Barbosa P R, Barbosa Filho J, de Sá C A
Hospital Universitário Gaffrée Guinle-UniRio, Rio de Janeiro.
Arq Bras Cardiol. 1996 Nov;67(5):325-9.
To establish the influence of age, sex and the presence of coronary heart disease on heart rate variability.
The heart rate variability was studied in the time and frequency domain in 77 normal (group I) and 30 coronary heart disease patients (group II). The ECG was recorded during 300 seconds with the patients breathing at their spontaneous rate and at a rate between 10 and 15/ minutes (0.16 to 0.25 Hz).
Both time and frequency domain variables were lower in group II than in group I. Energy content in spectral bands decreased with increasing age. No change was observed in relation to the patient's gender. During controlled breathing we found that in both groups the energy concentrated in the range of 0.17 to 0.25 Hz but it only increased in group I.
Heart rate variability is an important tool for studying the influence of the autonomic system on heart rate modulation. These influences decrease with age and with the presence of coronary heart disease. The controlled breathing maneuver enabled us to precisely separate normal from coronary heart disease patients.
