Eivind Solheim

Ablation Effect Indicated by Impedance Fall is Correlated with Contact Force Level During Ablation for Atrial Fibrillation

Previous studies have validated the use of impedance fall as a measure of the effects of ablation. We investigated whether catheter‐to‐tissue contact force correlated with impedance fall during atrial fibrillation ablation.

Treatment of atrial fibrillation by silencing electrical activity in the posterior inter-pulmonary-vein atrium

AIMS The recurrence of atrial fibrillation (AF) after pulmonary vein (PV) isolation is still a challenge. We investigated a new approach to treating AF patients by silencing electrical activity in the posterior inter-pulmonary-vein atrium (PIA). METHODS AND RESULTS Three ablation steps are required to obtain PIA electrical silence: electrical PV isolation, the creation of two lines of lesions between the two superior and inferior PVs and the abolition of residual electrical signals within the PIA. The endpoint was the electrical silence and the inability to pace in the PIA. The posterior inter-pulmonary-vein atrium silence was obtained in 42 AF patients (56 +/- 9 years, four women). Recurrence of AF and atrial flutter was observed in 14 (33.3%) patients after the first procedure. Freedom from atrial arrhythmias after the second procedure was displayed by 94.4, 85.7, and 60.0% of patients with paroxysmal, persistent, and permanent AF, respectively. The left atrium (LA) volume was larger, and the percentages of the silent area of the LA surface and voltages were lower in patients with AF recurrence than in recurrence-free patients. CONCLUSION Posterior inter-pulmonary-vein atrium electrical silence can greatly decrease the AF recurrence. The clinical AF recurrence may be related to an enlarged LA, a low percentage of electrically silent area, and low voltage in the LA.

Spatial Relationships between the Pulmonary Veins and Sites of Complex Fractionated Atrial Electrograms During Atrial Fibrillation

Background: Pulmonary vein (PV) isolation is used for the treatment of atrial fibrillation (AF). Complex fractionated atrial electrogram (CFAE) mapping has been introduced to guide AF ablation. However, the spatial relationship between PV and CFAE is not well defined.

Effect of flecainide on the extension and localization of complex fractionated electrogram during atrial fibrillation

Abstract Aims. Complex fractionated electrogram (CFE) ablation in addition to pulmonary vein isolation is an accepted strategy for the treatment of non-paroxysmal atrial fibrillation (AF). We sought to determine the effect of flecainide on the distribution and extension of CFE areas. Methods. Twenty-three non-paroxysmal AF patients were enrolled in this prospective study. A first CFE map was obtained under baseline conditions by sampling 5 s of continuous recording from the distal electrodes of the ablation catheter. Intravenous flecainide (1 mg/kg) was administered over 10 min and followed by 30-min observation time. A second CFE map was obtained with the same modalities. CFE-mean values, CFE areas, and atrial electrogram amplitude were retrieved from the electro-anatomical mapping system (Ensite NavX). Results. After flecainide administration, CFE-mean values increased (111.5 ± 55.3 vs. 132.3 ± 65.0 ms, p < 0.001) with a decrease of CFE area (32.9%) in all patients. Atrial electrogram amplitude decreased significantly (0.30 ± 0.31 vs. 0.25 ± 0.20 mV, p < 0.001). We observed 80.9% preservation of CFE areas. A CFE mean of 78 ms was the best cutoff for predicting stable CFE areas. Conclusions. Flecainide reduces the extension of CFE areas while preserving their spatial localization. A CFE-mean value <80 ms may be crucial to define and locate stable CFE areas.

Magnetic navigation for ablation of cardiac arrhythmias

BACKGROUND The first use of magnetic navigation for radiofrequency ablation of supraventricular tachycardias, was published in 2004. Subsequently, the method has been used for treatment of most types of tachyarrhythmias. This paper provides an overview of the method, with special emphasis on usefulness of a new remote-controlled magnetic navigation system. MATERIAL AND METHODS The paper is based on our own scientific experience and literature identified through a non-systematic search in PubMed. RESULTS The magnetic navigation system consists of two external electromagnets (to be placed on opposite sides of the patient), which guide an ablation catheter (with a small magnet at the tip of the catheter) to the target area in the heart. The accuracy of this procedure is higher than that with manual navigation. Personnel can be quickly trained to use remote magnetic navigation, but the procedure itself is time-consuming, particularly for patients with atrial fibrillation. The major advantage is a considerably lower radiation burden to both patient and operator, in some studies more than 50 %, and a corresponding reduction in physical strain on the operator. The incidence of procedure-related complications seems to be lower than that observed with use of manually operated ablation catheters. Work is ongoing to improve magnetic ablation catheters and methods that can simplify mapping procedures and improve efficacy of arrhythmia ablation. The basic cost for installing a complete magnetic navigation laboratory may be three times that of a conventional electrophysiological laboratory. INTERPRETATION The new magnetic navigation system has proved to be applicable during ablation for a variety of tachyarrhythmias, but is still under development.

Entrapment and retrieval of a diagnostic electrophysiological catheter in the Chiari network

The Chiari networks are reticulated fibers of embryological remnant venous valves in the right atrium. In patients with this congenital variation, manipulation of diagnostic catheters can be difficult, and there is a substantial risk of entrapment during electrophysiological studies. We report a case of successful retraction of a diagnostic catheter entangled in the Chiari network with the use of a lead extraction tool during a scheduled atrial fibrillation ablation. Rescheduled cryoablation was performed without complication and provided a good outcome.

Incidence and clinical predictors of subsequent atrial fibrillation requiring additional ablation after cavotricuspid isthmus ablation for typical atrial flutter

Abstract Objectives: We sought to investigate the incidence of atrial fibrillation after catheter ablation for typical atrial flutter and to determine the predictors for symptomatic atrial fibrillation that required a further additional dedicated ablation procedure. Design: 127 patients underwent elective cavotricuspid isthmus ablation with the indication of symptomatic, typical atrial flutter. The occurrence of atrial flutter, atrial fibrillation, cerebrovascular events and the need for additional ablation procedures for symptomatic atrial fibrillation was assessed during long-term follow-up. Results: The majority of patients (70%) manifested atrial fibrillation during a follow-up period of 68 ± 24 months, and a significant proportion (42%) underwent one or multiple atrial fibrillation ablation procedures after an average of 26 months from the index procedure. Recurrence of typical atrial flutter was rare. Ten patients (8%) suffered cerebrovascular events. Earlier documentation of atrial fibrillation (OR 3.53), previous use of flecainide (OR 3.33) and left atrial diameter (OR 2.96) independently predicted occurrence of atrial fibrillation during the follow-up. A combination of pre- and intra-procedural documentation of atrial fibrillation (OR 3.81) and previous use of flecainide (OR 2.43) independently predicted additional atrial fibrillation ablation. Discussion: Atrial fibrillation occurred in the majority of patients after ablation for typical atrial flutter and 42% of them required an additional dedicated ablation procedure. Pre- and intraprocedural documentation of atrial fibrillation together with previous use of flecainide independently predicted atrial fibrillation occurrence and a need for additional ablation. Anticoagulation treatment should be continued in high-risk patients in spite of clinical disappearance of atrial flutter.

Catheter ablation of tachyarrhythmias in children and adolescents

BACKGROUND Catheter ablation has been increasingly applied in children and adolescents with tachyarrhythmias. The aim of this article is to assess the results of ablation therapy of tachycardias in patients below 18 years of age at Haukeland University Hospital. MATERIAL AND METHODS 141 patients (70 boys and 71 girls, aged 5-17 (13.5 +/- 3.5 ) years with tachyarrhythmias underwent an electrophysiologic study and catheter ablation in the period 1992-2007. RESULTS Ablation was successfully performed in 138/141 (98%) patients., The procedure was repeated (3 patients twice) until the arrhythmia substrate disappeared in 16 of 138 patients. 81/141 (57%) patients had accessory pathways; 52 (37%) had double atrioventricular nodal pathways, 48 had concealed and 33 patients had overt (classical Wolff-Parkinson-White-syndrome) atrioventricular pathways. 8 (6%) patients had other atrial or ventricular tachyarrhythmias and 4 (3%) had organic heart disease. Use of a 3D mapping system was decisive for success for ablation in patients with complex cardiac diseases. Procedure-related complications were observed in 2/141 (1.4%) patients of whom one had a temporary third degree and one had a permanent first-degree atrioventricular block which did not entail further treatment. CONCLUSION Catheter ablation of tachycardia in children and adolescents is a safe treatment method with a high success rate and few complications and should be preferred before drug therapy.

Atrio-pulmonary vein conduction delay during pulmonary vein isolation for atrial fibrillation is related to vein anatomy, age, and focal activity.

Background: During pulmonary vein isolation for treatment of atrial fibrillation (AF), a significant delay in atrio‐pulmonary vein (PV) conduction is often observed. We sought to investigate this conduction delay in various PV in individual patients.