I'm at the UCSF Medical Center hooked up to a 12 lead EKG. Now I'm going to compare the results of this test versus the 1 lead EKG on the Apple Watch. If I look at my apps now, I'll notice that there's now an EKG app. These squiggly lines over here. And it's pretty simple to use. I just put my finger on the digital crown and it's starts taking the EKG, counts down for about 30 seconds. And it actually shows it live as it's happening. So we see that you have these two narrow beats and intermittently you have this wider, early beat. That, that one right there, that one right there. So normal, normal, early. Normal, normal, early. And that matches what we see on the EKG where you have normal, normal, early, and wide. So this would be really useful to screen for this or to have the first understanding that you have these early beats. It wouldn't tell us precisely where in the heart, apart from the fact that it's coming from the lower chamber. Where it says 12 lead EKG that Gives us, essentially a fuller picture, can tells us precisely where in the lower chamber it's coming from. And am I going to die? Is something wrong with me? [LAUGH] You are not going to die. These early beats are very common. In some people they can lead to problems in the long-term. But let's take a look at how this actually works on the Apple watch An update to watchOS gave users access to two FDA-cleared features on the Apple Watch. An irregular heart rhythm notification and an EKG app exclusive to the series four. Both of which could warn users of potentially life-threatening heart conditions. Heart rate is not new to the Apple Watch or wearables in general. So the optical sensor on fitness trackers or smart watches essentially uses changes in light that is reflected based on the pulse. When the heart beats and the [UNKNOWN] pump into the vessels, more light gets absorbed between beats when there's less blood, more light gets reflected back into the receivers. The Apple Watch also uses this optical sensor to measure heart rhythm. And alerts users when the pattern suggests atrial fibrillation, a heart condition which can increase your risk of stroke and other serious heart complications. So the heart rate [MUSIC] Is the frequency of the heartbeat over time, but doesn't tell you anything about the pattern of those beats. The rhythm has more to do with the relative spacing of those beats. But to get a definitive diagnosis, the doctor needs more information. We would wanna have an electrical confirmation of a diagnosis of atrial fibrillation before we decide on acting on that and not base it, in general, on the pulse recording alone. That's where the EKG comes in. The EKG, or electrocardiogram, uses electrodes to measure the electrical activity that results from each expansion and contraction of the heart. The Apple watch has one electrode on the back crystal and one electrode on the digital crown. Place your finger on the digital crown to close the circuit and stay still for 30 seconds to get a read. So that's creating the same sort of connection between your left arm and your right arm. But the results from the single EKG on the apple watch, which users can share as a PDF with their doctors, gave Doctor Marcus enough information to detect my early heartbeat. And could help Doctors reach a diagnosis sooner. And so there is this hope that we might detect those people, who otherwise didn't know they had atrial fibrillation. And, then treat them appropriately. The flip side is, is that we recognize So there's a risk of false positive results. The Apple Watch is the only direct to consumer device with a built in EKG. But there are other devices, like the Cardioband, the let you take an EKG outside the doctor's office. Apple Watch competitors like Armour and Fitbit are also working to improve their heartrate monitoring as more tech companies focus on healthcare as a way to breath new life into wearables. I probably don't have AFib, but I would have never known about my early heart beat without an EKG. And now, I might just have to pay another visit to Dr. Marcus to get it checked out. [MUSIC]