Ablation of Complex Fractionated Electrograms Improves Outcome in Persistent Atrial Fibrillation of Over 2 Year's Duration.

Aim: There is controversy and sparse data on whether substrate based techniques in addition to pulmonary vein isolation (PVI) confer benefit in the catheter ablation of persistent atrial fibrillation (AF), especially if long standing. We performed an observational study to assess whether substrate based ablation improved freedom from atrial arrhythmia.

Methods: A total of 286 patients undergoing first ablation procedures for persistent AF with PVI only(n = 79), PVI plus linear ablation(n = 85), or PVI plus complex fractionated electrogram (CFAE) and linear ablation(n = 107) were followed.

Improved outcome and cost effectiveness in ablation of persistent atrial fibrillation under general anaesthetic.

Aims: Outcome of persistent atrial fibrillation (AF) ablation remains suboptimal. Techniques employed to reduce arrhythmia recurrence rate are more likely to be embraced if cost-effectiveness can be demonstrated. A single-centre observational study assessed whether use of general anaesthesia (GA) in persistent AF ablation improved outcome and was cost-effective.

Diagnostic yield of molecular autopsy in patients with sudden arrhythmic death syndrome using targeted exome sequencing.

Aims: The targeted genetic screening of Sudden Arrhythmic Death Syndrome (SADS) probands in a molecular autopsy has a diagnostic yield of up to 35%. Exome sequencing has the potential to improve this yield. The primary aim of this study is to examine the feasibility and diagnostic utility of targeted exome screening in SADS victims, utilizing familial clinical screening whenever possible.

A minimal or maximal ablation strategy to achieve pulmonary vein isolation for paroxysmal atrial fibrillation: a prospective multi-centre randomized controlled trial (the Minimax study).

Aims: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillation (AF). The intervenous ridge (IVR) may be incorporated into ablation strategies to achieve PVI; however, randomized trials are lacking. We performed a randomized multi-centre international study to compare the outcomes of (i) circumferential antral PVI (CPVI) alone (minimal) vs.

P wave morphology in guiding the ablation strategy of focal atrial tachycardias and atrial flutter.

Focal atrial tachycardias arise preferentially from specific locations within the atria. Careful analysis of the P wave can provide useful information about the chamber and likely site of origin within that chamber. Macro-reentrant atrial flutter also tends to occur over a limited number of potential circuits.

Cardiac resynchronisation therapy: pacemaker versus internal cardioverter-defibrillator in patients with impaired left ventricular function.

Objective: Studies have shown beneficial effects of cardiac resynchronisation therapy (CRT) on mortality among patients with heart failure. However the incremental benefits in survival from CRT with a defibrillator (CRT-D) are unclear. The choice of appropriate device remains unanswered.

Mechanisms of atrial mitral regurgitation: insights using 3D transoesophageal echo.

Aims: Functional mitral regurgitation (FMR) is a consequence of mitral annular enlargement, leaflet tethering and reduced co-aptation. The importance of the left atrium (LA) as a cause of mitral regurgitation (MR) is less clear. We applied a co-aptation index using three-dimensional (3D) transoesophageal echocardiography to FMR and MR secondary to LA dilatation (atrial mitral regurgitation, AMR).

Supraventricular arrhythmias late after orthotopic cardiac transplantation: electrocardiographic and electrophysiological characterization and radiofrequency ablation.

Aims: Cardiac transplantation (CTX) is an effective treatment for end-stage heart disease. Cardiac arrhythmias are increasingly recognized and associated with significant morbidity and mortality. We aim to describe the clinical and electrophysiological characteristics of patients with atrial arrhythmias occurring late after CTX.

Targeted left ventricular lead placement to guide cardiac resynchronization therapy: the TARGET study: a randomized, controlled trial.

Objectives: This study sought to assess the impact of targeted left ventricular (LV) lead placement on outcomes of cardiac resynchronization therapy (CRT).

Background: Placement of the LV lead to the latest sites of contraction and away from the scar confers the best response to CRT. We conducted a randomized, controlled trial to compare a targeted approach to LV lead placement with usual care.

Cardiac resynchronization therapy optimization using noninvasive cardiac output measurement.

Aims: Noninvasive cardiac output (CO) measurement (NICOM) is a novel method to assess ventricular function and offers a potential alternative for optimization of cardiac resynchronization therapy (CRT) devices. We compared the effect of NICOM-based optimization to no optimization (empiric settings) on CRT outcomes.

Methods: Two hundred and three patients undergoing CRT were assessed in two consecutive nonrandomized groups; an empiric group (n = 54) was programmed to "out of the box" settings with a fixed AV delay of 120 ms and a VV delay of 0 ms; and the optimization group (n = 149) underwent adjustments of both the AV and VV delays according to the greatest improvement in resting CO.

An unusual atrial tachycardia in a patient with Friedreich ataxia.

We present the unusual association of an atrial tachycardia with Friedreich ataxia. The arrhythmia was initially suspected to be focal in origin; however, use of a three-dimensional mapping system demonstrated that the tachycardia was macro-reentrant. This was subsequently treated successfully by linear ablation.

Impact of VV optimization in relation to left ventricular lead position: an acute haemodynamic study.

Aims: Left ventricular (LV) lead placement to the most delayed segment offers the greatest potential benefit to cardiac resynchronization therapy (CRT). We assessed the impact of interventricular (VV) optimization on acute changes in cardiac output (CO) in patients with and without LV pacing of the most delayed segment.

Methods And Results: In 124 patients, the most delayed segment was defined by speckle tracking radial strain and the LV lead position by biplane fluoroscopy.

The impact of the right ventricular lead position on response to cardiac resynchronization therapy.

Introduction: Left ventricular (LV) lead placement to the latest contracting area (concordant LV lead) is associated with better response to cardiac resynchronization therapy (CRT) compared to a discordant LV lead. However, the effect of the right ventricular (RV) lead site on CRT response is unclear. We investigated the relationship of the RV and LV lead positions on CRT response.

Effect of low-amplitude two-dimensional radial strain at left ventricular pacing sites on response to cardiac resynchronization therapy.

Background: Left ventricular (LV) lead placement to areas of scar has detrimental effects on response to cardiac resynchronization therapy (CRT). Speckle-tracking radial two-dimensional strain offers assessment of the extent of regional myocardial deformation. The aim of this study was to assess the impact of LV lead placement at areas of low-amplitude strain on CRT response.

An entirely subcutaneous implantable cardioverter-defibrillator.

Background: Implantable cardioverter-defibrillators (ICDs) prevent sudden death from cardiac causes in selected patients but require the use of transvenous lead systems. To eliminate the need for venous access, we designed and tested an entirely subcutaneous ICD system.

Methods: First, we conducted two short-term clinical trials to identify a suitable device configuration and assess energy requirements.

Non-invasive cardiac output measurements based on bioreactance for optimization of atrio- and interventricular delays.

Aims: Non-invasive cardiac output monitoring (NICOM) based on bio-reactance offers a portable method to assess ventricular function. Optimization of cardiac resynchronization therapy (CRT) by echocardiography is labour-intensive. We compared the ability of NICOM and echocardiography to facilitate optimum CRT device programming.

Characterization of the suitability of coronary venous anatomy for targeting left ventricular lead placement in patients undergoing cardiac resynchronization therapy.

Aims: Recent studies suggest differences in coronary venous anatomy between patients with ischaemic (I) and non-ischaemic (N) cardiomyopathy. We hypothesize that these differences may affect the potential for left ventricular (LV) lead targeting in patients undergoing cardiac resynchronization therapy.

Methods And Results: The retrograde contrast venograms were retrospectively reviewed in 133 patients (age 68 +/- 9 years, 101 males).

Left ventricular lead placement in cardiac resynchronization therapy: where and how?

Cardiac resynchronization therapy (CRT) offers proven benefit to patients with refractory symptomatic chronic heart failure (New York Heart Association Class III or IV), severe left ventricular (LV) systolic dysfunction (LV ejection fraction <35%), and LV dyssynchrony (QRS width >120 ms). Cardiac resynchronization therapy has the potential to improve survival and functional capacity, reduce hospital admissions, and promote LV reverse remodelling. Although difficult to truly evaluate, up to 30% of patients do not attain symptomatic benefit.

P-wave morphology in focal atrial tachycardia: development of an algorithm to predict the anatomic site of origin.

Objectives: The purpose of this study was to perform a detailed analysis of the P-wave morphology (PWM) in focal atrial tachycardia (AT) and construct and prospectively evaluate an algorithm for identification of the anatomic site of origin.

Background: Although smaller studies have described the PWM from particular anatomic locations, a detailed algorithm characterizing the likely location of a tachycardia associated with a P-wave of unknown origin has been lacking.

Methods: The PWMs for 126 consecutive patients undergoing successful radiofrequency ablation of 130 ATs are reported.

Rapid decline in acute stimulation thresholds with steroid-eluting active-fixation pacing leads.

Background And Aim: There is an increasing use of active-fixation leads for cardiac pacing, yet concerns remain regarding initial high stimulation thresholds. The aim was to perform a detailed analysis of pacing parameters at the time of implantation to determine when lead repositioning should be considered.

Methods: We performed a prospective observational study of consecutive new pacemaker implants.

Focal atrial tachycardia from the ostium of the coronary sinus: electrocardiographic and electrophysiological characterization and radiofrequency ablation.

Objectives: The goal of this study was to characterize the electrocardiographic and electrophysiologic features and frequency of focal atrial tachycardia (AT) originating from the coronary sinus ostium (CS).

Background: The ostium of the coronary sinus has been described as a site of origin of AT, but detailed characterization of these tachycardias is limited.

Methods: Thirteen patients (6.