At last your head can rule your heart

HAVING A heart-to-heart with your heart will soon become reality as doctors prepare to develop the first voice-activated pacemaker.

Medical scientists believe it will be possible to tell an intelligent pacemaker when to speed up the pumping rate of a heart, with simple vocal commands warning of an impending bout of exercise.

Richard Vincent, professor of medical science and consultant cardiologist at the University of Sussex, told the science festival that the improvements in pacemaker technology over the past 30 years were leading to the complete rewiring of the heart's electrical system.

Originally, pacemakers controlled one of the two larger chambers of the heart - the ventricles - but newer versions are also controlling the other chambers, enabling doctors to improve pumping efficiency as well as preventing arrhythmic contractions.

Although some pacemakers can respond to vibrations to boost pumping rates during exercise, Professor Vincent said the next stage was to incorporate a voice-activated chip that would respond to a patient's vocal signature. Telling the heart to speed up before climbing a flight of stairs or going for a jog would also enable the pacemaker to learn to associate that particular activity with a certain level of physical stress, he said.

"We are trying to tailor a pacemaker's performance to a person's level of exercise to get an improved quality of exercise. Pacemakers will be able to mimic the spontaneous pacemaking ability of the heart like nothing before."

It is already possible to interrogate some types of pacemaker by placing a device over the chest that emits radio- frequency signals. A voice- activated pacemaker is a logical development, which should be possible to make with existing technology.

When pacemakers were first used in 1965 they weighed up to 150g (about 5oz), were 2cm (about 1in) thick and emitted a constant pulse rate of 70 beats a minute, with a battery life of three years. Now they are as thin as a biscuit, weigh 25g and can last 15 years, emitting up to 100,000 pulses a day.