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YOUR heartbeat is as distinctive as your signature, American researchers
believe. Doctors may one day be able to call up your medical records simply by
clipping a pulse monitor onto your finger.

There is plenty of anecdotal evidence that doctors can identify patients by
their electrocardiogram (ECG) signals, says Mark Wiederhold of the Science
Applications International Corporation of San Diego. So he decided to find out
if there could be something in it.

Three volunteers performed various tasks while a team of researchers measured
the spacing between a number of specific points on their ECG signals. Some of
the tasks were designed to relax them and some were stressful. “To stress
subjects they were placed in a virtual reality driving simulator, and told to
drive as fast as possible without causing damage or injury,” says
Wiederhold.

His team found that although each person’s ECG was different, the intervals
between peaks on their ECG as a proportion of the pulse remained constant
whatever their physiological state. Wiederhold suspects that this is because the
ECG is a function of the basic physical features of the heart.

Wiederhold says that a patient’s ECG could be used to identify them if the
researchers are able to establish that every person has a unique heartbeat. “I
think commercial systems could probably be available in less than a year,” he
says, “because the majority of technology we have been using is off-the-shelf.”
However, the team will have to carry out trials with a far larger number of
people.

“There is a genuine need for non-imaging dynamic biometric systems, perhaps
in ways that we haven’t even begun to imagine,” says Jim Wayman, director of the
National Biometric Test Center at San José State University in
California.