Science

Consider anxiety in ordering heart tests: study

Doctors diagnosing potential cardiac problems should take the patient's anxiety and depression into account when ordering heart tests, a new Canadian study suggests.

Doctors diagnosing potential cardiac problems should take the patient's anxiety and depression into account when ordering heart tests, a new Canadian study suggests.

An ECG stress test is often used to look for coronary artery disease. During the test, electrodes from an electrocardiography machine are connected to the patient while they exercise on a treadmill.

But in people affected by anxiety or depression, heart disease could be falling under the radar in the ECG tests, according to the study. 

Researchers in Montreal tested more than 2,000 patients with ECG as well as a more expensive and sensitive procedure known as nuclear exercise stress testing, or SPECT, which requires the injection of a radioactive dye into the bloodstream followed by a nuclear scan to assess whether blood flow to the heart is normal during exercise.

"When patients with anxiety had both tests done, nearly 25 per cent of the patients did not seem to have heart disease based on the ECG but were found to have the disease when we looked at the SPECT results," study author Prof. Simon Bacon of the department of exercise science at Montreal's Concordia University said Friday.

"This means that a number of people may be under-diagnosed if they only have the ECG test."

Among patients without anxiety, the ECG missed a diagnosis of heart disease about 20 per cent of time.

Anxiety factor

The study's authors suggested that physicians consider doing additional screening of patients, such as simple pencil and paper tests, to assess for anxiety and depression.

If a patient scores high for depressive or anxiety symptoms and has an ECG result that doesn't suggests heart disease, Bacon said, doctors should consider sending them for more tests to be sure.

The Montreal researchers said about 20 per cent of people with cardiac illness also suffer from anxiety or depression — twice the rate among the general population.

Doctors need to be aware of the role that anxiety can play, agreed Dr. Andy Wielgosz, a professor of medicine and epidemiology at the University of Ottawa and a spokesperson for the Heart and Stroke Foundation of Canada, which helped fund the research.

But Wielgosz cautioned cost-effectiveness studies are needed before screening for anxiety is introduced into routine clinical practice.

SPECT exercise testing is available in academic centres in Canada. It costs around $200 compared with $50 for an ECG exercise test, Bacon said.

The study appears in the Journal of Cardiopulmonary Rehabilitation and Prevention. It was also funded by Quebec's health funding agency, the Canadian Institutes of Health Research and the Social Sciences and Humanities Research Council of Canada.

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