The manufacturer who was to provide the study devices decided not to do so.

This is a single-center, non-randomized study to collect validation data for submission to the Food and Drug Administration (FDA) to support a 510(k) device clearance for a smartwatch ECG.

1. Obtain a simultaneous recording of a Lead I (RA-LA) ECG from the Smartwatch and a clinical standard device (GE Cardiosoft ECG). Subsequent recordings will be acquired from the other models of the Smartwatch as well as a recording utilizing the FDA-cleared KardiaMobile.
2. Compare the ECG waveforms from the Smartwatch to the GE and KardiaMobile devices to demonstrate equivalence in terms of cross correlation (correlation coefficient >.95) and RMS Difference (<10 microvolts).
3. Compare the algorithmic determination from the Smartwatch ECG to those of the GE and KardiaMobile to demonstrate equivalence.

Inclusion Criteria:

• Male or female > 18 years of age.
• Ability to understand and sign a written informed consent form, which must be obtained prior to initiation of any study procedures.
• Being seen in the OU Cardiac Electrophysiology Outpatient Clinic.

Exclusion Criteria:

• Inability or refusal of the patient and/or the patient's legally acceptable representative to provide written informed consent for any reason.
• Other conditions that in the opinion of the Lead Investigator may increase risk to the subject and/or compromise the quality of the clinical trial.