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Updated: Sep 27, 2026
Cardiac Response to β-Adrenergic Stimulation Determined by Pressure-Volume Loop Analysis
Published on: May 19, 2021
Differential systolic and diastolic effects of beta-adrenergic stimulation in patients with severe left ventricular
Claudio Marcassa1, Michele Galli, R Campini
1Division of Cardiology, Salvatore Maugeri Foundation IRCCS, Scientific Institute of Veruno (NO), National Research Council, Pisa, Italy. cmarcassa@fsm.it
Insights
Beta-adrenergic stimulation improves diastolic function in patients with severe left ventricular (LV) dysfunction, even with blunted systolic responses. These positive lusitropic effects on diastolic function emerge earlier than improvements in systolic function.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Patients with severely depressed left ventricular (LV) function exhibit an attenuated inotropic response to beta-adrenergic stimulation.
- Limited data exist on the effects of beta-adrenergic stimulation on LV diastolic function in humans.
Purpose of the Study:
- To evaluate the impact of dobutamine infusion on LV systolic and diastolic function in patients with severe ventricular dysfunction.
Main Methods:
- Studied 26 stable patients with healed myocardial infarction and LV ejection fraction (EF) < 35%.
- Assessed LV ejection fraction (LVEF), volumes, peak ejection rate (PER), peak filling rate (PFR), and systolic pressure-to-end-systolic volume ratio at dobutamine infusion rates of 5 and 10 gamma x kg(-1) x min(-1).
Main Results:
- At 5 gamma x kg(-1) x min(-1), heart rate and LVEF were unchanged, but PFR significantly increased.
- At 10 gamma x kg(-1) x min(-1), LVEF, PER, and PFR increased significantly, while heart rate remained unchanged.
- No significant changes in LV volumes or contraction synchronicity were observed; systolic pressure-to-end-systolic volume ratio increased at 10 gamma x kg(-1) x min(-1).
Conclusions:
- Beta-adrenergic stimulation can induce a positive lusitropic response in patients with ischemic heart disease and severe LV dysfunction, despite attenuated inotropic and chronotropic responses.
- Effects on diastolic function occur earlier than effects on systolic function.
Background:
An attenuated inotropic response to beta-adrenergic stimulation has been documented in patients with severely depressed left ventricular (LV) function. Scant data exist regarding the effect of beta-adrenergic stimulation on LV diastolic function in human beings. Our objective was to evaluate the effect of dobutamine infusion on LV systolic and diastolic function in patients with severe ventricular dysfunction.
Methods And Results:
We studied 26 patients (60 +/- 9 years) in stable condition with healed myocardial infarction and LV ejection fraction (EF) less than 35% by radionuclide ventriculography. LVEF, volumes, peak ejection rate (PER), peak filling rate (PFR), and peak systolic pressure-to-end-systolic volume ratio were calculated at the infusion rate of 5 and 10 gamma x kg(-1) x min(-1). At 5 gamma x kg(-1) x min(-1), no changes were observed in heart rate (75 +/- 16 beats/min vs 75 +/- 15 beats/min at rest), LVEF (23% +/- 8% vs 22% +/- 7%), and PER (1.40 +/- 0.48 end-diastolic volume per second [EDV/s] vs 1.30 +/- 0.48 EDV/s); however, a significant increase in PFR was observed (1.11 +/- 0.36 EDV/s vs 0.86 +/- 0.30 EDV/s, P < .01). At 10 gamma x kg(-1) x min(-1), an increase in LVEF (25% +/- 10%, P < .01) and PER (1.60 +/- 0.57 EDV/s, P < .01) was observed; PFR (1.25 +/- 0.36 EDV/s, P < .05) also increased, whereas heart rate (78 +/- 18 beats/min) was unchanged. No significant changes in LV volumes or in indices of LV contraction synchronicity were observed during infusion. Finally, the peak systolic pressure-to-end-systolic volume ratio was unchanged at 5 gamma x kg(-1) x min(-1) and significantly increased at 10 gamma x kg(-1) x min(-1).
Conclusions:
In stable patients with ischemic heart disease and severe LV dysfunction, beta-adrenergic stimulation may still induce a positive lusitropic response, despite attenuated inotropic and chronotropic responses; moreover, the effects on diastolic function occur earlier than those on systolic function.
