The objective of this study is to evaluate the accuracy of four heart rate monitors in cardiac rehabilitation patients during typical, supervised cardiac rehabilitation involving exercise on a treadmill and/or stationary bicycle.

This study will assess the accuracy of four of the best-selling optical heart rate monitors when worn by cardiac rehabilitation patients.

During testing, each subject will wear:

1. Two different optical heart rate monitors (one on each wrist)
2. A Polar chest-strap based monitor
3. ECG leads

The types of wrist-worn heart rate monitors assigned to each subject will be randomly assigned.

The location (left or right wrist) will also be randomly assigned.

Heart rate will be assessed using each of the 4 monitors with the subject on the exercise machines under each of the following conditions:

1. Pre-exercise
2. Treadmill: at 3, 5 and 7 min.
3. Stationary Cycle: at 3, 5 and 7 min.

Inclusion Criteria:

• Age > 18 years
• Patients enrolled in cardiac rehabilitation program at Cleveland Clinic Main Campus

Exclusion Criteria:

• Presence of a cardiac pacemaker
• Known chronic and persistent heart rhythm disorders
• Tattoos around the wrist or forearm area
• Use of a radial artery graft for coronary artery bypass grafting