Could your child have a heart arrhythmia?

Dampening the enthusiasm for screening is the thorny issue of who would read the large volume of ECGs. "If you're a cardiologist who is expert in long Q-T syndrome, you'll pick this up more reliably on an ECG than a general cardiologist or a family doctor," says Dr. Robert Hamilton, a pediatric cardiologist at Sick Kids. There are also the social and financial costs of false positives – readings that suggest nonexistent abnormalities. "These cause people psychological distress and require more resources for further medical testing," says Kirsh. And what's the best time to screen? In infancy? Just before or just after puberty, when symptoms of these conditions often begin to manifest themselves? The answers to such questions must be considered by any screening strategy.

Genetic sleuthing
Scientists are homing in on the lethal genes. In St. John's, Nfld., researchers at Memorial University, led by molecular geneticist Dr. Terry-Lynn Young, are studying 16 large extended kinships encompassing some 1,200 people – all thought to be genetically linked to a common 18th-century ancestor. Their family bibles are full of the names of people who, over the generations, died inexplicably at a young age. The culprit is now thought to be ARVC. "The youngest victim we've studied was a man of 19, who died eight years ago, and the youngest person undergoing treatment is a 13-year-old boy," says geneticist Kathleen Hodgkinson, who specializes in genetic counselling.

Deborah Roberts belongs to one of these extended families. "We'd all meet at the funeral of some 19-year-old relative who just dropped dead and whisper about the family curse," says Deborah, who grew up in Mount Pearl, Nfld. The 46-year-old mother of a son with ARVC was herself diagnosed with the abnormality after a blood test and a heart biopsy in 1997. She was later implanted with a defibrillator.

Two of Deborah's sons have normal hearts, but her middle son, Adam, was diagnosed with ARVC at age 15 and implanted with a defibrillator. Now 21, he's thinking about his future as a parent. "We want to stamp out this defect in this generation," says Deborah. "My son is talking about having in vitro fertilization and genetic embryo testing with his future wife so the defect won't be passed on to their children."

Although conventional CPR training is now mandatory for all high school students in Alberta, Manitoba and Ontario, experts support the placement of automated external defibrillators in schools and the training of students in their use. "If we're going to give teenagers vaccines to protect against sexually transmitted diseases and teach them how to avoid pregnancy," says Kirsh, "then we can take the three to five hours needed to teach them how to save someone's life."

Warning signs and risk factors
You and your family should be tested for an inherited heart arrhythmia if you have any of the following:

• A family history of sudden death in young, healthy relatives (i.e., under age 40). For example, a drowning of a strong swimmer in a backyard pool or a death involving a single-car accident with no evidence of external cause, such as skidding or driver impairment

• Episodes of fainting or seizures during or directly after exercise, at times of acute excitement or emotional distress, or after hearing a loud noise, such as an alarm clock

• Consistent or unusual chest pain and/or shortness of breath during exercise

• A frequently racing heart rate or palpitations 

For information about training in cardiac resuscitation, contact:
• ACT Foundation, www.actfoundation.ca
• Canadian Red Cross, www.redcross.ca
• Heart and Stroke Foundation of Canada, www.heartandstroke.ca
• St. John Ambulance, www.sja.ca
You can also phone your local office of any of the above.