Czynniki warunkujące zmienność rytmu serca u chorych z przewlekłym migotaniem przedsionków Determinants of heart rate variability in chronic atrial fibrillation
Year: 2004
Type: article
Study design: Observational Study
Abstract: Background: Analysis of heart rate variability (HRV) is a reliable method of noninvasive estimation of cardiac autonomic control in patients with sinus rhythm.In these patients determinants of HRV have been already recognised.The authors propose a new index based on a numerical evaluation of the return map, HRV fraction (HRVF), which can be successfully applied in the presence of atrial fibrillation (AF).The aim of this study was to characterise the determinants of HRV in chronic AF.Material and methods: 155 consecutive patients with chronic AF were examined (93 male, 62 female, mean age 64 ± 11 years, range 25-84).In each patient a 24-hour ECG was performed and standard time-domain HRV parameters, as well as HRVF, were obtained.Two groups were compared: patients with HRVF within normal limits (≥ 35%, n = 114) and those with low HRVF (< 35%, n = 38).Multifactorial analysis was performed, taking into account the following parameters: age (< 65, ≥ 65), gender, clinical diagnosis (dilated cardiomyopathy, uncomplicated CAD, previous MI and others than CAD, non-CAD), diabetes (yes, no), b-blockers use (yes, no), NYHA class (I-II, III-IV), left ventricular ejection fraction (LVEF < 30, 30-49, ≥ 50), left ventricular end-diastolic diameter (LVEDD > 60, £ 60) and heart rate (< 70, 70-89, ≥ 90 bpm).Results: Age and gender did not influence HRV in patients with AF.However, low HRV was more frequently observed in patients aged ≥ 65 years.Previous MI appeared to be a signifiant determinant of HRV, being twice more frequent in patients with low HRV.Conversely, nonischaemic aetiology was associated with higher HRV.Decreased HRV was more frequent in patients with higher NYHA classes (III-IV).The presence of diabetes coexisted with low HRV.No relationship between beta-blockers use and HRV was observed.The most significant determinant of HRV was LVEF.Low HRV was 2 times more frequent in those with LVEF < 30%, while normal HRV was associated with normal LVEF.Almost half of patients with cardiomegaly (> 60 mm) had reduced HRV compared with 80% of those characterised by normal LVEDD and normal HRV.Heart rate was the second most significant determinant of HRV in AF.Reduced HRV was associated with heart rate > 90 bpm in almost 50% of patients compared with ~80% of patients with normal HRV who had heart rate < 90 bpm.
Source: Via Medica Journals
Language: Polish
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2310977784