Abstract 14829: Effect of n-3PUFA on Heart Rate Variability. Data from the GISSI-HF Holter Substudy
BACKGROUND: n-3PUFA supplementation in the GISSI-HF study reduced total mortality in pts with chronic heart failure (CHF) but the mechanism of action is still an open question. One of the study hypotheses was the effect on the autonomic tone since various studies suggest that n-3PUFA can increase heart rate variability (HRV) in CHF.
OBJECTIVE: to evaluate the effect of 1 g/day n-3PUFA versus placebo (PL) on HRV.
METHODS: GISSI-HF prospectively enrolled pts with HF of any cause in NYHA class II-IV. Twenty-four hour Holter recordings were analyzed in 314, 302, 293 pts at baseline, 3 and 12 mo respectively. Baseline characteristics were compared by chi-square test, t-test or non parametric Wilcoxon two-sample test.
RESULTS: At baseline 32% of the pts were >70 years old, 81 % were males, 92% presented a LVEF <40% and 81% were in NYHA class II. Mean±SD value of the mean of all normal RR intervals (meanRR), the standard deviation of normal-to-normal (NN) intervals (SDNN) and the very low frequency component (VLF) were 864±28 ms, 111±45 ms and 384±246 ms2 respectively. Study groups were well matched for baseline characteristics and for betablocker treatment during follow up. Overall 12 mo mortality was 17/314 (5.4%). The 3 indexes of HRV increased over 3 mo in the n-3PUFA group (p=0.01 vs PL, Figure), independently of the frequency of dietary fish consumption (n-3PUFA intake). These effects were slightly attenuated over 12 mo for RR mean (p=0.06) and VLF (p=0.07) and lost for SDNN. The post-hoc analysis in pts compliant with study treatment (n=248) showed similar overall results.
CONCLUSIONS: the increase in HRV was maximal after 3 mo of treatment with n-3PUFA. This effect may help explaining mortality benefits first observed in GISSI-Prevenzione and then extended in GISSI-HF trial.
Figure: Effect of randomized treatment on changes of HRV measures at defined time points. Least Square Means (LSM) have been calculated by analysis of covariance, adjusting for their respective baseline values.
- © 2011 by American Heart Association, Inc.