Current of injury predicts adequate active lead fixation in permanent pacemaker/defibrillation leads.

Objectives: The aim of this study was to determine whether current of injury can guide adequate placement of active-fixation pacing leads.

Background: Active-fixation leads cause injury to the myocardium at the time of fixation, manifested as a current of injury (COI) that may result in acute elevation of pacing thresholds. The relationship of COI to subsequent improvement in pacing thresholds is not clear.

Cardiac resynchronization therapy in patients with heart failure and conduction abnormalities other than left bundle-branch block: analysis of the Multicenter InSync Randomized Clinical Evaluation (MIRACLE).

Background: Cardiac resynchronization therapy (CRT) has been proposed as a treatment for patients with congestive heart failure (CHF) and prolonged QRS durations. Previous studies have predominantly included patients with left bundle-branch block (LBBB). The Multicenter InSync Randomized Clinical Evaluation (MIRACLE) investigators assessed the efficacy of CRT in patients with CHF with QRS durations > or = 130 ms and found that CRT lead to improvement in several measures of functional capacity and exercise tolerance.

Do positive health expectations and optimism relate to quality-of-life outcomes for the patient with an implantable cardioverter defibrillator?

Purpose: Clinical trials with the implantable cardioverter defibrillator (ICD) have demonstrated desirable outcomes in terms of mortality and morbidity among patients with potentially lethal arrhythmias. This study examined the "resilience factors" of positive health expectations and global optimism prospectively using the general quality-of-life (QOL) scores of newly implanted ICD patients.

Methods: The study enrolled 88 newly implanted ICD patients (mean age, 65.

Pyoderma gangrenosum with a contiguous erosion of the distal ulna.

Background: Pyoderma gangrenosum (PG) has been described in association with sterile neutrophilic infiltration of several organ systems, including the skeleton. The most frequent cause of bony disease in PG has been chronic, recurrent, multifocal osteomyelitis, a sterile inflammatory disease of children and young adults mimicking infectious osteomyelitis. Bony erosions have been only rarely described in direct contiguity to a PG ulcer.

Women and the implantable cardioverter defibrillator: a lifespan perspective on key psychosocial issues.

The clinical success of the implantable cardioverter defibrillator (ICD) in reducing mortality suggests that more women will be receiving ICDs in the future. The impact of ICD therapy in women is unique in western societies; the ICDs scar and lump in the pectoral area can lead to body image concerns due to the emphasis on women's physical attractiveness. Social support and roles are challenged because women's reaction to stress has been characterized by a "tend and befriend" response, involving cultivating and utilizing social networks, rather than the "fight or flight" response more typical of men.

Left atrial tachycardia originating from the mitral annulus-aorta junction.

Background: At the mitral annulus-aorta (MA-Ao) junction, the left atrium is continuous through the subaortic curtain with the musculature of the anterior mitral leaflet. Under experimental conditions, this region can generate abnormal electrical activity. In patients with left atrial tachycardia, we investigated whether this region could be the source of this arrhythmia.

Highlights of Heart Rhythm 2004, the Annual Scientific Sessions of the Heart Rhythm Society: May 19 to 22, 2004, in San Francisco, California.

Heart Rhythm 2004, the 25th Annual Scientific Sessions of the Heart Rhythm Society (formerly the North American Society of Pacing and Electrophysiology), met in San Francisco in May 2004. The meeting is the world's premier forum for the presentation of research and the exchange of state-of-the-art information in cardiac electrophysiology and pacing. Major new research findings were presented on the value of implantable cardioverter-defibrillator therapy, noninvasive methods for risk stratification, treatment of vasovagal syncope, radiofrequency ablation for atrial fibrillation, resynchronization therapy for heart failure, and new insights from basic science into the mechanisms of cardiac arrhythmias.

Microvolt T-wave alternans distinguishes between patients likely and patients not likely to benefit from implanted cardiac defibrillator therapy: a solution to the Multicenter Automatic Defibrillator Implantation Trial (MADIT) II conundrum.

Background: In 2003, the Centers for Medicaid and Medicare Services recommended QRS duration as a means to identify MADIT II-like patients suitable for implanted cardiac defibrillator (ICD) therapy. We compared the ability of microvolt T-wave alternans and QRS duration to identify groups at high and low risk of dying among heart failure patients who met MADIT II criteria for ICD prophylaxis.

Methods And Results: Patients with MADIT II characteristics and sinus rhythm had a microvolt T-wave alternans exercise test and a 12-lead ECG.

The World Trade Center attack: increased frequency of defibrillator shocks for ventricular arrhythmias in patients living remotely from New York City.

Objectives: The goal of this study was to determine whether the World Trade Center (WTC) attack on September 11, 2001, had an effect on the occurrence of ventricular arrhythmias among patients with implantable cardioverter-defibrillators (ICDs) living in Florida.

Background: Increased frequencies of ICD therapies for ventricular arrhythmias were reported among patients in New York City after the attack on the WTC. Whether this effect also occurred in patients living geographically distant from New York is unknown.

Histone acetyltransferase-dependent chromatin remodeling and the vascular clock.

Rhythmic gene expression is central to the circadian control of physiology in mammals. Transcriptional activation of Per and Cry genes by heterodimeric bHLH-PAS proteins is a key event in the feedback loop that drives rhythmicity; however, the mechanism is not clearly understood. Here we show the transcriptional coactivators and histone acetyltransferases, p300/CBP, PCAF, and ACTR associate with the bHLH-PAS proteins, CLOCK and NPAS2, to regulate positively clock gene expression.

Termination of paroxysmal supraventricular tachycardia by tecadenoson (CVT-510), a novel A1-adenosine receptor agonist.

Objectives: The aim of this study was to evaluate tecadenoson safety and efficacy during conversion of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm.

Background: Tecadenoson (CVT-510), a novel adenosine receptor (Ado R) agonist, selectively activates the A1 Ado R and prolongs atrioventricular (AV) nodal conduction at doses lower than those required to cause A2 Ado R-mediated coronary and peripheral vasodilation. Unlike adenosine, which non-selectively activates all four Ado R subtypes and produces unwanted effects, tecadenoson appears to terminate AV node-dependent supraventricular tachycardias without hypotension and bronchoconstriction.

Association of NOD2 with Crohn's disease in a homogenous Irish population.

Linkage of IBD to the pericentromeric region of chromosome 16 has been widely confirmed by analyses of multiple populations. The NOD2 gene is located in the peak region of linkage on chromosome 16 and thought to be involved in the activation of nuclear factor (NF) kappaB in response to bacterial components. Mutations in the NOD2 gene are found to be strongly associated with susceptibility to Crohn's disease (CD).

Risks and benefits of rate control versus maintenance of sinus rhythm.

There are 2 fundamental approaches to managing patients with recurrent atrial fibrillation (AF): to restore and maintain sinus rhythm with cardioversion and/or antiarrhythmic drugs, or to control the ventricular rate only. Over the past few years, there have been several important prospective clinical trials comparing rate control with rhythm control in patients with recurrent AF. The Pharmacological Intervention in Atrial Fibrillation (PIAF) trial was the first prospective randomized study to test the hypothesis of equivalency between the 2 management strategies for AF.

Demonstration of a left atrial input to the atrioventricular node in humans.

Background: During right atrial stimulation, the anterior and posterior approaches provide inputs to the atrioventricular (AV) node. The purpose of the present study was to determine how activation proceeding from the left atrium reaches the AV node.

Methods And Results: We studied AV nodal conduction during right and left atrial (coronary sinus) stimulation in 46 patients (27 women and 19 men; mean age, 46+/-4 years) who had structurally normal hearts.

A sperm-associated WD repeat protein orthologous to Chlamydomonas PF20 associates with Spag6, the mammalian orthologue of Chlamydomonas PF16.

cDNAs were cloned for the murine and human orthologues of Chlamydomonas PF20, a component of the alga axoneme central apparatus that is required for flagellar motility. The mammalian genes encode transcripts of 1.4 and 2.

Ventricular dyssynchrony in dilated cardiomyopathy: the role of biventricular pacing in the treatment of congestive heart failure.

Despite advances in pharmacologic therapy, the prognosis of patients with advanced congestive heart failure (CHF) remains poor. Many of these patients have cardiac conduction abnormalities, such as left bundle-branch block or interventricular conduction delays, that can lead to ventricular dyssynchrony (abnormal ventricular activation that results in decreased ventricular filling and abnormal ventricular wall motion). Biventricular pacing is an alternative, nonpharmacologic therapy under active investigation for the treatment of CHF.

Frequency of symptomatic atrial fibrillation in patients enrolled in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study.

Introduction: The frequency of symptomatic paroxysmal atrial fibrillation (AF) may identify subsets with different characteristics. Because the approach to AF now is so varied, ranging from drug therapy to surgery and catheter ablation, the frequency of AF may have important therapeutic implications if the frequency identifies subsets with distinguishing features.

Methods And Results: The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Study is evaluating patients with AF who are at high risk for stroke.

The effects of hormones on arrhythmias in women.

The reproductive hormones play a significant role in modulating the presentation and behavior of numerous types of arrhythmias. Differences exist between men and women in normal electrophysiology; along with heart rate, the QT interval is a basic parameter that is affected by the presence or absence of certain reproductive hormones. Women have a lower prevalence of atrial fibrillation, yet they have a higher mortality once atrial fibrillation is established.