Heart Rhythm via MedWorm.com

EP News Clinical

Heart Rhythm — Mon, 26 Dec 2011 05:00:00 +0100

Imazio and colleagues (Circulation 2011 Nov 22; 124(21):2290–2295. Epub 2011 Nov 16 PMID: 22090167) evaluated colchicine (C) for the prevention of post-operative AF (POAF) after cardiac surgery in 336 patients in a multicenter, double-blind, placebo (P) controlled randomized trial. Patients were in sinus rhythm before starting the intervention (P or C 1.0 mg twice daily starting on postoperative day 3 followed by a maintenance dose of 0.5 mg twice daily for 1 month). The primary endpoint was the incidence of POAF at 1 month. Despite well-balanced baseline characteristics, patients on C had a reduced incidence of POAF (12.0% versus 22.0%, respectively; P = 0.021; relative risk reduction, 45%) with a shorter in-hospital stay (9.4 ± 3.7 versus 10.3 ± 4.3 days; P = 0.040). Side effects wer...

EP News: Basic and Translational

Heart Rhythm — Mon, 26 Dec 2011 05:00:00 +0100

During the American Heart Association Annual Meeting, Rizzo et al (Circulation 2011:124:A13059) reported pathological characteristics of stellate ganglia resected from 5 long QT syndrome (LQTS) and 5 catecholaminergic polymorphic ventricular tachycardia (CPVT) patients. Control stellate ganglia were obtained from 4 accidently deceased patients. Sections were immunostained with antibodies against various lymphocyte markers. The authors found that stellate ganglia of all 10 LQTS/CVPT patients had mild but distinct inflammatory infiltrates composed of T-lymphocytes and macrophages. These cells were diffusely spread, but also clustered in small foci or even inside ganglion cells. These findings are interpreted as T cell-mediated ganglionitis. The authors conclude that a low grade cytotoxic T c...

You shouldn’t take it with you: Postmortem device reuse

Heart Rhythm — Mon, 26 Dec 2011 05:00:00 +0100

Antiarrhythmia devices—pacemakers and implantable cardioverter-defibrillators (ICDs)—are expensive scarce world resources that are available to the majority of the population in the economic “haves” countries but rarely to those without means in the economic “have-nots” countries. Impoverished or developing nations implant what devices they can primarily for life-threatening atrioventricular block, often only in younger patients. ICDs, for any indications, are beyond their scope of practice for all but the richest minority. Generators, leads, and the technical knowledge to implant devices are often obtained through humanitarian assistance, for example, the Pacemaker Banks established under the direction of the philanthropic organization Heartbeat International. Physicians train...

EP News: Clinical

Heart Rhythm — Wed, 07 Dec 2011 05:00:00 +0100

Watanabe et al (Circ Arrhythm Electrophysiol 2011;[Epub ahead of print], PMID 22028457) investigated the clinical and genetic characteristics of early repolarization associated with idiopathic ventricular fibrillation (IVF). Fifty patients with IVF and early repolarization (J waves) were compared to 250 controls. Ventricular fibrillation was inducible by programmed stimulation in 15 of 29 patients (52%). Heart rate was slower and PR interval and QRS duration were longer in patients than in controls. Nonsynonymous variants in SCN5A in 3 unrelated patients were identified. His-ventricular interval was prolonged in all patients carrying an SCN5A mutation. Sodium channel blocker challenge resulted in augmentation of early repolarization and/or development of ventricular fibrillation in all of ...

EP News: Basic and Translational

Heart Rhythm — Mon, 05 Dec 2011 05:00:00 +0100

Rosas-Ballina et al (Science 2011;334:98, PMID 21921156) determined whether vagus nerve stimulation induces increased acetylcholine release in the spleen by measuring acetylcholine in perfusate samples collected by microdialysis. Acetylcholine levels were elevated within minutes after electrical vagus nerve stimulation and reached peak levels within 20 minutes. This indicates that action potentials originating in the vagus nerve can enhance acetylcholine release in the spleen. They also identified an acetylcholine-producing, memory phenotype T-cell population in mice that is integral to the inflammatory reflex. These acetylcholine-producing T cells are required for inhibition of cytokine production by vagus nerve stimulation. A major finding of this study is the surprising functional role ...

State of the Journal 2012

Heart Rhythm — Mon, 05 Dec 2011 05:00:00 +0100

We begin the ninth year of HeartRhythm with the Journal well positioned for continued growth and success. It remains strong with about 1500 annual submissions, an acceptance rate less than 20%, time to first decision 8.5 days, and time to electronic publication after acceptance 3–5 days. We have had a very positive response from readers about the focus issues and will continue them. We have started a new Point/Counterpoint series and hope those will be successful. (Source: Heart Rhythm)

Subject Index to Volume 6

Heart Rhythm — Thu, 01 Dec 2011 02:36:38 +0100

(Source: Heart Rhythm)

Author Index to Volume 8

Heart Rhythm — Thu, 01 Dec 2011 02:36:38 +0100

(Source: Heart Rhythm)

Executive Summary from the First Annual Heart Rhythm Society Research Forum: A Vision for Our Research Future, “Dream, Discover, Develop, Deliver”

Heart Rhythm — Thu, 01 Dec 2011 02:36:38 +0100

Washington, DC December 14–15, 2010 (Source: Heart Rhythm)

The Chinese herb extract Wenxin Keli: Atrial selectivity from the Far East

Heart Rhythm — Wed, 23 Nov 2011 05:00:00 +0100

More than 10,000 medicinals are used in China, and more than 100,000 Chinese medicinal recipes have been listed. Traditional Chinese medicines were first documented about 2500 years ago by Confucian scholars and are now used by millions around the world. As one of the positive signs of world globalization, the integration of the traditional Chinese and Western medical practices has begun in multiple medical centers, and there is increasing evidence that several herbs or combinations of herbs used in traditional Chinese medicines have reproducible pharmacological effects. Recently, there has been a growing interest in elucidating the mechanisms by which traditional Chinese recipes are beneficial so as to further comprehend mechanisms and implement active pharmacophores. In cardiac electroph...

Letter to the Editor—Atrial fibrillation: An inflammatory and autoimmune disorder

Heart Rhythm — Mon, 21 Nov 2011 05:00:00 +0100

Atrial fibrillation (AF) is an established inflammatory disorder. Autoimmunity has been suggested to play an important role as autoantibodies have been identified in AF. Identification of contactin-2 on His-Purkinje cells by Pallante et al raises the potential of TH17 cells in the pathogenesis of AF. Contactin-2 is an identified target of TH17 in the gray matter of patients with multiple sclerosis and animals with experimental autoimmune encephalomyelitis—both of which are TH1 and TH17 autoimmune disorder. Recently, psoriasis, another TH1-, TH17-, and TH22-mediated disease, has been identified as a risk factor for AF. On the basis of these findings, we propose that AF is a T-cell autoimmune disorder involving cytotoxic TH1, TH17, and possibly TH22 cells acting on His-Purkinje cells. This...

Reply to the Editor—Atrial Fibrillation: An Inflammatory and Autoimmune Disorder

Heart Rhythm — Fri, 18 Nov 2011 05:00:00 +0100

Many factors contribute to the pathogenesis of atrial fibrillation, including electrical, structural, neurohumoral, and inflammatory mechanisms. Our review indicated that various autoantibodies that may play a role in the development and maintenance of atrial fibrillation have been identified. Indeed, mounting evidence demonstrates correlations between diseases with autoimmune mechanisms, including Graves' disease, celiac disease, and psoriasis, and an increased risk of atrial fibrillation. Schairer and Levis suggested that T-cell–mediated autoimmune disorders should be considered in the pathogenesis of atrial fibrillation. Such mechanisms in atrial fibrillation are currently unknown and unexplored. They proposed the intriguing hypothesis that atrial fibrillation is a T-cell autoimmune d...

Reply to the Editor—Persistent Atrial Fibrillation

Heart Rhythm — Mon, 14 Nov 2011 05:00:00 +0100

We thank Drs. Parkash and Tang for their interest in our recent work. The authors outlined that additional substrate ablation beyond the pulmonary veins is required in patients with persistent atrial fibrillation (AF); however, it does result in similar outcomes irrespective to the approach used to target the substrate. This is true when recurrences are not further classified according to arrhythmia mechanism. When arrhythmia recurrences are distinguished between AF and atrial tachycardia (AT), the impact of ablation complexity becomes evident: an increasing extensiveness of substrate ablation is associated with a decrease of AF and increase of AT recurrences. Furthermore, the distinction of the mode of recurrent arrhythmia is of particular importance because recurrence of AT is considered...

To the Editor–Ablation of persistent atrial fibrillation

Heart Rhythm — Mon, 14 Nov 2011 05:00:00 +0100

Rostock et al confirm the difficulty faced in the ablation of persistent atrial fibrillation (AF) in their study examining the long-term success of catheter ablation in this group of patients, with a single procedure efficacy at 27%. They comment on atrial substrate modification with various approaches to catheter ablation. We believe that the substrate—both electrophysiological and structural—is crucial to address in patients with persistent AF. We found in a meta-analysis of randomized studies of catheter ablation in AF that irrespective of the approach used in persistent AF in addition to pulmonary vein isolation, the results are similar. The most important aspect to catheter ablation in this group is additional ablation beyond pulmonary vein isolation. The other concept that is imp...

Shock-induced focal arrhythmias: Not driven by calcium?

Heart Rhythm — Thu, 10 Nov 2011 05:00:00 +0100

Shock-induced focal arrhythmias have been documented experimentally and are plausible mechanisms for clinically observed postshock transient ectopic beats and reinduction of atrial and ventricular fibrillations. This important clinical problem usually occurs after cardioversion and needs more focused research studies. Postshock focal arrhythmias and dysfunctions are likely associated with shock-induced electroporation, which is characterized by the transient formation of aqueous pores in the cardiomyocyte membrane. The transient electroporation-induced pores allow free movement of ions and lead to loss of intracellular potassium and intracellular accumulation of sodium and calcium. A previous study using microelectrode recordings showed that high-intensity shocks (in a clinically relevant ...

Full Report from the First Annual Heart Rhythm Society Research Forum: A Vision for Our Research Future, “Dream, Discover, Develop, Deliver”

Heart Rhythm — Thu, 10 Nov 2011 05:00:00 +0100

Introduction (Source: Heart Rhythm)

EP News: Basic and Translational

Heart Rhythm — Wed, 09 Nov 2011 05:00:00 +0100

Tandri et al (Sci Transl Med 2011;3:102ra96 PMID 21957174) studied the effects of electrical stimulation on conduction block in cardiac tissues. Electrical stimulation has been applied to nervous tissue to cause reversible conduction block, but it has not been explored sufficiently in cardiac tissue. The authors show that reversible propagation block can be achieved in cardiac tissue by holding myocardial cells in a refractory state for a designated period of time by applying a sustained sinusoidal high-frequency alternating current; in doing so, reentrant arrhythmias are terminated. The authors demonstrate proof of concept by using several models, including optically mapped monolayers of neonatal rat ventricular cardiomyocytes, Langendorff-perfused guinea pig and rabbit hearts, intact ane...

EP News: Clinical

Heart Rhythm — Fri, 28 Oct 2011 04:00:00 +0100

Wichter and colleagues (J Nucl Med 2011. Epub ahead of print PMID 21908389) investigated the influence of adrenergic dysfunction on arrhythmias in 42 patients with ARVD with (123)I-MIBG SPECT scans. An abnormal tracer uptake was detected in 25 patients (59%). The extents of right ventricular dilation and regional wall motion abnormalities as well as electrocardiographic markers of de- or repolarization were not significantly different between patients with normal and abnormal scans. Patients with abnormal scans experienced life-threatening ventricular tachyarrhythmias significantly more often (22 of 25 patients [88%]) and independent of the extent of right ventricular dysfunction than did those with a normal sympathetic innervation (6 of 17 patients [35%]; P (Source: Heart Rhythm)

Arrhythmic Risk Stratification in Patients With Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy Associated Desmosomal Mutations