Outflow tract premature ventricular depolarizations after atrial fibrillation ablation may reflect autonomic influences.

Purpose: Autonomic modulation following catheter ablation of atrial fibrillation may promote the development of catecholamine-sensitive arrhythmias, such as outflow tract (OT) ventricular premature depolarizations (VPDs). The purpose of this study was to determine the incidence and prognostic significance of OT VPDs occurring in patients after atrial fibrillation (AF) ablation.

Methods: We prospectively examined 53 consecutive patients undergoing wide-area circumferential antral pulmonary vein (PV) isolation; no patients had evidence of OT VPDs on 24 h of preprocedural telemetry monitoring.

Contact electroanatomic mapping derived voltage criteria for characterizing left atrial scar in patients undergoing ablation for atrial fibrillation.

Background: Criteria have not been established for identifying LA scar using electroanatomic mapping (EAM). It is also unclear if voltage criteria using EAM may assist in identifying areas of pulmonary vein (PV) reconnection in patients undergoing repeat AF ablation.

Objectives: To characterize left atrial (LA) voltage in patients undergoing atrial fibrillation (AF) ablation.

Resetting and entrainment of reentrant ventricular tachycardia associated with myocardial infarction.

Resetting and entrainment are specific responses to programmed stimulation that are useful in determining the mechanism of ventricular tachycardia (VT), localizing critical components of a reentrant circuit to guide ablation, determining how antiarrhythmic drugs affect the tachycardia, and developing antitachycardia pacing modalities. While resetting and entrainment have certain things in common, they differ significantly in the ability to characterize the properties of VT. Only resetting, which is the interaction of a single extrastimulus with the tachycardia, can characterize the properties of the VT itself.

Scar progression in patients with nonischemic cardiomyopathy and ventricular arrhythmias.

Background: Disease progression in patients with nonischemic cardiomyopathy (NICM) is poorly understood.

Objective: To assess left ventricular (LV) scar progression and dilatation by using endocardial electroanatomic mapping.

Methods: We studied 13 patients with NICM and recurrent ventricular tachycardia.

Risk of stroke or transient ischemic attack after atrial fibrillation ablation with oral anticoagulant use guided by ECG monitoring and pulse assessment.

Introduction: We sought to gain insight into stroke risk after atrial fibrillation (AF) ablation.

Methods And Results: We followed 1,990 patients for >1 year (49 ± 29 months) who underwent AF ablation. Prior to stopping oral anticoagulants (OAC), we performed 3-week transtelephonic ECG monitoring (TTM) and taught patients heart rate and pulse assessment.

Catheter ablation of ventricular fibrillation: importance of left ventricular outflow tract and papillary muscle triggers.

Background: Monomorphic ventricular premature depolarizations (VPDs) have been found to initiate ventricular fibrillation (VF) or polymorphic ventricular tachycardia (PMVT) in patients with and without structural heart disease.

Objective: The purpose of this study was to describe and characterize sites of origin of VPDs triggering VF and PMVT.

Methods: The distribution of mapping-confirmed VPDs, electrophysiology laboratory findings, and results of radiofrequency catheter ablation were analyzed.

Meta-analysis of gender differences in residual stroke risk and major bleeding in patients with nonvalvular atrial fibrillation treated with oral anticoagulants.

Studies comparing gender-specific outcomes in patients with atrial fibrillation (AF) have reported conflicting results. Gender differences in cerebrovascular accident/systemic embolism (CVA/SE) or major bleeding outcomes with novel oral anticoagulant (NOAC) use are not known. The goal of this analysis was to perform a systematic review and meta-analysis evaluating gender differences in residual risk of CVA/SE and major bleeding outcomes in patients with nonvalvular AF treated with either warfarin or NOAC.

Unipolar voltage abnormality is associated with greater left ventricular dysfunction in ischemic cardiomyopathy.

Introduction: Following myocardial infarction (MI), left ventricular function is determined by cardiac remodeling occurring in both infarcted and noninfarcted myocardium (NIM). Unipolar voltage mapping may detect remodeling changes in NIM that are associated with the left ventricular ejection fraction (LVEF). We aimed to identify (1) unipolar voltage characteristics in patients with chronic MI, and (2) association of voltage abnormalities with degree of left ventricular dysfunction (LVD).

Left atrial volume best predicts recurrence after catheter ablation in patients with persistent and longstanding persistent atrial fibrillation.

Introduction: Patients with persistent and longstanding persistent atrial fibrillation (AF) have a higher recurrence rate after antral pulmonary vein isolation (PVI). We sought to determine the clinical, invasive, and noninvasive diastolic function parameters that are associated with AF recurrence after ablation in patients with persistent and longstanding persistent nonvalvular AF.

Methods And Results: We studied 125 consecutive patients with persistent and longstanding persistent AF who underwent antral PVI at our institution between April 2009 and April 2011.

Comparison of left atrial electrophysiologic abnormalities during sinus rhythm in patients with different type of atrial fibrillation.

Objective: The purpose of this study is to explore the left atrium (LA) electrophysiologic abnormalities in atrial fibrillation (AF) patients detected during sinus rhythm and to determine the relationship between the type of AF and the electrophysiologic substrate in the LA.

Methods: Eighty patients with AF (30 paroxysmal AF, 22 persistent AF, and 28 long-standing AF) and 20 age- and sex-matched patients with left-sided accessory pathway were prospectively studied. High-density three-dimensional electroanatomic mapping was performed during sinus rhythm in LA, which was divided into six segments for regional analysis.

Characterization of trans-septal activation during septal pacing: criteria for identification of intramural ventricular tachycardia substrate in nonischemic cardiomyopathy.

Background: Identification of intramural basal-septal ventricular tachycardia (VT) substrate is challenging in nonischemic cardiomyopathy. We sought to (1) characterize normal/abnormal trans-septal right ventricular (RV) to left ventricular activation; (2) assess the effect of opposite RV pacing on left ventricular septal bipolar electrograms (EGMs); and (3) establish criteria for the identification of intramural septal VT substrate.

Methods And Results: Endocardial activation mapping and local EGM assessment of the left interventricular septum was performed during RV basal septal pacing in 40 patients undergoing VT ablation with no evidence of septal scar (group 1, n=14) and with septal scar (group 2, n=26) defined by low septal unipolar voltage (<8.

Treatment Considerations for a Dual Epidemic of Atrial Fibrillation and Heart Failure.

Atrial fibrillation (AF) and heart failure (HF) have emerged as major cardiovascular epidemics in developed nations over the past decade. They share similar risk factors, seem to mutually accelerate progression and are associated with increased morbidity and mortality. Their relationship involves complex hemodynamic, neuro-hormonal, inflammatory and electrophysiologic mechanisms, which go beyond just mutual risk factors.

Nonischemic cardiomyopathy substrate and ventricular tachycardia in the setting of coronary artery disease.

Background: Patients with coronary artery disease (CAD) may have ventricular tachycardia (VT) from a separate nonischemic process. Catheter ablation in these patients can be misguided by abnormalities of coronary arteries.

Objective: To identify (1) the prevalence of unanticipated nonischemic VT in patients with known CAD presenting with VT and (2) the substrate and VT characteristics of this unique subset of patients.

Assessing arrhythmia burden after catheter ablation of atrial fibrillation using an implantable loop recorder: the ABACUS study.

Introduction: Arrhythmia monitoring in patients undergoing atrial fibrillation (AF) ablation is challenging. Transtelephonic monitors (TTMs) are cumbersome to use and provide limited temporal assessment. Implantable loop recorders (ILRs) may overcome these limitations.

Relationship between voltage map "channels" and the location of critical isthmus sites in patients with post-infarction cardiomyopathy and ventricular tachycardia.

Objectives: The goal of this study was to determine the relationship of the ventricular tachycardia (VT) isthmus to channels of preserved voltage on an electroanatomic voltage map in postinfarction cardiomyopathy.

Background: Substrate mapping in patients with postinfarction cardiomyopathy and VT may involve lowering the voltage cutoff that defines the scar (<1.5 mV) to identify "channels" of relative higher voltage within the scar.

Role of triggering pulmonary veins in the maintenance of sustained paroxysmal atrial fibrillation.

Background: Triggers from thoracic veins have been implicated not only in the initiation, but also in the perpetuation of paroxysmal atrial fibrillation (PAF). To investigate their role we studied the distribution and stability of dominant frequencies (DFs) during PAF and the response to isolation of the triggering pulmonary vein (PV).

Methods And Results: Triggering structures inducing PAF were identified during isoproterenol challenge in 26 patients (15 males, 55 ± 8.

Inducibility of atrial fibrillation and flutter following pulmonary vein ablation.

Introduction: Prior reports demonstrate prognostic value in noninducibility of atrial arrhythmias after atrial fibrillation (AF) ablation and suggest their utility in guiding additional ablation lesion sets. The type and mechanism of induced atrial arrhythmias, their relationship to the underlying atrial substrate, and prognostic significance of induced organized atrial arrhythmias are unknown.

Methods And Results: One hundred forty-four patients (30 women; median age 60 years; 54% with paroxysmal AF) undergoing AF ablation (circumferential pulmonary vein isolation and focal ablation of nonvein triggers on isoproterenol) were evaluated prospectively.

Apical ventricular tachycardia morphology in left ventricular nonischemic cardiomyopathy predicts poor transplant-free survival.

Background: The scar of patients with left ventricular (LV) nonischemic cardiomyopathy (NICM) and ventricular tachycardia (VT) typically originates at or near the mitral annulus and extends a variable distance toward the apex.

Objective: To determine whether electrocardiograms of VT with LV apical exit sites would identify patients with larger scars extending a greater distance from the base toward the apex and decreased heart transplant/left ventricular assist device (LVAD)-free survival.

Methods: Consecutive patients with LV NICM undergoing VT ablation between May 2008 and April 2011 were studied.

Efforts to enhance catheter stability improve atrial fibrillation ablation outcome.

Background: Contemporary techniques to enhance anatomical detail and catheter contact during atrial fibrillation (AF) ablation include (1) the integration of preacquired tomographic reconstructions with electroanatomical mapping (3-dimensional image integration [I-EAM]), (2) the use of steerable introducers (SIs), and (3) high-frequency jet ventilation (HFJV).

Objective: To prove that using these stabilizing techniques during AF ablation improves 1-year procedural outcome.

Methods: We studied 300 patients undergoing AF ablation at our institution.

New unipolar electrogram criteria to identify irreversibility of nonischemic left ventricular cardiomyopathy.

Objectives: This study sought to assess the value of left ventricular (LV) endocardial unipolar electroanatomical mapping (EAM) in identifying irreversibility of LV systolic dysfunction in patients with left ventricular nonischemic cardiomyopathy (LVCM).

Background: Identifying irreversibility of LVCM would be helpful but cannot be reliably accomplished by bipolar EAM or cardiac magnetic resonance identification of macroscopic scar.

Methods: Detailed endocardial LV EAM was performed in 3 groups: 1) 24 patients with irreversible LVCM (I-LVCM) but with no or minimal macroscopic scar (<15% LV surface) evidenced on bipolar voltage EAM and/or cardiac magnetic resonance; 2) 14 patients with reversible ventricular premature depolarization-mediated LVCM (R-LVCM); and 3) 17 patients with structurally normal hearts.