Congenital Heart Disease Tests: 6-Minute-Walk

As a young girl, I often watched shows like The Bionic Woman in admiration of the ease and speed with which she moved. I dreamed of running a marathon, even though I had trouble running one lap around the track field. I had hope in modern medicine and what the future might bring.

Some of the medicine and technological advancements that have been discovered since 1983, the year I first was diagnosed with my heart and lung problem, require being seen by medical doctors and scientists who specialize in my specific heart and lung physiology, which is usually at a medical facility located in large metropolitan areas, such as New York, Cleveland, Pittsburgh, Philadelphia and Raleigh/Durham.

An example of why I choose to be seen at a major medical facility or clinic that specializes in Adult Congenital Heart Disease is because of the new medicines and treatments that are researched and developed. These tests and medicines prescribed for me there are routine, but may not have even been heard of at most other hospitals.

One such test that is routinely given every three to four months for my congenital heart and lung disease is called a 6-Minute-Walk Test. This test measures my pulse rate and oxygen saturation (O2 Sat) in a short span walk lasting a total of six minutes. The test measures how much oxygen I’m getting and how fast and low the O2 Sat drops upon minimal to mild exertion.

In preparing for the 6-Minute-Walk, I make sure I wear comfortable shoes and clothes. The technician straps a pulse oximeter reader to my forehead and I carry the monitor around my neck so it is not in the way when I walk. An EKG test is done before and after the test. I’m hooked up to a small tank of oxygen that I pull while walking. I am started on 4 liters of O2 and the technician increases the O2 as I walk and as my O2 Sat level drops. I look almost like the “Bionic Woman” when all the apparatus is hooked up, but hardly match the speed and distance.

When I begin the test my O2 Sat is around 85%. And, as the picture shows, my O2 Sat dropped to 57% upon completion, and probably went even lower during the walk.

This specific test is used to see how my O2 Sat drops during exertion and to see how the medicine I’ve been prescribed is working. The goal is to have my O2 Sat level as high as possible on exertion, and with the new medicine I'm prescribed and with oxygen therapy, my O2 Sat has improved.

Anyone in the medical field knows, or any patient knows, that when an O2 Sat falls under 90% it causes alarm to the nursing staff and doctors, so an O2 Sat falling below 85% is even greater cause for concern. Using the oxygen with medicine therapy helps the heart from overworking and thus prevents me from going into complete heart failure sooner than expected.

Doctors don’t know how my body uses such low oxygen, but over time my body has compensated and I’m used to it. It’s normal for me, but hardly normal at all. Isn’t it amazing what our hearts can do?

After the 6-Minute-Walk test at Duke University Medical Center, which has an Adult Congenital Heart Clinic, my doctor, Dr. Terry Ann Fortin, was concerned because I have been having trouble keeping up with my regimen and routine of taking my medicines and using my oxygen. Dr. Fortin specializes in ACHD and also specializes in Pulmonary Hypertension (secondary) that comes with some CHD. I had been worrying about my vitamin D levels, but Dr. Fortin sat with me and told me straight out that I am most likely going to die from CHD and pulmonary hypertension and from NOT using my oxygen, not vitamin D deficiency. And since I've been sort of unsettled in my living environment over the past five years, she also told me to get somewhere and take your medicine and use your oxygen, because taking the medicine and using the oxygen requires consistency on a daily basis.

I am happy to report that since my last appointment I have been maintaining a better routine, and hopefully I will pass my next appointment with flying colors.