Circadian variation of variability and irregularity of heart rate in patients with permanent atrial fibrillation: relation to symptoms and rate control drugs.
The aim of the present study was to evaluate diurnal variations of the variability and irregularity of heart rate (HR) in patients with permanent atrial fibrillation (AF) with and without rate control drugs. Thirty-eight patients with permanent AF were part of an investigator-blind crossover study comparing diltiazem, verapamil, metoprolol, and carvedilol. We analyzed five Holter recordings per patient: at baseline (no rate control drug) and with each of the four drug regimens. HR, variability (SD; percentages of interval differences of successive RR intervals of >20, 50, and 80 ms; and root of the mean squared differences of successive RR intervals), and irregularity (approximate and sample entropy) parameters were computed in 20-min long nonoverlapping segments. Circadian rhythmicity was evaluated using cosinor analysis to each parameter series, which is characterized by the 24-h mean [midline statistic of rhythm (MESOR)] and excursion over the mean (amplitude). Arrhythmia-related symptoms were assessed by a questionnaire measuring symptom severity and frequency. HR and variability parameters showed a significant circadian variation in most patients, whereas only a small minority of the patients had circadian variations of irregularity parameters. Patients with circadian approximate entropy n at baseline had more severe symptoms (symptom severity: 9 ± 4 vs. 6 ± 5, P < 0.05, circadian vs. noncircadian variations). All drugs decreased the MESOR of HR and increased the MESOR of variability parameters. Only carvedilol and metoprolol decreased the normalized amplitude over 24 h of all parameters and HR. In conclusion, HR and RR variability parameters present a circadian variation in patients with permanent AF, whereas few patients demonstrated circadian fluctuations in irregularity parameters, suggesting different physiological mechanisms.
Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy; valentina.corino@polimi.it.
Valentina D A
VD
Corino
Center for Integrative Electrocardiology at Lund University, Department of Cardiology, Clinical Sciences, Lund University and Arrhythmia Clinic, Skåne University Hospital, Lund, Sweden; and.
Pyotr G
PG
Platonov
Department of Medical Research, Bærum Hospital, Vestre Viken Hospital Trust, Rud, Norway.
Steve
S
Enger
Department of Medical Research, Bærum Hospital, Vestre Viken Hospital Trust, Rud, Norway.
Arnljot
A
Tveit
Department of Medical Research, Bærum Hospital, Vestre Viken Hospital Trust, Rud, Norway.
Sara R
SR
Ulimoen
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology / Q000627:therapeutic use; D000368:Aged; D000369:Aged, 80 and over; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology* / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000503:physiopathology*; D002121:Calcium Channel Blockers / Q000494:pharmacology / Q000627:therapeutic use; D002940:Circadian Rhythm / Q000187:drug effects*; D015716:Electrocardiography, Ambulatory; D019277:Entropy; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged
D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D002121:Calcium Channel Blockers
calcium channel blockers; circadianity; irregularity; variability; β-blockers