Pericardial fat is associated with atrial fibrillation severity and ablation outcome.

Objectives: The aim of this study was to characterize the relationship between pericardial fat and atrial fibrillation (AF).

Background: Obesity is an important risk factor for AF. Pericardial fat has been hypothesized to exert local pathogenic effects on nearby cardiac structures above and beyond that of systemic adiposity.

The diagnosis and management of ventricular arrhythmias.

The term 'ventricular arrhythmias' incorporates a wide spectrum of abnormal cardiac rhythms, from single premature ventricular complexes to sustained monomorphic ventricular tachycardia (VT), polymorphic VT, and ventricular fibrillation. Sustained ventricular arrhythmias are the most common cause of sudden cardiac death. These arrhythmias occur predominantly in patients with structural heart disease, but are also seen in patients with no demonstrable cardiac disease.

Atrial protective effects of n-3 polyunsaturated fatty acids: a long-term study in ovine chronic heart failure.

Background: It has been suggested that omega-3 polyunsaturated fatty acids (n-3 PUFAs) may prevent the development of atrial fibrillation (AF).

Objective: The purpose of this study was to evaluate the impact of these agents on development of the AF substrate in heart failure (HF).

Methods: In this study, HF was induced by intracoronary doxorubicin infusions.

Sinus node revisited.

Purpose Of Review: Sinus node disease (SND) is a common clinical condition and is the most common indication for permanent pacemaker implantation. This review aims to revisit the complex sinus node anatomy, the evolving understanding of its pacemaking mechanisms, the atrial myopathy in SND and sinus node remodeling.

Recent Findings: Recent high-density noncontact mapping of the human sinus node showed multiple origins of sinus activation and exit sites with preferential pathways of conduction.

Reparative effects of allogeneic mesenchymal precursor cells delivered transendocardially in experimental nonischemic cardiomyopathy.

Objectives: This study set out to evaluate the safety and efficacy of allogeneic bone marrow mesenchymal precursor cells (MPC) delivered by multisegmental, transendocardial implantation in the setting of nonischemic cardiomyopathy (NICM).

Background: Prospectively isolated MPC have shown capacity to mediate cardiovascular repair in myocardial ischemia. However, their efficacy in NICM remains undetermined.

Characterization of atrial remodeling studied remote from episodes of typical atrial flutter.

Atrial electrical remodeling has been shown after termination of atrial flutter (AFL); however, whether abnormalities persist beyond an arrhythmic episode is not known. We aimed to characterize the atrial substrate, remote from arrhythmia, in patients with typical AFL. We compared 20 patients, studied remote from episodes of typical AFL and without a history of atrial fibrillation, to 20 reference patients.

Atrial remodeling in an ovine model of anthracycline-induced nonischemic cardiomyopathy: remodeling of the same sort.

Introduction: All preclinical studies of atrial remodeling in heart failure (HF) have been confined to a single model of rapid ventricular pacing. To evaluate whether the atrial changes were specific to the model or represented an end result of HF, this study aimed to characterize atrial remodeling in an ovine model of doxorubicin-induced cardiomyopathy.

Methods And Results: Fourteen sheep, 7 with cardiomyopathy induced by repeated intracoronary doxorubicin infusions and 7 controls, were studied.

Feasibility of high-density electrophysiological study using multiple-electrode array in isolated small animal atria.

1. High-density cardiac electrophysiological study (EPS) of small animal atria has been limited to optical mapping techniques, which require complex and expensive equipment setup. We aim to evaluate the feasibility of carrying out EPS in isolated atrial tissues using a custom made high-density multiple-electrode array (MEA).

Direction-dependent conduction in lone atrial fibrillation.

Background: Patients with lone atrial fibrillation (AF) have an abnormal atrial substrate.

Objective: The purpose of this study was to determine the role of direction-dependent conduction in patients with lone AF.

Methods: Twenty-four patients with paroxysmal lone AF and 24 reference patients with left-sided accessory pathways were studied.

New-onset atrial fibrillation and acute coronary syndrome.

Despite advances in the diagnosis and management of acute coronary syndrome (ACS), atrial fibrillation (AF) remains a commonly encountered complication leading to adverse short- and long-term outcomes across the whole spectrum of ACS. At present, the underlying mechanisms of AF in myocardial ischemia remain incompletely understood. This article evaluates the incidence and trends of new-onset AF in ACS, its impact on ACS management and the associated prognostic significance in patients with acute ischemic heart disease.

Assessment of myocardial fibrosis by endoventricular electromechanical mapping in experimental nonischemic cardiomyopathy.

Cardiac fibrosis plays an important prognostic role in nonischemic cardiomyopathy (NICM), making it a potential therapeutic target. Although electromechanical mapping has been used to identify myocardial scar and facilitate intramyocardial intervention in the setting of ischemic heart disease, its application has not been described in NICM. We assessed the detection of myocardial fibrosis by endoventricular electromechanical mapping in an experimental model of NICM.

Hypertension and atrial fibrillation: evidence of progressive atrial remodeling with electrostructural correlate in a conscious chronically instrumented ovine model.

Background: Hypertension accounts for more atrial fibrillation (AF) than any other predisposing factor.

Objective: The purpose of this study was to characterize the time course, extent, and electrostructural correlation of atrial remodeling in chronic hypertension.

Methods: Thirty-two sheep were studied: 21 with induced "one-kidney, one-clip" hypertension and 11 controls.

Characterization of cardiac remodeling in a large animal "one-kidney, one-clip" hypertensive model.

Objective: The aim of this study is to characterize cardiac remodeling in a large animal model of hypertension.

Methods: 23 sheep were subjected to unilateral nephrectomy followed by clamping of the remaining renal artery to 60% ("one kidney-one clip", 1K1C) 3 weeks later. Blood pressure (BP) was monitored invasively over 73+/-28 days.

Outcomes of long-standing persistent atrial fibrillation ablation: a systematic review.

Background: Ablation of long-standing persistent atrial fibrillation (AF) is highly variable, with differing techniques and outcomes.

Objective: The purpose of this study was to undertake a systematic review of the literature with regard to the impact of ablation technique on the outcomes of long-standing persistent AF ablation.

Methods: A systematic search of the contemporary English scientific literature (from January 1, 1990 to June 1, 2009) in the PubMed database identified 32 studies on persistent/long-standing persistent or long-standing persistent AF ablation (including four randomized controlled trials).

Short-term hypertension is associated with the development of atrial fibrillation substrate: a study in an ovine hypertensive model.

Background: Hypertension is frequently complicated by the development of atrial fibrillation (AF). However, the mechanisms of this link remain poorly understood. In addition, whether short-term hypertension can result in a substrate for AF is not known.

Prognostic impact of types of atrial fibrillation in acute coronary syndromes.

Atrial fibrillation (AF) has been established as an independent predictor of long-term mortality after acute myocardial infarction. However, this is less well defined across the whole spectrum of acute coronary syndromes (ACSs). The Acute Coronary Syndrome Prospective Audit is a prospective multicenter registry with 12-month outcome data for 3,393 patients (755 with ST-segment elevation myocardial infarction, 1942 with high-risk non-ST-segment elevation ACS [NSTE-ACS], and 696 with intermediate-risk NSTE-ACS).

Impact of research presentations at the annual scientific sessions of the Heart Rhythm Society.

Background: Abstract presentation at conferences provides the opportunity to rapidly communicate research findings. The outcome and impact of publications arising from cardiac electrophysiology abstracts are not known.

Objective: The purpose of this study was to examine the characteristics of abstracts presented at the annual scientific sessions of Heart Rhythm Society (HRS), their publication rate, and the indexed impact of subsequent publications.

Left atrial remodeling in patients with atrial septal defects.

Background: Information regarding left atrial (LA) substrate in conditions predisposing to atrial fibrillation (AF) is limited.

Objective: This study sought to characterize the left atrial remodeling that results from chronic atrial stretch caused by atrial septal defect (ASD).

Methods: Eleven patients with hemodynamically significant ASDs and 12 control subjects were studied.

Validation of cardiovascular magnetic resonance assessment of pericardial adipose tissue volume.

Background: Pericardial adipose tissue (PAT) has been shown to be an independent predictor of coronary artery disease. To date its assessment has been restricted to the use of surrogate echocardiographic indices such as measurement of epicardial fat thickness over the right ventricular free wall, which have limitations. Cardiovascular magnetic resonance (CMR) offers the potential to non-invasively assess total PAT, however like other imaging modalities, CMR has not yet been validated for this purpose.

Paroxysmal lone atrial fibrillation is associated with an abnormal atrial substrate: characterizing the "second factor".

Objectives: The purpose of this study was to determine whether patients with paroxysmal "lone" atrial fibrillation (AF) have an abnormal atrial substrate.

Background: While "AF begets AF," prompt termination to prevent electrical remodeling does not prevent disease progression.

Methods: Twenty-five patients with paroxysmal lone AF, without arrhythmia in the week prior, and 25 reference patients with left-sided accessory pathways were studied.

An ovine model of toxic, nonischemic cardiomyopathy--assessment by cardiac magnetic resonance imaging.

Background: There is a paucity of published experience investigating novel treatment strategies in preclinical and clinical studies of nonischemic cardiomyopathy. We set out to validate an ovine model of doxorubicin-induced cardiomyopathy, using cardiac magnetic resonance (CMR) to assess cardiac function.

Methods And Results: Ten Merino sheep (51 +/- 8 kg) underwent intracoronary infusions of doxorubicin (1 mg/kg dose) every 2 weeks.

High-density mapping of atrial fibrillation in humans: relationship between high-frequency activation and electrogram fractionation.

Introduction: Sites of complex fractionated atrial electrograms (CFAE) and dominant frequency (DF) have been implicated in maintaining atrial fibrillation (AF); however, their relationship is poorly understood.

Methods And Results: Twenty patients underwent biatrial high-density contact mapping (507 +/- 150 points/patient) during AF. CFAE were characterized using software to quantify electrogram complexity (CFE-mean).

Image integration using NavX Fusion: initial experience and validation.

Background: Three-dimensional virtual anatomic navigation is increasingly used during mapping and ablation of complex arrhythmias. NavX Fusion software aims to mold the virtual anatomy to the patient's computed tomography (CT) image; however, the accuracy and clinical usefulness of this system have not been reported.

Objective: The purpose of this study was to assess the accuracy and describe the initial experience of CT image integration using NavX Fusion for atrial fibrillation ablation.