Sudden death syndrome--an umbrella term for a range of heart conditions that can lead to cardiac arrest--is notorious for striking those who seem most fit.
That is because the condition, thought to be largely hereditary, is often triggered by overexertion. Tragically for some, the first symptom can be cardiac arrest.
It's possible, though costly, to screen for SDS. In fact, after soccer prodigy John Marshall died of a sudden heart attack at age 16 in 1994, the day before he was set to join Everton, testing became compulsory for professional athletes in several countries.
Good thing, especially for those who don't have the means that professional athletes do, that a doctor at Tel Aviv University may have just made testing for the condition far simpler and more affordable.
"There is such a significant overlap between what's normal and abnormal on an ECG [electrocardiogram] that we need additional screening parameters," Dr. Sami Viskin, a cardiologist at the Sackler Faculty of Medicine, said yesterday in a university press release. "This test, when done on people with strong symptoms, can really give...doctors a yardstick to compare those at risk for sudden death syndrome to those who would otherwise go on to live a healthy life."
Named after the doctor, the Viskin Test is easy on the patient, who simply undergoes a baseline ECG while resting in the supine position, and is then asked to stand quickly and remain still during continuous ECG recording.
What Viskin is looking for is an abnormally long QT interval, which is the amount of time it takes for the heart's left and right ventricles to depolarize and repolarize.
Normally, the QT interval lasts about a third of each heartbeat cycle. When the heart rate accelerates, the QT interval shortens; in people who have what is called Long QT Syndrome, the QT interval tends to last longer, which can trigger the heart to beat faster to try to keep up, and can in turn result in an arrhythmic beat. Put simply, the heart works harder to recharge after sudden changes in heart rate, sometimes to the point of cardiac arrest.
Viskin said that the most common symptoms for LQTS (of which there are seven types) are dizzy spells and fainting easily for no apparent reason. He said anyone who exhibits these symptoms, or who has a family history of LQTS, might benefit from his test. But he also clarifies that it should be used in conjunction with other ECG readings, and not alone.
"This test adds diagnostic value," he said. "And the beauty of the test is that it's easily done at the patient's bedside. It eliminates the need for more expensive IV tests and more strenuous exercise tests."