2 ARTERIAL EFFECTIVE REFLECTING SITES MAY APPEAR AS ONE TO THE HEART

被引:39
作者
BURATTINI, R
KNOWLEN, GG
CAMPBELL, KB
机构
[1] WASHINGTON STATE UNIV, DEPT PHARMACOL & PHYSIOL, PULLMAN, WA 99164 USA
[2] WASHINGTON STATE UNIV, DEPT VET CLIN MED & SURG, PULLMAN, WA 99164 USA
[3] WASHINGTON STATE UNIV, DEPT VET & COMPARAT ANAT, PULLMAN, WA 99164 USA
关键词
ARTERIAL PARAMETER ESTIMATION; ARTERIAL WAVE REFLECTION; HYPERTENSION; SINGLE-TUBE ARTERIAL MODEL; T-TUBE ARTERIAL MODEL; VASOCONSTRICTION;
D O I
10.1161/01.RES.68.1.85
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
The relation between reflected waves and features of ascending aortic pressure waveforms and impedance patterns was investigated with a modified T-tube model of the systemic arterial circulation. Ascending aortic pressure and flow and descending aortic flow were measured in 10 dogs under basal conditions and under the effect of an agent (methoxamine) that caused vasoconstriction and an increase of mean aortic pressure. A broad range of aortic pressure amplitudes and features was obtained. These waveshapes were classified into four groups. Under basal conditions, cases for which a prominent diastolic fluctuation was present (n = 8) were grouped in A. Cases for which this fluctuation was absent (n = 2) were grouped in B. Groups C (n = 4) and D (n = 3) included cases that, under vasoconstricted conditions, did or did not display, respectively, a diastolic fluctuation in pressure. Arterial T-tube model parameters were estimated by simultaneously fitting the model to both ascending and descending aortic flows with aortic pressure as input. A good fit was obtained in any case considered. After parameter estimation, forward and reflected waves and impedance patterns at the entrance of head circulation (head and upper limbs) and body circulation (trunk and lower limbs) as well as their merger in the ascending aorta were determined. T-tube input impedance compared well with impedance data points obtained from the ratio of corresponding harmonics of ascending aortic pressure and flow. In some cases (group A), modulus and phase spectra displayed two distinct minima, in the range from 0 to 10 Hz. In some other circumstances, these minima were less distinct (groups B and C) and could even appear as one (group D). Whether one or two minima appeared in the ascending aortic impedance spectra at low frequency and whether a prominent diastolic fluctuation did or did not appear in aortic pressure, pressure and flow waveshapes proximal to the heart were explained by the presence of two effective reflecting sites in the systemic circulation. In group B, a diastolic fluctuation in pressure was absent despite the fact that head-end and body end reflected waves were distinct. This happened because body-end reflected waves peaked corresponding to a minimum of the head-end reflected wave. In group D, a diastolic fluctuation in aortic pressure was absent because the body-end reflected wave moved into systole and superimposed on the head-end reflected wave. This superimposition was due to increased pulse wave velocity in the body transmission path as a result of decreased arterial distensibility. After comparing our T-tube model with a single-tube model representation of systemic circulation, we concluded that, in cases like those grouped in D, two effective reflecting sites appear as one to the heart.
引用
收藏
页码:85 / 99
页数:15
相关论文
共 35 条
[1]   MULTI-BRANCHED MODEL OF THE HUMAN ARTERIAL SYSTEM [J].
AVOLIO, AP .
MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING, 1980, 18 (06) :709-718
[2]   COMPARATIVE-STUDY OF PULSATILE ARTERIAL HEMODYNAMICS IN RABBITS AND GUINEA-PIGS [J].
AVOLIO, AP ;
OROURKE, MF ;
MANG, K ;
BASON, PT ;
GOW, BS .
AMERICAN JOURNAL OF PHYSIOLOGY, 1976, 230 (04) :868-875
[3]   EFFECT OF NITROPRUSSIDE ON WAVE REFLECTIONS IN PATIENTS WITH HEART-FAILURE [J].
BRIN, KP ;
YIN, FCP .
ANNALS OF BIOMEDICAL ENGINEERING, 1984, 12 (02) :135-150
[4]   A SIMPLE ALGORITHM FOR DEFINING THE MEAN CARDIAC CYCLE OF AORTIC FLOW AND PRESSURE DURING STEADY-STATE [J].
BURATTINI, R ;
FIORETTI, S ;
JETTO, L .
COMPUTERS AND BIOMEDICAL RESEARCH, 1985, 18 (04) :303-312
[5]   EFFECTIVE LENGTH OF THE ARTERIAL CIRCULATION DETERMINED IN THE DOG BY AID OF A MODEL OF THE SYSTEMIC INPUT IMPEDANCE [J].
BURATTINI, R ;
DICARLO, S .
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, 1988, 35 (01) :53-61
[6]   MODIFIED ASYMMETRIC T-TUBE MODEL TO INFER ARTERIAL WAVE REFLECTION AT THE AORTIC ROOT [J].
BURATTINI, R ;
CAMPBELL, KB .
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, 1989, 36 (08) :805-814
[7]   COMPUTER IDENTIFICATION OF MODELS FOR THE ARTERIAL TREE INPUT IMPEDANCE - COMPARISON BETWEEN 2 NEW SIMPLE-MODELS AND 1ST EXPERIMENTAL RESULTS [J].
BURATTINI, R ;
GNUDI, G .
MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING, 1982, 20 (02) :134-144
[8]  
BURATTINI R, 1989, VASCULAR DYNAMICS PH, P69
[9]   TIME-DOMAIN FORMULATION OF ASYMMETRIC T-TUBE MODEL OF ARTERIAL SYSTEM [J].
CAMPBELL, KB ;
BURATTINI, R ;
BELL, DL ;
KIRKPATRICK, RD ;
KNOWLEN, GG .
AMERICAN JOURNAL OF PHYSIOLOGY, 1990, 258 (06) :H1761-H1774
[10]   AN ALGORITHM FOR MACHINE CALCULATION OF COMPLEX FOURIER SERIES [J].
COOLEY, JW ;
TUKEY, JW .
MATHEMATICS OF COMPUTATION, 1965, 19 (90) :297-&