Key result
Modest alterations in loading conditions via methoxamine or nitroprusside infusion did not significantly affect the time constants of left ventricular isovolumic relaxation at a constant heart rate.
Why the study?
Does alteration of loading conditions with methoxamine or nitroprusside affect the rate of isovolumic left ventricular relaxation in humans?
Population
14 patients instrumented with micromanometer left ventricular and right atrial pacing catheters
Comparison
Infusion of methoxamine or nitroprusside to… vs Control conditions (baseline)
Authors
Loading...
Supports load-independent tau at fixed HR in humans; extends animal data but leaves open confirmation in larger cohorts.
Does alteration of loading conditions with methoxamine or nitroprusside affect the rate of isovolumic left ventricular relaxation in humans?
The time constants of left ventricular isovolumic relaxation are independent of modest alterations in loading conditions when heart rate is kept constant.
Starling et al. (1987) studied this question. Methoxamine or nitroprusside infusion vs. Control conditions was evaluated on Rate of isovolumic relaxation (time constants Tln and TD). Modest alterations in loading conditions via methoxamine or nitroprusside infusion did not significantly affect the time constants of left ventricular isovolumic relaxation at a constant heart rate.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: