Predictors of future onset of atrial fibrillation in hypertrophic cardiomyopathy.

Background: Novel predictors of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) are desirable.

Aim: To detect new multimodality imaging variables predictive of de novo AF in HCM.

Methods: Consecutive patients with HCM underwent clinical assessment and 48-hour Holter electrocardiography to detect AF episodes.

An Comparison and Evaluation of Sealing Ability of Newly Introduced C-point System, Cold Lateral Condensation, and Thermoplasticized Gutta-Percha Obturating Technique: A Dye Extraction Study.

Aim: The aim of this study is to compare and to evaluate sealing ability of newly introduced C-point system, cold lateral condensation, and thermoplasticized gutta-percha obturating technique using a dye extraction method.

Materials And Methodology: Sixty extracted maxillary central incisors were decoronated below the cementoenamel junction. Working length was established, and biomechanical preparation was done using K3 rotary files with standard irrigation protocol.

First clinical use of novel ablation catheter incorporating local impedance data.

Introduction: Successful catheter ablation is limited by both poor spatial resolution of abnormal local signals and inability to deliver an effective lesion due to poor tissue contact. We report first worldwide use of the Intellanav MiFi OI catheter (Boston Scientific), providing ultra-high density mapping and incorporating a "DirectSense" algorithm to measure local tissue impedance (LI).

Methods And Results: 31 patients (65±6 years, 20 male) underwent ablation.

Variability in pulmonary vein electrophysiology and fibrosis determines arrhythmia susceptibility and dynamics.

Success rates for catheter ablation of persistent atrial fibrillation patients are currently low; however, there is a subset of patients for whom electrical isolation of the pulmonary veins alone is a successful treatment strategy. It is difficult to identify these patients because there are a multitude of factors affecting arrhythmia susceptibility and maintenance, and the individual contributions of these factors are difficult to determine clinically. We hypothesised that the combination of pulmonary vein (PV) electrophysiology and atrial body fibrosis determine driver location and effectiveness of pulmonary vein isolation (PVI).

Comprehensive Multicenter Study of the Common Isthmus in Post-Atrial Fibrillation Ablation Multiple-Loop Atrial Tachycardia.

Background: Characteristics of multiple-loop atrial tachycardia (AT) circuits have never precisely examined.

Methods: In 193 consecutive post-atrial fibrillation ablation patients with AT, 44 multiple-loop ATs including 42 dual-loop AT and 2 triple-loop AT in 41 (21.2%) were diagnosed with the high-resolution mapping system and analyzed off-line.

New Insights Into an Old Arrhythmia: High-Resolution Mapping Demonstrates Conduction and Substrate Variability in Right Atrial Macro-Re-Entrant Tachycardia.

Objectives: Using high-resolution 3-dimensional (3D) mapping, the aim of this study was to further characterize right atrial macro-re-entrant tachycardias and answer unresolved questions in the understanding of this arrhythmia.

Background: Despite advances in understanding of the mechanisms of right atrial macro-re-entrant tachycardias, many questions lack definitive answers. The advent of high-resolution 3D mapping provides an opportunity to gain further insights into the nature of these common circuits.

High-density mapping and ablation of concealed low-voltage activity within pulmonary vein antra results in improved freedom from atrial fibrillation compared to pulmonary vein isolation alone.

Background: Despite advancements, the goal of durable pulmonary vein isolation (PVI) in all patients undergoing ablation for atrial fibrillation (AF) remains elusive. New high-density mapping (HDM) allows detection of concealed low-voltage signals (CLVSs) that persist after PVI and may represent vulnerabilities in the lesion set.

Objective: The purpose of this study was to determine the incidence of CLVSs after PVI and the effect of CLVS ablation on outcomes.

Comparing Reentrant Drivers Predicted by Image-Based Computational Modeling and Mapped by Electrocardiographic Imaging in Persistent Atrial Fibrillation.

Electrocardiographic mapping (ECGI) detects reentrant drivers (RDs) that perpetuate arrhythmia in persistent AF (PsAF). Patient-specific computational models derived from late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) identify all latent sites in the fibrotic substrate that could potentially sustain RDs, not just those manifested during mapped AF. The objective of this study was to compare RDs from simulations and ECGI (RD/RD) and analyze implications for ablation.

Useful Electrocardiographic Features to Help Identify the Mechanism of Atrial Tachycardia Occurring After Persistent Atrial Fibrillation Ablation.

Objectives: The purpose of this study was to describe and identify useful electrocardiographic characteristics to help identify the mechanism of atrial tachycardia (AT) occurring after persistent atrial fibrillation (PsAF) ablation.

Background: Electrocardiographic analysis to help identify the mechanism of AT after PsAF ablation is much limited by the fact that remodeling and ablation alter the normal activation pattern.

Methods: All consecutive patients who underwent mapping and ablation of AT after PsAF ablation were included.

Benefits of left ventricular endocardial pacing comparing failed implants and prior non-responders to conventional cardiac resynchronization therapy: A subanalysis from the ALSYNC study.

Objective: Cardiac resynchronisation therapy (CRT) is limited by a substantial proportion of non-responders. Left ventricular endocardial pacing (LVEP) may offer enhanced possibility to deliver CRT in patients with a failed attempt at implantation and to improve clinical status of CRT non-responders.

Methods: The ALternate Site Cardiac ResYNChronisation (ALSYNC) study was a prospective, multi-centre cohort study that included 118 CRT patients with a successfully implanted endocardial left ventricular (LV) lead, including 90 failed coronary sinus (CS) implants and 28 prior non-responders who had worsened or unchanged heart failure status after at least 6 months of optimal conventional CRT therapy.

Influence of contact force on voltage mapping: A combined magnetic resonance imaging and electroanatomic mapping study in patients with tetralogy of Fallot.

Background: Voltage criteria for ventricular mapping have been obtained from small series of patients and prioritizing high specificity.

Objective: The purpose of this study was to analyse the potential influence of contact force (CF) on voltage mapping and to define voltage cutoff values for right ventricular (RV) scar using the tetralogy of Fallot as a model of transmural RV scar and magnetic resonance imaging (MRI) as reference.

Methods: Fourteen patients (age 32.

Relationship Between Fibrosis Detected on Late Gadolinium-Enhanced Cardiac Magnetic Resonance and Re-Entrant Activity Assessed With Electrocardiographic Imaging in Human Persistent Atrial Fibrillation.

Objectives: This study sought to assess the relationship between fibrosis and re-entrant activity in persistent atrial fibrillation (AF).

Background: The mechanisms involved in sustaining re-entrant activity during AF are poorly understood.

Methods: Forty-one patients with persistent AF (age 56 ± 12 years; 6 women) were evaluated.

Long-Term Outcome of Substrate Modification in Ablation of Post-Myocardial Infarction Ventricular Tachycardia.

Background: Long-term results of substrate modification for ablation of ventricular tachycardia (VT) have not been reported. We report long-term outcomes of substrate elimination targeting local abnormal ventricular activities (LAVA) for post-myocardial infarction VT.

Methods And Results: One hundred fifty-nine consecutive patients undergoing first ablation were included (65±11 years, 92% implantable cardioverter defibrillators, 54% storms, and 73% appropriate shocks).

Characteristics of Single-Loop Macroreentrant Biatrial Tachycardia Diagnosed by Ultrahigh-Resolution Mapping System.

Background: Biatrial tachycardia (BiAT) is a rare form of atrial macroreentrant tachycardia, in which both atria form a critical part of the circuit. We aimed to identify the characteristics and precise circuits of single-loop macroreentrant BiATs.

Methods And Results: We identified 8 patients (median age, 59.

Arrhythmogenic response to isoproterenol testing vs. exercise testing in arrhythmogenic right ventricular cardiomyopathy patients.

Aims: To compare the arrhythmic response to isoproterenol and exercise testing in newly diagnosed arrhythmogenic right ventricular cardiomyopathy (ARVC) patients.

Methods And Results: We studied isoproterenol [continuous infusion (45 µg/min) for 3 min] and exercise testing (workload increased by 30 W every 3 min) performed in consecutive newly diagnosed ARVC patients. Both tests were evaluated with regard to the incidence of (i) polymorphic premature ventricular contractions (PVCs) and couplet(s) or (ii) sustained or non-sustained ventricular tachycardia (VT) with left bundle branch block [excluding right ventricular outflow tract VT]; and compared to a control group referred for the evaluation of PVCs without structural heart disease.

Correlation between computer tomography-derived scar topography and critical ablation sites in postinfarction ventricular tachycardia.

Background: Myocardial wall thickness (WT) in patients with a prior myocardial infarction has been used to indicate scarring. However, the correlation of WT with sites critical to ventricular tachycardia (VT) has not been previously investigated. The purpose of this study was to correlate electroanatomic mapping data obtained during VT ablation with WT determined by cardiac computed tomography (CT).

High-density contact and noninvasive mapping of focal atrial tachycardia: Evidence of dual endocardial exits from an epicardial focus.

We report a case of recurrent focal atrial tachycardia (AT) which mechanisms could be resolved by using noninvasive electrocardiographic imaging (ECGI) reconstructing epicardial potentials and rapid high-density endocardial contact mapping (Rhythmia™, Boston Scientific, Natick, MA, USA). ECGI demonstrated focal activity from the anterior of the left superior pulmonary vein antrum, although Rhythmia™ showed focal activity from the high anterior left atrium with the 2 focus originating from the site where identical to the focus on the ECGI map with slightly delay (by 8 ms). Elimination of the AT by radiofrequency applications for both of the endocardial focuses indicated the dual endocardial exits from an epicardial focus.

Cardiac Imaging in Patients With Ventricular Tachycardia.

Ventricular tachycardia (VT) is a major cause of sudden cardiac death. The majority of malignant VTs occur in patients with structural heart disease. Multimodality imaging techniques play an integral role in determining the underlying etiology and prognostic significance of VT.

Electrical storm in the early phase of HeartMate II device implantation: Incidence, risk factors and prognosis.

Background: Ventricular arrhythmia is common after left ventricular assist device (LVAD) implantation, especially in the early postoperative phase (<30 days).

Aim: To identify the incidence of and risk factors for electrical storm (ES) occurring within 30 days of HeartMate II implantation.

Methods: We reviewed data from all consecutive patients undergoing HeartMate II device implantation at our institution from January 2008 to December 2014.

Revisiting anatomic macroreentrant tachycardia after atrial fibrillation ablation using ultrahigh-resolution mapping: Implications for ablation.

Background: Anatomic macroreentrant atrial tachycardias (MATs) are conventionally reported to depend on the cavotricuspid isthmus, the mitral isthmus, or the left atrial roof, and are commonly seen following catheter ablation for atrial fibrillation.

Objectives: To define the precise circuits of anatomic MAT with ultrahigh-resolution mapping.

Methods: In 57 patients (mean age, 62 years; 10 female) who developed ≥1 anatomic MAT, we analyzed 88 MAT circuits including 16 peritricuspid, 42 perimitral, and 30 roof-dependent circuits, using high-density mapping and entrainment.