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).
One study investiating DHEA inconjunction with an aromatase inhibitor (AI) found that the combination was more potent at increasing testosterone than either in isolation (8.5nmol/L increase in combination, 3.5nmol/L with DHEA, 4.9nmol/L with the AI atamestane); pairing DHEA with an AI also reduced the inevitable spike in estrogen to 2/3rds that seen with DHEA alone.