Stress ECG was informative: Khaw

16 Jun 2010, Today

Question

Name of the Person: Dr H T Ong

Are stress ECGs unnecessary?

THE effort by Health Minister Khaw Boon Wan to get the public to learn from his own experience, via Facebook and in press interviews, is to be lauded.

It is, however, important that patients do not draw incorrect lessons from his experience of bypass surgery. Mr Khaw was reported to have undergone "unnecessary tests, such as electrocardiograms (ECG) while exercising".

Doing an ECG while exercising (called a stress ECG) is very useful in providing reliable information on the future outlook, or prognosis, for a patient.

A chart developed at Duke University Medical Centre accurately predicts a person's yearly risk of death based on the duration of exercise, the discomfort felt and the changes in the ECG.

Recent trials have shown that compared to taking medication alone, revascularisation by stenting or surgery does not reduce heart attack or prevent death in most patients with stable coronary artery disease.

Thus, it is incorrect to assume that bypass surgery or opening a block will benefit all patients and automatically reduce future adverse outcome. The main factor deciding the need for intervention is the presence of patient discomfort, or being at high prognostic risk as determined from the stress test.

Furthermore, it is now equally clear that the degree of obstruction does not predict the future potential of a heart attack. The impression that more severe degrees of obstruction are more likely to close fully and therefore must be stented or bypassed has been proven wrong when objectively tested by large, multi-centre trials recruiting thousands of patients.

Whether a calcium score test and CT angiography are more valuable than a stress ECG is still being debated upon in the cardiology journals.

It is good that Mr Khaw is happy with his decisions and outcome but patients should not take his experience as a call to forsake the stress ECG for a CT scan or angiography, especially in view of the significant radiation exposure and financial cost of the latter.

Any decision on investigative test and treatment option should be carefully thought over and discussed between patient, family and doctor, remembering the limitations and consequences at every stage.

Reply

Name of the Person: Karen Tan (Ms)

Press Secretary to Minister for Health

Minister Khaw welcomes Dr H T Ong’s letter on stress ECGs and fully agrees with his sound advice that “Any decision on investigative test and treatment option should be carefully thought over and discussed between patient, family and doctor, remembering the limitations and consequences at every stage” (Today, Jun 15, “Are stress ECGs unnecessary?”).

Even in Mr Khaw’s case, the stress ECG test (which showed abnormal reading at stage IV of stress test) was valuable as it helped to confirm the preliminary finding of the calcium score test that he had a heart problem.

But as Mr Khaw was initially in denial of his problem, two other investigations were carried out, in addition to the calcium score and stress ECG tests, before he finally accepted the reality and consented to a coronary angiogram. The range of tests undertaken, at the insistence of the patient, helped him to get over his self-denial and prepare him mentally for the eventual bypass surgery. However, in hindsight, it was a reckless move. This was the context in which Mr Khaw made the comment.