Atrial flutter is an abnormality of the heart rhythm, resulting in a rapid and sometimes irregular heartbeat. Such abnormalities, whether in the rate or regularity of the heartbeat, are known as arrhythmias. The main danger of atrial flutter is that the heart does not pump blood well when it is beating too fast. When blood is not pumped well, vital organs, such as the heart and brain, may not get enough oxygen from the blood.
The range varies with the window casing. Aluminum windows are relatively common and have a life expectancy of about 15 to 20 years. They can cost $348 per window (figure 50% to 100% more for new construction windows). Other popular window options include vinyl (lasts between 20 to 40 years) and wood (lasts about 30 years).
The lifespan on a typical quality glass aquarium is about 10 years with regular use. It's not to say that it won't last 15 or more, but for my money its worth replacing after that period of time. I had an aquarium blow out when I was on vacation a few years back and that one was only 6 or 7 years old. I believe it was an AGA 22 gallon too.