- 122 of 1,110 patients (11%) referred for evaluation of exertional symptoms had unrevealing graded exercise tests and underwent additional, customized exercise testing at the same session
- For 39% of the 122 patients, the customized testing provided a diagnostic explanatory finding or reproduced symptoms in the absence of pathology
- Sequential use of standardized maximal-effort graded testing and additional customized testing, if indicated, has the potential to increase the diagnostic yield of exercise testing
For diagnosis and management of cardiovascular disease, a key goal of exercise testing is to reproduce the patient's exertional symptoms. Guidelines recommend that protocols should be individualized according to the type of subject being tested and the reason for testing.
Even so, most exercise laboratories rely on the Bruce protocol or another single protocol that features graded intensity and large increments in work. Often, such protocols do not replicate the physiologic conditions under which the patient experienced symptoms.
Led by cardiologists Meagan M. Wasfy, MD, Aaron L. Baggish, MD, director of the Cardiovascular Performance Program, and Clinical Fellow in Medicine Timothy W. Churchill, MD, researchers in the Corrigan Minehan Heart Center of Massachusetts General Hospital have become the first to demonstrate that after an unrevealing maximal-effort graded exercise test, customized additional testing improves diagnostic yield. Their report appears in the American Journal of Cardiology.
Standardized Graded Testing
The researchers analyzed prospectively collected data on 1,110 patients referred to the Cardiovascular Performance Program at Mass General between December 2011 and October 2017 because of exertional symptoms. This program cares for active individuals, ranging from recreationally active to elite athletes.
To begin, all patients perform a maximal-effort graded exercise test with continuous measurement of gas exchange. In consultation with the referring physician and exercise physiologist, patients choose the machine best suited to their regular form of exercise: a treadmill, upright cycle or rowing machine. The patient and exercise physiologist also collaborate to choose the exercise protocol.
Additional Exercise Testing
In the cohort studied, 122 patients (11%) underwent additional, customized testing at the same session. The rationale for additional testing was that the graded test was normal and did not provoke symptoms (74%) or the findings were unrelated to the patient's chief complaint (26%).
Again in collaboration with the exercise physiologist, the patient chose the exercise modality and protocol (no measurement of gas exchange):
- Sprints on the treadmill, cycle or rowing machine (70%)
- Longer-term, submaximal exercise (22%)
- Race simulation (5%)
- Other: boxing, burpees, squat jumps or wall sits (2%)
Additional testing was judged positive in 39% of patients:
- The findings were not available from the initial graded exercise test
- It provided evidence of a clinically actionable diagnosis that explained the presenting complaint (21%)
- In other cases, it reproduced the presenting symptoms in the absence of demonstrable cardiopulmonary pathology, such that reassurance could be given (18%)
Additional testing was most frequently positive in patients presenting with dyspnea (71%) or lightheadedness/syncope (61%). Testing had a lower yield in patients presenting with chest pain (41%) or palpitations (21%). Additional testing was not positive in any of the four patients presenting with exertional intolerance.
Not Just for Sports Cardiologists
Because high-risk cardiovascular conditions must be definitively diagnosed or excluded as a cause of symptoms so sports cardiology patients can return to training or competition, the researchers suggest that symptom reproduction may be equally relevant in more typical clinical practice. They say it can improve care efficiency and reduce the need for costly, invasive subsequent testing, thereby improving patient satisfaction.
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