Exercise test performance and detection of myocardial ischemia may be influenced by mood and/or anxiety disorders and greater efforts should be made to include routine mood and/or anxiety disorder screening as part of exercise stress testing protocols, according to a study published Nov. 11 ahead-of-print in the Journal of Cardiopulmonary Rehabilitation and Prevention.
The study cohort of 2,271 patients referred for nuclear exercise stress testing underwent a structured psychiatric interview to assess for anxiety disorders. Exercise performance parameters were assessed during ECG treadmill testing, after which patients underwent SPECT imaging.
Analyses revealed that patients with anxiety disorders exhibited lower peak exercise systolic blood pressure and rate pressure products than patients without anxiety disorders. When major depressive disorder was included as an additional covariate, the previous results became trends.
Results also indicated a lower rate of electrically positive ECG tests and a higher rate of false-negative diagnoses of myocardial ischemia according to ECG among patients with anxiety disorders. Including major depressive disorder as a covariate rendered the effects of anxiety disorders nonsignificant, according to the researchers. There was no evidence of reduced exercise performance in patients with anxiety disorders.
"An ECG is usually reliable for most people, but our study found that people with a history of cardiac illness and affected by anxiety or depression may be falling under the radar," said study co-author Simon Bacon, PhD, professor in the Concordia Department of Exercise Science, Montreal and a researcher at the Montreal Heart Institute.
The discovery is significant because 20 percent of people with cardiac illness also suffer from anxiety or depression. "When prescribing and performing cardiac tests, doctors should be aware of the psychological status of their patients, since it may affect the accuracy of ECG test alone," warned senior researcher Kim Lavoie, PhD, professor of psychology at the Université du Québec à Montréal and a researcher at the Montreal Heart Institute. "ECG tests are not detecting as many heart problems as nuclear tests among many of these patients, particularly those that are depressed, and physicians may be under diagnosing people at risk," added Lavoie.
The study also found that patients with anxiety disorders were younger and more likely to be smokers than patients without anxiety disorders. Participants with anxiety disorders were also less likely to be taking aspirin or lipid-lowering medication, which can protect against some cardiac events.
To ensure heart disease doesn't go undetected, physicians should consider administering a brief questionnaire before conducting ECGs to determine whether patients are highly anxious or depressed, according to the researchers. If so, their exercise performance should be carefully monitored. In the event of a negative (i.e. normal) ECG result, doctors may want to refer patients for SPECT testing.
"Our study indicates that detection of heart irregularities during ECGs may be influenced by the presence of mood or anxiety disorders," concluded lead investigator Roxanne Pelletier, PhD of the Université du Québec à Montréal and Montreal Heart Institute. "Greater efforts should be made to include routine mood or anxiety disorder screening as part of exercise stress-testing protocols."