Different impact of long-detection interval and anti-tachycardia pacing in reducing unnecessary shocks: data from the ADVANCE III trial.

Aims: A long-detection interval (LDI) (30/40 intervals) has been proved to be superior to a standard-detection interval (SDI) (18/24 intervals) in terms of reducing unnecessary implantable cardioverter defibrillator (ICD) therapies. To better evaluate the different impact of LDI and anti-tachycardia pacing (ATP) on reducing painful shocks, we assessed all treated episodes in the ADVANCE III trial.

Methods And Results: A total of 452 fast (200 ms < cycle length ≤ 320 ms) arrhythmic episodes were recorded: 284 in 138 patients in the SDI arm and 168 in 82 patients in the LDI arm (106/452 inappropriate detections).

Continuous rhythm monitoring for ventricular arrhythmias after alcohol septal ablation for hypertrophic cardiomyopathy.

Objective: The purpose of the present study was to determine the incidence of ventricular arrhythmias before and after alcohol septal ablation (ASA).

Background: In patients with hypertrophic obstructive cardiomyopathy (HOCM), gradient reduction by ASA is an alternative for surgical myectomy. However, concerns exist about whether the induction of a myocardial scar during ASA may create substrate for ventricular arrhythmias.

Efficacy of long detection interval implantable cardioverter-defibrillator settings in secondary prevention population: data from the Avoid Delivering Therapies for Nonsustained Arrhythmias in ICD Patients III (ADVANCE III) trial.

Background: Three trials demonstrated recently that a long detection window reduces implantable cardioverter-defibrillator (ICD) therapy in primary prevention patients. Avoid Delivering Therapies for Nonsustained Arrhythmias in ICD Patients III (ADVANCE III) was the only trial that enrolled both primary and secondary prevention patients.

Methods And Results: Of the 1902 patients enrolled in the ADVANCE III trial, 477 received a defibrillator for secondary prevention; 248 patients were randomly assigned to a long detection setting (30 of 40 intervals) and 229 to the nominal setting (18 of 24 intervals) for ventricular arrhythmias with cycle length ≤ 320 ms.

Safety of pulmonary vein isolation and left atrial complex fractionated atrial electrograms ablation for atrial fibrillation with phased radiofrequency energy and multi-electrode catheters.

Aims: Recently, a multi-electrode catheter system using phased radiofrequency (RF) energy was developed specifically for atrial fibrillation (AF) ablation: the pulmonary vein ablation catheter (PVAC), the multi-array septal catheter (MASC), and the multi-array ablation catheter (MAAC). Initial results of small trials have been promising: shorter procedure times and low adverse event rates. In a large single-centre registry, we evaluated the adverse events associated with multi-electrode ablation catheter procedures with PVAC alone, or combined with MASC and MAAC.

Freedom from paroxysmal atrial fibrillation after successful pulmonary vein isolation with pulmonary vein ablation catheter-phased radiofrequency energy: 2-year follow-up and predictors of failure.

Aims: In patients with paroxysmal atrial fibrillation (PAF) the pattern of atrial fibrillation (AF) episodes and the total AF burden, may be related to the efficacy of pulmonary vein isolation (PVI). We evaluated (pre)-procedural factors explaining the long-term outcome after PVI, using a ring-shaped multielectrode ablation catheter [pulmonary vein ablation catheter (PVAC)].

Methods And Results: A total of 120 consecutive patients with PAF were treated with the PVAC.

Arrhythmia detection after atrial fibrillation ablation: value of incremental monitoring time.

Background: After pulmonary vein isolation (PVI), patients need to be followed to analyze the effect of the treatment. We evaluated the influence of the duration of Holter monitoring on the detection of arrhythmia recurrences after a single PVI at 12 months.

Methods: Consecutive patients with paroxysmal atrial fibrillation (AF) underwent successful PVI with phased radiofrequency and pulmonary vein ablation catheter.

Early recurrence of atrial fibrillation as a predictor for 1-year efficacy after successful phased RF pulmonary vein isolation: evaluation of complaints and multiple Holter recordings.

Background: Early arrhythmia recurrences after pulmonary vein isolation (PVI) for atrial fibrillation (AF) are accepted as part of the blanking period. Their relevance for long-term efficacy is not well-known. We evaluated patients, who came to hospital with a documented recurrence of AF, or had a registered episode of AF on the 24-hour Holter 6 weeks after PVI and compared it with long-term outcome.

Pulmonary vein anatomy and long-term outcome after multi-electrode pulmonary vein isolation with phased radiofrequency energy for paroxysmal atrial fibrillation.

Aims: We evaluated the effect of pulmonary vein (PV) anatomical characteristics on PV isolation (PVI) and long-term efficacy of ablation with phased radiofrequency (RF) energy and pulmonary vein ablation catheter (PVAC) multi-electrode catheter.

Methods And Results: Before the procedure, PV anatomy was visualized by magnetic resonance imaging (MRI). Consecutive patients with paroxysmal atrial fibrillation were treated with the PVAC with successful acute isolation.

Pulmonary vein isolation and left atrial complex-fractionated atrial electrograms ablation for persistent atrial fibrillation with phased radio frequency energy and multi-electrode catheters: efficacy and safety during 12 months follow-up.

Aims: Ablation for persistent atrial fibrillation (AF) remains a difficult and time-consuming procedure with varying degrees of success. We evaluated the long-term effects of a novel approach for ablation of persistent AF using multi-electrode catheters.

Methods And Results: In 89 patients with longstanding persistent AF (>1 year), multi-electrode ablation was performed with a pulmonary vein ablation catheter (PVAC), a multi-array septal catheter (MASC), and a multi-array ablation catheter (MAAC) for ablation of complex-fractionated atrial electrograms (CFAE) at the septum, left atrial (LA) roof, floor, posterior wall, and mitral isthmus.

Characterization of in vitro and in vivo lesions made by a novel multichannel ablation generator and a circumlinear decapolar ablation catheter.

Introduction: The aim of this study is to characterize ablation lesions using varying ratios of bipolar:unipolar energy and to show the feasibility of a circular decapolar pulmonary vein ablation catheter (PVAC) to create transmural lesions in an in vivo porcine superior vena cava (SVC) model.

Methods And Results: Ablations were performed on (1) isolated blocks of bovine myocardium, (2) thigh muscle preparations (4 pigs), and (3) the junction between SVC and right atrium (6 pigs). Radiofrequency (RF) energy was delivered simultaneously to all electrodes (target temperature 60 degrees C, maximum power 10 W/electrode) with various ratios of bipolar:unipolar energy.

Pulmonary vein isolation by duty-cycled bipolar and unipolar radiofrequency energy with a multielectrode ablation catheter.

Background: Pulmonary vein (PV) isolation for ablation of atrial fibrillation (AF) remains a complex and lengthy procedure.

Objective: The purpose of this study was to evaluate the feasibility and safety of a novel multielectrode catheter that delivers duty-cycled bipolar and unipolar radiofrequency (RF) energy.

Methods: Patients eligible for catheter ablation of paroxysmal AF after screening with magnetic resonance imaging and transesophageal echocardiography were included in the study.

Noninvasive imaging of cardiac venous anatomy with 64-slice multi-slice computed tomography and noninvasive assessment of left ventricular dyssynchrony by 3-dimensional tissue synchronization imaging in patients with heart failure scheduled for cardiac resynchronization therapy.

Objectives of this study were to perform a prospective head-to-head comparison between multi-slice computed tomography (MSCT) venography and invasive venography in cardiac resynchronization therapy (CRT) candidates as well as to evaluate the relation between left ventricular (LV) lead position and effect on LV dyssynchrony and immediate response to CRT. Twenty-one consecutive heart failure patients scheduled for CRT implantation were prospectively enrolled to undergo 64-slice MSCT to visualize the venous system, invasive venography during device implantation, and tri-plane tissue synchronization imaging (TSI) before and after implantation. Excellent agreement between MSCT and invasive venography was noted.

Epicardium-derived cells in development of annulus fibrosis and persistence of accessory pathways.

Background: The developmental mechanisms underlying the persistence of myocardial accessory atrioventricular pathways (APs) that bypass the annulus fibrosis are mainly unknown. In the present study, we investigated the role of epicardium-derived cells (EPDCs) in annulus fibrosis formation and the occurrence of APs.

Methods And Results: EPDC migration was mechanically inhibited by in ovo microsurgery in quail embryos.

Periostin expression by epicardium-derived cells is involved in the development of the atrioventricular valves and fibrous heart skeleton.

The epicardium is embryologically formed by outgrowth of proepicardial cells over the naked heart tube. Epicardium-derived cells (EPDCs) migrate into the myocardium, contributing to myocardial architecture, valve development, and the coronary vasculature. Defective EPDC formation causes valve malformations, myocardial thinning, and coronary defects.

Cardiac malformations and myocardial abnormalities in podoplanin knockout mouse embryos: Correlation with abnormal epicardial development.

Epicardium and epicardium-derived cells have been shown to be necessary for myocardial differentiation. To elucidate the function of podoplanin in epicardial development and myocardial differentiation, we analyzed podoplanin knockout mouse embryos between embryonic day (E) 9.5 and E15.

Nkx2.5-negative myocardium of the posterior heart field and its correlation with podoplanin expression in cells from the developing cardiac pacemaking and conduction system.

Recent advances in the study of cardiac development have shown the relevance of addition of myocardium to the primary myocardial heart tube. In wild-type mouse embryos (E9.5-15.

Persistence of functional atrioventricular accessory pathways in postseptated embryonic avian hearts: implications for morphogenesis and functional maturation of the cardiac conduction system.

Background: During heart development, the ventricular activation sequence changes from a base-to-apex to an apex-to-base pattern. We investigated the possibility of impulse propagation through remnants of atrioventricular (AV) connections in quail hearts.

Methods And Results: In 86 hearts (group A, HH30-34, n=15; group B, HH35-44, n=65; group C, 5 to 6 months, n=6) electrodes were positioned at the left atrium, right ventricular base, left ventricular (LV) base, and LV apex.

Epicardium-derived cells are important for correct development of the Purkinje fibers in the avian heart.

During embryonic development, the proepicardial organ (PEO) grows out over the heart surface to form the epicardium. Following epithelial-mesenchymal transformation, epicardium-derived cells (EPDCs) migrate into the heart and contribute to the developing coronary arteries, to the valves, and to the myocardium. The peripheral Purkinje fiber network develops from differentiating cardiomyocytes in the ventricular myocardium.

Benefit of combined resynchronization and defibrillator therapy in heart failure patients with and without ventricular arrhythmias.

Objectives: We attempted to assess the efficacy of combined cardiac resynchronization therapy-implantable cardioverter-defibrillator (CRT-ICD) in heart failure patients with and without ventricular arrhythmias.

Background: Because CRT and ICDs both lower all-cause mortality in patients with advanced heart failure, combination of both therapies in a single device is challenging.

Methods: A total of 191 consecutive patients with advanced heart failure, left ventricular ejection fraction <35%, and a QRS duration >120 ms received CRT-ICD.

Serial reevaluation for ARVD/C is indicated in patients presenting with left bundle branch block ventricular tachycardia and minor ECG abnormalities.

Introduction: Diagnosis of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is based on a set of criteria proposed by the International Task Force (TF) for Cardiomyopathies in 1994. To fulfill these criteria, presence of both electrocardiographic and anatomical abnormalities must be assessed with ECG and imaging techniques, respectively. This may be difficult in patients with early/mild forms of the disease as detectable structural abnormalities may still be absent.

Ablation of focal atrial arrhythmia in patients with congenital heart defects after surgery: role of circumscribed areas with heterogeneous conduction.

Background: In patients late after surgical repair of congenital heart disease (CHD), areas with abnormal electrophysiologic properties may serve as slow conducting pathways within a macroreentrant circuit or may be the source of focal atrial tachycardia.

Objectives: The purpose of this study was to evaluate the role of abnormal areas during focal atrial tachycardia prior to ablation.

Methods: Electroanatomic activation mapping of 62 atrial tachycardias was performed in 43 consecutive patients (37 +/- 12 years) after surgical repair of CHD.

Identification of successful catheter ablation sites in patients with ventricular tachycardia based on electrogram characteristics during sinus rhythm.

Background: Zones of slow conduction facilitate reentry, the major mechanism of ventricular tachycardia (VT) after myocardial infarction (MI). Identification of these zones during sinus rhythm (SR) is desirable for radiofrequency (RF) catheter ablation of VT. Local conduction velocity may correlate with electrogram duration.

Rate versus rhythm control in atrial fibrillation.

AF remains the most common and most challenging arrhythmia. Although several new treatment modalities are available to restore and maintain sinus rhythm, the long-term success of such a strategy remains disappointing, often making rate control a good alternative. Factors associated with failures to restore and maintain sinus rhythm thereafter are a longer duration of AF, older patient age, atrial dilatation, poor functional class or heart failure, and hypertension.

Recent advances in drug therapy for atrial fibrillation.

Despite the major new insights into our knowledge of the mechanisms underlying initiation and perpetuation of atrial fibrillation (AF) gained in the last decade, the treatment of this common arrhythmia remains unsatisfactory in many patients. Although several new treatment modalities (e.g.