high blood pressure
"I was born with high blood pressure and a slight arrhythmia. I've been taking atenolol since I was a kid, as soon as it was medically safe for a kid to be on a beta blocker, so I've been on it for about twenty years now. It works great for me. Might make me a bit drowsy, but I take it at bedtime for that reason.
Docs tried to take me off of it once because they worried about an interaction with albuterol for my asthma. Worst mistake of my life and I made them put me back on it. 
For those worried about the above interaction between atenolol and albuterol, I did some research using scholarly articles and medical journals. Atenolol is a selective beta inhibitor and doesn't affect the same betas that albuterol increases. They're okay together."