This paper introduces an adaptive filtering algorithm based on the LMS principle to inhibit the ventricular interference in the atrial epicardial mapping experiments.
Algorithms ; Electrocardiography ; Epicardial Mapping ; Heart Ventricles

If heart function is normal, the atrial cells are excited in a stable rhythm. But this would change during atrial fibrillation. In this paper, after comparing with the method of characteristic point, we use the dominant frequency method to analyze the activation pattern under sinus and atrial fibrillation rhythm in different parts of atria based on epicardial mapping system. It is found that the activation rhythm changes a lot in different parts of atria, and the automaticity of atrial cells change obviously in somewhere. The result shows that dominant frequency method is very suitable for the analysis of atrial fibrillation signal. What's more, we also roughly discuss the role of this method in exploring the driving sources during atrial fibrillation.
Atrial Fibrillation ; Epicardial Mapping ; Heart Atria ; Humans

Adult ; Electrocardiography ; methods ; Epicardial Mapping ; Humans ; Male ; Tachycardia, Ventricular ; physiopathology

This paper presents an algorithm for data interpolation and approximation used in the whole atria mapping. Multilevel B-splines are introduced to compute the whole atria surface through a set of irregularly spaced points and to draw the 3D isopotential map, which can reflect the conduction process of depolarization in complex arrhythmia such as atrial fibrillation.
Algorithms ; Electrocardiography ; Epicardial Mapping ; Models, Cardiovascular ; Signal Processing, Computer-Assisted

In order to realize real-time sampling and display in 128-channeled Epicardial Mapping System whose sampling frequency is 2 kHz per channel, the article introduces a mapping software and preliminarily validates its practicability. The software is designed in MFC, using multiple-thread technology and buffering and pumping values method.
Epicardial Mapping ; Signal Processing, Computer-Assisted ; Software ; Software Design

A new denoising method is presented in the paper, based on the independent component analysis(ICA) and the noise independent component selection measurement which is the dispersivity of the independent component's projection coefficients to each electrode. The results indicate that the method can denoise EPM signals with giving prominence to electrodes' true depolarization signals. So it' s fit well for the EPM system.
Electrodes ; Epicardial Mapping ; methods ; Membrane Potentials ; Pericardium ; physiology

WPW syndrome is the most common variaty of preexcitaton syndrome in which whole or part of ventricular muscle is activated by the atrial impulse earlier than would be expected if the impulse reached the ventricle by way of normal conduction system alone. WPW syndrome result from existence of accessory muscle bridge(atrio ventricular connection) between atrium and ventricle. The ventricular complex observed in WPW syndrome during periods of sinus rhythm is the result of fusion, with intial phase of ventricular activation representing excitation via accessory pathway and later forces produced by excitation of residual portions of ventricle via normal His-purkinje system. The variations in QRS aberrancy in WPW syndrome depend on varying degree of preexcitation. This experimental study was undertaken to increase our knowledge on the ventricular fusion in WPW syndrome through epicardial mapping after experimental induction of ventricular preexcitaion of WPW type. In 5 normal dogs, the heart was widely exposed through transverse thoracotomy and positioned in a pericardial cradle, then electric wires were fixed on the epicardium of right atrium and ventricular bases(anterobasal and posterobasal) areas of right ventricle, anterobasal and poaterobasal areas of left ventricle for atrial and ventricular pacing. Epicardial mapping was then performed during atrial pacing alone and during atrioventricular sequential pacing at the same rate. Atrioventricular sequential pacing was done with various short AV intervals(60-110 msec) for the purpose of premature stimulation on ventricular base. In mapping we used the grid system which consisted of 29 areas to cover the right ventricle and 23 areas to cover the left ventricle. We drew 9 epicardial ishochrone maps in 5 dogs. The epicardial data during atrio-ventriclar sequential pacing were then compared with those during atrial pacing at an identical rate to study the ventricular fusion in WPW syndrome. The results were as follows; 1) The preexciting wave spread radially from the stimulated basal area to the right and left(or anterior and posterior wall) and the apex. 2) Preexciting wavefronts collided with the normal wavefronts in a wide range of ventricular activation time. 3) Preexcitation widened according to the degree of the shortening of the AV interval. 4) The duration of ventricular activation was greater in preexcited ventricles than in normally activated ventricles. The more prematurely the ventricle was stimulated, the greater the duration of ventricular activation was.
Animals ; Dogs ; Epicardial Mapping ; Heart ; Heart Atria ; Heart Ventricles ; Pericardium ; Thoracotomy ; Wolff-Parkinson-White Syndrome*

This paper discusses the law of atrial electrical activity propagation (the timing of signal and the conduction velocity) under the sinus rhythm before and after AF caused by high-frequency electrical stimulation. The paper analyzes how different doses of acetylcholine affect the conductivity of the atrial cells of dogs. This result can also help the diagnoses and treatment of human's AF.
Acetylcholine ; pharmacology ; Animals ; Dogs ; Epicardial Mapping ; Heart Atria ; cytology ; drug effects ; physiopathology ; Mechanotransduction, Cellular

Catheter Ablation ; methods ; Child ; Epicardial Mapping ; Female ; Heart Aneurysm ; complications ; surgery ; Humans ; Tachycardia, Ventricular ; complications ; surgery

For over 3 decades, it has been known that reentry circuits for ventricular tachycardia (VT) are not limited to the subendocardial myocardium. Rather, intramural or subepicardial substrates may also give rise to VT, particularly in those with non-ischemic cardiomyopathy. Percutaneous epicardial mapping and ablation has been successfully introduced for the treatment of such subepicardial VT. Herein, we review the indications for epicardial ablation and the identification of epicardial VT by electrocardiographic and imaging modalities. We also discuss the optimal technique for epicardial access and the implications of epicardial fat which has the potential to mimic scar, decreasing the specificity of electrogram morphology and impeding energy delivery to the tissue. Finally, we also report on possible complications of the procedure and strategies to mitigate adverse events.
Cardiomyopathies ; Catheter Ablation ; Cicatrix ; Electrocardiography ; Epicardial Mapping ; Myocardium ; Sensitivity and Specificity ; Tachycardia, Ventricular