Background-Reduced electrogram amplitude has been shown to correlate with diseased myocardium. We describe a novel individualized approach for catheter ablation of atrial fibrillation (AF) based on low-voltage areas (LVAs) in the left atrium (LA). We sought to assess (1) the incidence of LVAs in patients undergoing AF catheter ablation, (2) the distribution of LVAs within the LA, and (3) the effect of an individualized ablation strategy on long-term rhythm outcomes. Methods and Results-In 178 patients with paroxysmal or persistent AF, LA voltage maps were created during sinus rhythm after circumferential pulmonary vein isolation. Subsequent substrate modification was confined to the presence of LVA (<0.5 mV) and inducible regular atrial tachycardias. LVAs were identified in 35% and 10% of patients with persistent and paroxysmal AF, respectively. The LA roof and the anterior, septal, and posterior wall LA were most often affected. The 12-month atrial tachycardias/AF-free survival was 62% for patients without LVAs and 70% for patients with LVAs and tailored substrate modification (P=0.3). Success rate in a comparison group of 26 LVA patients without further substrate modification was 27%. Conclusions-LVAs can be found at preferred sites in 10% of patients with paroxysmal AF and in 35% of patients with persistent AF. This is the first clinical report describing a consistent voltage-based approach for substrate modification in addition to circumferential pulmonary vein isolation irrespective of AF type. Application of this limited individualized approach may have the potential to compensate for the impaired 12-month outcome of patients with endocardial structural defects. (Circ Arrhythm Electrophysiol. 2014;7:825-833.)

No abstract

AF ablation still has a considerable number of major complications that may be life threatening or may lead to severe residues. Atrial-esophageal fistula is still observed despite continuous systematic methods to prevent it. Stroke, tamponade, and vascular complications are the most frequent major complications. However, in most patients treatment can be conservative and results in complete recovery. Advanced age and congestive heart failure seem to be associated with an increased risk of complications.

In this single-centre study, individually tailored substrate modification guided by voltage mapping was associated with a significantly higher arrhythmia-free survival rate compared with a conventional approach applying linear ablation according to AF type.

A generalized two‐step and interdependent control of basic and acidic peroxidases (EC 1.11.1.7) is observed in plant responses to different physical and chemical stimuli. An interpretative model consisting of a pathway of reactions is presented on the basis of our own data and the literature. Stress‐induced membrane depolarization would generate different species of free radicals and peroxides, which in turn initiate lipid peroxidation. The degradation of cell membranes is suggested to bring about rapid changes in ionic fluxes (especially release of K+ which would result in an enhanced endogenous Ca/K ratio) and in leakage of solutes (among them electron donors such as ascorbic acid and phenolic substances). The increased intracellular relative calcium level results in: 1) activated secretion of basic peroxidases into the free space where, in association with the electron donors and maybe with the circulating indole‐3‐acetic acid (IAA), they eliminate the peroxides; and 2) facilitated binding of basic peroxidases to membrane structures allowing a role as 1‐aminocyclopropane‐1‐carboxylic acid (ACC)‐oxidases. The resulting IAA and ACC oxidase‐mediated changes in ethylene production would further induce (this time through the protein synthesis machinery) an increase in activity of phenylalanine ammonia‐lyase (EC 4.31.5) and acidic peroxidases. The resulting lignification and cell wall rigidification determines the growth and/or the developmental response to the initial stress.