Cardiology researchers have been eagerly taking up consumer electronic devices that include pulse oximeters. Being able to conveniently measure the level of oxygen in someone’s blood is a useful tool, whether one is interested in sleep apnea or COVID-19.
The news that the new Apple Watch includes a pulse oximeter prompted Lab Land to check in with Amit Shah, an Emory cardiologist who has been experimenting with similar devices to discriminate patients with heart failure from those with other conditions.
Shah, together with Shamim Nemati, now at UCSD, and bioinformatics chair Gari Clifford recently published a pilot study on detecting heart failure using the Samsung Simband. The Simband was a prototype device that didn’t make it to the consumer market, but it carried sensors for optical detection of blood volume changes (photoplethysmography), like on the Apple Watch.
Heart failure causes symptoms such as shortness of breath and leg swelling, but other conditions such as anemia or lung diseases can appear similarly. The idea was to help discriminate people who might need an examination by echocardiogram (cardiac ultrasound).
The study was performed with 97 patients undergoing bedside echo monitoring at Emory hospitals from 2015 to 2016. About half had heart failure. Study participants were asked to wear the device for 5 minutes resting in a chair, and perform 5 Valsalva maneuvers: holding their breath, straining, then breathing out through the mouth like blowing up a balloon. This test puts stress on the body’s ability to regulate blood pressure and heart rate, which is generally impaired in heart failure.
The pilot study achieved an accuracy of 74 percent from the wristband alone, which could be increased to 82 percent by adding information about the patients that was already available from their charts.
Shah says he would like to use devices containing pulse oximeters to obtain overnight oxygen readings, which could provide even more crunchable data. He and colleague Anish Shah are currently testing a wearable electrocardiogram patch made by VivaLNK in a study examining the relationship between heart disease and depression.