To witness such human deterioration and to know the only way to truly effect change was to carry on filming and bring the documentary film to a wider audience - was an incredibly difficult process.
However the impact my film had has been extraordinary. Viewers wrote to me by the thousands, donating money, and forming petitions demanding change from their MPs and MEPs.
Some gave up their jobs and went to Bulgaria to help, taking supplies, food, clothing and medical aid.
This year I returned to Bulgaria to find out exactly what has happened to some of the key characters from the original film. Once again I was shocked by what I found.
I witnessed the miraculous improvements that can happen in badly-damaged children when decent care is finally given to them.
"I came back from England last year and, man, they had me fed up with this stuff [says Mayan elder Apolinario Chile Pixtun]."
At Cornell University, Ann Martin, who runs the "Curious? Ask an Astronomer" Web site, says people are scared.
"It's too bad that we're getting e-mails from fourth-graders who are saying that they're too young to die," Martin said. "We had a mother of two young children who was afraid she wouldn't live to see them grow up."
... Chile Pixtun, a Guatemalan, says the doomsday theories spring from Western, not Mayan ideas.
"If I went to some Mayan-speaking communities and asked people what is going to happen in 2012, they wouldn't have any idea," said Jose Huchim, a Yucatan Mayan archaeologist.
"That the world is going to end? They wouldn't believe you. We have real concerns these days, like rain."
... John Gay, a pediatric cardiologist at Mercy, was talking with a local dentist who had visited the Yucatan Peninsula to do dental work. The dentist was surprised by how many children there had heart defects - and little prospects at proper care.
The next year, Gay organized a medical mission to Yucatan. Some children were in such bad condition their extremities were purple.
"We were met with a great deal of suspicion," Gay said. "These people were saying, 'Let's get this straight. You're going to take care of our children. You're going to fly them there and back for free and provide free health care?' "
A few took the offer and returned in better health. And the program grew each year.
You could look at Alicia Stessman's visit to the pediatric heart unit at Mercy around 1980 as happenstance. After all, she came only to visit a friend's sick child.
But when she was there, Alicia heard Spanish spoken in the hallway. She was told of Mercy's program for impoverished Mexican children. The Stessmans both spoke Spanish, and both understood life in a foreign land.
"I really fell in love with the program when I met the parents," Alicia Stessman said.
"They were crying, worried, nervous about their children. They didn't know what was going to happen."
Three decades later, the Stessmans still visit the 30 Mexican children who get heart surgeries at Mercy every year. They've also visited Yucatan to help doctors choose a new group of children for surgeries.
The Stessmans pick up the children and parents at the airport. They sit in the waiting room to calm parents as children go through surgery. They celebrate when a surgery goes well. They mourn in the rare instance when it doesn't.
"The Stessmans have been very helpful in allaying those fears of these families," said Thomas Becker, the pediatric cardiologist now in charge of the Yucatan program. "The big payoff is when you go back and you see the kids you operated on before. The parents can't wait to show you how well their kids look, all dressed up and healthy. That's how we get paid, by this big outpouring of love, and the Stesssmans are such a big part of that."