What Is Ischemia?

Ischemic heart disease (IHD), is the most common type of heart disease and cause of heart attacks. The disease is caused by plaque building up along the inner walls of the arteries of the heart, which narrows the arteries and reduces blood flow to the heart.

While the symptoms and signs of coronary artery disease (CAD) are noted in the advanced state of disease, most individuals with coronary artery disease show no evidence of disease for decades as the disease progresses before the first onset of symptoms, often a “sudden” heart attack, finally arises. Symptoms of stable ischaemic heart disease include angina (characteristic chest pain on exertion) and decreased exercise tolerance. Unstable IHD presents itself as chest pain or other symptoms at rest, or rapidly worsening angina. The risk of artery narrowing increases with age, smoking, high blood cholesterol, diabetes, high blood pressure, and is more common in men and those who have close relatives with CAD.

ECG (Electrocardiogram)

An ECG is a simple, painless test that detects and records the heart's electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). An ECG also records the strength and timing of electrical signals as they pass through the heart. An ECG can show signs of heart damage due to CHD and signs of a previous or current heart attack.

Stress Test ECG

During stress test, you exercise to make your heart work hard and beat fast while heart tests are done. If you can't exercise, you may be given medicine to raise your heart rate.

When your heart is working hard and beating fast, it needs more blood and oxygen. Plaque-narrowed arteries can't supply enough oxygen-rich blood to meet your heart's needs.

A stress test can show possible signs and symptoms of CHD, such as:

• Abnormal changes in your heart rate or blood pressure
• Shortness of breath or chest pain
• Abnormal changes in your heart rhythm or your heart's electrical activity

Myocardial Perfusion Image

MPI is the only widely available method of assessing myocardial perfusion directly. It therefore has a clear role in the diagnosis of CHD in patients presenting with chest pain. An inducible perfusion abnormality indicates impaired perfusion reserve, which in turn usually corresponds to epicardia coronary obstruction. The site, depth and extent of the abnormality provide diagnostic and management information that cannot be determined reliably from other tests such as the ECG. Conversely, normal stress MPI indicates the absence of coronary obstruction and hence of clinically significant disease.