Background:Heart rate variability is considered an important instrument in the assessment of patients with the impairment of left ventricular function in the course of circulatory failure and ischaemic heart disease. Atrial fibrillation is viewed upon as a restriction to this method. The aim of the present work was to establish the correlation between echocardiographic haemodynamic parameters of left ventricle and the indices of HRV time domain analysis.
Material/Methods: The study was based on the analysis of 24-hour ECG records of 50 patients with non-rheumatic atrial fibrillation, taking into account the following indices of HRV time domain analysis: SDNN, SDANN, SDNN index, rMSSD, pNN50. In addition, transthoracic echocardiography was performed in order to determine shortening fraction, ejection fraction, mitral wave deceleration time and left ventricular end-diastolic diameter. The patients were divided into groups with the use of mean echocardiographic parameter as a border value.
Results: Indices of HRV time domain analysis did not correlate with any echocardiographic parameter characterising left ventricular diastolic function. The group of patients with impaired left ventricular systolic function displayed significantly lower values of SDNN and SDANN in relation to the group without significant systolic dysfunction of left ventricle. The remaining indices did not differ between analysed groups with respect to echocardiographic parameters of left ventricular systolic function.
Conclusions: Our study indicates that SDNN and SDANN may be useful in managing patients with non-rheumatic atrial fibrillation and impaired function of left ventricle.

Keywords: Atrial Fibrillation, heart rate variability, shortening fraction, left ventricular end-diastolic diameter