title: Simultaneous analysis of beat by beat systemic arterial pressure and heart rate variabilities in ambulatory patients.
abstract: The analysis of power spectral density (PSD) or RR variability in the electrocardiogram (ECG) has suggested that, in the early phase of essential hypertension, sympatho-vagal interaction is characterized by a sympathetic predominance. Recently, we have developed a high fidelity, direct arterial pressure ambulatory recording system which allows a beat by beat computer analysis of arterial pressure and heart rate. A microminiature tip transducer (Millar, diameter 0.8 mm) is inserted percutaneously into the radial artery and connected to a Holter two-channel magnetic tape recorder. The tip transducer has a wide band pass (> 1 kHz), excellent stability (congruent to 2 mmHg/24 h) and does not require a perfusion line. The overall frequency response of the entire recording-reproducing system is better than 20 Hz (-3 dB). The ECG and pressure signals are analysed with automatic autoregressive modelling algorithms to provide a quantitative estimate of blood pressure and heart rate variability through the computation of the PSD. In seven hypertensive patients, systolic arterial pressure and variance were higher during the day (157 +/- 9 mmHg and 122 +/- 9 mmHg2) than during the night (122 +/- 4 mmHg and 30 +/- 3 mmHg2). The PSD of RR and of systolic arterial pressure consisted of a predominant low frequency peak (congruent to 0.09 cycles/beat) during the day, and two peaks at low and high (congruent to 0.25 cycles/beat) frequency during the night. While RR variance was similar during both day- and night-time, a predominant low frequency peak was observed during the day.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Istituto Ricerche Cardiovascolari, CNR, Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Pagani
authors.forename: R
authors.initials: R
authors.lastname: Furlan
authors.forename: S
authors.initials: S
authors.lastname: Dell'Orto
authors.forename: P
authors.initials: P
authors.lastname: Pizzinelli
authors.forename: G
authors.initials: G
authors.lastname: Baselli
authors.forename: S
authors.initials: S
authors.lastname: Cerutti
authors.forename: F
authors.initials: F
authors.lastname: Lombardi
authors.forename: A
authors.initials: A
authors.lastname: Malliani
mesh_terms: D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000295:instrumentation; D003201:Computers; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008875:Middle Aged; D013997:Time Factors; D014160:Transducers, Pressure