The aim of the study – complex evaluation of atrial electrical instability based on structural and functional myocardial condition, electrophysiological heart properties and some neurohumoral markers in pts with paroxysmal atrial fibrillation (AF) depending on arrhythmia induction during transesophageal electrophysiological examination (TEE).
Material and methods. 133 pts with non-valvular paroxysmal AF were included in the study. Left atrial electrical stimulation with increasing frequency (up to 200 imp./min) and overfrequency was applied for stable paroxysmal AF induction. Observed pts were divided in 2 groups: 1st group consisted of 103 pts with induced paroxysmal AF; 2nd group included 30 pts without inducible paroxysmal AF. The following instrumental methods were used: Holter ECG monitoring with analysis of heart rate variability, two-dimensional, and Doppler echocardiography. The function of heart conducting system, atrial vulnerability (AV) and vasoactive substances blood levels were explored by TEE. Vasoactive substances levels in blood were studied by radioimmunoassay.
Results. Atrial electrical instability in pts with induced atrial fibrillation was associated with increased number of supraventricular extrasystoles, increased RMSSD and PNN50. High atrial vulnerability in pts with induced paroxysm was conditioned by decreased frequency characteristics of atrial fibrillation, reduction of atrial cycle length during arrhythmia, attenuation of sinus node function.
Conclusion. In pts with induced atrial fibrillation paroxysm atria vulnerability was associated with parasympathetic tonus increase. At the same time, sympathetic domination is found at the arrhythmia launch.