J. Tank et al., ASSESSMENT OF THE HEMODYNAMIC REGULATION TYPE USING A FUZZY CLASSIFICATION TOOLBOX, Journal of cardiovascular diagnosis and procedures, 15(2), 1998, pp. 107-114
Citations number
18
Categorie Soggetti
Radiology,Nuclear Medicine & Medical Imaging","Cardiac & Cardiovascular System
Noninvasive methods are available to detect heart rate, systolic heart
function and blood pressure, on a beat-to-beat basis at rest and duri
ng standardized tests. Hence, a multivariate approach that allows more
insight into the capacity of the cardiovascular system can be realize
d for clinical routine. Electrocardiography, the first time derivative
of the transthoracic impedance (dZdt), the basal impedance (Zo), and
the finger arterial blood pressure were measured beat-to-beat in patie
nts in supine body positions (7 min). The physiological signals mere t
ransferred to an IBM PC and analyzed after analog-to-digital conversio
n (sample rate 200 Hz). Upper arm blood pressure was measured every 3
min using an automated oscillometric device. The mean values of heart
rate, arterial blood pressure at the upper arm and at the finger, and
systolic heart function (maximum of the first time derivative of the i
mpedancecardiogram divided by the basal impedance, dZdt/Zo) were analy
zed for 110 healthy, male volunteers who were investigated consecutive
ly. To characterize functional classes at rest, a fuzzy classification
toolbox was used. Five classes were found that included normotensives
and nontreated mild hypertensives (n = 32). The fuzzy pattern of each
cluster was described using four out of a variety of parameters (body
mass index, mean arterial pressure, mean arterial pressure at the fin
ger, dZdt/Zo). Low or normal mean arterial pressure and high or normal
volume blood flow was obtained mostly in young persons with normal bo
dy composition (group I and II). Groups III-V seem to reflect the chan
ges of the cardiovascular interrelationship caused by increasing aorti
c input impedance, peripheral resistance, and decreased systolic left
ventricular function, with a transition state of normal or even high f
low values against increased afterload (group III). The groups illustr
ate hemodynamic regulation caused by individual patterns of autonomic
efferences and target organ response. The obtained knowledge about dif
ferent hemodynamics at rest allows us to adapt therapy procedures to i
ndividual patients.