Krzysztof Narkiewicz

Issues in the development of new combinations of blood pressure lowering drugs

The George Institute for International Health and University of Sydney, Australia, Department of Physiology, University of Melbourne, Australia, Department of Hypertension and Diabetology, University of Gdansk, Poland, International Center for Circulatory Health, National Heart & Lung Institute, Imperial College, London, UK, Hospital Clinico Universitario, University of Valencia, Spain, Istituto Auxologico Italiano, Milan, Italy and Department of Clinical Medicine, University of Milano-Bicocca, Milan, Italy

Ordinal pattern statistics for RR intervals during head-up tilt test in patients with the history of vasovagal syncope

We apply ordinal pattern analysis to quantify differences in distribution of patterns of length 3 and 4 in basal state and during head-up tilt test (HUTT) in patients with the history of syncope and positive (HUTT(+)) or negative (HUTT(-)) responses to the test. We identify the patterns related to prevalence of sympathetic or parasympathetic cardiac modulation as well as describe the relations between the response to the test and distribution of the patterns.

Temporal changes in complexity of cardiovascular regulation during head-up tilt test by entropic measures of fluctuations of heart period intervals and systolic blood pressure

Dynamical aspects of cardiovascular regulation in the head-up tilt test are revealed through the properties of the approximate entropy and sample entropy of increments between subsequent heart period intervals and increments between subsequent systolic blood pressure values. Marked differences are observed in the dynamical response to the tilt test of healthy subjects prone to spontaneous fainting and those who are less susceptible to fainting.

Temporal increment distributions of RR-intervals reveal dynamics of cardiac regulation in head-up tilt test

Dynamical aspects of cardiovascular regulation are revealed in the head-up tilt test by the properties of the distribution of time-increments between subsequent heart contractions. The Generalized Porta Index (GPI) is introduced and then calculated for the pooled probability density functions. GPI reveals marked differences between the dynamical response to the tilt test of healthy subjects prone to spontaneous fainting and those who are less susceptible.

THE INFLUENCE OF NORMAL SLEEP AND OBSTRUCTIVE SLEEP APNEA ON CORONARY ARTERY ENDOTHELIAL CELLS MIGRATION: PP.6.237

Endothelial cells migration and proliferation play an important role in the growth and development of new blood vessels and endothelium healing. This process occurs in response to injury, inflammation and immune reactions. Endothelial function seems to play a significant role in a pathophysiology of cardiovascular complications including sleep-disordered breathing. The aim of the study was to evaluate the coronary artery endothelial cells chemotaxis induced by serum obtained from healthy and severe obstructive sleep apnea subjects. Material and Methods: 12 healthy and 12 severe obstructive sleep apnea subjects (AHI > 30) free from other co-morbidities without any treatment underwent standard polysomnography. Blood was collected at three time-points: at 21:00 before sleep,at 6:00 after arousal and at 11.00 (after five hours of normal day activity). Serum chemoattractant activity for human coronary endothelial cells was assessed using a QCMTM 24-well colorimetric cell migration assay kit (Chemicon) following the manufacturers instructions. Results: In healthy subjects serum chemoattractant activity peaked in the morning after arousal (p = 0,02). This pattern was disturbed in severe obstructive sleep apnea subjects where serum induced chemotaxis was weaker than in normal controls (p = 0,01) and did not vary significantly in different time-points (OSA vs healthy at 6:00 p < 0,001, p = ns in the OSA group). Conclusion: Normal sleep influences chemotaxis of the coronary artery endothelial cells. The processes occurring during obstructive sleep apnea can impair endothelial cells migration activity. This phenomenon might play a role in a pathophysiology of cardiovascular complications in obstructive sleep apnea patients and might be helpful in understanding the influence of the circadian rhythm on prevalence of cardiovascular events. Figure 1. No caption available.