Gentler heart defibrillator uses way less energy

Rather than one big shock to the heart, a series of 5 small pulses can also restore our heart beats, scientists show. And it uses 84% less energy.
Written by Janet Fang, Contributor

Scientists have found a nicer, milder, and literally less shocking way to reset the electrical turbulences of our hearts. And they’ve slashed the amount of energy needed!

Less dramatic, yes… but the method could become a less damaging alternative to the standard cardiac defibrillation, commonly described as a reset button for the heart.

Although that life-saving single high-energy jolt restores the heart’s natural rhythm, it can also damage heart tissue, burn skin, and cause serious pain.

The new technique delivers a series of 5 low-energy, electrical pulses to the fibrillating heart (the kind you need to defib) – when electrical impulses travel around in chaotic spirals, preventing the heart from pumping blood.

This is an average energy reduction of 84% compared to standard defibrillation, which has been using 1,000 volts of electricity to reset hearts after cardiac arrest since the 1950s.

Each of the 5 pulses delivers only one-seventh as much energy.

According to the international team of researchers, led by Max Planck Institute’s Stefan Luther and Flavio Fenton, the method works because heart muscle isn’t uniform.

So this technique stimulates these natural heterogeneities – such as blood vessels and fatty tissues – to redistribute the current around the heart, restoring normal rhythm. These ‘virtual electrodes’ essentially amplify the voltage applied to tissue, Nature News explains.

  1. Using implanted electrodes, the team induced arrhythmias, or irregularities in the beating, in the isolated chambers of dog hearts.
  2. They used dyes to trace the electrical waves they generated and imaged tissue as their structures changed to the current.
  3. Then they experimented with various intensities of the electric field they applied, emitting different waves.

They found that 5 small, sequential pulses progressively restored order to the electrical chaos they caused.

Up until now, the "brute force" approach is considered the only reliable way to combat the disordered pattern of electrical activity in the structurally complicated heart, Fenton says.

The voltage the technique requires is at or below what researchers believe is the pain threshold for electric shocks, but Fenton thinks it may be possible to further optimize the virtual electrodes to reduce the voltage even more. They hope this technique will be translated to the clinic.

The study was published in Nature today.

Image by dee_thai via Flickr

This post was originally published on Smartplanet.com

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