It had been the usual pleasant dinner visit for the 74-year-old aunt, and it was nearly time for her to depart when suddenly she collapsed in the doorway, gasping. A member of the family tried for a pulse reading and failed. Someone grabbed the phone, called the emergency fire and ambulance number for Fairfax County (691-2233) - "and within two minutes," according to the family, a rescue team from the county and from the Vienna Volunteer Fire Department was on the scene, complete with one of those mobile cardiac units like the ones you see in the TV medical series.

The unit is practically a hospital on wheels; calmly but quickly, the team members were able to take necessary readings and talk directly to the hospital about immediate treatment. Today, the woman is recuperating at home. This kind of story about those mobile units is nothing new, to be sure. But as a grateful member of the family told us, it wasn't just the amazing machiner - "but the people who came with it. They were fantastic."

They are, and their work can spell the difference between life and death. The mobile cardiac units may be expensive, but as many a heart-attack victim around town will attest, the teams who perform this emergency work are priceless. Whether it's the Vienna department, the Bethesda-Chevy Chase Rescue Sauad or the paid members of these operations, they deserve the year-around support of all of us who may someday need their critical help in a hurry.