A stable ultraminiature catheter-tip pressure transducer

Millar, Huntly; Baker, Lisa

doi:10.1007/bf02477303

Cited by 92 publications

(31 citation statements)

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“…Details of the use of this catheter, and the methods and techniques for calculating systemic input impedance, were published earlier (Murgo et al, 1980(Murgo et al, , 1981a(Murgo et al, , 1981b. Details of the technical characteristics of pressure and velocity sensors, including frequency response, drift characteristics, calibration techniques, etc., have been described previously TABLE 1 Basic Patient Data Patient P-1 P-2 P-3 P-4 P-5 P-6 P-7 P-8 P-9 P-10 (Murgo and Millar, 1972;Millar and Baker, 1973;Nichols and Walker, 1974;Murgo, 1975;Murgo et al, 1977).…”

Section: Patient Selection and Catheterization Techniquesmentioning

confidence: 99%

Input impedance of the pulmonary arterial system in normal man. Effects of respiration and comparison to systemic impedance.

Murgo¹,

Westerhof

1984

Circulation Research

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SUMMARY. Input impedance of the pulmonary arterial system was determined in 10 subjects undergoing elective cardiac catheterization. No cardiovascular or pulmonary disease was found in these patients. In five of the subjects, systemic arterial input impedance was also obtained, so that both systems could be compared. Pulmonary and systemic peripheral resistances were 79 ± 9 dynes sec/cm 5 (mean ± SEM) and 1016 ± 50 dynes sec/cm 5 , respectively. Characteristic impedance of the pulmonary circulation was lower than the characteristic impedance of the systemic circulation: 20 ± 1 dynes sec/cm 5 vs. 47 ± 9 dynes sec/cm ! , respectively. Pulmonary pressure and flow spectra for both systems are also presented. The amplitudes of the harmonics of pressure and flow are smaller for the pulmonary circulation, which is consistent with the lower pressures and more rounded waveforms of the normal pulmonary circulation. In all 10 subjects, input impedance of the pulmonary system was examined during both the inspiratory and expiratory phases of respiration. There was no difference between inspiration and expiration in either pulmonary vascular resistance (77 ± 10 dynes sec/cm ! vs. 80 ± 9 dynes sec/cm 5 , respectively), characteristic impedance (20 ± 1 dynes sec/cm 5 vs. 20 ± 1 dynes sec/cm 5 ) or in the overall impedance spectrum. Quiet respiration, thus, has no effect on the pulmonary arterial load, and changes in pressure and flow must result from alterations in right ventricular performance. (CircRes 54: 666-673, 1984) UNLIKE the systemic circulation, the pulmonary vascular system in normal man is a low pressure system which is entirely exposed to changes in intrathoracic pressure during respiration. The effects of these changes on the physical characteristics of the human pulmonary circulation are unknown. It is of physiological and clinical importance to know how the pulmonary vasculature is affected by respiration, especially when evaluating the relationships between this vascular bed and right ventricular function. To study such effects, it is necessary to describe the pulmonary circulation in quantitative terms. One method is to calculate pulmonary input impedance. The input impedance of a vascular bed not only provides information about the pulsatile pressure-flow relationships, but also yields information regarding the physical characteristics of that bed (Randall and

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Section: Patient Selection and Catheterization Techniquesmentioning

confidence: 99%

Input impedance of the pulmonary arterial system in normal man. Effects of respiration and comparison to systemic impedance.

Murgo¹,

Westerhof

1984

Circulation Research

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“…Details of the technical characteristics and calibrations of these sensors, analog and digital processing techniques, and their application to the human circulation have been described previously (Murgo and Millar, 1972;Millar and Baker, 1973;Nichols et al, 1977;Murgo, 1975;Murgo et al, 1977;Nichols et al, 1980).…”

Section: Patient Selection and Catheterization Techniquesmentioning

confidence: 99%

Effects of exercise on aortic input impedance and pressure wave forms in normal humans.

Murgo¹,

Westerhof

Giolma

et al. 1981

Circulation Research

106

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SUMMARY The effects of supine bicycle exercise on the input impedance of the ascending aorta were studied in thirteen male subjects undergoing cardiac catheterization, but in whom no cardiovascular disease was found. Ascending aortic flow velocity and pressure were recorded simultaneously from a multisensor catheter with an electromagnetic flow velocity probe and a pressure sensor mounted at the same location. A second pressure sensor at the catheter tip provided left ventricular pressure. Fick cardiac outputs were used to scale the velocity signal to instantaneous volumetric flow. Input impedance was calculated from 10 harmonics of aortic pressure and flow. For each subject, impedance moduli and phases from a minimum of 15 beats during rest and exercise were averaged. Peripheral resistance decreased from a resting value of 1142 ± 51 (± SE) dynes sec/cm 6 to 712 ± 39 dynes sec/cm 6 during exercise. Characteristic impedance remained unchanged with a resting value of 47 ± 4 dynes sec/cm 5 and an exercise value of 45 ± 4 dynes sec/cm 5 . These results were associated with an increase in aortic pressure (96 ± 2 to 111 ± 2 mm Hg) and pulse wave velocity implying a decrease in aortic compliance. An increase in aortic cross-sectional area apparently offsets the effects of these changes in compliance and pulse wave velocity to result in an unchanged characteristic impedance. The increase in pulse wave velocity caused wave reflections to occur earlier during exercise, but the general characteristics of the pressure wave shapes remained unchanged. Circ Res 48: 334-343, 1981

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“…In 22 control subjects and 25 HCM patients, a modification of this catheter contained an electromagnetic aortic flow velocity probe (Carolina Medical Electronics, Inc., King, N. C., Millar Instruments, Inc., 1975) located 9 cm from the tip or, in a later design, adjacent to the aortic pressure sensor (see Table I). The technical and calibration details of the solid state pressure sensors and the flow velocity probe have been presented elsewhere (19)(20)(21)(22)(23)(24)(25)(26).…”

Section: Introductionmentioning

confidence: 99%

Dynamics of left ventricular ejection in obstructive and nonobstructive hypertrophic cardiomyopathy.

Murgo¹,

et al. 1980

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A B S T R A C T The purpose of this study was to examine the dynamics of left ventricular ejection in patients with obstructive and nonobstructive hypertrophic cardiomyopathy (HCM). 30 patients with HCM and 29 patients with no evidence of cardiovascular disease were studied during cardiac catheterization. Using a single multisensor catheter, electromagnetically derived ascending aortic flow velocity and high fidelity left ventricular and aortic pressures were recorded during rest (tl = 47) and provocative maneuvers (it = 23). Dynamic ventricular emptying during rest was also analyzed with frame-by-frame angiography (n = 46). Left ventricular outflow was independently derived from both flow velocity and angiographic techniques. The HCM patients were subdivided into three groups: (I) intraventricular gradients at rest (n = 9), (II) intraventricular gradients only with provocation (n = 12), and (III) no intraventricular gradients despite provocation (n = 9). During rest, the percentage of the total systolic ejection period during which forward aortic flow existed was as follows (mean+ 1 SD): group I, 69+17% (flowv), 64±6% (angio); group II, 63 +14% (flow), 65±+6% (angio); group III, 61+16% (flow), 62±+4% (angio); control group, 90±o5% (flow), 86±+9% (angio). No significant difference was observed between any of the HCM subgroups, but compared with the control group, ejection was completed much earlier in systole independent of the

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A stable ultraminiature catheter-tip pressure transducer

Cited by 92 publications

References 0 publications

Input impedance of the pulmonary arterial system in normal man. Effects of respiration and comparison to systemic impedance.

Input impedance of the pulmonary arterial system in normal man. Effects of respiration and comparison to systemic impedance.

Effects of exercise on aortic input impedance and pressure wave forms in normal humans.

Dynamics of left ventricular ejection in obstructive and nonobstructive hypertrophic cardiomyopathy.

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