Recording the heart rhythm with an electrocardiogram while the patient is having an episode confirms the diagnosis. This can be done by a life squad, in an emergency room or a physician's office capable of performing electrocardiograms.
Other types of monitors can be used to record the heart's electrical activity at home, school or any remote location. In rare circumstances, implanted monitors can be used to record rhythms that are brief and infrequent.
After diagnosis, you should be talk with your cardiologist about the risks of the fast rhythm and the risks and benefits of its treatment. If the fast rhythm has a "benign" course with little impact on daily life, observation may be warranted.
On the other hand, an infrequent fast rhythm that is a cause for concern to either the patient, family or physician may require therapy. If the fast rhythm recurs despite therapy, the symptoms usually would be the same as before therapy.
It is helpful to learn how to take your child's pulse and to know the "normal" heart rate for their age. Your doctor can help you learn this skill. The ability to count your child's heart rate can be reassuring to you and helpful to your doctor when making a diagnosis.