Age-adjustment of HRV measures and its prognostic value for risk assessment in @entity1 late after XXXX .

@entity1 @entity2286 @entity1188 @entity299 @entity583 @entity204 @entity4297
THE AIMS OF OUR STUDY WERE: (1) to establish the normal limit of the heart rate variability (HRV) indices in a healthy population and in its four age-related subgroups, including a new HRV index, @entity299 ; and (2) to analyse the frequency and predictive @entity4297 in a population of post- @entity1188 @entity1 in respect to the cut-points chosen (raw or age-adjusted). METHODS: Normal population of 296 healthy subjects (81 f, 215 m, aged 47+/-10 years) and post- @entity1188 population of 298 @entity1 (>3 months after acute MI, 65 f, 233 m, aged 56+/-10) were examined. The normal population was divided into 4 subsets based on age at entry: <35, 35-44, 45-54 and >54 years. Based on a 24 h ECG the standard HRV analysis was performed to obtain the following indices: mean RR interval, SDNN and SDANN. A new index of HRV, @entity299 ( @entity299 , %) was calculated based on a numerical processing of the RR intervals return map. All @entity1 were followed for 24 months. The endpoints of the study were @entity204 (of any reason) and @entity204 . RESULTS: Means and normal limits for SDNN, SDANN and @entity299 were: 147+/-36 ms [95% CI 89-220], 136+/-36 ms [79-212] and 53+/-9% [35-68]. The HRV values below the lower normal limit (LNL) were observed in 20-25% of post-MI @entity1 . During a 2 year follow-up there were 36 deaths (total mortality 12.1%), while cardiac mortality was 9.1% (27 cases). The prognostic value of the analysed indices was similar (sens approximately 53-61%, spec approximately 79-84%, @entity2286 22-26%, NPV 93-94%) irrespective of the cut-points chosen (calculated either for the entire population or age-related). Multivariate Cox regression analysis showed that a decrease of any index below the LNL was associated with a approximately 2.5 and approximately 4-6 times greater risk for @entity204 and @entity204 , irrespective of the cut-points chosen. CONCLUSIONS: The age-dependence of the HRV indices does not seem to significantly influence their prognostic value. Thus, a single cut-point of a particular HRV index, based on the entire population, is sufficient to be treated as a risk predictor. In the late phase of @entity583 the value of any global HRV index lying below the lower normal limit indicates independently an increased risk of @entity204 , especially @entity204 . The new index ( @entity299 ) seems to be a promising substitute for currently used standard indices.
