The Master Two Step exercise stress test.
Paul Goldfinger, MD, FACC. Re-post from Blogfinger.net 2015.
In 1929, a brilliant doctor at Mt. Sinai Hospital in New York City, took an interest in the diagnosis of coronary heart disease. He was Arthur M. Master, MD, and he was trying to figure out how to diagnose underlying coronary artery disease in someone who seems healthy. This was at a time when there were no tools such as angiograms available.
He decided that he might be able to bring the diagnosis to the surface by having the subject perform exercise using a simple device—-a 2 step staircase which would enable the patient to exercise while being attached to an ECG machine. The Master’s Two Step test was the first exercise stress test, but it later fell into disfavor and was not in use when I began my cardiology residency at “Sinai” in the late 1960’s.
In 1963, a cardiologist at the University of Washington, Dr. Robert Bruce, developed the Bruce protocol for exercise stress testing using a treadmill. When I was in my final year of the cardiology residency at Mt. Sinai, we were required to do a clinical research project for 6 months. My fellow resident was Elliot Stein, MD who later also came to New Jersey to practice. We approached Dr. Arnold Katz, the chief at that time, regarding a project. He said, “Why don’t you do something with exercise.”
We were clueless about what to do. We then spoke to Dr. Ephraim Donoso at the hospital who said, “We have a treadmill in the basement that no one has ever used..” So we marched over to the hospital library where we discovered a paper by Dr. Bruce. There were very few published studies to guide us, no one at the hospital knew much about it, and the Bruce procedure had not been standardized.
Because treadmill testing was so new, we had to figure it out for ourselves. It took a lot of time, study and experimentation. We used Dr. Bruce’s basic protocol, but all the fine points had to be worked out. We tested volunteers. The hardest part was figuring out how to get good quality ECG strips during the motion of exercise. Dr. Master used to get his ECG strips after exercise, but that wasn’t very accurate and probably was the weak spot that doomed the two step test.
Among many questions which had to be resolved was what to do with the patient when we got him off the machine. We decided to sit him down at the end of the table. But two people nearly passed out, and we decided that the blood was pooling in their legs following exercise, so lying them down solved that problem.
6 months wasn’t enough time to do more than studying the science, designing a working protocol, and setting up the lab, so we never actually performed a research trial, but we learned a lot about exercise physiology and stress testing. Eventually we set up what would be the first treadmill exercise testing lab at the hospital where the exercise stress test was first invented by Dr. Master with his wooden two steps.
When I arrived at the Portsmouth Naval Hospital in Virginia, I thought I would be really special and introduce our testing methods there. But I was humbled when my chief Cmdr. Charlie Shaeffer had already set up their treadmill lab at that 1,400 bed teaching hospital. However, two years later, arriving at Dover General Hospital and Medical Center in New Jersey, I was able to start a cardiology department and exercise testing lab there.
A modern setup for treadmill stress testing. Quinton Labs
Over the years, the treadmill stress test has been refined and made more accurate with the development of noise reduction cable technology, echocardiography and nuclear cardiology to offer more sophisticated end points beyond just the ECG. In recent years the indications for the test were carefully studied. We learned that it is not a screening test to be done on the entire population. When applied carefully it is a valuable diagnostic and prognostic tool.
JANET KLEIN AND HER PARLOR BOYS
Thank you Dr. Artel. Your discussion will help our most discerning readers get this straight. I don’t know how many doctors are using stress testing with such understanding.—-PG
I feel the need to add something here.
The positive predictive value of a test, or the likelihood that an abnormal test really does indicate the presence of disease is directly proportional to the prevalence of a disease in the group you are testing. For example, the likelihood of coronary artery disease (pre-test probability) existing in a group of college students is so low that even if you obtained an abnormal treadmill stress test on one of them, you wouldn’t believe the results anyway. The false-positives would be greater than the true-positives. Therefore, individuals like these do not get tested. On the other side, a cigarette smoker in their 60s with high blood pressure, type II diabetes, high cholesterol, and a family history of people having heart attacks in their 50s, who is complaining of chest pain radiating to their neck and left shoulder that occurs when they climb stairs and gets better with rest, and this has been getting worse over the past two weeks has such a high pre-test probability of having coronary artery disease that even if a stress test just happened to be negative, we still wouldn’t believe it, therefore we would not screen such an individual (or at least I wouldn’t) and they would probably be sent by their doctor straight for a coronary angiogram, despite any of the risks involved.
Then there are the people in the middle: people in their 40s-60s who have only one or two cardiac risk factors among smoking, family history, high blood pressure, high cholesterol, diabetes, and who may or may not have typical symptoms of angina, or have a non-specific abnormality on their resting EKG. The pre-test probability of these individuals is intermediate. A positive stress test here has much more meaning than for the college students, and a negative stress test here has much more meaning compared to the person with one foot in the grave and one foot on a banana peel. THESE are the individuals who benefit the most from a treadmill stress test, because the results have a much greater likelihood of guiding the treatment.
The AHA and the ACC have published guidelines stating that asymptomatic individuals in general without other concerns for having coronary artery disease should NOT be routinely stress tested. Dr. Goldfinger is absolutely correct when he says that proper clinical judgement has to take priority in making the decision, but I think that the scenarios above more directly answer the question of why the whole majority of the population does not require a stress test.
Thank you Dr. G for the very informative and easy to understand explanation to my question. I knew I was smarter than a “3rd grader”. 😃
New Kid: OK, here is an explanation: A good screening test must be accurate and not result in false positives or false negatives. A mammogram is that sort of a test, although it has certain inadequacies which must be considered when the test is used to screen the general population.
Coronary artery disease causes buildup of plaque in the heart’s arterial circulation. But that buildup very often doesn’t narrow the arteries enough to reveal abnormalities during a stress test. So someone can be in danger of a heart attack and yet have a totally normal stress test, and that is quite common, thus ruling out the stress test as a good way to screen the general population
The stress test is helpful to a physician in selected cases, such as someone who has chest pains of uncertain origin or to evaluate a patient who is engaging in an exercise program. It also provides prognostic data in known heart patients and other information such as to assess a patient’s vital signs, ECG and heart rhythm during exercise.
But as a screening test for the general population, it is simply inadequate to the task, and that is why none of the major cardiology organizations recommend it for screening. The best way to screen for underlying coronary disease is for the physician to do a careful history, physical exam, and risk factor evaluation and preventive treatment.
The only test which could provide a definitive diagnosis is a coronary angiogram, but it is invasive, risky and expensive. No one has suggested performing coronary angiograms on everybody.
Really, too technical and complicated for an answer to my question? If you made the statement I think it deserves an explanation.
The recent death of David Goldberg, a Silicon Valley CEO, occurred while he was exercising on a treadmill. Because treadmills are powered electrically (vs. for example, an elliptical machine) they are more hazardous. But traumatic deaths due to treadmills are relatively rare. I think the guy in our picture should be holding on during his stress test. Most deaths on treadmills occur because someone has had a cardiac event and then goes flying.
Anyone who does exercise on a treadmill needs to be careful of falling or otherwise losing control. If you are a person who has some cardiac risk factors, such as a 50 year old male smoker with high cholesterol, who wants to start doing aerobic workouts, for example on a treadmill, a stress test would be a good idea first. It would indicate your fitness status and would give some confidence in terms of cardiac risk.
But even a negative stress test does not rule out the possibility of underlying coronary heart disease. Talk to your doctor before you embark on such a program.
The answer is highly technical and complicated, but the bottom line is that the treadmill stress test is not accurate enough to use to screen the general population.
As a screening tool why is the treadmill test not recommended for the majority of the population?