New smartphone app can check your heart health

Scientists have developed an app that lets you check your heart health non-invasively using the smartphone camera.
Earlier, checking heart health would require a 45-minute scan from an ultrasound machine but can now be accomplished by simply holding your phone up to your neck for a minute or two.
Researchers, including those from California Institute of Technology in the US, developed a technique that can infer the left ventricular ejection fraction (LVEF) of the heart by measuring the amount that the carotid artery displaces the skin of the neck as blood pumps through it.
LVEF represents the amount of blood in the heart that is pumped out with each beat. In a normal heart, this LVEF ranges from 50 to 70 per cent.

When the heart is weaker, less of the total amount of blood in the heart is pumped out with each beat, and the LVEF value is lower.
LVEF is a key measure of heart health, one upon which physicians base diagnostic and therapeutic decisions, researchers said.

To measure LVEF using the technique developed at Caltech, doctors simply held iPhones against the volunteers' necks for one to two minutes.
Afterwards, the volunteers immediately received an MRI examination, and data from both tests were compared.
The app works because the walls of arteries are almost completely elastic - they expand and contract with each beat of the heart.

That expanding and contracting can be measured and described as a waveform that encodes information about the heart. For the study, the team used an iPhone 5, but any smartphone with a camera will work.
"In a surprisingly short period of time, we were able to move from invention to the collection of validating clinical data," said Mory Gharib, professor at Caltech.
To test the app, researchers conducted clinical trials with 72 volunteers between the ages of 20 and 92 years at an outpatient magnetic resonance imaging (MRI) facility.
LVEF is most commonly measured using an ultrasound machine during a procedure known as echocardiography.

Echocardiography, however, requires a trained technician, an expensive ultrasound machine, and up to 45 minutes of a patient's time.
The study was published in Journal of Critical Care Medicine.