Methodology

How ECG Tracker+ processes a recording

ECG Tracker+ turns an Apple Watch waveform into informational measurements and visualizations on your iPhone. This page explains the data flow, the boundaries of each output, and what the app does not claim.

From HealthKit to a local result

  1. You choose whether to grant read access to ECG recordings in HealthKit.
  2. The app imports the original Apple Watch waveform and associated metadata.
  3. On-device processing finds beat timing and estimates waveform landmarks and intervals.
  4. The app presents signal-quality context, informational estimates, possible pattern flags, and trends in app-generated values.
  5. You can export a PDF containing the waveform, informational measurements, and Apple Watch classification.

Core ECG processing happens on your iPhone. ECG recordings and analysis stay on your paired Apple devices. Optional feedback and diagnostics may be sent to Sentry.

What each output means

Signal quality

The signal-quality score describes how usable the recording appears for the app’s calculations. It does not prove that a value is clinically correct.

Intervals and QTc

PR, QRS, QT, and QTc are algorithm-generated estimates. QTc depends on the QT and R-R estimates plus the selected correction formula. Single-lead and automated values can differ from clinician-reviewed 12-lead measurements.

HRV

rMSSD and SDNN are calculated from beat intervals in a 30-second recording. These ultra-short estimates are not interchangeable with standardized five-minute or 24-hour HRV values.

Possible premature-beat patterns

Possible PAC and PVC pattern flags are review cues. Artifact and other rhythms can resemble these patterns. A flag is not a confirmed event, and no flag does not rule out ectopy.

Claims we do not make

  • ECG Tracker+ does not diagnose, detect, confirm, rule out, screen for, or treat a medical condition.
  • It does not claim clinical-grade or medical-grade accuracy.
  • It does not replace a 12-lead ECG, ambulatory monitor, or professional evaluation.
  • A confidence or quality score does not establish clinical correctness.
  • Trends describe changes in app-generated estimates, not changes in health, risk, stress, fitness, or recovery.

We do not publish sensitivity, specificity, or clinical-equivalence claims without product-specific validation evidence.

Editorial and source policy

Educational pages use primary sources from Apple, regulators, professional cardiology organizations, and peer-reviewed research. Material medical claims are mapped to sources. Copy is reviewed to keep app estimates separate from clinical conclusions.

Questions about this methodology can be sent to contact@ecgtrackerplus.com.

ECG Tracker+

Explore your Apple Watch ECG in more detail

View the full waveform, informational measurements, trends, and possible premature-beat pattern flags on your iPhone. Processing stays on-device.

Download on theApp Store