrS with arrhythmic events have been limited. We sought to compare various clinical, ECG, and electrophysiological parameters according to SCN5A genotype in a large cohort of BrS probands with first arrhythmic event., Methods: Survey on Arrhythmic Events in Brugada Syndrome is a survey of 10 Western and 4 Asian countries, gathering 678 patients with BrS with first arrhythmic event. Only probands were included, and SCN5A genotype adjudicated. Patients without appropriate genetic data were excluded. Associations of genotype with clinical features were analyzed., Results: The study group comprised 392 probands: 92 (23.5%) SCN5A+ (44 pathogenic/likely pathogenic [P/LP] and 48 variants of unknown significance) and 300 (76.5%) SCN5A-. SCN5A missense variants and the patients hosting them were similar regardless of adjudication. A higher proportion of patients with P/LP were pediatric (<16 years) compared with SCN5A- (11.4% versus 3%, P =0.023). The proportion of females was higher among patients with P/LP compared with SCN5A - (18.2% versus 6.3%, P =0.013). P/LP probands were more likely to have a family history of sudden cardiac death compared with SCN5A - (41.9% versus 16.8%, P <0.001). A higher proportion of patients with P/LP were White compared with SCN5A- (87.5% versus 47%, P <0.001). Ethnicity (odds ratio, 5.41 [2.8-11.19], P <0.001) and family history of sudden cardiac death (odds ratio, 2.73 [1.28-5.82], P =0.009) were independent variables associated with P/LP genotype following logistic regression., Conclusions: The genetic basis of BrS has a complex relationship with gender, ethnicity, and age. Probands hosting a P/LP variant tended to experience their first arrhythmic event at a younger age and to have events triggered by fever compared with patients with SCN5A- . In addition, they were more likely to be White and to have family history of sudden cardiac death. Among females, a P/LP variant suggests an increased risk of being symptomatic. This association should be further studied on an ethnically specific basis in large prospectively collected international cohorts.

Background: A male predominance in Brugada syndrome (BrS) has been widely reported, but scarce information on female patients with BrS is available., Objective: The purpose of this study was to investigate the clinical characteristics and long-term prognosis of women with BrS., Methods: A multicenter retrospective study of patients diagnosed with BrS and previous electrophysiological study (EPS) was performed., Results: Among 770 patients, 177 (23%) were female. At presentation, 150 (84.7%) were asymptomatic. Females presented less frequently with a type 1 electrocardiographic pattern (30.5% vs 55.0%; P <.001), had a higher rate of family history of sudden cardiac death (49.7% vs 29.8%; P <.001), and had less sustained ventricular arrhythmias (VAs) on EPS (8.5% vs 15.1%; P = .009). Genetic testing was performed in 79 females (45% of the sample) and was positive in 34 (19%). An implantable cardioverter-defibrillator was inserted in 48 females (27.1%). During mean (± SD) follow-up of 122.17 ± 57.28 months, 5 females (2.8%) experienced a cardiovascular event compared to 42 males (7.1%; P = .04). On multivariable analysis, a positive genetic test (18.71; 95% confidence interval [CI] 1.82-192.53; P = .01) and atrial fibrillation (odds ratio 21.12; 95% CI 1.27-350.85; P = .03) were predictive of arrhythmic events, whereas VAs on EPS (neither with 1 or 2 extrastimuli nor 3 extrastimuli) were not., Conclusion: Women with BrS represent a minor fraction among patients with BrS, and although their rate of events is low, they do not constitute a risk-free group. Neither clinical risk factors nor EPS predicts future arrhythmic events. Only atrial fibrillation and positive genetic test were identified as risk factors for future arrhythmic events., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: Monitoring of patients after ablation had wide variations in the ESC-EHRA atrial fibrillation ablation long-term (AFA-LT) registry. We aimed to compare four different monitoring strategies after catheter AF ablation., Methods and Results: The ESC-EHRA AFA-LT registry included 3593 patients who underwent ablation. Arrhythmia monitoring during follow-up was performed by 12-lead electrocardiogram (ECG), Holter ECG, trans-telephonic ECG monitoring (TTMON), or an implanted cardiac monitoring (ICM) system. Patients were selected to a given monitoring group according to the most extensive ECG tool used in each of them. Comparison of the probability of freedom from recurrences was performed by censored log-rank test and presented by Kaplan-Meier curves. The rhythm monitoring methods were used among 2658 patients: ECG (N = 578), Holter ECG (N = 1874), TTMON (N = 101), and ICM (N = 105). A total of 767 of 2658 patients (28.9%) had AF recurrences during follow-up. Censored log-rank test discovered a lower probability of freedom from relapses, which was detected with ICM compared to TTMON, ECG, and Holter ECG (P < 0.001). The rate of freedom from AF recurrences was 50.5% among patients using the ICM while it was 65.4%, 70.6%, and 72.8% using the TTMON, ECG, and Holter ECG, respectively., Conclusion: Comparing all main electrocardiographic monitoring methods in a large patient sample, our results suggest that post-ablation recurrences of AF are significantly underreported by TTMON, ECG, and Holter ECG. The ICM estimates AF ablation recurrences most reliably and should be a preferred mode of monitoring for trials evaluating novel AF ablation techniques., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Aims: To define the clinical characteristics and long-term clinical outcomes of a large cohort of patients with idiopathic ventricular fibrillation (IVF) and normal 12-lead electrocardiograms (ECGs)., Methods and Results: Patients with ventricular fibrillation as the presenting rhythm, normal baseline, and follow-up ECGs with no signs of cardiac channelopathy including early repolarization or atrioventricular conduction abnormalities, and without structural heart disease were included in a registry. A total of 245 patients (median age: 38 years; males 59%) were recruited from 25 centres. An implantable cardioverter-defibrillator (ICD) was implanted in 226 patients (92%), while 18 patients (8%) were treated with drug therapy only. Over a median follow-up of 63 months (interquartile range: 25-110 months), 12 patients died (5%); in four of them (1.6%) the lethal event was of cardiac origin. Patients treated with antiarrhythmic drugs only had a higher rate of cardiovascular death compared to patients who received an ICD (16% vs. 0.4%, P = 0.001). Fifty-two patients (21%) experienced an arrhythmic recurrence. Age ≤16 years at the time of the first ventricular arrhythmia was the only predictor of arrhythmic recurrence on multivariable analysis [hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.18-0.92; P = 0.03]., Conclusion: Patients with IVF and persistently normal ECGs frequently have arrhythmic recurrences, but a good prognosis when treated with an ICD. Children are a category of IVF patients at higher risk of arrhythmic recurrences., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: There is limited information on ethnic differences between patients with Brugada syndrome (BrS) and arrhythmic events (AEs)., Objective: The purpose of this study was to compare clinical, electrocardiographic (ECG), electrophysiological, and genetic characteristics between white and Asian patients with BrS and AEs., Methods: The Survey on Arrhythmic Events in Brugada Syndrome is a multicenter survey from Western and Asian countries, gathering 678 patients with BrS and first documented AE. After excluding patients with other (n = 14 [2.1%]) or unknown (n = 30 [4.4%]) ethnicity, 364 (53.7%) whites and 270 (39.8%) Asians comprised the study group., Results: There was no difference in AE age onset (41.3 ± 16.1 years in whites vs 43.3 ± 12.3 years in Asians; P = .285). Higher proportions of whites were observed in pediatric and elderly populations. Asians were predominantly men (98.1% vs 85.7% in whites; P < .001) and frequently presented with aborted cardiac arrest (71.1% vs 56%; P < .001). Asians tended to display more spontaneous type 1 BrS-ECG pattern (71.5% vs 64.3%; P = .068). A family history of sudden cardiac death was noted more in whites (29.1% vs 11.5%; P < .001), with a higher rate of SCN5A mutation carriers (40.1% vs 13.2% in Asians; P < .001), as well as more fever-related AEs (8.5% vs 2.9%; P = .011). No difference was observed between the 2 groups regarding history of syncope and ventricular arrhythmia inducibility., Conclusion: There are important differences between Asian and white patients with BrS. Asian patients present almost exclusively as male adults, more often with aborted cardiac arrest and spontaneous type 1 BrS-ECG. However, they have less family history of sudden cardiac death and markedly lower SCN5A mutation rates. The striking difference in SCN5A mutation rates should be tested in future studies., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Cardiac resynchronization therapy (CRT) is a cornerstone of therapy for patients with heart failure, reduced left ventricular (LV) ejection fraction, and a wide QRS complex. However, not all patients respond to CRT: 30% of CRT implanted patients are currently considered clinical non-responders and up to 40% do not achieve LV reverse remodelling. In order to achieve the best CRT response, appropriate patient selection, device implantation, and programming are important factors. Optimization of CRT pacing intervals may improve results, increasing the number of responders, and the magnitude of the response. Echocardiography is considered the reference method for atrioventricular and interventricular (VV) intervals optimization but it is time-consuming, complex and it has a large interobserver and intraobserver variability. Previous studies have linked QRS shortening to clinical response, echocardiographic improvement and favourable prognosis. In this review, we describe the electrocardiographic optimization methods available: 12-lead electrocardiogram; fusion-optimized intervals (FOI); intracardiac electrogram-based algorithms; and electrocardiographic imaging. Fusion-optimized intervals is an electrocardiographic method of optimizing CRT based on QRS duration that combines fusion with intrinsic conduction. The FOI method is feasible and fast, further reduces QRS duration, can be performed during implant, improves acute haemodynamic response, and achieves greater LV remodelling compared with nominal programming of CRT., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Background: Sudden death of a newborn is a rare entity, which may be caused by genetic cardiac arrhythmias. Among these diseases, Long QT syndrome is the most prevalent arrhythmia in neonates, but other diseases such as Brugada syndrome, Short QT syndrome and Catecholaminergic Polymorphic Ventricular Tachycardia also cause sudden death in infants. All these entities are characterized by well-known alterations in the electrocardiogram and the first symptom of the disease may be an unexpected death. Despite the low prevalence of these diseases, the performance of an electrocardiogram in the first hours or days after birth could help identify these electrical disruptions and adopt preventive measures. In recent years, there has been an important impulse by some experts in the scientific community towards the initiation of a newborn electrocardiogram-screening program, for the detection of these electrocardiographic abnormalities. In addition, the use of genetic analysis in neonates could identify the cause of these heart alterations. Identification of relatives carrying the genetic alteration associated with the disease allows adoption of measures to prevent lethal episodes., Conclusion: Recent technological advances enable a comprehensive genetic screening of a large number of genes in a cost-effective way. However, the interpretation of genetic data and its translation into clinical practice are the main challenges for cardiologists and geneticists. However, there is important controversy as to the clinical value, and cost-effectiveness of the use of electrocardiogram as well as of genetic testing to detect these cases. Our review focuses on these current matters of argue., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Background: Previously proposed algorithms to predict the ventricular tachycardia (VT) exit site have been based on diverse left ventricular models, but none of them identify the precise region of origin in the electroanatomic map. Moreover, no electrocardiographic (ECG) algorithm has been tested to predict the region of origin of scar-related VTs in patients with nonischemic cardiomyopathy., Objective: The purpose of this study was to validate a simple ECG algorithm to identify the segment of origin (SgO) of VT relative to the 17-segment American Heart Association model in patients with structural heart disease (SHD)., Methods: The study included 108 consecutive patients with documented VT and SHD [77 (71%) with coronary artery disease]. A novel frontal plane axis-based ECG algorithm (highest positive or negative QRS voltage) together with the polarity in leads V 3 and V 4 was used to predict the SgO of VT. The actual SgO of VT was obtained from the analysis of the electroanatomic map during the procedure. Conventional VT mapping techniques were used to identify the VT exit., Results: In total, 149 12-lead ECGs of successfully ablated VT were analyzed. The ECG-suggested SgO matched with the actual SgO in 122 of the 149 VTs (82%). In 21 of the 27 mismatched ECG-suggested SgOs (77.8%), the actual SgO was adjacent to the segment suggested by the ECG. There were no differences in the accuracy of the algorithm based on the SgO or the type of SHD., Conclusion: This novel QRS axis-based algorithm accurately identifies the SgO of VT in the 17-segment American Heart Association model in patients with SHD., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: There is limited information on gender differences in patients with Brugada syndrome (BrS) who experienced arrhythmic events (AEs)., Objective: The purpose of this study was to compare clinical, electrocardiographic (ECG), electrophysiological, and genetic characteristics between males and females in patients with BrS with their first AE., Methods: The multicenter Survey on Arrhythmic Events in BRUgada Syndrome collected data on the first AE in 678 patients with BrS including 619 males (91.3%) and 59 females (8.7%) aged 0.27-84 years (mean age 42.5 ± 14.1 years) at the time of AE occurrence., Results: After excluding pediatric patients, it was found that females were older than males (49.5 ± 14.4 years vs 43 ± 12.7 years, respectively; P = .001). Higher proportions of females were observed in the pediatric and elderly populations. In Asians, the male to female ratio for AEs was ≈9-fold higher than that in White. Spontaneous type 1 BrS ECG was associated with an earlier onset of AEs in pediatric females. A similar prevalence (≈65%) of spontaneous type 1 BrS ECG was present in males and females above the age of 60 years. Females less frequently showed spontaneous type 1 BrS ECG (41% vs 69%; P < .001) or arrhythmia inducibility at electrophysiology study (36% vs 66%; P < .001). An SCN5A mutation was more frequently found in females (48% vs 28% in males; P = .007)., Conclusion: This study confirms that female patients with BrS are much rarer, display less type 1 Brugada ECG, and exhibit lower inducibility rates than do males. It shows for the first time that female patients with BrS with AE have higher SCN5A mutation rates as well as the relationship between gender vs age at the onset of AEs and ethnicity., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: The literature on fever-related arrhythmic events (AEs) in Brugada syndrome (BrS) is currently limited to few case reports and small series., Objective: The present study aimed to describe the characteristics of fever-related AE in a large cohort of patients with BrS., Methods: The Survey on Arrhythmic Events in Brugada Syndrome is a multicenter study on 678 patients with BrS with first AE documented at the time of aborted cardiac arrest (n = 426) or after prophylactic implantable cardioverter-defibrillator implantation (n = 252)., Results: In 35 of 588 patients (6%) with available information, the AE occurred during a febrile illness. Most of the 35 patients were male (80%), Caucasian (83%), and proband (70%). The mean age at the time of AE was 29 ± 24 years (range 0.3-76 years). Most patients (80%) presented with aborted cardiac arrest and 6 (17%) with arrhythmic storm. Family history of sudden death, history of syncope, and spontaneous type 1 Brugada electrocardiogram were noted in 17%, 40%, and 71% of patients, respectively. Ventricular fibrillation was induced at electrophysiology study in 9 of 19 patients (47%). An SCN5A mutation was found in 14 of 28 patients (50%). The highest proportion of fever-related AE was observed in the pediatric population (age <16 years), with a disproportionally higher event rate in the very young (age 0-5 years) (65%). Males were involved in all age groups and females only in the pediatric and elderly groups. Fever-related AE affected 17 Caucasians aged <24 years, but no Asians aged <24 years., Conclusion: The risk of fever-related AE in BrS markedly varies according to age group, sex, and ethnicity. Taking these factors into account could help the clinical management of patients with BrS with fever., (Copyright © 2018 Heart Rhythm Society. All rights reserved.)

Background: Detailed information on the profile of patients with Brugada syndrome (BrS) presenting their first arrhythmic event (AE) after prophylactic implantation of an implantable cardioverter-defibrillator (ICD) is limited., Objectives: The objectives of this study were (1) to compare clinical, electrocardiographic, electrophysiologic, and genetic profiles of patients who exhibited their first documented AE as aborted cardiac arrest (group A) with profiles of those in whom the AE was documented after prophylactic ICD implantation (group B) and (2) to characterize group B patients' profile using the class II indications for ICD implantation established by HRS/EHRA/APHRS expert consensus statement in 2013., Methods: A survey of 23 centers from 10 Western and 4 Asian countries enabled data collection of 678 patients with BrS who exhibited their AE (group A, n = 426; group B, n = 252)., Results: The first AE occurred in group B patients 6.7 years later than in group A (mean age 46.1 ± 13.3 years vs 39.4 ± 15.1 years; P < .001). Group B patients had a higher incidence of family history of sudden cardiac death and SCN5A mutations. Of the 252 group B patients, 189 (75%) complied with the HRS/EHRA/APHRS indications whereas the remaining 63 (25%) did not., Conclusion: Patients with BrS with the first AE documented after prophylactic ICD implantation exhibited their AE at a later age with a higher incidence of positive family history of sudden cardiac death and SCN5A mutations as compared with those presenting with aborted cardiac arrest. Only 75% of patients who exhibited an AE after receiving a prophylactic ICD complied with the 2013 class II indications, suggesting that efforts are still required for improving risk stratification., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to compare patient response to cardiac resynchronization therapy (CRT) using fusion-optimized atrioventricular (AV) and interventricular (VV) intervals versus nominal settings., Background: The additional benefit obtained by AV- and VV-interval optimization in patients undergoing CRT remains controversial. Previous studies show short-term benefit in hemodynamic parameters; however, midterm randomized comparison between electrocardiogram optimization and nominal parameters is lacking., Methods: A group of 180 consecutive patients with left bundle branch block treated with CRT were randomized to fusion-optimized intervals (FOI) or nominal settings. In the FOI group, AV and VV intervals were optimized according to the narrowest QRS, using fusion with intrinsic conduction. Clinical response was defined as an increase >10% in the 6-min walk test or an increment of 1 step in New York Heart Association functional class. The left ventricular (LV) remodeling was defined as >15% decrease in left ventricular end-systolic volume (LVESV) at 12-month follow-up. Additionally, patients with LVESV reduction >30% relative to baseline were considered super-responders; by contrast, negative responders had increased LVESV relative to baseline., Results: Participant characteristics included a mean age of 65 ± 10 years, 68% male, 37% with ischemic cardiomyopathy, LV ejection fraction 26 ± 7%, and QRS 180 ± 22 ms. Baseline QRS was shortened significantly more by FOI, compared with nominal settings (-56.55 ± 17.65 ms vs. -37.81 ± 22.07 ms, respectively; p = 0.025). At 12 months, LV reverse remodeling was achieved in a larger proportion of the FOI group (74% vs. 53% [odds ratio: 2.02 (95% confidence interval: 1.08 to 3.76)], respectively; p = 0.026). No significant differences were observed in clinical response (61% vs. 53% [odds ratio: 1.43 (95% confidence interval: 0.79 to 2.59)], respectively; p = 0.24)., Conclusions: Device optimization based on FOI achieves greater LV remodeling, compared with nominal settings. (ECG Optimization of CRT: Evaluation of Mid-Term Response [BEST]; NCT01439529)., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Implantable cardioverter-defibrillator (ICD) indications for primary prevention in Brugada syndrome (BrS) are still debated., Objectives: The authors investigated the long-term outcome after ICD implantation in a large cohort of BrS patients., Methods: Of a total of 370 patients with BrS in follow-up (age 43 ± 14 years; 74% male), 104 patients (28.1%) were treated with ICDs. The authors analyzed the long-term incidence of shocks and complications., Results: An ICD was implanted for secondary prevention in 10 patients (9.6%) and for primary prevention in 94 patients (90.4%). After a follow-up of 9.3 ± 5.1 years, 21 patients (20.2%) experienced a total of 81 appropriate shocks (incidence rate 2.2 per 100 person-years). The rate of appropriate shocks was higher in secondary prevention patients (p < 0.01). However, 4 of the 45 asymptomatic patients (8.9%) experienced appropriate ICD therapy, all with a spontaneous type 1 electrocardiogram and inducible ventricular arrhythmias. In the multivariable analysis, type 1 electrocardiogram with syncope (hazard ratio: 4.96; 95% confidence interval: 1.87 to 13.14; p < 0.01) and secondary prevention indication (hazard ratio: 6.85; 95% confidence interval: 2.29 to 20.50; p < 0.01) were significant predictors of appropriate therapy. Nine patients (8.7%) experienced 37 inappropriate shocks (incidence rate 0.9 per 100 person-years). Twenty-one patients (20.2%) had other ICD-related complications (incidence rate 1.4 per 100 person-years). Three patients (2.9%) died (1 electrical storm and 2 noncardiovascular deaths)., Conclusions: ICD therapy is an effective therapy in high-risk patients with BrS. However, it is also associated with a significant risk of device-related complications. Special care during ICD implantation, adequate device programming, and regular follow-up may allow reducing the number of adverse events., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Isolated cases of monomorphic ventricular tachycardia (MVT) in patients with Brugada syndrome (BrS) have been reported., Objective: We aimed to describe the incidence and characteristics of MVT in a cohort of patients with BrS who had received an implantable cardioverter-defibrillator (ICD)., Methods: Data from 834 patients with BrS implanted with an ICD in 15 tertiary hospitals between 1993 and 2014 were included., Results: The mean age of enrolled patients was 45.3 ± 13.9 years; 200 patients (24%) were women. During a mean follow-up of 69.4 ± 54.3 months, 114 patients (13.7%) experienced at least 1 appropriate ICD intervention, with MVT recorded in 35 patients (4.2%) (sensitive to antitachycardia pacing in 15 [42.8%]). Only QRS width was an independent predictor of MVT in the overall population. Specifically, 6 (17.1%) patients presented with right ventricular outflow tract tachycardia (successfully ablated from the endocardium in 4 and epicardial and endocardial ablation in 1), 2 patients with MVT arising from the left ventricle (1 successfully ablated in the supra lateral mitral annulus), and 2 (5.7%) patients with bundle branch reentry ventricular tachycardia. Significant structural heart disease was ruled out by echocardiography and/or cardiac magnetic resonance imaging., Conclusion: In this retrospective study, 4.2% of patients with BrS implanted with an ICD presented with MVT confirmed as arising from the right ventricular outflow tract tachycardia in 6, patients with MVT arising from the left ventricle in 2, and patients with bundle branch reentry ventricular tachycardia in 2. Endocardial and/or epicardial ablation was successful in 80% of these cases. These data imply that the occurrence of MVT should not rule out the possibility of BrS. This finding may also be relevant for ICD model selection and programming., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: It is thought that dedicated bipolar are more susceptible to T-wave oversensing when compared with integrated bipolar leads. This could be of extreme importance in patients with Brugada syndrome (BrS) because T-wave oversensing in this population is more frequent when compared with other implantable cardioverter defibrillator (ICD) recipients without BrS. We aimed to compare the incidence of T-wave oversensing in patients with BrS according to the type of lead (integrated bipolar versus true/dedicated bipolar)., Methods and Results: All patients diagnosed with BrS with an ICD implant in 10 tertiary hospitals between 1993 and 2013 were included in the study. A total of 480 patients were included (mean age, 45.6±14 years). During a mean follow-up of 74.9±51.7 months (median, 69; range, 2-236), 28 patients had T-wave oversensing (5.8%), leading to inappropriate shock in 18 (3.8%). All these events occurred in patients with true bipolar ICD leads (P=0.01) and in 2 patients it was solved instantaneously by changing the configuration from a dedicated to an integrated bipolar sensing configuration. In the stepwise multivariate models, only integrated bipolar ICD leads (hazard ratio, 0.34; 95% confidence interval, 0.171-0.675; P=0.002) was independent predictor of non-T-wave oversensing., Conclusions: T-wave oversensing is a potential reason of inappropriate shocks in patients with BrS receiving ICDs. In the vast majority it can be solved by reprogramming. However, in some patients it still requires invasive intervention. Importantly, incidence is significantly lower using an integrated bipolar lead system when compared with a dedicated bipolar lead system and hence the latter should be routinely used in BrS cases., (© 2015 American Heart Association, Inc.)

Background: The proximity of the outflow tracts (OTs) frequently results in an overlap in surface electrocardiographic features of ventricular arrhythmias originating from this anatomic region, particularly when the transition occurs in lead V3. In addition, no reliable criteria to discriminate between a right ventricular OT (RVOT) and a left ventricular OT (LVOT) site of origin (SOO) are derived from intracardiac mapping., Methods and Results: A series of 15 patients underwent ablation because of OT ventricular arrhythmias having a V3 transition, and a septal earliest activation on the RVOT was included in the study. Electrocardiographic and mapping data were collected to analyze accuracy in predicting the RVOT versus the LVOT SOO of the ventricular arrhythmia. A 10-ms isochronal map area in the RVOT was smaller in the RVOT SOO group (1.2 [0.4-2.1] versus 3.4 [2.4-3.9] cm2, respectively; P=0.004) and had a shorter perpendicular diameter (13 [7-17] versus 28 [20-29] mm; P=0.001) and a higher longitudinal/perpendicular axis ratio (1.04 [0.95-1.11] versus 0.49 [0.44-0.57]; P=0.001). A 10-ms isochronal map area>2.3 cm2 predicted an LVOT origin with 85.7% sensitivity and 87.5% specificity, whereas a longitudinal/perpendicular axis ratio<0.8 predicted an LVOT origin with 100% sensitivity and 100% specificity. Electrocardiography-derived parameters showed lower values of sensitivity and specificity. The distal coronary sinus activation mapping did not permit distinction between RVOT and LVOT SOO., Conclusions: The 10-ms isochronal map area and the longitudinal/perpendicular axis ratio accurately predict the RVOT versus the LVOT SOO in patients with OT ventricular arrhythmias, a V3 transition, and a septal earliest activation.

Introduction: Echocardiographic optimization of the VV interval may improve CRT response, but it is time-consuming and not routinely performed. The aim of this study was to compare the response to cardiac resynchronization therapy (CRT) when the interventricular pacing (VV) interval was optimized by tissue Doppler imaging (TDI) to CRT response when it was optimized following QRS width criteria., Methods and Results: The study included 156 consecutive CRT patients with severe heart failure and left bundle-branch block configuration. Atrioventricular interval was selected according to a pulsed Doppler assessment, and VV optimization was randomly assigned to echocardiography (ECHO group, n = 78) or electrocardiography (ECG group, n = 78). Optimal VV was defined for the ECHO group as producing the best LV intraventricular synchrony according to TDI displacement curves and for the ECG group as resulting in the narrowest QRS measured from the earliest deflection. At 6-month follow-up, percentage of echocardiographic responders (defined as neither death nor heart transplantation and a LV end-systolic volume reduction >10%) was higher in the ECG optimized group (50.0% vs 67.9%; P = 0.023), whereas clinical response (defined as neither death nor heart transplantation and >10% improvement in the 6-minute walking test) was similar in both groups (71.8% vs 73.1%; P = 0.858)., Conclusions: VV optimization based on QRS width obtained a higher percentage of responders in terms of LV reverse remodeling compared to the TDI method., (© 2011 Wiley Periodicals, Inc.)