Which beneficial effect do cardiac glycosides NOT provide?

Cardiac glycosides, such as digoxin, are commonly used to treat various heart conditions, particularly heart failure and certain types of arrhythmias. They primarily work by increasing the force of myocardial contraction (improved cardiac contractility), which helps the heart pump more effectively. Additionally, cardiac glycosides can decrease the heart rate and have an antiarrhythmic effect by acting on the conduction system of the heart, thus stabilizing abnormal heart rhythms.

However, increased signs of dyspnea (difficulty breathing) are not a beneficial effect of cardiac glycosides. In fact, their therapeutic use is aimed at alleviating symptoms of heart failure, which often include dyspnea. By improving cardiac output and efficiency, cardiac glycosides help reduce pulmonary congestion and improve respiratory function. Therefore, instead of providing a positive effect, increased signs of dyspnea against the backdrop of cardiac glycoside use would be indicative of potential complications or lack of efficacy in treatment.