Prognostic value of heart rate variability during long-term follow-up in patients with mild to moderate heart failure

Objectives.We sought to assess the prognostic value of heart rate variability measures, including Poincaré plots, in patients with mild to moderate chronic heart failure.Background.Mortality is high in patients with heart failure, and many of them die suddenly. However, identification of high risk patients, particularly those with an increased risk for sudden death, has remained difficult.Methods.We studied 95 patients with heart failure (mean [±SD] age 60 ± 8 years, left ventricular ejection fraction 0.29 ± 0.09, New York Heart Association functional class II [81%] and III [19%]) during up to 4 years of follow-up. Heart rate variability measures and Poincaré plots were obtained from 24-h Holter recordings.Results.During follow-up, 17 (18%) of the 95 patients died. In 15 patients, death was cardiac related (11 patients experienced sudden death). None of the conventional time and frequency domain measures of heart rate variability were related to survival. In contrast, abnormal Poincaré plots identified a significantly higher risk for all-cause cardiac death (Cox proportional hazards ratio 5.7, 95% confidence interval [CI] 1.6 to 20.6, univariate analysis) and for sudden cardiac death (hazards ratio 6.8, 95% CI 1.5 to 31.4) compared with those with normal Poincaré plots. Patients with abnormal Poincaré plots were shown to have a lower left ventricular ejection fraction (0.26 ± 0.10 vs. 0.31 ± 0.08, p < 0.05) and higher plasma norepinephrine concentrations (506 ± 207 pg/ml vs. 411 ± 175 pg/ml, p < 0.05). In multivariate analysis, abnormal Poincaré plots still had independent prognostic value, both for all-cause cardiac mortality and for sudden cardiac death (hazards ratio 5.3, 95% CI 1.2 to 17.1, hazards ratio 4.5, 95% CI 1.0 to 27.5, respectively.Conclusions.Heart rate variability analysis, as assessed by Poincaré plots, has independent prognostic value in patients with mild to moderate chronic heart failure and identifies an increased risk for all-cause and sudden cardiac death in these patients

The Chronic Kidney Disease Epidemiology Collaboration equation outperforms the Modification of Diet in Renal Disease equation for estimating glomerular filtration rate in chronic systolic heart failure

Aims The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula estimates glomerular filtration rate (GFR) better than the simplified Modification of Diet in Renal Disease (sMDRD) formula in numerous populations. It has not previously been validated in heart failure patients. Methods and results The GFR was measured in 120 patients with chronic systolic heart failure (CHF) using [I-125]iothalamate clearance (GFR(IOTH)) and estimated using the sMDRD and CKD-EPI equations. Accuracy, bias, and prognostic performance were compared. Cockcroft-Gault, CKD-EPI serum cystatin C, and CKD-EPI creatinine-serum cystatin C equations were compared in secondary analyses. Mean age was 59 +/- 12 years, 80% were male. Mean LVEF was 29 +/- 10%. Mean GFR(IOTH) was 74 +/- 27 mL/min/1.73 m(2), and mean estimated GFR was 66 +/- 23 mL/min/1.73 m(2) (CKD-EPI) and 63 +/- 21 mL/min/1.73m(2) (sMDRD). CKD-EPI showed less bias than sMDRD (-8 +/- 15 vs. -11 +/- 16 mL/min/1.73 m(2), P <0.001). Both equations underestimate at higher and overestimate at lower GFR(IOTH). Eleven patients (9%) were accurately reclassified into lower CKD classes with CKD-EPI. Cockcroft-Gault showed lower bias (-3 +/- 16 mL/min/1.73 m(2)) but worse precision and accuracy. Cystatin C-based estimation showed the lowest bias (-3 +/- 14 mL/min/1.73 m(2)) and the best precision and accuracy. Prognostic value did not differ between all GFR estimates Conclusion The CKD-EPI equation more accurately estimates measured GFR than the sMDRD equation in CHF patients, with less bias and greater accuracy and precision. The prognostic power of all GFR assessments was equivalent. Based on better performance and equal risk prediction, we believe the CKI-EPI equation should be the preferred creatinine-based GFR estimation method in heart failure patients, particularly those with preserved or moderately impaired renal function