Prevalence of Undiagnosed Sleep Apnea in Patients With Atrial Fibrillation and its Impact on Therapy.

Objectives: This study sought to evaluate the proportion of patients with atrial fibrillation (AF) who also have undiagnosed sleep apnea and examine the impact of its diagnosis on adherence to sleep apnea therapies.

Background: Sleep apnea is a modifiable risk factor for AF. However, the proportion of patients with AF who also have undiagnosed sleep apnea and the impact of its diagnosis on therapy have not been well studied.

Activation Mapping With Integration of Vector and Velocity Information Improves the Ability to Identify the Mechanism and Location of Complex Scar-Related Atrial Tachycardias.

Background: Activation mapping of scar-related atrial tachycardias (ATs) can be difficult to interpret because of inaccurate time annotation of complex electrograms and passive diastolic activity. We examined whether integration of a vector map can help to describe patterns of propagation to better explain the mechanism and location of ATs.

Methods: The investigational mapping algorithm calculates vectors and applies physiological constraints of electrical excitation in human atrial tissue to determine the arrhythmia source and circuit.

Infarct-Related Ventricular Tachycardia: Redefining the Electrophysiological Substrate of the Isthmus During Sinus Rhythm.

Objectives: In this study, the scientific objective was to characterize the electrophysiological substrate of the ventricular tachycardia (VT) isthmus during sinus rhythm.

Background: The authors have recently described the electrophysiological characteristics of the VT isthmus using a novel in vivo high-resolution mapping technology.

Methods: Sixteen swine with healed infarction were studied using high-resolution mapping technology (Rhythmia, Boston Scientific, Cambridge, Massachusetts) in a closed-chest model.

High-Power and Short-Duration Ablation for Pulmonary Vein Isolation: Biophysical Characterization.

Objectives: This study sought to examine the biophysical properties of high-power and short-duration (HP-SD) radiofrequency ablation for pulmonary vein isolation.

Background: Pulmonary vein isolation is the cornerstone of atrial fibrillation ablation. However, pulmonary vein reconnection is frequent and is often the result of catheter instability, tissue edema, and a reversible nontransmural injury.

High-power and short-duration ablation for pulmonary vein isolation: Safety, efficacy, and long-term durability.

Introduction: PV reconnection is often the result of catheter instability and tissue edema. High-power short-duration (HP-SD) ablation strategies have been shown to improve atrial linear continuity in acute pre-clinical models. This study compares the safety, efficacy, and long-term durability of HP-SD ablation with conventional ablation.

Atrial Substrate and Triggers of Paroxysmal Atrial Fibrillation in Patients With Obstructive Sleep Apnea.

Background: Obstructive sleep apnea (OSA) is associated with atrial remodeling, atrial fibrillation (AF), and increased incidence of arrhythmia recurrence after pulmonary vein (PV) isolation. We aimed to characterize the atrial substrate, including AF triggers in patients with paroxysmal AF and OSA.

Methods And Results: In 86 patients with paroxysmal AF (43 with ≥moderate OSA [apnea-hypopnea index ≥15] and 43 without OSA [apnea-hypopnea index <5]), right atrial and left atrial voltage distribution, conduction velocities, and electrogram characteristics were analyzed during atrial pacing.

Evaluation of ablation catheter technology: Comparison between thigh preparation model and an in vivo beating heart.

Background: An in vivo animal thigh model is the standard technique for evaluation of ablation catheter technologies, including efficacy and safety of ablation. However, the biophysics of ablation in a thigh model may not be similar to a beating heart.

Objective: The purpose of this study was to compare efficacy and safety of ablation between a thigh preparation model and a beating heart.

Evaluation of a novel high-resolution mapping technology for ablation of recurrent scar-related atrial tachycardias.

Background: Rhythmia is a new technology capable of rapid and high-resolution mapping. However, its potential advantage over existing technologies in mapping complex scar-related atrial tachycardias (ATs) has not yet been evaluated.

Objective: The purpose of this study was to examine the utility of Rhythmia for mapping scar-related ATs in patients who had failed previous ablation procedure(s).

Incidence and risk factors for symptomatic heart failure after catheter ablation of atrial fibrillation and atrial flutter.

Aims: To determine the incidence and risk factors for development of symptomatic heart failure (HF) following catheter ablation for atrial fibrillation (AF) and atrial flutter.

Methods And Results: We prospectively enrolled consecutive patients undergoing pulmonary vein isolation (PVI) or cavotricuspid isthmus (CTI) ablation between November 2013 and June 2014. Post-discharge symptoms were assessed via telephone follow-up and clinic visits.

Pulmonary vein isolation using the Rhythmia mapping system: Verification of intracardiac signals using the Orion mini-basket catheter.

Background: During pulmonary vein isolation (PVI), a circular lasso catheter is positioned at the junction between the left atrium (LA) and the pulmonary vein (PV) to confirm PVI. The Rhythmia mapping system uses the Orion mini-basket catheter with 64 electrodes instead of the lasso catheter. However, its feasibility to determine PVI has not been studied.

Should Adenosine Test be Performed Systematically at the End of Atrial Fibrillation Ablation Procedure?

Pulmonary vein (PV) reconnection is a major limitation of atrial fibrillation (AF) ablation and is a significant contributor for arrhythmia recurrence, particularly in patients with paroxysmal AF. Recent technological advances, including the use of steerable sheaths and force sensing catheters resulted in reduced incidence of PV reconnection; however its incidence remains unacceptably high. Additional efforts to reduce pulmonary vein reconnection include the use adenosine to detect dormant PV to left atrial (LA) electrical conduction as well as identification of non-PV triggers.

Radiofrequency ablation annotation algorithm reduces the incidence of linear gaps and reconnection after pulmonary vein isolation.

Background: A common mechanism of atrial fibrillation recurrence after catheter ablation is resumption of pulmonary vein (PV) conduction due to gaps in the ablation line. These gaps may go unrecognized owing to inadequate ablation lesion annotation.

Objective: To examine the utility of an automated radiofrequency (RF) ablation annotation algorithm for the detection and treatment of ablation gaps during pulmonary vein isolation (PVI).

Acute pulmonary vein reconnection is a predictor of atrial fibrillation recurrence following pulmonary vein isolation.

Purpose: Arrhythmia recurrence following pulmonary vein isolation (PVI) occurs predominantly due to the reconnection of previously isolated pulmonary veins (PVs). The prognostic implications of detection and treatment of acute PV reconnection are not well understood. We aim to examine the prognostic significance of acute PV reconnection on arrhythmia recurrence at 1 year following PVI.

How we implemented a resident-led medical simulation curriculum in a large internal medicine residency program.

Mannequin-based simulation in graduate medical education has gained widespread acceptance. Its use in non-procedural training within internal medicine (IM) remains scant, possibly due to the logistical barriers to implementation of simulation curricula in large residency programs. We report the Massachusetts General Hospital Department of Medicine's scale-up of a voluntary pilot program to a mandatory longitudinal simulation curriculum in a large IM residency program (n = 54).

Multi-sensor esophageal temperature probe used during radiofrequency ablation for atrial fibrillation is associated with increased intraluminal temperature detection and increased risk of esophageal injury compared to single-sensor probe.

Background: Radiofrequency (RF) ablation in the posterior left atrium has risk of thermal injury to the adjacent esophagus. Increased intraluminal esophageal temperature has been correlated with risk of esophageal injury. The objective of this study was to compare esophageal temperature monitoring (ETM) using a multi-sensor temperature probe with 12 sensors to a single-sensor probe during catheter ablation for atrial fibrillation (AF).

Severity of esophageal injury predicts time to healing after radiofrequency catheter ablation for atrial fibrillation.

Background: The delivery of radiofrequency (RF) energy to the posterior left atrium creates a risk of injury to the adjacent esophagus. Esophageal endoscopy (EGD) is used to screen patients at risk for esophageal thermal injury after RF ablation.

Objective: The purpose of this study was to analyze the macroscopic features of the severity of esophageal injuries induced by RF ablation to the left atrium as seen by EGD and evaluate the association of these descriptions with the time elapsed until complete healing.