 The first sign that Ken Jeffries was vulnerable to heart disease was a heart attack suffered when the 57-year-old was at the airport waiting for a flight collapsing to the floor of the Charlotte Douglas International Airport. He has his lucky stars to thank for his flight being bound for Knoxville, the same place Claire Serby was going. She's a registered nurse from a heart and vascular hospital center in Charlotte. Serby told news media it was the way he was breathing and snoring that alerted her to the heart attack. With a makeshift orderly staff of airport bystanders,