Inclusion Criteria:

•  Adult participants (>22 years; Frontier X is approved for use in this age group) who participate in >4 days a week of >150 minutes total per week of moderate to high intensity exercise who were prescribed a 7-14 day ambulatory ECG monitor for clinical purposes.

• Patients must agree to wear the Frontier X monitor for the prescribed duration and use the Frontier X Plus application

Exclusion Criteria:

• Current use of Implanted Cardiac Devices

• Pregnancy

• Known allergies to any of the materials listed in the “List of Patient-Contacting Materials”

• Presence of skin injuries or broken skin in the area where the chest strap is worn

• Inability to use a compatible mobile device required for the operation of the study device

• Any cognitive or physical limitations that, in the opinion of the investigator, limits the participant’s ability to fully follow study procedures

• Medical restrictions on exercise for safety including cardiac, orthopedic or other relevant past medical history

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 11/05/2025. Questions regarding updates should be directed to the study team contact.