RESUMO
BACKGROUND: Short-term variability of blood pressure can be used as an index of sympathetic vascular modulation and has been studied in patients with hypertension. AIM: The aim of this study was to characterise blood pressure variability (BPV) and its prognostic value in patients with congestive heart failure. METHODS AND RESULTS: 104 patients with congestive heart failure due to ischemia (n = 104) or idiopathic cardiomyopathy (n = 50) in New York Heart Association (NYHA) class II (n = 50), III (n = 71), IV (n = 33), and 40 healthy subjects were studied. The mean ejection fraction was 0.33 +/- 0.10. Continuous non-invasive BP recordings were obtained for 3,600 seconds with a photoplethysmographic finger device in patients and control subjects at rest. Patients with chronic heart failure (CHF) had significantly less pronounced BPV than control subjects. Diastolic blood pressure (DBP) variability was related to left ventricular ejection and to peak oxygen uptake. BPV was not different in patients with ischemic or idiopathic CHF. During the mean follow up (+/- SD) of 565 +/- 215 days, 44 patients died (28.6%). All deaths were cardiac related. Cox's univariate analysis identified the following factors to be predictors of death: peak oxygen uptake (p = 0.01), ejection fraction (p = 0.008), and among BPV parameters: total spectral amplitude (TA) for DBP (p = 0.002), very low frequencies over total amplitude (VLF/TA) for DBP (p = 0.005) and for mean blood pressure (MBP) (p = 0.03), and very low over high frequencies ratio (VLF/HF) for DBP (p = 0.002). Multivariate analysis showed that BPV predicted survival independently of EF or peak VO2. Kaplan-Meier survival curves revealed that VLF/TA < 55% for DBP, MBP and SBP are useful risk factors. One-year survival in patients with VLF/TA < 55% of DBP was 53% compared with 95% in those with VLF/TA > 55% (p = 0.005). CONCLUSIONS: Decreased BPV in patients with CHF is related to left ventricular dysfunction. Analysis of BPV can identify patients with CHF who have an increased risk of cardiac death.