Characteristics of R-R intervals in patients with continuous atrial
fibrillation and subsequent heart failure
Abstract
Introduction: Atrial fibrillation (AF) predisposes patients to heart
failure (HF) and a resultant increase in mortality, however, little is
known regarding what characteristics of AF are related to HF. Our aim is
to clarify the characteristics of AF with subsequent HF by analysis of
R-R interval during every 1-h segment. Method and Results: We
retrospectively analyzed 188 Holter electrocardiograms of patients with
continuous AF. A histogram of normal R–R intervals was plotted for each
hour, the mean R-R intervals (mean R-R) and the standard deviation of
R–R intervals (SD R–R) were calculated. Mean R-R and SD R-R
demonstrated circadian variations in 167 patients without subsequent HF.
In 21 patients with subsequent HF, SD R–Rs were significantly shorter
than those in patients without HF at 1:00–2:00 (174.9 ± 46.4 vs. 207.3
± 67.5 ms), at 2:00–3:00 (180.4 ± 42.8 vs. 212.7 ± 68.1 ms), at
3:00–4:00 (181.9 ± 52.7 vs. 216.1 ± 71.0 ms), and at 4:00–5:00 (187.9
± 50.0 vs. 220.7 ± 72.0 ms). Mean R-R and SD R-R kept in low values
during night-time in β-blocker users of the HF group. The attenuation of
circadian variations of mean R-R and SD R-R were also recognized in
patients with reduced ejection fraction. Conclusions: The analyses of
R-R interval under the consideration of the circadian variations and the
usage of β-blocker were suspected to predict subsequent HF in patients
with continuous AF.