Why this matters now
Ten years ago, catching a brief AFib episode at home was nearly impossible unless you happened to be wearing a Holter monitor that week. Today, a watch on your wrist can detect AFib, record a usable ECG, and send it to us. This has fundamentally changed how we diagnose and follow rhythm problems.
That power comes with a small set of pitfalls — false alarms, anxiety about every notification, and “incidental” AFib in people who feel fine and are not sure what to do with the information. We try to use these tools with intention, not as a default.
The main consumer tools
Apple Watch (and similar smartwatches)
The Apple Watch uses two technologies. Photoplethysmography (PPG) — an optical sensor on the underside — passively monitors the pulse and flags irregular rhythms suggestive of AFib. The on-demand ECG is a single-lead recording taken when you touch the digital crown for 30 seconds. The ECG is high quality and is the recording we actually use to confirm AFib.
The other major-brand smartwatches (Samsung, Fitbit, Garmin) have similar capabilities, with varying accuracy. As a category they are reasonably reliable for AFib detection and less reliable for nuanced arrhythmias.
Kardia and other handheld ECG devices
The KardiaMobile is a small two-electrode device that pairs with your phone and records a 30-second ECG. The six-lead version (KardiaMobile 6L) is more detailed. These are inexpensive, durable, and easy for patients to use to capture symptomatic episodes.
Phone-based pulse apps
These work, but the recording quality is much lower than a dedicated device. We use them only when nothing else is available.
Medical-grade tools we order
When we need more rigorous data than a wearable can provide, we use:
- Holter monitor — a small recorder with several leads worn for 24 to 48 hours. The classic device. Best for symptoms that happen most days.
- Patch monitor (Zio XT, BodyGuardian) — a small adhesive patch worn for 7–14 days that continuously records and stores ECG data. Excellent for catching less frequent episodes.
- Mobile cardiac telemetry (MCT) — real-time monitoring that transmits to a monitoring center. Used for higher-risk symptoms where prompt action might be needed.
- Implantable loop recorder (ILR) — a small device the size of a paperclip placed under the skin in the chest. It continuously monitors for up to several years. Used for very infrequent or unexplained syncope, cryptogenic stroke workup, or post-ablation follow-up in selected patients.
Choosing the right tool
We match the device to the question:
- “Am I having AFib right now during this symptom?” A Kardia or watch ECG, recorded during the symptom, is ideal.
- “How often am I in AFib?” A 14-day patch monitor gives a clean answer for most patients.
- “Did my AFib come back after ablation?” Watch + Kardia at home, plus a patch monitor or loop recorder for follow-up at defined intervals.
- “My fainting episodes are months apart and we have no recording.” Implantable loop recorder.
- “I have palpitations but no AFib diagnosis.” Start with a watch or Kardia. Move to a patch if those are normal.
Limitations and false alarms
A few practical notes:
- PPG notifications are not diagnoses. When your watch flags an irregular rhythm, the next step is to record an actual ECG with the watch (or a Kardia). Movement, poor sensor contact, and certain other arrhythmias can produce false-positive notifications.
- Sleep is a common false positive. Some watches flag short irregular runs at night that turn out to be sinus rhythm with frequent ectopy or just sensor artifact.
- Single-lead ECGs miss some things. They are great for AFib and PACs/PVCs. They are not the right tool for some other arrhythmias that need more leads.
- More monitoring can fuel anxiety. Some patients check their watch dozens of times a day. We will sometimes ask a patient to stop wearing the watch for a while, because constant vigilance is itself a kind of treatment burden.
Practical tips
- Send us the recordings. If you have made an ECG during a symptom, save it as a PDF and bring it (or your phone) to the visit. Better yet, send the PDF through the patient portal before the visit so we can review it ahead of time.
- Note the time and context. A few sentences with each recording — what you were doing, what you felt, how long it lasted — is enormously useful.
- Do not change medications based on a watch notification. Call us. We will look together.
- Make space without the watch. Especially for patients with significant anxiety around rhythm, a defined “watch-free” period each week can be helpful.
When to check in with us
Bring any unusual recordings to your visit — even ones the device labeled as “normal.” If a wearable repeatedly flags an irregular rhythm and you have no formal AFib diagnosis, that is a reason to schedule a visit, not to wait. We will pick the right next test and build the right monitoring plan with you.