A prospective study in paediatric, adolescent and young adult patients aged 7 to 18 years to evaluate the agreement between QTc measured using 12 lead electrocardiogram (ECG) and the wearable device ECG.

Rationale: Leveraging existing wearable technology has the ability to scale routine screening strategies across large populations and can facilitate ambulatory care. In recent years, wearable technology has rapidly diffused into consumer markets and provides unique opportunities to engage individuals on health issues of personal interest, and to collect personal health data. One example of such technology is the ability to perform electrocardiogram (ECG) type traces on wearable devices. However, utilization of this data source to improve patient outcomes has not been fully realized in the health care field. An app-based heart ECG algorithm that can be remotely analysed for QTc prolongation with potential to then notify the user of such potential irregularities could lead to widespread screening, detection and initiation of treatment solutions (i.e. correction of electrolytes, alteration of exacerbating medications, cardiac monitoring etc).

Trial Design: This will be a prospective, single arm, experimental, non-significant risk study conducted with the assistance of eligible participants. Parents or mature minors will download the Beat to Beat app, once consented.

Once consented the wearable device will be paired to the parent/guardians phone following the steps provided by the wearable device app. Once the device is paired and the study coordinator has assisted with the download of 'Beat to Beat' app, the patients will then be able to commence the ECG readings. A 12 lead ECG will be performed by the study team and immediately following this, an ECG will be recorded on the wearable device. The wearable device will be placed on the left wrist for a Lead I reading, on the left lower abdomen for a Lead II reading and in the fourth intercostal space left parasternal for a chest V2 Lead reading. Recording of the 12 lead ECG and wearable device ECG will be repeated again 4 days later. Once both timepoints (and two device recordings for each time period) have been completed the ECGs will be retrieved from the Beat to Beat app. Both the 12 lead and wearable device ECG will be de-identified and given a patient identifier before being uploaded into the REDCap database.

Inclusion Criteria:

• Paediatric or adolescent diagnosis of cancer AND an inpatient of The Royal Children's Hospital, Melbourne for at least 5 days at the time of consent.

• Patient age ≥ 7 years at time of eligibility screening

• If age < 18 years, parent or guardian able to provide consent

• Parental or participant ( if > 18 years of age) possession of the following at time of eligibility screening, ascertained from automatic hardware/software/device pairing check:

  1. iPhone (6s or later) with iOS version 15.0 or later defined as iPhone model/iOS version used to complete screening eligibility.
  2. Proficient in written and spoken English, defined by self-report of comfort reading, writing, and speaking English on iPhone.
  3. Valid phone number associated with iPhone, ascertained from self-report.
  4. Valid email address, ascertained from self-report.
  5. Participants or parents need to be able to press down on the wearable device crown for 30 seconds

Exclusion Criteria:

• Unable to wear the wearable device.
• < 18 years of age without guardian or parent to provide consent.
• Interpreter required for consent purposes.

The de-identified data set collected for this analysis of the Beat to Beat trial will be available 12 months after publication of the primary outcome.

The study protocol, analysis plan and consent forms will also be available. The data may be obtained from the Murdoch Children's Research Institute by emailing MCTC@mcri.edu.au.

The de-identified data set collected for the analysis of the trial will be available for six months after publication of the primary outcome. The study protocol can be obtained from Murdoch Children's Research Institute. Prior to access to any data the following would be required: a data access agreement must be signed by all relevant parties, the investigators of the study must see and approve the analysis plan describing how the data will be analysed. There must be also an agreement around appropriate acknowledgement in any future publications.

The data may be obtained from the Murdoch Children's Research Institute by emailing MCTC@mcri.edu.au