A.N. Solovyan.Structural and functional condition of the myocardium, heart rate variability and cardiac electrophysiological properties in different neuroautonomic types of paroxysmal atrial fibrillation.

The aim – to investigate the structural and functional parameters of the myocardium, heart rate variability, electrophysiological properties of the heart and their relationship in patients with paroxysmal atrial fibrillation (PAF), depending of the type of autonomic influence on the heart.
Material and methods. We enrolled 343 patients with non-valvular PAF. We used 2D- and Doppler-echocardiography, ECG ambulatory monitoring with hate rate variability (HRV) analysis. The function of the heart conduction system and atrial vulnerability were studied during transesophageal electrophysiological study. The assessment of atrial vulnerability was based on AF inducibility, heart rate threshold (HRT) and heart rate point (HRP) of AF induction.
Results. It was established, that atrial vulnerability increase in patients with vagal AF was caused by HRT decrease (Р=0.043) with a statistically significant HRV increase. Atrial electrical instability in patients with adrenergic form of AF was characterized by increase of the average heart rate (HR) and decrease of ff interval during AF. The statistically significant increase of Wenkebach point and AV node effective refractory period shortening predetermined the average HR increase during spontaneous paroxysm (Р<0,001). In patients with mixed form of AF we observed statistically significant increase of left atrium (LA) diameter, LA index, interventricular septum and left ventricle (LV) posterior thickness, decrease of LF ejection fraction and E/A ratio. Atrial arrhythmogenic readiness was characterized by statistically significant decrease of parameters of HRV, sinus node and AV node function, and increase of ff interval. Conclusion. Positive correlation of LA index and ff interval was found in patients with vagal form of AF. Negative correlation of LV end-diastolic dimension (EDD) with HRV and f-wave amplitude was detected in patients with adrenergic type of AF. We found correlation of EDD, LV end-diastolic volume and HRT in patients with mixed type of AF.

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