A Quantitative Analysis of Left Ventricular Myocardial Function in the Intact, Sedated Dog

Taylor, Roger R.; Ross, John; Covell, James W.; Sonnenblick, Edmund H.; Lewis, Robert M.

doi:10.1161/01.res.21.1.99

Cited by 92 publications

(47 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…They concluded that aortic valve opening tends to limit max dP/dt. In the present study, max dP/dt of single isovolumic beats was generally identical with that of the preceding auxotonic beat and a similar experience has been reported by others (6,32). It should be noted that in the studies of Wildenthal et al, an air pump was used to elevate aortic pressures and central pulse pressures were unusually wide at the heart rates studied.…”

Section: Introductionsupporting

confidence: 90%

Estimation of Vmax in auxotonic systoles from the rate of relative increase of isovolumic pressure: (dP/dt)kP

Wolk¹,

Keefe²,

Bing³

et al. 1971

J. Clin. Invest.

View full text Add to dashboard Cite

A B S T R A C T High speed oscilloscopic recordings (4000 mm/sec) of left ventricular pressure (micromanometer) and its first derivative were used to calculate contractile element velocity (Vce) during the isovolumic period of auxotonic beats in anesthetized dogs. At 0.5-2.0 msec intervals of isovolumic systole, Vce was derived as (dP/dt)/kP, where k = 24 cm-'. Plots of Vce and P yielded inverse curves from peak Vce to aortic valve opening pressure which averaged 27 msec in controls, and 11 msec during norepinephrine administration. Extrapolated Vmax, in muscle lengths/second, averaged 3.6 (controls), 3.6 (volume load), and 6.6 (norepinephrine). In each experimental state, Vmax was also determined from force-velocity relations of isovolumic beats (abrupt aortic occlusion) analyzed at 10 msec intervals from conventional pressure recordings.Vmax by both methods correlated well (r = 0.88). While good correlations were also noted between Vmax and maximum dP/dt, (max dP/dt)/integrated isovolumic pressure, (max dP/dt)/peak isovolumic pressure, and (max dP/dt)/kP, only the last two of these successfully distinguished changes between volume load and inotropic stimulation. Thus, assuming an unchanged series elasticity, the contractile state of the auxotonic ventricle may be determined utilizing a single high-fidelity catheter system and high speed recordings of isovolumic pressure. INTRODUCTIONThe contractile state of the myocardium can be characterized by the instantaneous relationship between developed force and contractile element velocity, provided that information regarding muscle length and time are

show abstract

Section: Introductionsupporting

confidence: 90%

Estimation of Vmax in auxotonic systoles from the rate of relative increase of isovolumic pressure: (dP/dt)kP

Wolk¹,

Keefe²,

Bing³

et al. 1971

J. Clin. Invest.

View full text Add to dashboard Cite

show abstract

“…In the seven patients in whom the effects of supine leg exercise were studied, dp/dt at any pressure throughout the period of isovolumic contraction rose significantly (P < 0.01), while (dp/dt)/CP1P increased strikingly, from 29 ' 9 that although peak ventricular dp/dt is exquisitely sensitive to changes in the inotropic state, it also can be affected to some degree by alterations of arterial diastolic pressure, which is a function of ventricular afterload and, therefore, of the peripheral vascular bed. Unless diastolic pressure is markedly elevated, peak dp/dt usually occurs Relation between left ventricular end-diastolic pressure and left ventricular dp/dt at a commotn level of isovolumetric pressure (40 mm Hg).…”

Section: Exercisementioning

confidence: 93%

Assessment of Cardiac Contractility

et al. 1971

Self Cite

View full text Add to dashboard Cite

SUMMARYIt was considered that the relationship between dp/dt and simultaneously developed pressure during the course of isovolumic contraction might afford a more accurate measure of contractility than the maximum rate of intraventricular pressure rise (peak dp/dt). In six cat papillary muscles contracting isometrically from any given preload, the ratio of the rate of tension development (dT/dt) to simultaneously occurring isometric tension always varied directly with the contractile state. This ratio rose slightly as preload was increased, but it was not affected by changes in afterload. In 17 experiments in an intact canine heart preparation in which left ventricular end-diastolic pressure was constant, dp/dt at any given pressure during isovolumetric contraction again was observed to be a function of the contractile state when the latter was enhanced by norepinephrine and acetylstrophanthidin. High-fidelity left ventricular pressures and dp/dt were recorded throughout isovolumic contraction in eight patients. Isoproterenol and exercise raised the level of dp/dt at any given pressure prior to ejection. Interventions known to alter ventricular loading but not to influence the contractile state, such as elevation of ventricular end-diastolic pressure by leg raising and increases in aortic pressure induced by methoxamine, did not influence this relation significantly. In conclusion, the determination of dp/dt and intraventricular pressure throughout isovolumic contraction in the presence of variable arterial pressure and small changes of preload provides a useful, simple, and experimentally verified approach to the assessment of alterations of the contractile state of the heart in intact man.

show abstract

“…A spherical model for the left ventricle was utilized, and the calculations were similar to those described previously by others*. 10 (table 1). There were no significant differences in the baseline cardiac outputs between the groups (table 1).…”

Section: Methodsmentioning

confidence: 99%

“…At rest in their cages, heart rate in the stressed animals was 20-30 beats/min faster than in the sham-operated or control dogs. Under the conditions of the experimental dT/ dl is the series elastic constant, numerically equal to 30 T.9 10 When left ventricular peak systolic pressures, peak systolic wall stress, peak dp/dt, and peak contractile element velocity( (VICE) at four matched levels of left ventricular enddiastolic pressure were compared, left ventricular performance appeared to be appreciably depressed (table 2, fig. 2).…”

Section: Methodsmentioning

confidence: 99%

Effects of Chronic Right Ventricular Volume and Pressure Loading on Left Ventricular Performance

et al. 1971

View full text Add to dashboard Cite

SUMMARYThe effects of chronic right ventricular (RV) distension on left ventricular (LV) funiction were assessed in dogs 3 weeks after pressure and volume loading of the RV lhad been produced by the emplacement of a constricting band around the pulmonary artery and the creation of tricuspid insufficiency. This resulted in ascites, RV hypertrophy and dilatation, an increase in RV end-diastolic pressure (EDP), and a reduction of RV and LV norepinephrine concentrations. Peak LV pressure, wall stress, and dp/dt were measured during isovolumic beats at LVEDP's of 1 to 20 mm Hg, and comparisons at matched EDP's were made among the normal, sham-operated, and RV stressed dogs. Under these circumstances, LV function appeared to be depressed appreciably. The effects of RV volume loading on the pressure-volume curve of the LV in the potassium-arrested heart were assessed in a separate group of dogs. The pressure-volume curve of the LV was shifted so that any given LV volume was associated with a higher LV pressure. Thus, when peak pressure and wall stress were related to LV end-diastolic volume rather than to LVEDP, the relationship did not appear to differ from normal; peak dp/dt and peak VCE, however, remained depressed. This depression may represent a decrease in LV contractility consequent to the chronic RV stress or may reflect alterations in LV geometry. Thus, when the RV is subjected to a chronic flow and pressure load, assessment of LV function may be unreliable when indices of contractility are employed that require measurements of LVEDP.

show abstract

A Quantitative Analysis of Left Ventricular Myocardial Function in the Intact, Sedated Dog

Cited by 92 publications

References 49 publications

Estimation of Vmax in auxotonic systoles from the rate of relative increase of isovolumic pressure: (dP/dt)kP

Estimation of Vmax in auxotonic systoles from the rate of relative increase of isovolumic pressure: (dP/dt)kP

Assessment of Cardiac Contractility

Effects of Chronic Right Ventricular Volume and Pressure Loading on Left Ventricular Performance

Contact Info

Product

Resources

About