QTvision Support
Contact: info@clinicianbuilt.com
We usually reply within two business days.
How do I get the best photo?
Use one strip, held flat and level, in even light with no glare, and fill the frame. If the photo is sideways, tap Rotate 90°.
How do I place the markers?
Pinch to zoom, then drag R′ to the previous R peak, Q to the QRS onset, R to the R peak, and T to the end of the T wave. Calculate becomes available once all four markers have been placed.
The Take Photo button is missing, or says camera access is off.
Open iPhone Settings > QTvision > Camera and turn it on. On devices without a camera, use Choose from Library.
Why a ratio instead of QTc?
QT and RR are measured on the same image, so no calibration is needed. The ratio equals the QTc only at 60 bpm; above 60 bpm it reads high and below 60 bpm it reads low. Obtain a formal QTc if the rate is below 60 or above 100 bpm or the result is not within range.
Where do the reference cut-points come from?
They are published adult QTc limits restated as ratios at 60 bpm. Full references are in the app's About screen and on the QTvision home page.
How do I delete my saved results?
Swipe left on a result in History, or delete the app to remove all of them.
Where is my data?
On your iPhone only. Images are never saved. See the Privacy Policy.
Is QTvision a medical device?
QTvision is a measurement aid for qualified healthcare professionals. It is not a diagnostic device and is not cleared or approved by FDA. It does not replace formal 12-lead QTc measurement or clinical judgment.
Requirements
iPhone with iOS 18 or later.
Contact: info@clinicianbuilt.com