Continuous Measurements of Left Ventricular Dimensions in Intact, Unanesthetized Dogs

Rushmer, Robert F.; Crystal, Dean K.; Wagner, Clyde; Ellis, Richard M.; Nash, Alden A.

doi:10.1161/01.res.2.1.14

Cited by 60 publications

(12 citation statements)

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“…In other words, exercise usually produces a decrease in both end-diastolic and end-systolic left ventricular volume; stroke work and usually stroke volume are, at the same time, increased. In general, the findings are in keeping with the older orthodiagraphic studies and closely parallel the results of Rushmer's elegant experiments (15) (Figure 7). The strong probability is that for any but resting conditions it is hazardous to follow the usual practice of calculating pressure work only (ignoring kinetic work altogether) and of using mean values (minute volume divided by pulse rate for stroke volume; systolic plus diastolic divided by 2 for mean pressure).…”

Section: Fig 4 Exercising Ejection (Left) and Velocity (Right) Curvsupporting

confidence: 89%

Left Ventricular Function at Rest and During Exercise*

Chapman¹,

Baker²,

Mitchell³

1959

J. Clin. Invest.

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Section: Fig 4 Exercising Ejection (Left) and Velocity (Right) Curvsupporting

confidence: 89%

Left Ventricular Function at Rest and During Exercise*

Chapman¹,

Baker²,

Mitchell³

1959

J. Clin. Invest.

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“…He also has recorded length changes internally. 25 These recordings more nearly approximate those we observed by using the external length gauge, as we applied it. Linden and Mitchell 20 recorded changes in myocardial segment length, but the length of the segment they studied was usually 25 mm., whereas the average total base-to-apex length of the dog heart approximates 5 to 8 cm.…”

Section: Left Ventricular Dimensional Changes In Awake Dogs During Thsupporting

confidence: 69%

Instantaneous Dimensional Changes of the Left Ventricle in Dogs

Hawthorne

1961

Circulation Research

132

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HE MOST meaningful way of determining the mechanisms operative in the moment-to-moment control of ventricular functions is to obtain an accurate estimate of the performance of the heart in intact, unanesthetized animals. For this purpose, we should monitor exactly both static and dynamic cardiac effort.1 The important factor to be followed, therefore, is that of total cardiac work, both in normal, intact animals and in animals under a variety of circumstances. An estimate of the total tension developed by the heart is required when trying to follow the work from moment to moment. As has been previously stated, "The total tension developed by the heart can be accurately calculated when one knows the systolic residual and the end-diastolic volumes, the end-systolic and end-diastolic intracavitary pressures, the rate of change of volume and pressure from moment to moment during the contraction of the heart, and the K value of Laplace's Equation." 2 Our own studies have evolved from an attempt to monitor the instantaneous changes in the external volume of the left ventricle in intact, unanesthetized dogs by a technique of electromagnetic plethysmography.3 This method permits the continuous recording of the summated external cross-sectional areas of the left ventricle. The external volume of a chamber, such as the left ventricle, is directly related to, and varies with, the mean cross-sectional area of the chamber times its length. AVhere the changes in length of this chamber are extremely small, the instantaneous volume will be directly related to the sum of a series of its simultaneously and instan-

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“…Rushmer and his co-workers (16,17) the external cross-sectional area of the left ventricle with an electromagnetic method and external circumference with a mercury and rubber strain gauge. After the sixth postoperative day (but not before) he found changes in these dimensions in diastole that were similar to our results for volume.…”

Section: Left Ventricular Fillingmentioning

confidence: 99%

Left Ventricular Filling and Diastolic Pressure-Volume Relations in the Conscious Dog

Noble

Milne

Goerke

et al. 1969

Circulation Research

133

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In 7 conscious dogs, left ventricular diastolic volume (V) was estimated by taking biplane cineradiographs with the left ventricular cavity previously outlined by permanent radiopaque markers. Left ventricular pressure (P) was measured with an implanted miniature transducer. There were two rapid filling periods during early and late diastole; little filling occurred during the middle third of diastole (diastasis). The diastolic pressure-volume relationship was approximately exponential and was fitted by the equation P = -a + be cY , where a, b, and c are positive constants; the relationship appeared to be determined principally by the elastic properties. The effects of infusions of saline, isoproterenol, calcium gluconate, and methoxamine suggested that viscous and inertial properties are also important determinants of diastolic left ventricular mechanics. No significant series viscosity was observed. Plastic properties were not detected. The elastic properties were not affected by agents having a positive inotropic effect. End-diastolic pressure often differed from that predicted by the exponential equation above, suggesting that it is not a reliable index of enddiastolic volume and left ventricular compliance. ADDITIONAL KEY WORDStantalum markers biplane cineradiography end-diastolic pressure left ventricular compliance isoproterenol elastic components myocardial plasticity series viscous element inertial properties left ventricular distensibility calcium methoxamine• The present study was undertaken to answer the following questions in the conscious dogs: (a) how does the volume of the left ventricle change during diastole; (b) what is the relationship between left ventric-

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Continuous Measurements of Left Ventricular Dimensions in Intact, Unanesthetized Dogs

Cited by 60 publications

References 0 publications

Left Ventricular Function at Rest and During Exercise*

Left Ventricular Function at Rest and During Exercise*

Instantaneous Dimensional Changes of the Left Ventricle in Dogs

Left Ventricular Filling and Diastolic Pressure-Volume Relations in the Conscious Dog

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