title: Effect of diurnal variability of heart rate on development of arrhythmia in patients with chronic obstructive pulmonary disease.
abstract: We examined the possible effect of diurnal variability of heart rate on the development of arrhythmias in patients with chronic obstructive pulmonary disease (COPD). Forty-one COPD patients (M/F: 39/2, mean age: 59+/-8.5 years) and 32 (M/F: 27/5, mean age: 57+/-11 years) healthy controls were included. Twenty-four hour ECG recordings were analyzed for atrial fibrillation (AF) or ventricular premature beats (VPB), and circadian changes in heart rate variability (HRV) were assessed by dividing the 24-h period into day-time (08:00-24:00 h) and night-time (24:00-08:00 h) periods. Night-time total (TP), low frequency (LF) and high frequency (HF) powers were similarly lower from day-time parameters in AF(-) COPD patients (HF 3.91+/-1 vs. 4.43+/-1.04 ms(2), P=0.001) and controls (HF 3.95+/-0.72 vs. 4.82+/-0.66 ms(2), P<0.001). The LF/HF ratios were also significantly reduced in the same patient groups (AF(-) COPD 1.35+/-0.21 vs. 1.27+/-0.19, P=0.04, controls 1.43+/-0.14 vs. 1.24+/-0.09, P<0.001). Night-time TP and LF were increased, HF unchanged and LF/HF significantly increased (1.11+/-0.25 vs. 1.19+/-0.27, P<0.05) in AF(+) COPD patients. Frequency of VPB was correlated with corrected QT dispersion (QTc(d)) (r=0.52, P=0.001) and the day-time/night-time HF ratio (r=0.43, P=0.02). Patients with QTc(d)>or=60 ms did not have the expected increase in night-time HF and had a statistically insignificant increase in LF/HF ratio. In COPD patients with QTc(d)<60 ms, circadian changes in HRV parameters were parallel with the controls. We concluded that COPD patients with arrhythmia had circadian HRV disturbances such as unchanged night-time parasympathetic tone and disturbed sympatho-vagal balance in favor of the sympathetic system all day long, which may explain the increased frequency of arrhythmia.
authors.affiliation: Department of Cardiology, Istanbul Faculty of Medicine, Istanbul, Turkey. tufantukek@hotmail.com
authors.forename: Tufan
authors.initials: T
authors.lastname: Tükek
authors.forename: Pinar
authors.initials: P
authors.lastname: Yildiz
authors.forename: Dursun
authors.initials: D
authors.lastname: Atilgan
authors.forename: Volkan
authors.initials: V
authors.lastname: Tuzcu
authors.forename: Mehmet
authors.initials: M
authors.lastname: Eren
authors.forename: Osman
authors.initials: O
authors.lastname: Erk
authors.forename: Seref
authors.initials: S
authors.lastname: Demirel
authors.forename: Vakur
authors.initials: V
authors.lastname: Akkaya
authors.forename: Murat
authors.initials: M
authors.lastname: Dilmener
authors.forename: Ferruh
authors.initials: F
authors.lastname: Korkut
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000097:blood / Q000209:etiology* / Q000503:physiopathology*; D001784:Blood Gas Analysis; D021081:Chronobiology Disorders / Q000097:blood / Q000150:complications* / Q000503:physiopathology*; D002940:Circadian Rhythm / Q000502:physiology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000150:complications* / Q000503:physiopathology*; D012129:Respiratory Function Tests; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors