A new study launches to validate Apple Watch’s ECG application in children during cancer therapy

Apple Watch QTc interval validation in clinical study

Murdoch Childrens Research Institute, Australia, is launching a new study this week to validate Apple Watch’s ECG application in children during and after cancer therapy.

Murdoch Children’s Research Institute (MCRI) is Australia’s largest child health research institute and one of the top three child health research institutes worldwide for research quality and impact.

The prospective study in pediatric, adolescent, and young adult patients aged 7 to 18 years to validate the use of the Apple Watch’s electrocardiogram (ECG) function in measuring QT prolongation during and or after cancer therapy.

Related reading:

What is QTc, and how you can check using Apple Watch

QT prolongation is the medical term for an extended interval between the heart contracting and relaxing. This condition can increase a person’s risk of experiencing abnormal heart rhythms and sudden cardiac arrest.

The reliability of the QTc measurements between standard and smartwatch ECG was also demonstrated with a Bland–Altman analysis using different formulas. These data show that a smartwatch can feasibly and reliably assess QT interval. 

If you have never checked your QTc before, you can do this easily by using the QTc-Calculator app on your Apple Watch. The app is free and available on the App store. How to check QTc on Apple Watch


This app enables doctors to calculate QTc quickly. You can enter either the heart rate or the length of the RR interval and the length of the QT interval.

There will be up to three results for QTc using three of nine different formulas: Bazett’s, Fridericia’s, Framingham’s, Hodges’s, Goto’s, Mayeda’s, Kawataki’s, Rautaharju’s a, and b formula.

Also, RR interval or heart rate and estimates of QT depending on heart rate is determined.

Objectives of the Murdoch Children’s Research Institute’s new Apple Watch Study

This new Australian study will attempt to understand the following:

Primary Objective:

To evaluate the agreement between QTc measured using 12 lead ECG and Apple Watch using mean absolute error calculations.

Secondary Objectives:

 1. To calculate the sensitivity and specificity for measuring prolonged QTc using the Apple Watch.

2. To calculate the interobserver variability between the two health care professional readings of QTc.

The central hypothesis is that Leveraging existing wearable technology to monitor QTc prolongation can scale routine screening strategies across large populations and facilitate ambulatory care. 

Utilizing the Apple Watch to monitor QTc prolongation in this study improves patient outcomes by facilitating real-time monitoring of potential irregularities, widespread screening, detection, and quicker initiation of treatment solutions.

The app, together with the device (Apple Watch), will record a V1 (Left wrist) or V2 (left ankle) ECG reading. These measurements will be conducted on Day 1 and Day 4 of inpatient stay.

A 2021 study by researchers at the Anderson Cancer Center, Houston, found that among the cancer patients, the QTc was longer in the inpatient setting when compared to both outpatient and emergency center areas. The most commonly prescribed QT-prolonging medications identified were ondansetron and methadone. 

With each passing day, it is becoming more apparent that wearables like the Apple Watch are here to stay as they can help improve people’s lives.

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Sudz Niel Kar
I am a technologist with years of experience with Apple and wearOS products, have a BS in Computer Science and an MBA specializing in emerging tech, and owned the popular site AppleToolBox. In my day job, I advise Fortune 500 companies with their digital transformation strategies and also consult with numerous digital health startups in an advisory capacity. I'm VERY interested in exploring the digital health and fitness-tech evolution and keeping a close eye on patents, FDA approvals, strategic partnerships, and developments happening in the wearables and digital health sector. When I'm not writing or presenting, I run with my Apple Watch Ultra or Samsung Galaxy Watch and closely monitor my HRV and other recovery metrics.


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