The skeptical cardiologist recently received this email from a reader:
With the new Apple Watch that’s out now, people have suggested my husband (who had a heart attack at 36) should get it since it could detect a heart attack. But I keep remembering what you said – that these devices can’t detect heart attacks and that Afib isn’t related to a heart attack most of the time – is that still the case? I don’t really know how to explain to people that it can’t do this, since absolutely everyone believes it does.
The answer is a resounding and unequivocal NO!
If we are using the term heart attack to mean what doctors call a myocardial infarction (MI) there should be no expectation that any wearable or consumer ECG product can reliably diagnose a heart attack.
The Apple Watch even in its latest incarnation and with the ECG feature and with rhythm monitoring activated is incapable of detecting a myocardial infarction.
Similarly, although the AliveCor Kardia ECG monitor is superb at diagnosing rhythm abnormalities it is not capable of detecting an MI
To make this even clearer note that when you record an ECG on the Apple Watch it intermittently flashes the following warning:
Note: “Apple Watch never checks for heart attacks”
How did such this idea take root in the consciousness of so many Americans?
Perhaps this article in 9-5 Mac had something to do with it
Scott Killian never imagined his Apple Watch might save his life, but that’s exactly what happened a few weeks ago when he had a heart attack in the middle of the night. Killian recently shared his personal experience with 9to5Mac, and the details of his story are absolutely amazing.
In clear cut cases the Apple Watch could make the difference between life and death,” says Roger Kay, president of Endpoint Technologies Associates. Because you wear the Apple Watch at all times, it can detect an early sign of a stroke or a heart attack, and that early indication is critical, he says.
And the Healthline article on the new Apple Watch also incorrectly implies it can diagnose MI:
The device, which was unveiled last week, has an electrocardiogram (ECG) app that can detect often overlooked heart abnormalities that could lead to a heart attack.
And if you are felled by a heart problem, the fall detector built into the Apple Watch Series 4 could alert medical professionals that you need help
Fox News and Healthline should modify their published articles to correct the misinformation they have previously provided.
And it is still true that although both Apple Watch and Kardia can diagnose atrial fibrillation the vast majority of the time acute heart attacks are not associated with atrial fibrillation.
Readers, please spread the word far and wide to friends and family-Apple Watch cannot detect heart attacks!
Skeptically Yours,
-ACP
6 thoughts on “Can The Apple Watch Or Kardia ECG Monitor Detect Heart Attacks?”
Pardon my ignorance, but would a mobile ECG monitor be able to detect heart attacks when the ST segment is elevated? I thought this was a possible sign of myocardial ischemia brought on by myocardial infarction.
Thank you,
Dear Finn the Cat,
I hereby pardon your ignorance!
You are correct that ST segment elevation is one of the cardinal signs of an acute myocardial infarction. However, doctors typically make the diagnosis off a 12 lead EKG and we generally like to see significant elevation in more than one lead. The original Kardia and the Apple Watch with a single lead I tracing could easily miss a myocardial infarction if the infarct was taking place in an area of the heart not represented by lead I. The 6L would do better and might be able to reliably detect an inferior myocardial infarction (leads II, III, AVF). I would love to see a study on its accuracy for inferior MI. However it would miss most anterior infarcts which tend to be the most serious.
In addition, none of these devices claim to be able to discern significant ST segment changes so we don’t really know what the sensitivity or specificity is.
Bottom line is DON”T RELY on Apple Watch to alert you if you are having a heart attack.
Here’s to hoping your feline left ventricle keeps pumping properly!
I first came across your website a year ago during persistent angina attacks, and returning now due to increasing episodes of symptoms akin to Afib. I bought a Kardia 2 yrs ago for the angina episodes, and looking to buy the Apple Series 4 for the Afib, as I want to try a wearable for more constant monitoring. What I would greatly appreciate if you had a basic guide for both the Kardia & Apple devices, specifically when and how to best employ them for unstable angina and detecting undiagnosed Afib. As in, what can I as a patient provide to you as a doctor for diagnosis in advance of a formal visit. I’m a US Iraq vet medically retired in the UK, and most of my concerns get dismissed out of hand as “anxiety”, not sure why they thought a stent would cure my anxiety though 😉
Chris,
Good question (s)! I will try to put the requested guide together and post something on it.
Your questions have been answered in my latest post
Glad you cleared this up for those who might believe those devices can detect a heart attack.