Search results for "Reentry"

Interpretation of epicardial mapping by means of computer simulations: Applications to calcium, lidocaine and to BRL 34915

1992

The aim of this work was to compare experimental investigations on effects of lidocaine, calcium and, BRL 34915 on reentries to simulated data obtained by use of a model of propagation based on the Huygens' construction method already described in previous works. Calcium and lidocaine effects are investigated on anisotropic conduction conditions. In both cases, reduction in conduction velocities are observed. In lidocaine case, a refractory area is located along the longitudinal axis. In agreement with experimental electrical mapping, the simulations show that the stabilization of reentrant excitation is mainly due to the existence of this refractory area around which the reentrant circuit …

Reentry devices for chronic arterial occlusions.

2019

A re-entry tachycardia triggered by the spontaneous interruption of an atrial tachycardia.

2015

The common atrioventricular nodal re-entry tachycardia is the most common form of paroxysmal supraventricular tachycardia. It starts frequently with a supraventricular ectopic beat that, on finding the fast pathway in refractory period, travels in the slow pathway as to appear as a prolongation of the PR interval on the ECG. In this study, we show a singular case of a common atrioventricular nodal re-entry tachycardia triggered by the spontaneous interruption of an atrial tachycardia.

Effect of local ischemia on induction of cardiac reentries

1992

In this paper, we study the effects of local ischemia on the process of triggering of reentry mechanism. We present computer simulations based on a cellular automata model of the propagation of the depolarizing wave through a ventricular surface element. We simulate a local area of ischemia where effects of refractory period dispersion are investigated. We use a gaussian distribution of the refractory periods characterized by a mean value and a standard deviation. These simulations show that there exist critical conditions necessary to initiate a reentry mechanism invading progressively the whole ventricle.

When, why, and how to perform wire-based antegrade dissection and reentry technique

2022

Antegrade dissection and reentry (ADR) refers to an attempt to cross a coronary chronic total occlusion (CTO) lesion through wire and/or equipment passage in the subintimal space followed by reentry to the distal true lumen. From the original subintimal tracking and reentry (STAR) technique description by Colombo in 2005, refinement of the technique, improved characteristics of the microcatheters and wires, and better understanding of subadventitial vessel trauma have led to higher success rates, lower complications rates, and improved long-term outcomes. In this chapter, we discuss the technique, its outcomes, and limitations.

Influence of surface morphology on melting of polymer crystals II. Loops of random length and partially random reentry

1972

Abstract The melting behavior of single crystals with loops of random length and partially random reentry has been calculated under two different assumptions: (1) at each temperature the loops have an equilibrium end-to-end distance distribution and (2) a certain end-to-end distance distribution of the loops, ω(h), determined by the kinetics of the crystallization is frozen in and maintained during the whole heating process. The ω(h) is calculated by considering the loop formation process during crystallization and by introducing a parameter λ which expresses the tendency of the chains for adjacent reentry. In both cases a melting range is obtained. In case 2, the melting range depends stro…

Guiding Principles for Chronic Total Occlusion Percutaneous Coronary Intervention. A Global Expert Consensus Document

2019

© American Heart Association, Inc.

Personalized Cardiac Computational Models: From Clinical Data to Simulation of Infarct-Related Ventricular Tachycardia.

2019

In the chronic stage of myocardial infarction, a significant number of patients develop life-threatening ventricular tachycardias (VT) due to the arrhythmogenic nature of the remodeled myocardium. Radiofrequency ablation (RFA) is a common procedure to isolate reentry pathways across the infarct scar that are responsible for VT. Unfortunately, this strategy show relatively low success rates; up to 50% of patients experience recurrent VT after the procedure. In the last decade, intensive research in the field of computational cardiac electrophysiology (EP) has demonstrated the ability of three-dimensional (3D) cardiac computational models to perform in-silico EP studies. However, the personal…

Effect of Atrial Capture Beats on the Subsequent Cycle During Slow Common Atrioventricular Nodal Reentry Tachycardia

2013

Electrocardiographic Diagnosis of Atrial Tachycardia: Classification, P-Wave Morphology, and Differential Diagnosis with Other Supraventricular Tachy…

2014

Atrial tachycardia is defined as a regular atrial activation from atrial areas with centrifugal spread, caused by enhanced automaticity, triggered activity or microreentry. New ECG classification differentiates between focal and macroreentrant atrial tachycardia. Macroreentrant atrial tachycardias include typical atrial flutter and other well characterized macroreentrant circuits in right and left atrium. Typical atrial flutter has been described as counterclockwise reentry within right atrial and it presents a characteristic ECG “sawtooth” pattern on the inferior leads. The foci responsible for focal atrial tachycardia do not occur randomly throughout the atria but tend to cluster at chara…