Südameglükosiidide

Südameglükosiidid are a group of naturally occurring compounds found in certain plants that have a significant effect on the heart muscle. These substances are chemically characterized by a steroid nucleus and one or more sugar molecules attached. Their primary pharmacological action is to increase the force of cardiac contraction, a property known as positive inotropy. This effect is achieved by inhibiting the sodium-potassium ATPase pump in cardiac cells, which leads to an increase in intracellular calcium concentration.

The therapeutic uses of cardiac glycosides are primarily in the management of heart failure and certain types of cardiac arrhythmias, particularly atrial fibrillation. By strengthening the heart's pumping action, they can improve symptoms such as shortness of breath and fatigue. In atrial fibrillation, they also help to slow down the rapid ventricular rate.

Despite their benefits, cardiac glycosides have a narrow therapeutic index, meaning the difference between an effective dose and a toxic dose is small. Overdose can lead to serious and potentially life-threatening side effects, including nausea, vomiting, visual disturbances (such as yellow or green halos), and severe cardiac arrhythmias. Therefore, careful monitoring of blood levels and patient symptoms is crucial when these medications are used. Common examples of plants containing cardiac glycosides include foxglove (Digitalis) and lily of the valley (Convallaria).