| Abstract: | Heart rate (HR) variations during night sleep and in the early predawn period in healthy subjects and patients with paroxisms of artrial fibrillation were used to assess HR circadian rhythms. Daily ECG monitoring was performed in 19 healthy subjects (mean age 36.0 +/- 7.05 years) and patients with paroxisms of atrial fibrillation (mean age 55.15 +/- 3.91 years). In healthy subjects, HR responsiveness during night sleep and in the early predawn hours was more prominent than in patients with paroxisms of atrial fibrillation. The number of HR spikes at night was 20.42 +/- 3.73 and 14.23 +/- 2.8 (p < 0.001) and one hour before waking 3.74 +/- 1.33 and 1.92 +/- 1.04 (p < 0.001) respectively; premorning activation coefficient was 0.19 +/- 0.007 and 0.13 +/- 0.007 (p < 0.05). It is concluded that HR responsiveness during the night sleep and the early predawn period in healthy subjects is higher than in patients with paroxisms of articular fibrillation. The number of HR spikes at night and one hour before waking as well as premorning activation coefficient can be used to assess RH circadian rhythms. |
