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Rodent Working Heart Model for the Study of Myocardial Performance and Oxygen Consumption
Published on: August 16, 2016
Norepinephrine alters exercise oxygen consumption in heart failure patients
K M Leclerc1, N P Steele, W C Levy
1Department of Cardiology, Brooke Army Medical Center, San Antonio, TX 78234, USA. kenneth.Leclerc@CEN.AMEDD.ARMY.MIL
Medicine and Science in Sports and Exercise
|December 29, 2000
Summary
Acute norepinephrine infusion impairs exercise oxygen utilization in heart failure patients, potentially explaining their exercise intolerance. The low-dose infusion was safe and well-tolerated in both heart failure and healthy individuals.
Area of Science:
- Cardiology
- Exercise Physiology
- Pharmacology
Background:
- Heart failure (HF) is characterized by reduced exercise capacity.
- Norepinephrine (NE) plays a role in cardiovascular regulation and exercise response.
- Understanding NE's impact on oxygen utilization in HF is crucial for managing exercise intolerance.
Purpose of the Study:
- To investigate the effects of acute norepinephrine (NE) infusion on exercise oxygen utilization in patients with heart failure (HF) compared to healthy adults.
- To assess the safety and tolerability of low-dose NE infusion in these populations.
Main Methods:
- Eleven healthy adults and 10 NYHA class II-III HF patients (ejection fraction <40%, no beta-blockers) participated.
- Subjects underwent steady-state and maximal ramp exercise testing under placebo or NE infusion.
- Evaluated oxygen consumption (VO2), hemodynamics, and serum lactate levels.
Main Results:
- NE infusion increased blood pressure and decreased heart rate in both groups.
- Heart failure patients had higher lactate levels, which increased with steady-state exercise.
- NE infusion tended to increase VO2 in HF patients but significantly impaired the VO2/W relationship, indicating reduced efficiency.
Conclusions:
- Acute low-dose norepinephrine infusion impairs oxygen utilization during exercise in stable heart failure patients, contributing to exercise intolerance.
- Low-dose NE infusion is safe and well-tolerated in compensated heart failure patients and healthy adults.
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