Effect of sudden changes in aortic pressure on left ventricular dp/dt

Wildenthal, K.; Mierzwiak, DS; Mitchell, J. H.

doi:10.1152/ajplegacy.1969.216.1.185

Cited by 67 publications

(17 citation statements)

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“…Further, it should be noted that during acute increases in afterload, an afterload mismatch can develop at any given level of inotropic state, either if the change in afterload is inadequately compensated by an accompanying change in preload or if the limit of the FrankStarling mechanism is reached (33). Our experiments differ from those previously reported (6,(28)(29)(30), in that volume was administered before phenylephrine in an attempt to allow maximal utilization of preload reserve during acute afterloading. During peak levels of left ventricular pressure, mean VCf declined and peak (+) dP/dt did not rise, suggesting that the limit of preload reserve had been reached.…”

Section: Interventions Before and After Beta-adrenergic Blockadementioning

confidence: 69%

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Pharmacologic and Hemodynamic Influences on the Rate of Isovolumic Left Ventricular Relaxation in the Normal Conscious Dog

Karliner¹,

LeWinter²,

Mahler³

et al. 1977

J. Clin. Invest.

231

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A B S T R A C T We studied the effects of acute pharmacologic and hemodynamic interventions on isovolumic left ventricular relaxation in 19 conscious dogs using micromanometer tip catheters. Isoproterenol (11 studies) augmented peak rate of rise of left ventricular pressure [(+) dP/dt] by 1,275+227 (SE) mm Hg/s (P < 0.001) and dP/dt at an isopressure point of 35 mm Hg during isovolumic relaxation [(-) dP/dt35] by 435±80 mm Hg/s (P < 0.001). Peak (-) dP/dt decreased by 467±89 mm Hg/s (P < 0.002). The time constant, T, derived from the logarithmic fall ofpressure during isovolumic relaxation, shortened from 20±2.8 to 14.9± 1.8 ms (P < 0.003). Calcium ( 11 studies) increased peak (+) dP/dt and (-) dP/dt35 (both P <0.0001); peak (-) dP/dt was unchanged. T shortened from 20.4±1.8 to 17.3±1.5 ms (P < 0.002). Volume (13 studies) did not affect either dP/dt or T. Phenylephrine (13 studies) augmented peak (-) dP/dt, but reduced (-) dP/dt35 (both P < 0.01); T lengthened from 22.1±1.5 to 32.5±1.5 ms (P < 0.01). In 15 studies, rapid atrial pacing increased peak (+) dP/dt and (-) dP/dt35 (both P < 0.01). In the first post-pacing beat, peak (-) dP/dt and (-) dP/dt35 decreased (both P <0.01), although peak (+) dP/dt increased furtier. T paralleled values of (-) dP/dt35. In five dogs, beta

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Section: Interventions Before and After Beta-adrenergic Blockadementioning

confidence: 69%

“…In previous studies it was observed that increased arterial pressure augmented peak (+) dP/dt, (6,(28)(29)(30) and peak (-) dP/dt (6). By contrast, in the conscious dog, Barnes et al reported that an increase in mean aortic pressure of48 mm Hg augmented peak (+) dP/dt by only 9% (25).…”

Section: Interventions Before and After Beta-adrenergic Blockadementioning

confidence: 93%

Pharmacologic and Hemodynamic Influences on the Rate of Isovolumic Left Ventricular Relaxation in the Normal Conscious Dog

Karliner¹,

LeWinter²,

Mahler³

et al. 1977

J. Clin. Invest.

231

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“…Although it has been shown that inotropic interventions do not affect series elasticity (8) and that both hypertrophy and myocardial failure do not influence the modulus of series elasticity (25), the extent to which mechanical asynergy may produce changes in active stiffness of the ventricle is not known. This consideration assumes importance, particularly in studies of the diseased human heart, since it has been shown that the functional series elasticity of the ventricle is decreased by experimental left ventricu-lar aneurysm (12 Mason and his associates maintain that max dP/dt "generally occurs at the maximum isovolumic pressure of ejecting beats" (30), and Wildenthal, Mierzwiak, and Mitchell (31) found that max dP/dt occurred at or within 5 msec before aortic end-diastolic pressure. The latter workers reported that abrupt elevations of aortic pressure between two ventricular beats generally increased max dP/dt and delayed the time at which max dP/dt was achieved in the afterloaded beat.…”

Section: Introductionmentioning

confidence: 99%

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.

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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

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“…Discussion max dp/dt max dp/dt was first suggested by Wiggers in 1927 [40], as an index of contractility and its change with variations in inotropic state has been confirmed by many workers [36], A number of authors have found, how ever, that dp/dt is importantly influenced by preload [35,36] and some what influenced by afterload [36,41] and rate [36], Wallace et al, using a right heart bypass preparation at constant rate and aortic pressure, found a 60-percent rise in dp/dt with a change in LVEDP from 5 to 11 cm of water [36], Veragut and Krayenbuehl found that reducing LVEDV in dogs from24 to 18 ml, decreased dp/dt 25 to 30% [35], Despite these crit icisms, this index has been widely employed and appears to be useful [5,18].…”

Section: Rf]mentioning

confidence: 75%

A Comparison of Empiric Contractile Indices in Intact Dogs

Patterson¹,

Kent²,

Peirce³

1972

Cardiology

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Since construction of ventricular function curves and computation of the maximum velocity of the contractile element (V_CEmax) are technically difficult, a number of other empiric contractility indices were compared in (1) chronically instrumented awake dogs and (2) in anesthetized dogs given slug doses of isoproterenol or volume loaded before and after autonomic blockade. Five indices: V_CEmax, max dp/dt, t-max dp/dt, (max dp/dt)/LVP_d, and (max dp/dt)/ IIT, were tested in unanesthetized animals and were found to correlate well with each other, the coefficient of correlation varying from 0.56 to 0.89. Ten indices: max dp/dt, t-max dp/dt, (max dp/dt)/LVP_d, (max dp/dt)/LVP_t, peak (dp/dt/LVP_t), t-peak (dp/dt/ LVP ), t-max flow, PEP, and V_CEmax (left ventricular end diastolic volume [LVEDV] both measured and assumed), were compared in the anesthetized animals. They were found to be satisfactorily reproducible, to respond well to small doses of isoproterenol but to be moderately sensitive to volume loading in the case of PEP, t-peak (dp/dt/LVP_t), (max dp/dt)/LVP_t, peak (dp/dt/LVP_t), max dp/dt and V_CEmax (LVEDV assumed None of these indices can be recommended without reservation and none is without merit. PEP can be calculated from data obtained by noninvasive methods and will be useful in the absence of significant mitral or aortic valve disease. V_CEmax offers advantages only if ventricular end diastolic volume is measured.

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Effect of sudden changes in aortic pressure on left ventricular dp/dt

Cited by 67 publications

References 0 publications

Pharmacologic and Hemodynamic Influences on the Rate of Isovolumic Left Ventricular Relaxation in the Normal Conscious Dog

Pharmacologic and Hemodynamic Influences on the Rate of Isovolumic Left Ventricular Relaxation in the Normal Conscious Dog

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

A Comparison of Empiric Contractile Indices in Intact Dogs

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