Author/Authors :
Pousset، نويسنده , , Francoise and Copie، نويسنده , , Xavier and Lechat، نويسنده , , Philippe and Jaillon، نويسنده , , Patrice and Boissel، نويسنده , , Jean-Pierre and Hetzel، نويسنده , , Martin and Fillette، نويسنده , , Frédéric and Remme، نويسنده , , Willem and Guize، نويسنده , , Louis and Heuzey، نويسنده , , Jean-Yves Le، نويسنده ,
Abstract :
Analysis of heart rate variability (HRV) provides a noninvasive index of autonomic nervous system activity. HRV has been shown to be reduced in heart failure. Preliminary data indicate that β blockers improve clinical status in patients with heart failure, but HRV improvement remains to be demonstrated. Fifty-four patients from the randomized double-blind, placebo-controlled Cardiac Insufficiency Bisoprolol Study were included in the HRV study. The bisoprolol daily dose was 5 mg once daily. We assessed HRV during 24-hour Hotter recordings before randomization and after 2 months of treatment. HRV was measured in the time domain by rootmean-square successive differences (rMSSD), the percentage of adjacent RR differences >50 ms (pNN50), and the SD of RR intervals (SDNN), and in the frequency domain by high-frequency (0.16 to 0.40 Hz) and low-frequency (0.04 to 0.15 Hz) power. Most patients were in New York Heart Association functional class III. The mean left ventricular ejection fraction was 27 ± 7%, and heart failure was idiopathic or ischemic. After 2 months, the patients receiving bisoprolol had a reduced mean heart rate compared with that in placebo patients (p = 0.0004). Bisoprolol increased 24-hour rMSSD (p = 0.04) and 24-hour pNN50 (p = 0.04), daytime SDNN (p = 0.05), and daytime high-frequency power (p = 0.03) power. Bisoprolol induced a significant increase in HRV parameters related to parasympathetic activity in heart failure. Increased vagal tone may contribute to the protective effect of β blockers and may have prognostic implications.
