Validation of the Performance of the Electrocardiogram (ECG) Function in the Masimo INVSENSOR00057

Inclusion Criteria: * Subject is 22 years of age or older * Subject is comfortable to read and communicate in English\* * Subject belongs to one of two groups: * Subjects without any prior arrhythmia diagnosis presenting in normal sinus rhythm (Group1) * Subjects with history of paroxysmal or persistent atrial fibrillation presenting in atrial fibrillation (Group 2) \*This is to ensure the subject can provide informed consent (as Masimo INVSENSOR00057 ECG study materials are currently available in English only) and can comply with study procedures. Exclusion Criteria: * Subjects who are physically unable to wear a wristwatch * Subjects whose skin is not intact (e.g., has open wounds, has inflamed tattoos or piercings, has visible healing wounds) in or at the vicinity of the device placement site. * Subjects with an implantable defibrillator or cardiac pacing device. * Subjects with a skin condition which would preclude proper ECG electrode placement.. * Subjects with known allergic reactions to adhesive tapes or ECG gel. * Subjects previously diagnosed with non-atrial fibrillation cardiac arrhythmia. * Subjects not suitable for the investigation at the discretion of the investigator or the clinical team