The high price of electrocardiograph (ECG) devices - with most hospital-grade devices costing thousands of dollars - is one of the barriers to access of this vital technology. There is a shortage of ECG devices in underserved areas and the devices available on the market currently are not adequate to solve this problem. Our solution is a low-cost high-quality open-access ECG device. This study intends to validate the study ECG device in human patients by demonstrating equivalence between the study ECG device and a gold standard device.

Inclusion Criteria:

- All study participants must be able to provide written informed consent prior to study procedure. This study has 2 Phases.

Phase 1:

• Healthy
• > 18 years of age

Phase 2:

• > 18 years of age
• non critical patients presenting to the emergency department (Victoria Hospital and University Hospital) with cardiac complaint

Exclusion Criteria:

• < 18 years old
• Unable to consent

Phase 1:

• > 70 years of age
• Previous history of cardiac disease (e.g., atrial fibrillation, myocardial infarction, congestive heart failure)
• current status of non-sinus heart rhythm

Phase 2:

- Critical patients in the ED where consent would inappropriately delay investigations or treatment