An Electrocardiogram (ECG/EKG) technician works in a cardiologist's office, a cardiac unit of a hospital, or an emergency department. The ECG/EKG technician may also work with patients who have had a heart attack, in an exercise physiology lab, or with patients who have had cardiac surgery. Many Certified Nursing Assistants take these courses to work in a hospital emergency room or telemetry unit. Students must be at least 18 years of age at time of registration.