PAC and PVC describe where a beat starts
A premature atrial contraction, or PAC, starts in an upper chamber of the heart. A premature ventricular contraction, or PVC, starts in a lower chamber.
Distinguishing them can depend on waveform details, timing, recording quality, and the ECG leads available. Artifact or another rhythm can also resemble a premature-beat pattern. ECG Tracker+ therefore labels these as possible patterns, not confirmed events.
One recording cannot measure your usual pattern
An Apple Watch ECG captures 30 seconds. It can preserve a moment when you noticed a sensation, but it cannot establish how often a pattern occurs across a day or longer period.
When professional evaluation is appropriate, a healthcare professional may use a standard ECG, a longer heart monitor, and other tests based on symptoms and history.
Discuss a pattern with a healthcare professional when it is new, frequent, increasing, persistent, or accompanied by symptoms. The right next step depends on the tracing, your symptoms, and your medical history.
A 30-second recording without a possible premature-beat flag does not rule out PACs, PVCs, or another rhythm issue outside that recording.
Use a flag as a review cue
A possible flag means the app marked timing and shape features for review. It is not a confirmed PAC or PVC and does not establish cause, burden, or risk.
Keep the full waveform and recording time available. A clinician can decide whether the tracing is useful and whether further evaluation is needed.
Can the app tell whether a premature beat is harmless?
No. The app cannot determine cause, clinical importance, or risk.
What should I share with a clinician?
Share the original waveform, recording time, Apple Watch classification, and any symptoms you recorded. ECG Tracker+ can export a PDF for that conversation.
Useful questions for your appointment
- Is the waveform clear enough to review?
- Does the marked beat need confirmation with a standard ECG or longer monitor?
- Could symptoms, medication, stimulants, illness, or another factor be relevant?
- What symptoms or changes should prompt earlier medical attention?
Contact local emergency services for chest pain or pressure, fainting, severe shortness of breath, or if you think you may be having a medical emergency. If you feel unwell or have other concerning symptoms, seek medical advice even when the recording or app result looks reassuring.