Homework 1: How to investigate coronary ischaemia?

Coronary ischaemia is the most common manifestation of coronary heart disease (CHD).

There are a few investigations which are most available and frequently used tests to identify coronary ischemia in clinical practice.

Exercise testing — Exercise testing appears to be the most suitable laboratory diagnostic test to document coronary ischemia in asymptomatic individuals (eg, patients with no history of CHD) and in those with a history of CHD or exertional angina. Exercise testing is frequently used to screen high risk, asymptomatic persons to identify those with asymptomatic CHD. Conventional ST segment analysis during ETT is moderately sensitive in detecting CHD. As a result, the diagnosis of myocardial ischemia by ETT in asymptomatic individuals must be confirmed by radionuclide imaging techniques (eg, thallium perfusion scintigraphy or exercise ventriculography) before the subject is labeled as having coronary ischemia.

Holter monitoring — Holter monitoring is the second most frequently used diagnostic test for coronary ischemia. It has the advantage of providing long-term ECG recording of ischemic and arrhythmic events while patients are engaged in routine daily activities out of the hospital. Episodes of transient ischemia during Holter monitoring are diagnosed by a sequence of ECG changes that include a flat or downsloping ST depression of at least 1 mm, with a gradual onset and offset that lasts for at least one minute.

Nuclear and echocardiographic imaging studies — Tests other than routine ETT and ambulatory monitoring may be necessary in certain circumstances. As an example, nuclear imaging tests such as stress thallium scintigraphy or exercise radionuclide ventriculography are recommended for the evaluation of coronary ischemia in patients who have an abnormal baseline ECG (eg, left ventricular hypertrophy or strain, bundle branch block, preexcitation syndrome), and those receiving digitalis, phenothiazines, or other drugs that produce repolarization changes. Pharmacologic stress tests with dipyridamole or adenosine plus thallium scintigraphy, or dobutamine stress echocardiography, can be utilized in those patients who are unable to ambulate or exercise (eg, due to advanced peripheral vascular disease)

Electron beam computed tomography — The severity of coronary artery calcification (CAC) on electron beam computed tomography (EBCT), as determined by a calcium score, can identify asymptomatic patients at high risk for coronary heart disease. However, it is not certain if this translates into identification of asymptomatic patients who have coronary ischemia.

In summary, these are the tests one can do to investigate coronary ischaemia:
Exercise treadmill test
Continuous ECG (Holter) monitoring
Exercise myocardial perfusion scintigraphy
Radionuclide angiocardiography
Pharmacologic stress scintigraphy
Hemodynamic monitoring