8.4 Dopamine and other catecholamines
The electrocardiographic effects of catecholamines, including agents such as dopamine and epinephrine, can be problematic to predict, since these agents have numerous effects on the heart. Catecholamines affect the currents that regulate repolarization of individual cells and fibers, and also can affect the heart rate, blood pressure, and serum potassium levels.
ECG changes caused by catecholamines are influenced by the route and rate of administration, as well as the dosage. For example, subcutaneous administration of epinephrine produces only sinus tachycardia and occasional premature beats. However, when administered intravenously, epinephrine may cause a variety of repolarization abnormalities, including ST changes. Intravenous infusion of isoproterenol, to give another example, may cause inversion of T waves.