Clinical Relevance of Day-by-Day Blood Pressure and Heart Rate Variability

Abstract

Both in normotensive and in hypertensive subjects, blood pressure (BP) is characterized by continuous fluctuations in relation to the different daytime and nighttime activities.1 Studies based on ambulatory BP monitoring (ABPM) have provided evidence that BP and heart rate (HR) variability (V) over 24 hours carry important pathophysiological information and have clinical relevance both in the diagnostic and prognostic assessments of hypertension. Different BPV and HRV patterns reflect specific features of autonomic cardiovascular regulation, and the magnitude of BP swings over the day and night has been shown to be associated with severity of organ damage and rate of cardiovascular events.2–5 As a consequence, it has been suggested recently that the benefits of hypertension treatment, in terms of organ damage prevention or regression and in terms of event rate reduction, might be greater by targeting not only mean BP level reduction but also the attenuation of the deranged BP variability found frequently in hypertensive patients.6 Traditional office BP measurements are unable to account for daily life BPV and HRV,1 which explains the growing interest toward out-of-office BP measurements, either through ABPM or, in more recent times, through home (H)BPM. In spite of its relevant advantages, however, routine use of ABPM has found only limited applicability in clinical practice up to now, partly because of its inconvenience in active patients and because of its impact on health care costs. Use of HBPM in the diagnosis and management of arterial hypertension, however, is continuously increasing, its rapid diffusion being favored by technological progress in the design and production of HBPM devices, by their progressively wider availability and lower cost, and by the increasing awareness among doctors and patients of the importance of regular out-of-office BP monitoring, even …