In vivo analysis of the origin and characteristics of gaseous microemboli during catheter-mediated irreversible electroporation.

Aims: Irreversible electroporation (IRE) ablation is a non-thermal ablation method based on the application of direct current between a multi-electrode catheter and skin electrode. The delivery of current through blood leads to electrolysis. Some studies suggest that gaseous (micro)emboli might be associated with myocardial damage and/or (a)symptomatic cerebral ischaemic events.

Clinical and pathological outcomes after irreversible electroporation of the pancreas using two parallel plate electrodes: a porcine model.

Background: Irreversible electroporation (IRE) by inserting needles around the tumor as treatment for locally advanced pancreatic cancer entails several disadvantages, such as incomplete ablation due to field inhomogeneity, technical difficulties in needle placement and a risk of pancreatic fistula development. This experimental study evaluates outcomes of IRE using paddles in a porcine model.

Methods: Six healthy pigs underwent laparotomy and were treated with 2 separate ablations (in head and tail of the pancreas).

Irreversible Electroporation of the Pancreas Using Parallel Plate Electrodes in a Porcine Model: A Feasibility Study.

Background: Irreversible electroporation (IRE) with needle electrodes is being explored as treatment option in locally advanced pancreatic cancer. Several studies have shown promising results with IRE needles, positioned around the tumor to achieve tumor ablation. Disadvantages are the technical difficulties for needle placement, the time needed to achieve tumor ablation, the risk of needle track seeding and most important the possible occurrence of postoperative pancreatic fistula via the needle tracks.

Low vulnerability of the right phrenic nerve to electroporation ablation.

Background: Circular electroporation ablation is a novel ablation modality for electrical pulmonary vein isolation. With a single 200-J application, deep circular myocardial lesions can be created. However, the acute and chronic effects of this energy source on phrenic nerve (PN) function are unknown.

Pulmonary vein stenosis after catheter ablation: electroporation versus radiofrequency.

Background: Radiofrequency ablation inside pulmonary vein (PV) ostia can cause PV stenosis. A novel alternative method of ablation is irreversible electroporation, but the long-term response of PVs to electroporation ablation is unknown.

Methods And Results: In ten 6-month-old pigs (60-75 kg), the response of PVs to circular electroporation and radiofrequency ablation was compared.

Practical ways to reduce radiation dose for patients and staff during device implantations and electrophysiological procedures.

Despite the advent of non-fluoroscopic technology, fluoroscopy remains the cornerstone of imaging in most interventional electrophysiological procedures, from diagnostic studies over ablation interventions to device implantation. Moreover, many patients receive additional X-ray imaging, such as cardiac computed tomography and others. More and more complex procedures have the risk to increase the radiation exposure, both for the patients and the operators.

Impact of pulmonary vein antrum isolation on left atrial size and function in patients with atrial fibrillation.

Purpose: The success of PVAI in eliminating AF has been proven; however, its impact on the LA remains uncertain. This study aimed to determine the impact of pulmonary vein antrum isolation (PVAI) on left atrial (LA) size and function in patients with atrial fibrillation (AF).

Methods: Consecutive patients with AF were included (n = 206).

Minimal coronary artery damage by myocardial electroporation ablation.

Aims: Radiofrequency catheter ablation is a successful treatment for cardiac arrhythmias, but may lead to major complications such as permanent coronary damage. Irreversible electroporation (IRE) is a new non-thermal ablation modality, but its effect on coronary arteries is still unknown.

Methods And Results: In a porcine model, epicardial IRE lesions were created at the base of the left ventricle in four hearts (group A) and directly on the left anterior descending artery (LAD) in five hearts (group B).

Myocardial lesion depth with circular electroporation ablation.

Background: Recently, we demonstrated the feasibility and safety of circular electroporation ablation in porcine pulmonary vein ostia, but the relationship between the magnitude of the application and lesion dimensions is still unknown.

Methods And Results: An in vivo porcine study was performed on left ventricular epicardium submerged under 10 mm of blood, using devices that mimic a 20-mm-diameter 7F circular ablation catheter. Model D contained 10 separate electrodes, whereas model M consisted of 1 circular electrode.

Complex fractionated electrograms in the right atrial free wall and the superior/posterior wall of the left atrium are affected by activity of the autonomic nervous system.

Background: Complex fractionated atrial electrograms (CFAEs) are supposed to be related to structural and electrical remodeling. Animal studies suggest a role of the autonomic nervous system (ANS). However, this has never been studied in humans.

Pulmonary vein antrum isolation leads to a significant decrease of left atrial size.

Aims: Pulmonary vein antrum isolation (PVAI) is an effective treatment for atrial fibrillation (AF); however, its impact on left atrial (LA) size is unknown. This study evaluates the impact of PVAI on LA size, and whether LA size differs between patients with a successful outcome and patients with AF recurrences.

Methods And Results: Seventy-nine patients (76% male, mean age 56 ± 8 years) with symptomatic, drug refractory AF (70% paroxysmal, 30% persistent/permanent) underwent radiofrequency PVAI.

Feasibility of electroporation for the creation of pulmonary vein ostial lesions.

Introduction: There is an obvious need for a better energy source for pulmonary vein (PV) antrum isolation.

Objective: We investigated the feasibility and safety of electroporation for the creation of PV ostial lesions.

Methods: After transseptal puncture, a custom 7F decapolar 20 mm circular ablation catheter was placed in the PV ostia of 10 pigs.

Left atrial volume and function assessment by magnetic resonance imaging.

Unlabelled: Left Atrial Volume and Function Assessment. 

Introduction: In patients with atrial fibrillation undergoing catheter ablation, magnetic resonance imaging (MRI) can determine left atrial (LA) volume and function before and after ablation. The most accurate, but time consuming, method to determine LA volume is the multiple slice method (MSM), which involves manual tracing of LA area on each slice.

RF catheter ablation: Lessons on lesions.

The present treatment of atrial fibrillation by radiofrequency catheter ablation requires long continuous lesions in the thin walled left atrium where side effects may lead to serious complications. Better understanding of the physical processes that take place during ablation may help to improve the quality, safety, and outcome of these procedures. These processes include the distribution of power between blood, tissue, and patient; the mechanisms of tissue heating and coagulum formation; the relation between tissue and electrode temperatures; and the effects of increased electrode size and internal and external electrode cooling.

Comparison of electrode cooling between internal and open irrigation in radiofrequency ablation lesion depth and incidence of thrombus and steam pop.

Background: Electrode cooling by circulating fluid within the electrode (closed loop) or open irrigation facilitates radiofrequency (RF) ablation. This study compared lesion parameters between closed loop and open irrigation with the use of a canine model.

Methods And Results: In 8 anesthetized dogs, the skin over the thigh muscle was incised and raised, forming a cradle superfused with heparinized blood (activated clotting time >350 seconds) at 37 degrees C.

Saline-irrigated radiofrequency ablation electrode with external cooling.

Introduction: Open flush, irrigated ablation electrodes may improve the safety of radiofrequency catheter ablation by preventing protein aggregation and coagulum formation. This is particularly important in left-sided procedures like catheter ablation of atrial fibrillation. Electrode cooling and the inherent loss of temperature feedback, however, grossly reduce the ability to monitor tissue heating.

Where to draw the mitral isthmus line in catheter ablation of atrial fibrillation: histological analysis.

Aims: A linear lesion between the left inferior pulmonary vein orifice and mitral annulus, the so-called mitral isthmus, may improve the success of catheter ablation for atrial fibrillation. Gaps in the lesion line, however, may facilitate left atrial flutter. The aim of the study was to determine the optimal location of the lesion line by serial sectioning of the isthmus area.

Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia in children aided by the LocaLisa mapping system.

Aims: In young patients, slow pathway ablation for treatment of atrioventricular nodal reentrant tachycardia (AVNRT) carries a small but definite risk of permanent AV block. The aim was to assess the efficacy of slow pathway ablation aided by the LocaLisa mapping system.

Patients And Methods: Radiofrequency (RF) modification of the slow AV nodal pathway was performed in 26 children < 19 years of age (median age 9.

Radiofrequency catheter ablation of junctional ectopic tachycardia with preservation of atrioventricular conduction.

Junctional ectopic tachycardia is a relatively rare disorder, frequently refractory to drug therapy, and with a poor prognosis in childhood. This report describes a successful radiofrequency catheter ablation of the focus of this arrhythmia in a 9-year-old girl with preservation of normal atrioventricular conduction, using precise catheter navigation with the LocaLisa system and carefully titrated RF delivery.

High incidence of thrombus formation without impedance rise during radiofrequency ablation using electrode temperature control.

The authors hypothesized that during RF ablation, the electrode to tissue interface temperature may significantly exceed electrode temperature in the presence of cooling blood flow and produce thrombus. In 12 anesthetized dogs, the skin over the thigh muscle was incised and raised to form a cradle that was superfused with heparinized canine blood (ACT > 350 s) at 37 degrees C. A 7 Fr, 4-mm or 8-mm ablation electrode containing a thermocouple was held perpendicular to the thigh muscle at 10-g contact weight.