If it's just the once, I wouldn't worry so much about it. How old is your cat? I do believe that the surgery to fix the animal might help calm the symptoms of craziness that occur during heat.

i have a 2 yr old and a 1 yr old. theyve never done that before. but their both in heat and i think their jealous of me. cause the oldest one loves my guy i swear lol shes sweet and behaves when hes around but when im there she misbehaves. plus when ever i try to disspipline her, he goes and pets them, cuddles them etc. so they keep acting up. i need to get em fixed.

Having your cats, or any other pets, spayed or nuetered will almost always eliminate this problem. Having them "fixed" is not only better for their health, it also helps control the overpopulation of animals and therefore prevents helpless animals from being put to sleep.

clean the area with vinegar---that will help get rid of the smell and will also help prevent her from peeing on that area again in the future

If it continues it could be her way of telling you that she has a bladder infection or something else. This happened with my beloved cat, KC. Vet said that since they can not tell us what is wrong with them that they will do things out of the ordinary to get your attention.

Something as simple as moving furniture, new person or tension could cause this type of behavior.

I would also invest in a mattress pad to prevent anymore damage to your mattress.

At one time we had a cat that pee'd on our sofa and it took 1 month to get the odor out and during that time we made sure we had no company... I got something from PetSmart just for that purpose to remove cat urine / odor and I also used straight Vinegar as well as lemon juice.

I do hope it was a one time incident and all works out....

~Zig

my female cat used to spay all over the place when she was honry. i watched animal planet and this women's cat peed on her clothes because the cat didnt want her owner to leave.
when you leave for long periods of time your cat may not like it.

If it was a single time, it is most likely due to stress. When in heat, hormones are magnified and stress comes on easier. When a cat is stressed, they often urinate outside the box as a way of telling us they're bothered.
Clean the stains with an enzymatic cleaner - other cleaners don't break down the molecules and really get it out. Natures Miracle and Zero Odor are the best ones. If you can't find all of the urine, use a hand-held black light to locate the stains.
Once her heat cycle ends, have her spayed. This is not only responsible, but it cuts down on many health risks an intact cat has. Do an internet search or ask your vet about low-cost spay/neuter clinics in your area.