01Privacy
MModeEF is built to collect as little as possible. There is no account, no server, and no patient-identifying information.
- —No sign-in or account is required to use the app.
- —No patient name or hospital number (HN) is ever entered or stored. Each measurement is identified only by the date and time it was taken.
- —All data — measurements, calculated results, and any photo you capture — stays on your device. It is stored locally and is never uploaded to a server, synced to the cloud, or shared with any third party.
- —Camera and Photo Library access are used only to capture or select a photo of an M-mode ultrasound screen. Text recognition (OCR) runs entirely on-device using Apple's Vision framework — the photo is never transmitted anywhere for processing.
- —A captured photo can still show a patient's name or HN if it's visible on the ultrasound screen itself. The app does not detect or crop this automatically — frame your photo to exclude that area when possible.
- —The app contains no analytics, no usage tracking, and no advertising.
- —Deleting a measurement from history removes it immediately. Deleting the app removes all remaining local data with it.
02Safety
Read before use
MModeEF is a basic point-of-care calculator, not a diagnostic tool. It must not be used to make treatment decisions on its own. Every result must be confirmed by a cardiologist before it is used for any clinical decision.
- Intended for use by licensed healthcare professionals as supporting information when considering the urgency of a cardiology referral — not for use by patients to self-assess.
- This is not a certified diagnostic device and does not replace a detailed echocardiogram performed and interpreted by a qualified professional.
- The Teichholz method used for EF assumes a normal, symmetric LV geometry. Accuracy decreases in patients with regional wall motion abnormality or an otherwise distorted LV shape.
- When using the photograph mode, on-device text recognition can misread a digit. Always check auto-filled values against the ultrasound screen itself before calculating — every field remains editable.
- If a value falls outside the physiologically plausible range, the app will flag it. Treat that as a prompt to re-measure or re-check the source image, not as a value to override without checking.
03Reference
Every formula in MModeEF is published and independently checkable — nothing is a black box.
Formulas
EF (%) = (EDV − ESV) / EDV × 100
EDV = 7.0 × (LVIDd)³ / (2.4 + LVIDd)
ESV = 7.0 × (LVIDs)³ / (2.4 + LVIDs)
FS (%) = (LVIDd − LVIDs) / LVIDd × 100
LV mass (g) = 0.8 × 1.04 × [(IVSd+LVIDd+LVPWd)³ − LVIDd³] + 0.6
(dimensions in cm; requires IVSd and LVPWd)
RWT = 2 × LVPWd / LVIDd
(RWT > 0.42 suggests a concentric geometric pattern)
EF severity classification
| Category | Male | Female |
|---|---|---|
| Normal | ≥ 52% | ≥ 54% |
| Mildly reduced | 41–51% | 41–53% |
| Moderately reduced | 30–40% | 30–40% |
| Severely reduced | < 30% | < 30% |
Sources
- Teichholz LE, Kreulen T, Herman MV, Gorlin R. Problems in echocardiographic volume determinations: echocardiographic-angiographic correlations in the presence or absence of asynergy. Am J Cardiol. 1976;37(1):7–11.
- Lang RM, Badano LP, Mor-Avi V, et al. Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015;28(1):1–39.
04Help
Two ways to get values into the app — pick whichever matches your ultrasound machine.
Photographing the M-mode screen, for a clean read
- If the machine has a cardiac package, place calipers and let it label and calculate IVSd, IVSs, LVIDd, LVIDs, LVPWd, LVPWs as usual — make sure all six are visible in one photo.
- If it doesn't, place calipers in this exact order, top to bottom on screen: IVSd, LVIDd, LVPWd, IVSs, LVIDs, LVPWs. At minimum, list LVIDd then LVIDs — that's enough to calculate EF.
- Hold the phone directly in front of the screen and parallel to it, fill the frame with the measurement panel, avoid glare, and hold steady.
- Check every auto-filled number against the screen before calculating. If a value is wrong, just edit it — nothing is locked.
Frequently asked
Auto-fill got a value wrong — what do I do?
Every field is editable regardless of how it was filled in. Correct it by hand and calculate as normal. If it's consistently wrong for your machine, the in-app "Show what OCR actually detected" panel (appears after taking a photo) shows exactly what text and numbers were found — useful if you want to report a pattern.
Do I need all six measurements?
No. LVIDd and LVIDs are the only two required — they're enough to calculate EF, EDV, ESV, and FS. IVSd, IVSs, LVPWd, and LVPWs are optional and only used for LV mass and RWT; leave them blank if your machine or workflow doesn't provide them.
Why isn't the EF number exactly what my machine calculated?
Small differences usually come down to rounding — the machine may use more decimal places internally than it displays on screen. Larger differences are worth double-checking your entered LVIDd/LVIDs against the source image.
Can I use this without a cardiac package on the ultrasound machine?
Yes — that's the main point-of-care use case. Manually place distance calipers on the machine at the widest point of the trace (end-diastole) and narrowest point (end-systole), then either enter the readings directly or photograph the screen and let the app read them by position.
Is my data backed up anywhere?
No — everything is local to the device only. If you need to keep a record, note the result elsewhere (such as the patient's chart) before deleting a measurement or the app.