New York, Jun 21 (IANS): Engineers have developed a new wearable, ultra-thin electronic device - e-tattoo - that could make heart monitoring easier and more accurate than existing electrocardiograph machines.

Developed by engineers from the University of Texas at Austin, the graphene-based 'e-tattoo' can be placed on the skin to measure a variety of body responses, from electrical to biomechanical signals.

The electronic device is so lightweight and stretchable that it can be placed over the heart for extended periods without any discomfort, according to the engineer's research, published in the Advanced Science journal.

Moreover, it measures cardiac health in two ways -- taking electrocardiograph and seismocardiography readings simultaneously.

Most of us are familiar with already existing technologies such as Electrocardiogram (ECG), a method that records the rates of electrical activity produced each time the heart beats and Seismocardiography (SCG), a measurement technique using chest vibrations associated with heartbeats.

Whereas, this new e-tattoo, powered remotely by a smartphone, is the first ultra-thin technology to measure both ECG and SCG.

"We can get much greater insight into heart health by the synchronous collection of data from both sources," said Nanshu Lu, Associate Professor at the University of Texas at Austin.

The ECG readings alone are not accurate enough for determining heart health but they provide additional information when combined with SCG signal recordings, said researchers.

The e-tattoo is made of a piezoelectric polymer called polyvinylidene fluoride, capable of generating its own electric charge in response to mechanical stress. Besides, it also includes 3D digital image correlation technology that is used to map chest vibrations in order to identify the best location on the chest to place the e-tattoo.

This device can be worn for days, providing constant heart monitoring.