Beat to Beat A Study in Paediatric, Adolescent and Young Adult Patients Who Are Undergoing or Have Undergone Cancer Therapy to Evaluate the Agreement Between QTc Measured Using 12 Lead Electrocardiogram (ECG) and a Wearable Device ECG

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.