You’re sitting on the couch, your heart does a weird little "flip-flop" in your chest, and suddenly that $400 piece of glass on your wrist feels like a potential lifesaver. Or maybe it’s just a fancy paperweight. Honestly, it depends entirely on which model you actually strapped on this morning.
The term "EKG" (or ECG, if you want to be formal) gets thrown around in Apple’s marketing like it's a standard feature on every single watch. It isn't.
If you bought the "budget" model thinking you were getting a pocket-sized cardiologist, you might be in for a rude awakening. Let's get into which models actually have the hardware to track your heart's electrical rhythm and why the one you might have bought doesn't.
The Definitive List: Which Apple Watch Has EKG?
Basically, if you want the EKG app, you need a watch with the "electrical heart sensor." This is different from the green lights on the back that measure your heart rate. Those just look at blood flow. An EKG actually measures the electrical timing of your heartbeat.
These are the models that have it:
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- Apple Watch Series 10 (The newest kid on the block)
- Apple Watch Series 9
- Apple Watch Series 8
- Apple Watch Series 7
- Apple Watch Series 6
- Apple Watch Series 5
- Apple Watch Series 4 (The one that started it all back in 2018)
- Apple Watch Ultra 2
- Apple Watch Ultra (1st Gen)
If you have any of those, you’ve got the goods. You just open the app with the little "squiggling red line" icon, hold your finger on the Digital Crown, and wait 30 seconds.
The "SE" Problem
Here is where most people get tripped up. The Apple Watch SE (1st generation, 2nd generation, and the 2024/2025 iterations) does NOT have the EKG feature. None of them. Not even the newest SE.
Apple keeps the price down on the SE by ripping out the expensive electrical components in the Digital Crown. You’ll still get "High and Low Heart Rate" notifications, and it might even tell you if your rhythm looks "irregular" based on the optical sensor (which is kinda like a broad guess), but you cannot take an actual EKG. If you try to find the app on an SE, it simply isn't there.
How the Tech Actually Works (In Plain English)
It’s pretty wild when you think about it. A standard EKG in a hospital is a "12-lead" setup. They stick ten cold, sticky patches all over your chest and limbs to get a 3D view of your heart.
The Apple Watch is a "single-lead" EKG.
When you rest your finger on the Digital Crown, you are literally completing a circuit. The electrical signal travels from your heart, down your left arm, through the watch, through the crown, into your right arm, and back to your heart.
It’s a 1D view.
It's sort of like looking through a keyhole. You can see if the person in the room is jumping up and down (Atrial Fibrillation), but you can’t see what color their shirt is or if they have a hidden injury.
What it can actually find
The FDA cleared this tech specifically to look for Atrial Fibrillation (AFib). That’s when the upper chambers of your heart are just quivering instead of beating properly. It’s a major cause of strokes.
If your watch says "Sinus Rhythm," it means your heart is beating in a steady, normal pattern.
If it says "Inconclusive," it’s usually because your heart rate is too high (above 120 or 150 BPM depending on your software version), too low, or you were moving around too much.
The Dangerous Misconceptions
I’ve heard people say, "My Apple Watch EKG was normal, so I'm not having a heart attack."
Stop right there. This is the most dangerous mistake you can make. The Apple Watch cannot detect heart attacks. It can't see blocked arteries. It can't see a "widowmaker."
If you have chest pain, pressure, or shortness of breath, and your watch says "Sinus Rhythm," ignore the watch. Call 911. The watch is looking for rhythm (electricity), not plumbing (blood flow).
Also, it doesn't look for other things like:
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- Blood clots.
- Strokes.
- High blood pressure (though some newer models have "Hypertension" notifications, that’s not the EKG doing the work).
- Valve issues.
Real-World Nuance: Version 1 vs. Version 2
Did you know there are two versions of the EKG app?
Version 1 was the original. It could only check for AFib if your heart rate was between 50 and 120 BPM. Anything higher and it just gave up and said "Inconclusive."
Version 2 (which rolled out around Series 6) bumped that upper limit to 150 BPM. This was a huge deal because AFib often makes your heart race. If you're using an older Series 4, you might find it's a lot pickier about when it actually gives you a result.
Setting It Up (Because It’s Not Automatic)
You can't just buy the watch and expect it to work. You have to "onboard" in the Health app on your iPhone.
- Open the Health App.
- Tap Browse, then Heart.
- Look for Electrocardiograms (ECG).
- Follow the prompts. It'll ask for your age because you’re technically supposed to be 22 or older to use it (regulatory reasons, mostly).
Once it’s set up, you can export a PDF of your "strips" to show your doctor. Honestly, most cardiologists I've talked to actually like this. It gives them a "snapshot" of what was happening at the exact moment you felt that weird thumping, which is way better than you trying to describe it three weeks later in their office.
Actionable Next Steps
If heart health is your primary reason for buying a watch, don't cheap out on the SE. You'll regret it the second you feel a palpitation and realize you can't check it.
- Buying New? Grab the Series 10 or the Ultra 2. They have the most refined sensors and the fastest processing.
- Buying Used? Look for a Series 7 or 8. They have the larger screens which make reading the EKG waveform way easier on the eyes.
- Check Your Region: If you're traveling or buying a watch from another country, be careful. The EKG feature is geo-locked. If the country doesn't have regulatory approval (like the FDA in the US), Apple disables the feature entirely at the software level.
Make sure your watch fits snugly. If it's loose, the "noise" from your arm moving will ruin the reading. Rest your arms on a table, take a deep breath, and keep still.
If you get an AFib notification and you weren't expecting it, don't panic, but don't ignore it either. Schedule a real EKG with a real doctor. Your watch is a scout, not a surgeon.