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Effects of 1-epinephrine on hemodynamics and cardiac function in coronary disease: dose-response studies
B H Sung1, C Robinson, U Thadani
1Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City.
Insights
Elevated epinephrine levels did not significantly alter cardiovascular hemodynamics in patients with coronary artery disease (CAD). However, CAD patients experienced more arrhythmias and chest pain during epinephrine infusion compared to healthy individuals.
Area of Science:
- Cardiology
- Pharmacology
- Physiology
Background:
- Epinephrine (adrenaline) is a key hormone in the sympathetic nervous system's stress response.
- Understanding its cardiovascular effects is crucial, especially in patients with coronary artery disease (CAD).
- Previous research has not fully elucidated the differential impact of epinephrine on cardiovascular performance in CAD versus normal subjects.
Purpose of the Study:
- To investigate the cardiovascular and arrhythmogenic effects of intravenous epinephrine infusion in patients with CAD.
- To compare the hemodynamic responses and ischemic thresholds to epinephrine between patients with CAD and healthy individuals.
- To assess the potential for epinephrine to induce myocardial ischemia and ventricular arrhythmias in the context of CAD.
Main Methods:
- Intravenous epinephrine infusion at escalating doses (0.06–0.24 µg/kg/min) in 22 CAD patients and 8 healthy controls.
- Continuous monitoring of hemodynamic parameters (e.g., heart rate, blood pressure, contractility, end-systolic volume).
- Assessment of plasma norepinephrine levels, epinephrine ischemic thresholds, and incidence of ventricular arrhythmias, chest pain, and ischemic ECG changes.
Main Results:
- Hemodynamic responses to epinephrine were similar between CAD patients and normal subjects.
- Increased myocardial contractility and decreased end-systolic volume were significantly greater in normal subjects than in CAD patients.
- CAD patients exhibited higher frequencies of ventricular arrhythmias (55% vs. 25%), chest pain (50% vs. 13%), and ischemic ECG changes (73% vs. 13%) during epinephrine infusion.
Conclusions:
- Epinephrine infusion can induce myocardial ischemia, chest pain, and arrhythmias in patients with CAD.
- Despite these adverse effects, overall hemodynamics and ventricular pump function were maintained in CAD patients.
- The study highlights differential responses in contractility and ventricular volume between CAD patients and healthy individuals under epinephrine stress.
Abstract:
To assess the effects of elevated epinephrine levels on cardiovascular performance in patients with coronary artery disease (CAD), epinephrine was infused intravenously into eight patients with normal coronary anatomy and 22 patients with CAD at dose rates of 0.06, 0.12, 0.18, and 0.24 micrograms/kg/min. Hemodynamic responses to epinephrine were not significantly different between the two groups. However, contractility increased significantly more (P less than 0.05) and end-systolic volume decreased significantly more (P less than 0.025) in normal subjects than in those with CAD. Plasma norepinephrine concentrations increased significantly (P less than 0.05) at 0.24 micrograms/kg/min epinephrine, indicating activation of sympathetic nervous system. Epinephrine ischemic thresholds ranged from 652 to 3362 pg/ml. Patients with CAD compared with normal subjects had more frequent ventricular arrhythmias (55% vs. 25%), chest pain (50% vs. 13%), and ischemic ECG changes (73% vs. 13%). These results indicate that although epinephrine induced myocardial ischemia in CAD, hemodynamics and ventricular pump function were maintained.