Sergio Cerutti

Bio: Sergio Cerutti is an academic researcher from Polytechnic University of Milan. The author has contributed to research in topics: Heart rate variability & Population. The author has an hindex of 45, co-authored 301 publications receiving 22803 citations.

Analysis of short-term oscillations of R-R and arterial pressure in conscious dogs

Abstract: We studied the neural determinants of the second (i.e., high frequency, HF)- and third-order (i.e., low frequency, LF) spontaneous oscillations of heart period (R-R interval) and arterial pressure (AP) in conscious dogs, with the hypothesis that they might furnish quantitative markers of autonomic controlling activities. Spectral analysis of simultaneous R-R and AP variabilities quantified these oscillations that were also evaluated in units normalized by total power to focus on the balance of these two major components. At rest we observed a prevalent HF component (approximately 0.25 Hz) in R-R and AP variabilities that was synchronous with respiration. This HF component of R-R variability disappeared after atropine infusion and can be considered a marker mostly of vagal activity. When baroreceptor unloading, obtained by moderate hypotension, increased sympathetic activity the LF component increased in R-R, systolic, and diastolic AP variabilities. This increase in LF was not present after ganglionic blockade or after chronic arterial baroreceptor denervation. After chronic bilateral stellectomy, hypotension was not accompanied by an increase in LF component of R-R variability, while LF component remained in AP variability. An increase in LF component of R-R and AP variabilities was observed during transient coronary artery occlusion.

Sympathovagal interaction during mental stress. A study using spectral analysis of heart rate variability in healthy control subjects and patients with a prior myocardial infarction.

Abstract: We tested the hypothesis that psychological stress testing in the clinical laboratory provokes changes in the sympathetic and vagal activities regulating heart rate that can be assessed noninvasively using spectral analysis of RR variability To account for the effects on respiration produced by talking, this study was performed with two different procedures: the IKT (ie, a computer-controlled mental task that is performed in silence and does not entail human confrontation) and a stressful interview Finally, we assessed whether ischemic heart disease modifies the spectral changes induced by psychological stress by comparing a group of healthy subjects (age, 38 +/- 2 years) with a group of patients (age, 52 +/- 3 years) recovering from 1-month-old myocardial infarctions The findings indicate that psychological stress induced marked changes in the sympathovagal balance, which moved toward sympathetic predominance The low-frequency component of RR variability, a marker of sympathetic activity, increased from 58 +/- 5 normalized units (NU) to 68 +/- 3 NU with the IKT and to 76 +/- 3 NU with the interview This increase was absent in the group of post-myocardial infarction patients However, arterial pressure increased significantly in both groups of subjects The possibility of age playing an important role in determining the differences observed was disproved by the findings of a marked increase in low frequency with mental stimuli in an additional group of borderline hypertensive subjects with ages (55 +/- 2 years) comparable to those of post-myocardial infarction patients

Heart rate variability and its sympatho-vagal modulation

Abstract: The activity of sinus node pacemaker cells is under continuous regulation mainly effected by neural mechanisms. Hence the study of the variability of heart period, especially when assessed in the frequency domain with spectral analysis, was proposed about 15 years ago [l] as a probe for the evaluation of its autonomic control. Initially three spectral components of heart rate variability (HRV) were defined, while the factors considered as modulating them included sympathetic and parasympathetic activities, humoral factors such as the renin-angiotensin system or complex patterns like thermoregulation. On the basis of (i) an attempt to analyse cardiovascular neural regulation in closed-loop conditions, (ii) a different spectral methodology using autoregressive algorithms [21, (iii> simultaneous spectral analysis of both heart rate and arterial pressure variabilities providing the possibility of calculating crossspectra and their coherence, we reached the conclusion that only two spectral components were soundly analysable in a time span of a few hundred cycles-i.e., the time series usually selected to afford an adequate number of events, adequate stationarity and some appraisal of dynamic changes [3]. Hence, apart from a very low frequency (VLF) component [41, short-term variability appeared to consist mainly of an oscillation at low frequency (LF), usually around 0.1 Hz largely related to vasomotor activity, and of a high frequency (HF) oscillation, related to respiratory activity and under control conditions often around 0.25 Hz. Since our initial studies [2], we observed that the power of the LF component was percentually increased during manoeuvres exciting sympathetic activity while HF was

Heart rate variability signal processing: a quantitative approach as an aid to diagnosis in cardiovascular pathologies

Abstract: The heart rate variability (HRV) signal carries important information about the systems controlling heat rate and blood pressure, mainly elicited by autonomic nervous system (sympathetic and parasympathetic) controls. The present paper illustrates methods of HRV signal processing by using autoregressive (AR) modeling and power spectral density estimate. The information enhanced in this way seems to be particularly sensitive in discriminating various cardiovascular pathologies (hypertension, myocardial infarction, diabetic neuropathy, etc.). This method provides a simple non-invasive analysis, based on the processing of spontaneous oscillations in heart rate. Particular emphasis is directed to the algorithms used and to their direct application by using proper computerized techniques: only a few paradigmatical examples will be illustrated as preliminary results.

Health effects of fine particulate air pollution: lines that connect

Abstract: Efforts to understand and mitigate the health effects of particulate matter (PM) air pollution have a rich and interesting history. This review focuses on six substantial lines of research that have been pursued since 1997 that have helped elucidate our understanding about the effects of PM on human health. There has been substantial progress in the evaluation of PM health effects at different time-scales of exposure and in the exploration of the shape of the concentration-response function. There has also been emerging evidence of PM-related cardiovascular health effects and growing knowledge regarding interconnected general pathophysiological pathways that link PM exposure with cardiopulmonary morbidity and mortality. Despite important gaps in scientific knowledge and continued reasons for some skepticism, a comprehensive evaluation of the research findings provides persuasive evidence that exposure to fine particulate air pollution has adverse effects on cardiopulmonary health. Although much of this research has been motivated by environmental public health policy, these results have important scientific, medical, and public health implications that are broader than debates over legally mandated air quality standards.

Recommendations for the evaluation of left ventricular diastolic function by echocardiography

Abstract: Recommendations for the evaluation of left ventricular diastolic function by echocardiography

Power spectral analysis of heart rate and arterial pressure variabilities as a marker of sympatho-vagal interaction in man and conscious dog.

Abstract: In 57 normal subjects (age 20-60 years), we analyzed the spontaneous beat-to-beat oscillation in R-R interval during control recumbent position, 90 degrees upright tilt, controlled respiration (n = 16) and acute (n = 10) and chronic (n = 12) beta-adrenergic receptor blockade. Automatic computer analysis provided the autoregressive power spectral density, as well as the number and relative power of the individual components. The power spectral density of R-R interval variability contained two major components in power, a high frequency at approximately 0.25 Hz and a low frequency at approximately 0.1 Hz, with a normalized low frequency:high frequency ratio of 3.6 +/- 0.7. With tilt, the low-frequency component became largely predominant (90 +/- 1%) with a low frequency:high frequency ratio of 21 +/- 4. Acute beta-adrenergic receptor blockade (0.2 mg/kg IV propranolol) increased variance at rest and markedly blunted the increase in low frequency and low frequency:high frequency ratio induced by tilt. Chronic beta-adrenergic receptor blockade (0.6 mg/kg p.o. propranolol, t.i.d.), in addition, reduced low frequency and increased high frequency at rest, while limiting the low frequency:high frequency ratio increase produced by tilt. Controlled respiration produced at rest a marked increase in the high-frequency component, with a reduction of the low-frequency component and of the low frequency:high frequency ratio (0.7 +/- 0.1); during tilt, the increase in the low frequency:high frequency ratio (8.3 +/- 1.6) was significantly smaller. In seven additional subjects in whom direct high-fidelity arterial pressure was recorded, simultaneous R-R interval and arterial pressure variabilities were examined at rest and during tilt. Also, the power spectral density of arterial pressure variability contained two major components, with a relative low frequency:high frequency ratio at rest of 2.8 +/- 0.7, which became 17 +/- 5 with tilt. These power spectral density components were numerically similar to those observed in R-R variability. Thus, invasive and noninvasive studies provided similar results. More direct information on the role of cardiac sympathetic nerves on R-R and arterial pressure variabilities was derived from a group of experiments in conscious dogs before and after bilateral stellectomy. Under control conditions, high frequency was predominant and low frequency was very small or absent, owing to a predominant vagal tone. During a 9% decrease in arterial pressure obtained with IV nitroglycerin, there was a marked increase in low frequency, as a result of reflex sympathetic activation.(ABSTRACT TRUNCATED AT 400 WORDS)