What is the effect of catecholamines (Catecholamines) on the heart?

From the Guidelines

Catecholamines have a significant impact on the heart, increasing heart rate, contractility, and cardiac output, but also potentially leading to increased myocardial oxygen consumption, tachycardia, and arrhythmias, as noted in a study published in 2018 1.

Key Effects of Catecholamines on the Heart

• Increase heart rate (chronotropy) and contractility (inotropy) by binding to beta-1 receptors in cardiac tissue, as seen with epinephrine, norepinephrine, and dopamine 1.
• Enhance conduction velocity (dromotropy) and raise blood pressure by constricting blood vessels through alpha-1 receptor activation, which can be beneficial in treating conditions like cardiogenic shock but also poses risks of excessive vasoconstriction 1.
• Increase myocardial oxygen consumption, which can be particularly concerning in patients with pre-existing heart disease or those at risk for cardiac complications, as highlighted in a comparison of epinephrine with dobutamine in patients recovering from CABG 1.

Clinical Use and Considerations

• Synthetic catecholamines are used in medical settings to treat conditions such as cardiogenic shock, with specific dosing recommendations: epinephrine at 0.1-0.5 mcg/kg/min, norepinephrine at 0.01-3 mcg/kg/min, and dopamine at 2-20 mcg/kg/min, depending on the desired effect and patient response 1.
• The choice of catecholamine and dosing strategy should consider the potential for tachycardia, arrhythmias, and increased cardiac work, balancing the benefits of improved cardiac output against the risks of cardiac complications, as discussed in the context of norepinephrine's effects on cardiac function and output 1.

Important Considerations for Patient Management

• Monitoring for signs of excessive catecholamine exposure, such as tachycardia, arrhythmias, and evidence of increased myocardial oxygen demand, is crucial when administering these agents, especially in critically ill patients or those with underlying cardiac disease 1.
• The potential for catecholamines to impair coronary vasodilatory reserve postoperatively, as suggested by studies comparing the effects of different catecholamines on coronary blood flow and myocardial oxygen consumption, should be considered in the management of patients undergoing cardiac surgery 1.

From the FDA Drug Label

Cyclopropane or halogenated hydrocarbon anesthetics increase cardiac autonomic irritability and may sensitize the myocardium to the action of certain intravenously administered catecholamines, such as dopamine This interaction appears to be related both to pressor activity and to the β-adrenergic stimulating properties of these catecholamines, and may produce ventricular arrhythmias and hypertension. Cardiac effects of dopamine are antagonized by β-adrenergic blocking agents, such as propranolol and metoprolol. Increased Heart Rate, Blood Pressure, and Ventricular Ectopic Activity − A 10 to 20 mm increase in systolic blood pressure and an increase in heart rate of 5 to 15 beats/minute have been noted in most patients

Catecholamines can have several effects on the heart, including:

• Increasing heart rate and blood pressure due to their β-adrenergic stimulating properties
• Producing ventricular arrhythmias and hypertension when interacting with certain anesthetics
• Increasing ventricular ectopic activity, with approximately 5% of patients experiencing increased premature ventricular beats during infusions These effects are dose-related and can be antagonized by β-adrenergic blocking agents such as propranolol and metoprolol 2, 3.

From the Research

Effects of Catecholamines on the Heart

• Catecholamines, such as norepinephrine, epinephrine, and dopamine, are released into circulation in response to stress and injury, and have both beneficial and detrimental effects on the heart 4.
• These amines can increase cardiocerebral and renal blood flow, but high and rising catecholamine levels are associated with worsening of prognosis in patients with heart failure 4, 5.
• Catecholamines mediate their effects in the heart through beta 1- and beta 2-receptors, and prolonged receptor stimulation can result in a reduction in beta-receptor sensitivity 5.
• Excessively high catecholamine loads can cause myocardial damage in otherwise normal hearts, and have been implicated in several pathologies, including cardiac hypertrophy, heart failure, and cardiomyopathy 5, 6, 7.

Clinical Implications

• The use of epinephrine versus norepinephrine in cardiac arrest patients with post-resuscitation shock has been studied, and results suggest that norepinephrine may be associated with lower all-cause and cardiovascular-specific mortality 8.
• Catecholamines can also produce cardiac dysfunction by inducing intracellular Ca2+ overload in cardiomyocytes, and their oxidation products can produce coronary spasm, arrhythmias, and cardiac dysfunction 6.
• Sustained elevation of circulating catecholamines for prolonged periods of time can produce pathological conditions, such as cardiac hypertrophy and heart failure, hypertension, and posttraumatic stress disorder 7.

Mechanisms of Action

• Catecholamines interact with adrenergic receptors present on cell membranes of all visceral organs and smooth muscles, leading to activation of signaling pathways and consequent alterations in organ function and smooth muscle tone 7.
• The rise in circulating epinephrine and norepinephrine can cause increased blood pressure and cardiac output, relaxation of bronchial, intestinal and many other smooth muscles, mydriasis, and metabolic changes that increase levels of blood glucose and free fatty acids 7.