Morten Kristian Off

Significance of Late Recurrence of Atrial Fibrillation during Long‐Term Follow‐Up after Pulmonary Vein Isolation

Background and Study Objective: Patients with paroxysmal or persistent atrial fibrillation (AF) can be treated by pulmonary vein (PV) isolation. Although the recurrence rate after the procedure is relatively high, the long‐term outcomes after initially recurrence‐free procedures remains unclear. We examined the rates of recurrence of AF after PV isolation.

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.

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.

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.