Teenagers don't routinely drop dead of cardiac failure. As a cause of death among individuals aged 12 to 19, heart disease barely even rates, staking out a mere 3 percent of all fatalities. It makes sense: heart problems are so often accumulative, the result of a lifelong progression toward disease. Accidents, meanwhile, just happen.
So, when a 13-year-old boy died suddenly of cardiac arrest, it signaled a greater concern. Heart disease at a young age is more often than not the result of a built-in abnormality—a fate predicted by faulty genes. It's reasonable then for such a death to cause concern among those that might happen to share the same genes. With this in mind, a large number of the boy's relatives underwent genetic testing. Twenty of them were subsequently diagnosed with long QT syndrome, an inherited heart rhythm condition characterized by bouts of fast, chaotic heartbeats. It can lead to seizures and even sudden death. It's the sort of thing you'd really want to know about.

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