PMID: 9442476Jan 27, 1998Paper

Aortic peak flow velocity as an index of myocardial contractility in the conscious rat

Methods and Findings in Experimental and Clinical Pharmacology
R T Dowell, A A Houdi

Abstract

The present studies were conducted in conscious, instrumented rats to evaluate measurements of aortic peak flow velocity (PFV) as an index of myocardial contractility. Because our previous studies had characterized/verified procedures to determine pressure-derived indices of contractile function in the anesthetized, ventilated, open-chest rat, we first correlated PFV with (a) maximum rate of left ventricular pressure development (max +dP/dt) and (b) a contractility index derived by dividing max +dP/dt by left ventricular pressure at max +dP/dt [(dP/dt)/P] in anesthetized rats (n = 5). The positive inotropic agent, isoproterenol, given by bolus intravenous injection (0.2 microgram), significantly and concurrently increased dP/dt, (dP/dt)/P, and PFV. The negative inotropic agent, propranolol, given by bolus intravenous injection (2 mg/kg), significantly and concurrently attenuated all of the above measurements. When control, isoproterenol, and propranolol responses were used to calculate multivariate correlation coefficients among dP/dt, (dP/dt)/P, and PFV, r values ranged from 0.74 (PFV vs. dP/dt) to 0.84 (dP/dt vs. (dP/dt)/P) to 0.91 (PFV vs. (dP/dt)/P). A separate group of rats (n = 4) was surgically implanted with ascending a...Continue Reading

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