Continuous measurement of internal left ventricular diameter.

Horwitz, Lawrence D.; Bishop, V. S.; Stone, H. L.; Stegall, H F

doi:10.1152/jappl.1968.24.5.738

Cited by 49 publications

(21 citation statements)

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“…The transit time of 5 mHz ultrasound between ultrasonic crystal pairs was measured with a multichannel sonomicrometer (Scheussler and Assoc., San Diego, CA) using the electronics of Franklin (12) and was converted to distance assuming constant velocity of sound in blood of 1.55 mm/ ,gs. The resolution of this system has been reported at 0.07 mm with 5-mHz signals (13). High fidelity and fluid LV pressure, the first derivative of high fidelity LV pressure (dP/dt), aortic pressure, aortic flow velocity, and the dimensions of regional (group 1) or transverse LV diameter (group 2) ultrasonic crystal pairs were recorded on an 8 channel forced-ink pen oscillograph (Beckman Instruments Inc., Fullerton, CA) at a paper speed of 25 mm/s.…”

Section: Methodsmentioning

confidence: 99%

“…In the remaining 12 dogs (group 2), two 5-mHz piezoelectric crystals (4 mm in diameter) were also implanted along the greatest internal left ventricular transverse diameter, one on the anterior and the other on the posterior endocardial wall for continuous measurement of LV internal dimension and global percentage of shortening (13) in lieu of regional crystal pairs. In six of these dogs, electromagnetic cuff type flow probes (Zepeda Instruments, Seattle, WA) were placed around the ascending aorta.…”

Section: Methodsmentioning

confidence: 99%

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Direct and indirect effects of calcium entry blocking agents on isovolumic left ventricular relaxation in conscious dogs.

Walsh¹,

O’Rourke²

1985

J. Clin. Invest.

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To assess the direct and indirect effects of the commonly used calcium entry blockers (CEB) upon the major determinants of isovolumic left ventricular relaxation, we administered equidepressant intracoronary (IC, n = 7) and equihypotensive intravenous (n = 12) dosages of diltiazem (16±3 SE ,Ag/kg IC and 63±9 gg/kg i.v.), verapamil (10±2 and 57±5 Ag/kg), and nifedipine (1±0.1 and 8±0.3 ,g/kg) to preinstrumented awake dogs with normal ventricular function. The time constant of left ventricle (LV) relaxation, analyzed by two methods (T1, from the linear relation of the natural logarithm of LV pressure and time; T2, from the linear relation of LV pressure and negative high fidelity LV pressure), was significantly and equivalently prolonged by IC diltiazem (T, + 48%, P < 0.02), verapamil (T1 + 43%, P < 0.001), and nifedipine (T1 + 30%, P < 0.03). Lesser amounts of each CEB that did not affect rate of LV pressure development or extent of shortening produced no change in T1 or T2. By contrast, intravenous calcium entry blockade either produced no significant change (diltiazem and verapamil) or shortened (nifedipine T1 -18%, P < 0.01) LV isovolumic relaxation. However, after beta adrenergic blockade with propranolol (2 mg/kg i.v., n = 6) no change in ventricular relaxation was observed during nifedipine and the time constant was significantly prolonged by verapamil (T1 + 15%, P < 0.05).We conclude that calcium entry blockade directly impairs normal left ventricular relaxation: This effect is closely linked to the negative inotropic properties of these drugs. The prolongation of isovolumic relaxation produced by calcium blockade is attenuated or even reversed by reflex sympathetic stimulation and favorably altered loading conditions during systemic administration.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Direct and indirect effects of calcium entry blocking agents on isovolumic left ventricular relaxation in conscious dogs.

Walsh¹,

O’Rourke²

1985

J. Clin. Invest.

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“…The indices compared as measures of isovolumic relaxation were peak (-) dP/dt, the value of (-) dP/dt at a common isovolumic pressure, and the time constant, T, recently described by Weiss et al (11 (13). The pacing wires, ultrasound crystal, and micromanometer leads, and the left ventricular catheter were implanted subcutaneously in the neck, where they could be easily exposed for subsequent study.…”

Section: Introductionmentioning

confidence: 99%

“…The signals from the ultrasonic diameter gauges were calibrated for diameter equivalents of 15-50 mm in steps of 5 mm (12). This system permitted continuous recording of left ventricular internal diameter (13). The error in left ventricular diameter measurement induced by angular distortion up to 300 was less than 4% of the total measured distance (14).…”

Section: Introductionmentioning

confidence: 99%

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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“…It is possible, however, that another internal diameter with a different axis lengthens before the onest of ejection or that mitral or aortic valve area moves out of the ventricular cavity. Horwitz et al (1968) ;McDonald (1970) ;Bove (1971) ;and Rankin et al (1976)). Vokonas et al (1973) found no significant changes in left ventricular minor axis dimension of normal subjects.…”

Section: Discussionmentioning

confidence: 99%

The mechanical cardiac cycle. Shortening time of the internal diameter of the canine left ventricle.

et al. 1981

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Continuous measurement of internal left ventricular diameter.

Cited by 49 publications

References 0 publications

Direct and indirect effects of calcium entry blocking agents on isovolumic left ventricular relaxation in conscious dogs.

Direct and indirect effects of calcium entry blocking agents on isovolumic left ventricular relaxation in conscious dogs.

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

The mechanical cardiac cycle. Shortening time of the internal diameter of the canine left ventricle.

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