For children diagnosed with congenital heart disease, physical activities may come with limitations. The St. Louis Children’s and Washington University Heart Center combines the benefits of exercise with the expertise of pediatric cardiologists specializing in exercise physiology to aid children with heart disease.
Dr. Orr joins the show to discuss exercise physiology services at St. Louis Children’s Hospital and when to refer to a specialist.
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Exercise Physiology Lab at St. Louis Children's Hospital
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Learn more about William "Billy" Orr, MD
William "Billy" Orr, MD
William "Billy" Orr, MD is a Washington University pediatric cardiologist at St. Louis Children's Hospital.Learn more about William "Billy" Orr, MD
Transcription:
Melanie Cole (Host): For children diagnosed with congenital heart disease; physical activities may come with limitations. The St. Louis Children’s and Washington University Heart Center combines the benefits of exercise with the expertise of pediatric cardiologists specializing in exercise physiology to aid children with heart disease. Joining us today to discuss this is Dr. William Orr. He’s a Washington University Pediatric Cardiologist at St. Louis Children’s Hospital. Dr. Orr, it’s a pleasure to have you join us today. What is pediatric exercise physiology? What’s this new burgeoning field all about?
William “Billy” Orr, MD (Guest): Basically breaking down what it is, it’s just studying the body’s way of utilizing the oxygen that we breathe from the environment and transporting that oxygen into the body, into the muscles and making sure that the muscles can use the oxygen in the mitochondria and seeing what the exercise capacity of a certain individual is and that way also, if there is a breakdown along one of those chains of the way to transport the oxygen, we can kind of study and figure out what is the rate limiting factor.
Host: Doctor when you say we study, what does exercise physiology entail? What kinds of conditions are you looking at? What are some of the goals that you can tell us about?
Dr. Orr: So, the basic test will bring a patient in and this patient can have anything ranging from just some exercise exertional symptoms like chest pain or maybe passing out or even palpitations all the way up to the patient that maybe only has a single ventricle and at baseline is cyanotic. And so, we actually what we do is we test them, and we can test them on either a treadmill or a bicycle and the goal is to get that patient with a little bit of coaching up to maximum effort so maximal voluntary effort. As we are testing this child, we are usually measuring the gas exchange with a metabolic cart and so they have a mask or a mouthpiece in and we can measure breath by breath information of the amount of oxygen they are breathing and the amount of CO2 that they are breathing out as well as the heart rate changes, and the heart rhythm changes with EKG. So, they are hooked up to a few things that give us tons and tons of data and all those data points have values and we can look at all those values in relation to the patient’s presenting symptoms and try to decipher if maybe the patient is limited in their exercise capacity from a respiratory component or maybe a cardiovascular etiology or even a metabolic component down into the cellular level.
Host: Well thank you for that very comprehensive answer. So, tell us a little bit about the exercise physiology lab at St. Louis Children’s Hospital. What are you using it for and how is it helping to evaluate a wide range of patients?
Dr. Orr: We currently share our equipment with the Division of Pulmonology and so, we have the ability to test patients either on a bicycle or a treadmill and you’ll find varying data throughout the country on which institutions use what and so the fact that we are able to use both types of ergometers as they are called; give us an advantage because they both have kind of pros and cons to each on which one is better for what reason. We also can do tests like I mentioned while analyzing your gas exchange and also your EKGs and so we may have patients who come in just for testing of exercise capacity if they have exercise symptoms or maybe if they actually have a congenital heart lesion or an acquired congenital heart lesion or a heart defect that they need some clearance to participate in sports and your average pediatrician or even the cardiologist thinks it’s necessary based on certain guidelines to test their maximum capacity to give more formal recommendations on what they are allowed to do.
And then you have the patients that come in who have maybe even just one ventricle or they are in heart failure and so you are testing those patients to help guide management on whether that patient needs to maybe have a interventional cath or maybe that’s a little more data to help decide if the patient should go to surgery or even maybe that patient now is sick enough to the point where they need to be evaluated and listed for heart transplant. So, the data that we can get from this is a noninvasive way to obtain a lot of good information to maybe guide the referring cardiologist’s decision on which direction to take the care or the further management of their patient.
Host: Well it’s so interesting and as I said, it’s a bit of a new field this pediatric exercise physiology and while you’re determining which patients can benefit from it, tell us a little bit. Give us some examples about the usefulness of tests. Help us to identify the rate limiting factor and certain patients with limited exercise capacity. Kind of combine that all for us Doctor.
Dr. Orr: You know if you look into the literature, you won’t find a whole lot of data specifically related to the congenital heart patients and exercise capacity. You’ll find a lot on the adult world. There’s a lot of good research that are coming out of some of the bigger institutions with more well established exercise labs. A lot of the stuff is like you said, almost a little bit of a new frontier and so the data that we are getting is very interesting and it’s fun to kind of relate to the actual patient and what they also have going on to try to make it the total package in the information we can.
Not only is it in the cyanotic heart lesions but our patients that have an inherited arrythmia or a channelopathy that they were born with and so they may present with an abnormal heart rhythm at peak exercise. So, we can actually put these patients on the treadmill, see what their heart rhythm does, figure out if we need to adjust their medications, if they need to go and have a formal electrophysiology study. We can even take patients that have pacemakers and put them on the treadmill to make sure their pacemaker is programmed correctly so as they start to exercise, their pacemaker senses that they are exercising and increases the heartrate appropriately so that way their quality of life is what you would want and hope for any kid that wants to just be a normal kid and go play. So, it depends on kind of what the question is that the exercise lab can try to help answer and then we do our best to kind of evaluate the patient.
Host: At what point would a pediatrician refer a patient for exercise physiology and to this lab? Is it that parents can request it, or a pediatrician’s office would order it? Do they first refer to a pediatric cardiologist? Tell us a little bit about how the process works for other providers.
Dr. Orr: That’s a good question. I think 99% of it is going to come through a referral pediatric cardiologist. So, if it gets to the point of a patient complaining of these types of symptoms; most likely a pediatrician is going to want formal recommendations from a cardiologist anyway. So, this test although sure anybody could order it and we put an interpretation may still be difficult to interpret what to do with these and also, they have to feel comfortable with saying that they are cleared for sports and et cetera.
So, most of the patients come through, have already seen a cardiologist or maybe a pediatric CT surgeon and then are coming straight from their clinic.
Host: So, as we wrap up, tell us what’s new and exciting. What’s coming down the pike for new studies at the lab, and where you’re talking about nuclear myocardium perfusion studies with exercise. Tell us a little bit about some of the exciting things that you are seeing coming down for the lab and what else a pediatrician or pediatric provider would need to know about this lab at St. Louis Children’s Hospital.
Dr. Orr: We’re actually working on a few new things right now. You had mentioned one of them the myocardial perfusion imaging which is basically working with the nuclear medicine department. The adults use this a lot over on the adult side if they have had an MI or they have a concern for coronary abnormality, they’ll actually exercise the patients and then at peak exercise, they’ll inject an isotope that will light up very nicely on MRI. And so you can see which parts of the myocardium are being perfused and maybe which parts are concerned for ischemia and so we have actually brought that test over using pretty much the same exact techniques and just brought that test over to Children’s which allows us to evaluate patients that meet indications for that. Now not every single patient is going to have an indication for that but if they’ve ever had an anomalous coronary or maybe they’ve had their coronaries reimplanted or they had Kawasaki’s disease, some of those are indications to evaluate further and maybe doing an MPI Study which is short for myocardial perfusion imaging would benefit from those.
Other things that we are working on currently are like a Fontan protocol so our patients that have a single ventricle that have a Fontan circulation. A lot of data has come out over the years about normal values in a Fontan patient and we’re trying to here at Children’s we already have a kind of comprehensive Fontan clinic that’s run by Katie Simpson one of our heart transplant physicians and so, trying to work with her and the heart failure team and just in general to come up with a protocol that standardizes how frequently and when and how to test these Fontan patients and then even to potentially enroll them into an exercise rehabilitation program.
And so, long term, I think some of my goals are to also develop protocols for heart transplant patients that would involve an exercise program and then retesting to make sure their exercise capacity is improving even any type of a sports and exercise rehab. So, there’s lots of interesting and fun ways that you can take this field which is really exciting. I look forward to kind of seeing how we can take this in the future.
And then I guess last comment that I would want families to know before getting a test or before requesting a test is that this is overall a very extremely safe type of testing. The kids, the patients will be encouraged and pushed kind of as hard as they can. We want them to get to their maximum voluntary effort. At any time during the test if the kid or the patient decides that they are done and they don’t want to go any further, then we stop the test and we are in there watching closely and if we see anything concerning then we can stop the test in the middle of it. We of course, want the data but it’s not worth if it’s going to put the patient at any harm at any point. So, it’s extremely safe test. We love to answer questions about the test and make sure everyone understands why they are doing it and what they are getting done. So, hope people don’t get nervous or anything coming into the exercise lab.
Host: That’s absolutely great information and what an exciting time to be doing what you ‘re doing Dr. Orr. Thank you so much for coming on and telling us all about the exercise physiology lab at St. Louis Children’s Hospital. That concludes this episode of Radio Rounds with St. Louis Children’s Hospital. To consult with a specialist or to learn more about services and resources available at St. Louis Children’s, please call the Children’s Direct Physician Access Line at 1-800-678-HELP. To learn more about this and other healthcare topics at St. Louis Children’s Hospital please visit our website at www.stlouischildrens.org for more information and to get connected with one of our providers. Please remember to subscribe, rate and review this podcast and all the other St. Louis Children’s Hospital podcasts. I’m Melanie Cole.
Melanie Cole (Host): For children diagnosed with congenital heart disease; physical activities may come with limitations. The St. Louis Children’s and Washington University Heart Center combines the benefits of exercise with the expertise of pediatric cardiologists specializing in exercise physiology to aid children with heart disease. Joining us today to discuss this is Dr. William Orr. He’s a Washington University Pediatric Cardiologist at St. Louis Children’s Hospital. Dr. Orr, it’s a pleasure to have you join us today. What is pediatric exercise physiology? What’s this new burgeoning field all about?
William “Billy” Orr, MD (Guest): Basically breaking down what it is, it’s just studying the body’s way of utilizing the oxygen that we breathe from the environment and transporting that oxygen into the body, into the muscles and making sure that the muscles can use the oxygen in the mitochondria and seeing what the exercise capacity of a certain individual is and that way also, if there is a breakdown along one of those chains of the way to transport the oxygen, we can kind of study and figure out what is the rate limiting factor.
Host: Doctor when you say we study, what does exercise physiology entail? What kinds of conditions are you looking at? What are some of the goals that you can tell us about?
Dr. Orr: So, the basic test will bring a patient in and this patient can have anything ranging from just some exercise exertional symptoms like chest pain or maybe passing out or even palpitations all the way up to the patient that maybe only has a single ventricle and at baseline is cyanotic. And so, we actually what we do is we test them, and we can test them on either a treadmill or a bicycle and the goal is to get that patient with a little bit of coaching up to maximum effort so maximal voluntary effort. As we are testing this child, we are usually measuring the gas exchange with a metabolic cart and so they have a mask or a mouthpiece in and we can measure breath by breath information of the amount of oxygen they are breathing and the amount of CO2 that they are breathing out as well as the heart rate changes, and the heart rhythm changes with EKG. So, they are hooked up to a few things that give us tons and tons of data and all those data points have values and we can look at all those values in relation to the patient’s presenting symptoms and try to decipher if maybe the patient is limited in their exercise capacity from a respiratory component or maybe a cardiovascular etiology or even a metabolic component down into the cellular level.
Host: Well thank you for that very comprehensive answer. So, tell us a little bit about the exercise physiology lab at St. Louis Children’s Hospital. What are you using it for and how is it helping to evaluate a wide range of patients?
Dr. Orr: We currently share our equipment with the Division of Pulmonology and so, we have the ability to test patients either on a bicycle or a treadmill and you’ll find varying data throughout the country on which institutions use what and so the fact that we are able to use both types of ergometers as they are called; give us an advantage because they both have kind of pros and cons to each on which one is better for what reason. We also can do tests like I mentioned while analyzing your gas exchange and also your EKGs and so we may have patients who come in just for testing of exercise capacity if they have exercise symptoms or maybe if they actually have a congenital heart lesion or an acquired congenital heart lesion or a heart defect that they need some clearance to participate in sports and your average pediatrician or even the cardiologist thinks it’s necessary based on certain guidelines to test their maximum capacity to give more formal recommendations on what they are allowed to do.
And then you have the patients that come in who have maybe even just one ventricle or they are in heart failure and so you are testing those patients to help guide management on whether that patient needs to maybe have a interventional cath or maybe that’s a little more data to help decide if the patient should go to surgery or even maybe that patient now is sick enough to the point where they need to be evaluated and listed for heart transplant. So, the data that we can get from this is a noninvasive way to obtain a lot of good information to maybe guide the referring cardiologist’s decision on which direction to take the care or the further management of their patient.
Host: Well it’s so interesting and as I said, it’s a bit of a new field this pediatric exercise physiology and while you’re determining which patients can benefit from it, tell us a little bit. Give us some examples about the usefulness of tests. Help us to identify the rate limiting factor and certain patients with limited exercise capacity. Kind of combine that all for us Doctor.
Dr. Orr: You know if you look into the literature, you won’t find a whole lot of data specifically related to the congenital heart patients and exercise capacity. You’ll find a lot on the adult world. There’s a lot of good research that are coming out of some of the bigger institutions with more well established exercise labs. A lot of the stuff is like you said, almost a little bit of a new frontier and so the data that we are getting is very interesting and it’s fun to kind of relate to the actual patient and what they also have going on to try to make it the total package in the information we can.
Not only is it in the cyanotic heart lesions but our patients that have an inherited arrythmia or a channelopathy that they were born with and so they may present with an abnormal heart rhythm at peak exercise. So, we can actually put these patients on the treadmill, see what their heart rhythm does, figure out if we need to adjust their medications, if they need to go and have a formal electrophysiology study. We can even take patients that have pacemakers and put them on the treadmill to make sure their pacemaker is programmed correctly so as they start to exercise, their pacemaker senses that they are exercising and increases the heartrate appropriately so that way their quality of life is what you would want and hope for any kid that wants to just be a normal kid and go play. So, it depends on kind of what the question is that the exercise lab can try to help answer and then we do our best to kind of evaluate the patient.
Host: At what point would a pediatrician refer a patient for exercise physiology and to this lab? Is it that parents can request it, or a pediatrician’s office would order it? Do they first refer to a pediatric cardiologist? Tell us a little bit about how the process works for other providers.
Dr. Orr: That’s a good question. I think 99% of it is going to come through a referral pediatric cardiologist. So, if it gets to the point of a patient complaining of these types of symptoms; most likely a pediatrician is going to want formal recommendations from a cardiologist anyway. So, this test although sure anybody could order it and we put an interpretation may still be difficult to interpret what to do with these and also, they have to feel comfortable with saying that they are cleared for sports and et cetera.
So, most of the patients come through, have already seen a cardiologist or maybe a pediatric CT surgeon and then are coming straight from their clinic.
Host: So, as we wrap up, tell us what’s new and exciting. What’s coming down the pike for new studies at the lab, and where you’re talking about nuclear myocardium perfusion studies with exercise. Tell us a little bit about some of the exciting things that you are seeing coming down for the lab and what else a pediatrician or pediatric provider would need to know about this lab at St. Louis Children’s Hospital.
Dr. Orr: We’re actually working on a few new things right now. You had mentioned one of them the myocardial perfusion imaging which is basically working with the nuclear medicine department. The adults use this a lot over on the adult side if they have had an MI or they have a concern for coronary abnormality, they’ll actually exercise the patients and then at peak exercise, they’ll inject an isotope that will light up very nicely on MRI. And so you can see which parts of the myocardium are being perfused and maybe which parts are concerned for ischemia and so we have actually brought that test over using pretty much the same exact techniques and just brought that test over to Children’s which allows us to evaluate patients that meet indications for that. Now not every single patient is going to have an indication for that but if they’ve ever had an anomalous coronary or maybe they’ve had their coronaries reimplanted or they had Kawasaki’s disease, some of those are indications to evaluate further and maybe doing an MPI Study which is short for myocardial perfusion imaging would benefit from those.
Other things that we are working on currently are like a Fontan protocol so our patients that have a single ventricle that have a Fontan circulation. A lot of data has come out over the years about normal values in a Fontan patient and we’re trying to here at Children’s we already have a kind of comprehensive Fontan clinic that’s run by Katie Simpson one of our heart transplant physicians and so, trying to work with her and the heart failure team and just in general to come up with a protocol that standardizes how frequently and when and how to test these Fontan patients and then even to potentially enroll them into an exercise rehabilitation program.
And so, long term, I think some of my goals are to also develop protocols for heart transplant patients that would involve an exercise program and then retesting to make sure their exercise capacity is improving even any type of a sports and exercise rehab. So, there’s lots of interesting and fun ways that you can take this field which is really exciting. I look forward to kind of seeing how we can take this in the future.
And then I guess last comment that I would want families to know before getting a test or before requesting a test is that this is overall a very extremely safe type of testing. The kids, the patients will be encouraged and pushed kind of as hard as they can. We want them to get to their maximum voluntary effort. At any time during the test if the kid or the patient decides that they are done and they don’t want to go any further, then we stop the test and we are in there watching closely and if we see anything concerning then we can stop the test in the middle of it. We of course, want the data but it’s not worth if it’s going to put the patient at any harm at any point. So, it’s extremely safe test. We love to answer questions about the test and make sure everyone understands why they are doing it and what they are getting done. So, hope people don’t get nervous or anything coming into the exercise lab.
Host: That’s absolutely great information and what an exciting time to be doing what you ‘re doing Dr. Orr. Thank you so much for coming on and telling us all about the exercise physiology lab at St. Louis Children’s Hospital. That concludes this episode of Radio Rounds with St. Louis Children’s Hospital. To consult with a specialist or to learn more about services and resources available at St. Louis Children’s, please call the Children’s Direct Physician Access Line at 1-800-678-HELP. To learn more about this and other healthcare topics at St. Louis Children’s Hospital please visit our website at www.stlouischildrens.org for more information and to get connected with one of our providers. Please remember to subscribe, rate and review this podcast and all the other St. Louis Children’s Hospital podcasts. I’m Melanie Cole.