Association of non-invasive electrocardiographic risk factors with left ventricular systolic function in post-myocardial infarction patients with mildly reduced or preserved ejection fraction: Insights from the PRESERVE-EF study.

BACKGROUND: Electrocardiographic non-invasive risk factors (NIRFs) have an important role in the arrhythmic risk stratification of post-myocardial infarction (post-MI) patients with preserved or mildly reduced left ventricular ejection fraction (LVEF). However, their specific relation to left ventricular systolic function remains unclear. We aimed to evaluate the association between NIRFs and LVEF in the patients included in the PRESERVE-EF trial. METHODS: We studied 575 post-MI ischemia-free patients with LVEF≥40% (mean age: 57.0 ± 10.4 years, 86.2% men). The following NIRFs were evaluated: premature ventricular complexes, non-sustained ventricular tachycardia (NSVT), late potentials (LPs), prolonged QTc, increased T-wave alternans, reduced heart rate variability, and abnormal deceleration capacity with abnormal turbulence. RESULTS: There was a statistically significant relationship between LPs (Chi-squared = 4.975; p < .05), nsVT (Chi-squared = 5.749, p < .05), PVCs (r= -.136; p < .01), and the LVEF. The multivariate linear regression analysis showed that LPs (p = .001) and NSVT (p < .001) were significant predictors of the LVEF. The results of the multivariate logistic regression analysis indicated that LPs (OR: 1.76; 95% CI: 1.02-3.05; p = .004) and NSVT (OR: 2.44; 95% CI: 1.18-5.04; p = .001) were independent predictors of the mildly reduced LVEF: 40%-49% versus the preserved LVEF: ≥50%. CONCLUSION: Late potentials and NSVT are independently related to reduced LVEF while they are independent predictors of mildly reduced LVEF versus the preserved LVEF. These findings may have important implications for the arrhythmic risk stratification of post-MI patients with mildly reduced or preserved LVEF.

Noninvasive risk factors for the prediction of inducibility on programmed ventricular stimulation in post-myocardial infarction patients with an ejection fraction ≥40% at risk for sudden cardiac arrest: Insights from the PRESERVE-EF study.

BACKGROUND: In the PRESERVE-EF study, a two-step sudden cardiac death (SCD) risk stratification approach to detect post-myocardial infarction (MI) patients with left ventricle ejection fraction (LVEF) ≥40% at risk for major arrhythmic events (MAEs) was used. Seven noninvasive risk factors (NIRFs) were extracted from a 24-h ambulatory electrocardiography (AECG) and a 45-min resting recording. Patients with at least one NIRF present were referred for invasive programmed ventricular stimulation (PVS) and inducible patients received an Implantable Cardioverter - Defibrillator (ICD). METHODS: In the present study, we evaluated the performance of the NIRFs, as they were described in the PRESERVE-EF study protocol, in predicting a positive PVS. In the PRESERVE-EF study, 152 out of 575 patients underwent PVS and 41 of them were inducible. For the present analysis, data from these 152 patients were analyzed. RESULTS: Among the NIRFs examined, the presence of signal averaged ECG-late potentials (SAECG-LPs) ≥ 2/3 and non-sustained ventricular tachycardia (NSVT) ≥1 eposode/24 h cutoff points were important predictors of a positive PVS study, demonstrating in the logistic regression analysis odds ratios 2.285 (p = .027) and 2.867 (p = .006), respectively. A simple risk score based on the above cutoff points in combination with LVEF < 50% presented high sensitivity but low specificity for a positive PVS. CONCLUSION: Cutoff points of NSVT ≥ 1 episode/24 h and SAECG-LPs ≥ 2/3 in combination with a LVEF < 50% were important predictors of inducibility. However, the final decision for an ICD implantation should be based on a positive PVS, which is irreplaceable in risk stratification.

Right ventricular outflow tract electroanatomical abnormalities in asymptomatic and high-risk symptomatic patients with Brugada syndrome: Evidence for a new risk stratification tool?

INTRODUCTION: Microstructural abnormalities at the epicardium of the right ventricular outflow tract (RVOT) may provide the arrhythmia substrate in Brugada syndrome (BrS). Endocardial unipolar electroanatomical mapping allows the identification of epicardial abnormalities. We evaluated the clinical implications of an abnormal endocardial substrate as perceived by high-density electroanatomical mapping (HDEAM) in patients with BrS. METHODS: Fourteen high-risk BrS patients with aborted sudden cardiac death (SCD) (12 males, mean age: 41.9 ± 11.8 years) underwent combined endocardial-epicardial HDEAM of the right ventricle/RVOT, while 40 asymptomatic patients (33 males, mean age: 42 ± 10.7 years) underwent endocardial HDEAM. Based on combined endocardial-epicardial procedures, endocardial HDEAM was considered abnormal in the presence of low voltage areas (LVAs) more than 1 cm2 with bipolar signals less than 1 mV and unipolar signals less than 5.3 mV. Programmed ventricular stimulation (PVS) was performed in all patients. RESULTS: The endocardial unipolar LVAs were colocalized with epicardial bipolar LVAs (p = .0027). Patients with aborted SCD exhibited significantly wider endocardial unipolar (p < .01) and bipolar LVAs (p < .01) compared with asymptomatic individuals. A substrate size of unipolar LVAs more than 14.5 cm2 (area under the curve [AUC]: 0.92, p < .001] and bipolar LVAs more than 3.68 cm2 (AUC: 0.82, p = .001) distinguished symptomatic from asymptomatic patients. Patients with ventricular fibrillation inducibility (23/54) demonstrated broader endocardial unipolar (p < .001) and bipolar LVAs (p < .001) than noninducible patients. The presence of unipolar LVAs more than 13.5 cm2 (AUC: 0.95, p < .001) and bipolar LVAs more than 2.97 cm2 (AUC: 0.78, p < .001) predicted a positive PVS. CONCLUSION: Extensive endocardial electroanatomical abnormalities identify high-risk patients with BrS. Endocardial HDEAM may allow risk stratification of asymptomatic patients referred for PVS.

Atrial substrate characterization in patients with atrial fibrillation and hypertrophic cardiomyopathy: Evidence for an extensive fibrotic disease.

INTRODUCTION: Data regarding the left atrial (LA) electroanatomical substrate in patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF) are missing. In this electroanatomical mapping (EAM) study, we evaluated the extent of LA fibrosis and its impact on catheter ablation outcomes in patients with HCM and AF. MATERIALS AND METHODS: High-density LA EAM was performed during AF in 28 consecutive patients with obstructive HCM and AF (42.9% displayed paroxysmal AF and 57.1% persistent AF). Propensity score (PS) matching analysis was performed to reduce the impact of potential confounding factors. PS were derived to match patients at a 1:1 ratio. Patients were matched according to age, sex and LA diameter. After PS, 28 non-HCM patients with AF were selected, and served as controls. Two different cut-off values of bipolar signal amplitude were investigated for fibrosis characterization (≤0.25 mV and ≤ 0.4 mV). HCM patients underwent pulmonary vein antral isolation (PVAI) and roof line, while non-HCM patients PVAI only. RESULTS: After the 3-month blanking period, 10 HCM patients (35.7%) displayed atrial arrhythmia recurrence. HCM patients with arrhythmia recurrence showed significantly greater low voltage areas defined as either bipolar voltage ≤0.25 mV (22.5 ± 10% vs. 5.5 ± 6.4%, p = 0.001) or ≤ 0.4 mV (32 ± 13.9% vs. 5.9 ± 5.1%, p < 0.001). The presence of low voltage areas ≤0.4 mV greater than 14.1% of the total LA area also predicted arrhythmia recurrence with excellent sensitivity (100%) and specificity (100%). Univariate analysis revealed that the extent of LA fibrosis was the only predictor of AF recurrence. After PS matching with non-HCM patients, patients with HCM exhibited wider fibrotic regions ≤0.25 mV compared to non-HCM patients (p = 0.016). CONCLUSIONS: High-density EAM reveals extensive LA fibrotic disease in patients with HCM, an event with certain implications in catheter ablation outcomes.

A novel variant of RyR2 gene in a family misdiagnosed as congenital long QT syndrome: The importance of genetic testing.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) and Long-QT syndrome (LQTS) are two distinct entities with similar clinical presentation and management but different clinical course. In this study, we present two family members presented with aborted sudden cardiac death (SCD) that was attributed to CPVT. The CPVT may be underrecognized in SCD victims and a diagnosis of "atypical LQTS" may warrant consideration of CPVT and analysis of RyR2 if the standard cardiac channel gene screen for LQTS is negative. Although the management of both channelopathies is quite common the clinical outcomes are different, with CPVT displaying a more malignant clinical course.

The aortic cusps are the predominant successful ablation site of idiopathic outflow-tract ventricular arrhythmias.

BACKGROUND: Data regarding the successful ablation site of idiopathic outflow tract (OT) ventricular arrhythmias (VAs) in the modern era of mapping and ablation are limited. METHODS AND RESULTS: Over a 4-year period, a total of 309 patients underwent detailed activation mapping of OT VAs including the right ventricular outflow tract (RVOT), the left ventricular outflow tract (LVOT) and the aortic cusps (AC), and the coronary venous system. 244 cases were successfully ablated at the index procedure (78.9%). The successful ablation site was more frequently located at the LVOT/ACs (51.6%) followed by RVOT (36.2%). In particular, the ACs was the predominant successful ablation site of idiopathic OT VAs (46.7%). An epicardial site of origin was predictor of ablation failure (p < 0.05). CONCLUSIONS: The ACs is the predominant successful ablation site of idiopathic OT VAs. TAKE-HOME MESSAGE: The aortic cusps are the predominant successful ablation site of idiopathic idiopathic outflow tract ventricular arrhythmias.

Arrhythmic risk stratification in post-myocardial infarction patients with preserved ejection fraction: the PRESERVE EF study.

AIMS: Sudden cardiac death (SCD) annual incidence is 0.6-1% in post-myocardial infarction (MI) patients with left ventricular ejection fraction (LVEF)≥40%. No recommendations for implantable cardioverter-defibrillator (ICD) use exist in this population. METHODS AND RESULTS: We introduced a combined non-invasive/invasive risk stratification approach in post-MI ischaemia-free patients, with LVEF ≥ 40%, in a multicentre, prospective, observational cohort study. Patients with at least one positive electrocardiographic non-invasive risk factor (NIRF): premature ventricular complexes, non-sustained ventricular tachycardia, late potentials, prolonged QTc, increased T-wave alternans, reduced heart rate variability, abnormal deceleration capacity with abnormal turbulence, were referred for programmed ventricular stimulation (PVS), with ICDs offered to those inducible. The primary endpoint was the occurrence of a major arrhythmic event (MAE), namely sustained ventricular tachycardia/fibrillation, appropriate ICD activation or SCD. We screened and included 575 consecutive patients (mean age 57 years, LVEF 50.8%). Of them, 204 (35.5%) had at least one positive NIRF. Forty-one of 152 patients undergoing PVS (27-7.1% of total sample) were inducible. Thirty-seven (90.2%) of them received an ICD. Mean follow-up was 32 months and no SCDs were observed, while 9 ICDs (1.57% of total screened population) were appropriately activated. None patient without NIRFs or with NIRFs but negative PVS met the primary endpoint. The algorithm yielded the following: sensitivity 100%, specificity 93.8%, positive predictive value 22%, and negative predictive value 100%. CONCLUSION: The two-step approach of the PRESERVE EF study detects a subpopulation of post-MI patients with preserved LVEF at risk for MAEs that can be effectively addressed with an ICD. CLINICALTRIALS.GOV IDENTIFIER: NCT02124018.

Right ventricular outflow tract low-voltage areas identify the site of origin of idiopathic ventricular arrhythmias: A high-density mapping study.

INTRODUCTION: Electronatomical mapping allows direct and accurate visualization of myocardial abnormalities. This study investigated whether high-density endocardial bipolar voltage mapping of the right ventricular outflow tract (RVOT) during sinus rhythm may guide catheter ablation of idiopathic ventricular arrhythmias (VAs). METHODS AND RESULTS: Forty-four patients (18 males, mean age: 38.1 ± 13.8 years) with idiopathic RVOT VAs and negative cardiac magnetic resonance imaging underwent a stepwise mapping approach for the identification of the site of origin (SOO). High-density electronatomical mapping (1096.6 ± 322.3 points) was performed during sinus rhythm and identified at least two low bipolar voltage areas less than 1 mV (mean amplitude of 0.20 ± 0.10 mV) in 39 of 44 patients. The mean low-voltage surface area was 1.4 ± 0.8 cm2 . Group 1 consisted of 28 patients exhibiting low-voltage areas and high-arrhythmia burden during the procedure. Pace match to the clinical VAs was produced in one of these low-voltage areas. Activation mapping established the SOO at these sites in 27 of 28 cases. Group 2 comprised 11 patients exhibiting abnormal electroanatomical mapping, but very low-arrhythmia burden during the procedure. Pace mapping produced a near-perfect or perfect match to the clinical VAs in one of these areas in 9 of 11 patients which was marked as potential SOO and targeted for ablation. During the follow-up period, 25 of 28 patients from group 1 (89%) and 7 of 9 patients from group 2 (78%) were free from VAs. CONCLUSIONS: Small but detectable very low-voltage areas during mapping in sinus rhythm characterize the arrhythmogenic substrate of idiopathic RVOT VAs and may guide successful catheter ablation.

Targeted ablation of specific electrogram patterns in low-voltage areas after pulmonary vein antral isolation in persistent atrial fibrillation: Termination to an organized rhythm reduces atrial fibrillation recurrence.

BACKGROUND: Ablation strategies have been developed to improve outcomes in patients with persistent atrial fibrillation (PsAF). However, the impact of atrial fibrillation (AF) termination on late AF recurrence is not well known. The aim of our study was to evaluate the impact of AF termination to atrial tachycardia (AT) or sinus rhythm (SR) during catheter ablation on late AF recurrence after the 3-month blanking period. METHODS AND RESULTS: We prospectively recruited 140 patients (mean age: 58.5 ± 12.3 years old, 74.3% males) with uninterrupted PsAF of a mean duration of 3.7 months. Pulmonary vein antral isolation (PVAI) was the first ablation step, and if AF did not terminate (to SR or AT), we ablated low-voltage areas less than 0.4 mV with specific electrogram characteristics. We successfully converted AF to AT or SR in 56 patients (40%) during PVAI (n = 24) or low-voltage ablation ( n = 32). The remaining 84 patients (60%) were electrically cardioverted to SR at the end of the procedure. One hundred patients (71.4%) maintained SR after a single procedure during a mean follow-up of 21.1 ± 0.8 months. Of the 56 patients with AF termination, 46 (82.1%) had no recurrence, while in the group of 84 patients without AF termination, 54 patients (64.3%) remained in SR ( P < 0.02). CONCLUSION: Ablation of PVAI and specific electrograms in low-voltage areas less than 0.4 mV can lead to encouraging outcomes with a low recurrence rate as well as a lower need for redo procedures.

Clinical characteristics and long-term clinical course of patients with Brugada syndrome without previous cardiac arrest: a multiparametric risk stratification approach.

AIMS: Risk stratification in Brugada syndrome (BrS) still represents an unsettled issue. In this multicentre study, we aimed to evaluate the clinical characteristics and the long-term clinical course of patients with BrS. METHODS AND RESULTS: A total of 111 consecutive patients (86 males; aged 45.3 ± 13.3 years) diagnosed with BrS were included and followed-up in a prospective fashion. Thirty-seven patients (33.3%) were symptomatic at enrolment (arrhythmic syncope). An electrophysiological study (EPS) was performed in 59 patients (53.2%), and ventricular arrhythmias were induced in 32 (54.2%). A cardioverter defibrillator was implanted in 34 cases (30.6%). During a mean follow-up period of 4.6 ± 3.5 years, appropriate device therapies occurred in seven patients. Event-free survival analysis (log-rank test) showed that spontaneous type-1 electrocardiogram pattern (P = 0.008), symptoms at presentation (syncope) (P = 0.012), family history of sudden cardiac death (P < 0.001), positive EPS (P = 0.024), fragmented QRS (P = 0.004), and QRS duration in lead V2 > 113 ms (P < 0.001) are predictors of future arrhythmic events. Event rates were 0%, 4%, and 60% among patients with 0-1 risk factor, 2-3 risk factors, and 4-5 risk factors, respectively (P < 0.001). Current multiparametric score models exhibit an excellent negative predictive value and perform well in risk stratification of BrS patients. CONCLUSIONS: Multiparametric models including common risk factors appear to provide better risk stratification of BrS patients than single factors alone.

Implantable devices to monitor patients with heart failure.

Reducing heart failure hospitalizations represents a major challenge for modern clinicians. Early detection of congestion plays a key role in disease management strategy. Apart from traditional methods (patient reporting symptoms, body weight monitoring), novel home-care strategies allow guided adjustments in medical therapy through telemonitoring embedded in cardiac electronic implantable devices or through stand-alone diagnostic devices for hemodynamic monitoring. Wireless pulmonary artery pressure monitoring seems to reduce re-admission risk and is currently approved for this purpose in patients with heart failure. Multiparameter monitoring is also appealing and could be a valuable tool in managing these patients. However, invasive techniques face several safety concerns and cost-effectiveness issues. Therefore, quest for future research and emerging technologies is necessary.

The efficacy of coronary sinus reducer in patients with refractory angina-A systematic review of the literature.

OBJECTIVES: The aim of our systematic review was to investigate the efficacy of coronary sinus (CS) reducer device in patients with refractory angina. BACKGROUND: The CS reducer device provides a therapeutic option for patients with coronary artery disease who are not suitable for revascularization. METHODS: Two independent investigators (GB and GT) systematically searched the Medline and Cochrane library databases for studies describing the efficacy and safety of the CS reducer in patients with refractory angina from January 1, 2000 until May 12, 2018 using the following terms: "coronary sinus (reducer OR reducing) device." Efficacy was defined as ≥1 unit improvement in the Canadian cardiovascular society (CCS) score. RESULTS: Our search strategy provided six studies (five observational studies and one randomized clinical trial) with 196 patients. The CS reducer device was effective in 146/186 (78.5%) patients. CCS score improved from 3.2 at baseline to 1.9 after 8.6 months of follow-up. The efficacy of CS reducer device was also demonstrated as an improvement in Seattle Angina Questionnaire score, dobutamine echocardiography, thalium single-photon emission computed tomography perfusion studies, 6-min-walk test and myocardial perfusion reserve index. Implantation failed in 4 of 196 (2%) patients and 5 patients (2.5%) had a complication during 30-day follow-up. CONCLUSIONS: The CS reducer is a promising treatment option for patients with refractory angina who are not candidates for revascularization. However, larger randomized control trials with long-term follow-up are needed to elucidate its role.

Right ventricular outflow tract high-density endocardial unipolar voltage mapping in patients with Brugada syndrome: evidence for electroanatomical abnormalities.

Aims: Epicardial structural abnormalities at the right ventricular outflow tract (RVOT) may provide the arrhythmia substrate in Brugada syndrome (BrS). Electroanatomical endocardial unipolar voltage mapping is an emerging tool that accurately identifies epicardial abnormalities in different clinical settings. This study investigated whether endocardial unipolar voltage mapping of the RVOT detects electroanatomical abnormalities in patients with BrS. Methods and results: Ten asymptomatic patients (8 males, 34.5 ± 11.2 years) with spontaneous type 1 ECG pattern of BrS and negative late gadolinium enhancement-cardiac magnetic resonance imaging (LGE-c-MRI) underwent high-density endocardial electroanatomical mapping (>800 points). Using a cut-off of 1 mV and 4 mV for normal bipolar and unipolar voltage, respectively, derived from 20 control patients without structural heart disease established by LGE-c-MRI, the extend of low-voltage areas within the RVOT was estimated using a specific calculation software. The mean RVOT area presenting low-voltage bipolar signals in BrS patients was 3.4 ± 1.7 cm2 (range 1.5-7 cm2). A significantly greater area of abnormal unipolar signals was identified (12.6 ± 4.6 cm2 [range 7-22 cm2], P: 0.001). Both bipolar and unipolar electroanatomical abnormalities were mainly located at the free wall of the RVOT. The mean RVOT activation time was significantly prolonged in BrS patients compared to control population (86.4 ± 16.5 vs. 63.4 ± 9.7 ms, P < 0.001). Isochronal mapping demonstrated lines of conduction slowing within the RVOT in 8/10 BrS patients. Conclusion: Wide areas of endocardial unipolar voltage abnormalities that possibly reflect epicardial structural abnormalities are identified at the RVOT of BrS patients.

A meta-analysis on the prognostic significance of inferolateral early repolarization pattern in Brugada syndrome.

Aims: The early repolarization (ER) pattern has been linked to an increased risk for arrhythmic death in various clinical settings. There are limited and conflicting data regarding the prognostic significance of ER pattern in Brugada syndrome (BS). The aim of this meta-analysis was to provide a detailed analysis of the currently available studies regarding the arrhythmic risk in patients with BS and ER pattern. Methods and results: Current databases were searched until May 2015. A random-effect meta-analysis of the effect of ER pattern on the incidence of arrhythmic events in patients with BS was performed. Five studies were included comprising a total of 1375 patients with BS. An ER pattern was reported in 177 patients (12.8%). During follow-up (44.9-93 months), 143 patients (10.4%) suffered an arrhythmic event. Overall, BS patients with ER pattern displayed an increased risk of arrhythmic events compared to patients without ER (OR 3.29, 95% CI: 2.06 to 5.26, P < 0.00001; Heterogeneity: P = 0.11, I2 = 48%). Three studies provided data regarding ER pattern location. Inferior, lateral, or inferolateral ER pattern location was observed in 20.3%, 32.2%, and 48%, respectively. An inferolateral ER location conferred the higher arrhythmic risk (OR 4.87, 95% CI: 2.64 to 9.01, P< 0.00001; Heterogeneity: P = 0.85, I2 = 0%). Conclusion: This meta-analysis suggests that the ER pattern is associated with a high risk of arrhythmic events in patients with BS. In particular, BS patients with inferolateral ER (global ER pattern) displayed the highest arrhythmic risk.

Left atrial voltage mapping using a new impedance-based algorithm in patients with paroxysmal atrial fibrillation.

AIMS: Atrial fibrosis is associated with the pathogenesis and progression of atrial fibrillation (AF). We sought to evaluate the extent of left atrial (LA) scarring in patients with paroxysmal AF (PAF) undergoing catheter ablation using a new impedance-based algorithm. METHODS: We prospectively enrolled 73 consecutive patients (43 males, 58 years) with PAF who underwent pulmonary vein antral isolation. We first performed high-density bipolar voltage mapping during sinus rhythm using Tissue Proximity Indicator (TPI), one of the features of the ConfiDense mapping module integrated in the electroanatomic mapping system. A dense LA shell was created initially without TPI (mean points 2,411) and subsequently activating TPI (mean points 1,167). Each point was classified according to the peak-to-peak bipolar voltage electrogram based on two criteria (criterion A: healthy >0.8 mV, border zone: 0.4-0.8 mV, scarred: <0.4 mV; criterion B: healthy: >0.5 mV, border zone: 0.25-0.5 mV, scarred: <0.25 mV). RESULTS: LA voltage analysis represented significantly smaller scarred areas when mapping was performed with TPI-ON compared with TPI-OFF in both voltage criteria (average LA voltage area: 3.02 ± 5.28 cm2 vs 9.15 ± 13.11 cm2 vs in criterion A and 1.19 ± 2.54 cm2 vs 5.61 ± 9.56 cm2 in criterion B). A statistically significant voltage difference was observed in all segments of the left atrium between the two mapping protocols, particularly on the inferior wall. CONCLUSION: A more specific delineation of LA fibrosis may be produced using the TPI feature of the ConfiDense mapping module, through elimination of false-positive annotated mapping points due to low contact.

Low-voltage areas detected by high-density electroanatomical mapping predict recurrence after ablation for paroxysmal atrial fibrillation.

INTRODUCTION: We aimed to evaluate the extent of atrial fibrosis in paroxysmal atrial fibrillation (AF) and the correlation with ablation outcomes after pulmonary vein antral isolation (PVΑI) using a mapping system with high-resolution and high-spatial sampling. METHODS AND RESULTS: We prospectively enrolled 80 consecutive patients (45 males, median age 60.26 years) with symptomatic paroxysmal AF who were scheduled for PVAI. Prior to PVAI, high-density bipolar voltage mapping (median number of 2,485 points) was carried out during sinus rhythm in all patients. Criteria for an adequate left atrium (LA) shell were > 2,000 points. Each acquired point was classified according to the peak-to-peak bipolar voltage electrogram based on two criteria (criterion A: healthy > 0.8 mV, border zone: 0.4-0.8 mV and scarred: < 0.4 mV, criterion Β: healthy: > 0.5 mV, border zone: 0.25-0.5 mV and scarred: < 0.25 mV). The extent of low-voltage area < 0.4 mV significantly predicted atrial tachyarrhythmia recurrence after the blanking period (P = 0.002). In univariate analysis, the presence of LA voltage areas < 0.4 mV more than 10% of the total surface area was the only significant predictor of arrhythmia recurrence. The analysis based on window B cutoff values failed to demonstrate any predictors of arrhythmia recurrence. CONCLUSION: These data demonstrate that the existence of LA voltage areas < 0.4 mV more than 10% of the total LA surface area predicts arrhythmia recurrence following PVAI for paroxysmal AF.

Prognosis, risk stratification, and management of asymptomatic individuals with Brugada syndrome: A systematic review.

Brugada syndrome (BrS) is a primary electrical disease associated with increased risk of sudden cardiac death due to polymorphic ventricular arrhythmias. The prognosis, risk stratification, and management of asymptomatic individuals remain the most controversial issues in BrS. Furthermore, the decision to manage asymptomatic patients with an implantable cardioverter-defibrillator should be made after weighing the potential individual risk of future arrhythmic events against the risk of complications associated with the implant and follow-up of patients living with such devices, and the accompanying impairment of the quality of life. Several clinical, electrocardiographic, and electrophysiological markers have been proposed for risk stratification of subjects with BrS phenotype, but the majority have not yet been tested in a prospective manner in asymptomatic individuals. Recent data suggest that current risk factors are insufficient and cannot accurately predict sudden cardiac death events in this setting. This systematic review aims to discuss contemporary data regarding prognosis, risk stratification, and management of asymptomatic individuals with diagnosis of Brugada electrocardiogram pattern and to delineate the therapeutic approach in such cases.

Arrhythmic risk stratification in heart failure: Time for the next step?

BACKGROUND: Primary prevention of sudden cardiac death by means of implantable cardioverter-defibrillators constitutes the holy grail of arrhythmology. However, current risk stratification algorithms lead to suboptimal outcomes, by both allocating ICDs to patients not deriving any meaningful survival benefit and withholding them from those erroneously considered as low-risk for arrhythmic mortality. METHODS: In the present review article we will attempt to present shortcomings of contemporary guidelines regarding sudden death prevention in ischemic and dilated cardiomyopathy patients and present available data suggesting encouraging results following implementation of multifactorial approaches, by using multiple modalities, both noninvasive and invasive. Invasive electrophysiological testing, namely programmed ventricular stimulation, will be discussed in greater length to highlight both its potential usefulness and currently ongoing multicenter studies aiming to provide evidence necessary to make the next step in sudden death risk stratification. RESULTS: Promising findings have been reported by multiple study groups regarding novel strategies for both negative selection of low and positive selection of relatively preserved ejection fraction patients as candidates for ICD implantation. CONCLUSIONS: The era of ejection fraction as the sole risk stratifier for arrhythmic risk in heart failure appears to be drawing to an end, especially if current underway large studies validate previous findings.

Adenosine-Guided Pulmonary Vein Antral Isolation for Paroxysmal Atrial Fibrillation: A Randomized Study.

OBJECTIVES: The prognostic significance of adenosine-mediated pulmonary vein (PV) dormant conduction and whether such conduction should be eliminated still remain controversial. This randomized study aimed to investigate whether adenosine-guided ablation of the reconnection gaps improves the long-term outcomes of pulmonary vein antral isolation (PVAI) for paroxysmal atrial fibrillation (AF). METHODS AND RESULTS: Consecutive patients with paroxysmal AF were randomly assigned to undergo (n = 80, group 1) or not (n = 81, group 2) adenosine testing following PVAI. Adenosine-mediated PV dormant conduction was unmasked in 26 patients (32.5%) of group 1. Successful elimination of the reconnection gaps was subsequently performed in all patients. During a mean follow-up period of 11.39 ± 5.10 months, 30 patients of group 1 (37.5%), and 27 patients of group 2 (33.3%) experienced arrhythmia recurrence. The Kaplan-Meier arrhythmia free survival curves failed to demonstrate any significant differences between study groups (log rank 0.217, P = 0.642). Fourteen of 26 (53.8%) patients with adenosine-mediated dormant conduction and subsequent elimination of reconnection gaps experienced AF recurrence during follow-up. On the contrary, only 16 of 54 patients without dormant conduction (29.6%) displayed arrhythmia recurrence (P = 0.049). Logistic regression analysis showed that adenosine-mediated PV reconnection (hazard ratio 0.292, 95% confidence interval 0.122-0.483; P = 0.01) was an independent predictor of AF recurrence. CONCLUSION: In this patients' cohort, adenosine-mediated PV reconnection is predictive of future arrhythmic events. Elimination of dormant conduction with additional ablation lesions does not improve the long-term outcome of the procedure compared to the standard PVAI.

Catheter Ablation of Ventricular Arrhythmias Arising from the Distal Great Cardiac Vein.

Catheter ablation of idiopathic ventricular arrhythmias arising from the distal great cardiac vein represents a great challenge. We report data regarding the electrocardiographic and electrophysiologic characteristics in two patients with ventricular arrhythmias arising from the distal great cardiac vein. The technical difficulties to advance and navigate the ablation catheter within the coronary venous system as well as the close proximity to the major coronary vessels are discussed.