When an arrhythmia causes the heart to beat too fast, the heart doesn't pump effectively. Specifically, there may not be enough time between heartbeats for the heart to fill with blood, causing blood to back up into the lungs.
The new non-steroidal and steroidal aromatase inhibitors are at least as effective as megestrol acetate (MA) as second-line hormonal agents in postmenopausal women with breast cancer.However, they are superior to MA in terms of tolerability and adverse effects.he Type I inhibitors have a steroidal structure similar to androgens and inactivate the enzyme irreversibly by blocking the substrate-binding site, and are therefore known as aromatase inactivators. Examples of such drugs include formestane and exemestane (Aromasin).
Males and females, mice and humans, all make estrogen from testosterone, thanks to an enzyme called aromatase. Women have a lot more estrogen in the circulation, of course. Aromatase is familiar to many women with breast cancer. Breast cancer growth driven by estrogen is thwarted by giving women drugs known as aromatase inhibitors, which prevent the conversion of testosterone to estrogen.