Electrocardiogram
A 12-lead ECG recorded at rest is normal in about half the patients with typical angina pectoris,but there may be signs of an old myocardial infarction. Although repolarization abnormalities,i.e., ST-segment and T-wave changes as well as left ventricular hypertrophy and intraventricular conduction disturbances, are suggestive of IHD, they are nonspecific. Typical ST-segment and T-wave changes that accompany episodes of angina pectoris and disappear thereafter are more specific.
Exercise ECG
Exercise testing can be very useful both in confirming the diagnosis of angina and in giving some indication as to the severity of the CAD. ST-segment depression of ≥ 1 mm suggests myocardial ischaemia, particularly if typical chest pain occurs at the same time.The test has a specificity of 80 per cent and a sensitivity of about 70 per cent of CAD. A strongly positive test (within 6 minutes of starting the bruce protocol) suggests ‘prognostic’ disease and helps to identify patients who should be offered coronary angiography. Exercise testing,however, can be misleading:
• A normal test does not exclude CAD (so-called false-negative test) although these patients, as a group, have a good prognosis.
• Up to 20 per cent of patients with positive exercise tests are subsequently found to have no evidence of coronary artery disease (so-called false-positive test).
Cardiac Scintigraphy
Myocardial perfusion scans both at rest and after stress (i.e. exercise or dobutamine) can be obtained using various radio nuclides (e.g. thallium or technetium MIBI–methoxyisobutylisone).Redistribution of the contrast agent is a sensitive indicator of ischaemia and can be particularly useful in deciding if a stenosis seen at angiography is giving rise to ischaemia. A normal stress perfusion scan makes significant CAD unlikely.
Echocardiography
This can be used to assess ventricular wall involvement and ventricular function. Regional wall motion abnormalities at rest reflect previous ventricular damage, is useful especially in women with coronary artery disease. Stress echo reveals wall motion changes during ischaemia.
Coronary Angiography
This test is done to delineate the exact coronary anatomy. Indications for coronary angiography are:
— Angina refractory to medical therapy
— Strongly positive exercise test— Unstable angina
— Angina occurring after myocardial infarction
— Patients under 50 years with angina or myocardial infarction
— Where the diagnosis of angina is uncertain
— Severe left ventricular dysfunction after myocardial infarction
— Non Q-wave myocardial infarction
— Treatment of angina
A 12-lead ECG recorded at rest is normal in about half the patients with typical angina pectoris,but there may be signs of an old myocardial infarction. Although repolarization abnormalities,i.e., ST-segment and T-wave changes as well as left ventricular hypertrophy and intraventricular conduction disturbances, are suggestive of IHD, they are nonspecific. Typical ST-segment and T-wave changes that accompany episodes of angina pectoris and disappear thereafter are more specific.
Exercise ECG
Exercise testing can be very useful both in confirming the diagnosis of angina and in giving some indication as to the severity of the CAD. ST-segment depression of ≥ 1 mm suggests myocardial ischaemia, particularly if typical chest pain occurs at the same time.The test has a specificity of 80 per cent and a sensitivity of about 70 per cent of CAD. A strongly positive test (within 6 minutes of starting the bruce protocol) suggests ‘prognostic’ disease and helps to identify patients who should be offered coronary angiography. Exercise testing,however, can be misleading:
• A normal test does not exclude CAD (so-called false-negative test) although these patients, as a group, have a good prognosis.
• Up to 20 per cent of patients with positive exercise tests are subsequently found to have no evidence of coronary artery disease (so-called false-positive test).
Cardiac Scintigraphy
Myocardial perfusion scans both at rest and after stress (i.e. exercise or dobutamine) can be obtained using various radio nuclides (e.g. thallium or technetium MIBI–methoxyisobutylisone).Redistribution of the contrast agent is a sensitive indicator of ischaemia and can be particularly useful in deciding if a stenosis seen at angiography is giving rise to ischaemia. A normal stress perfusion scan makes significant CAD unlikely.
Echocardiography
This can be used to assess ventricular wall involvement and ventricular function. Regional wall motion abnormalities at rest reflect previous ventricular damage, is useful especially in women with coronary artery disease. Stress echo reveals wall motion changes during ischaemia.
Coronary Angiography
This test is done to delineate the exact coronary anatomy. Indications for coronary angiography are:
— Angina refractory to medical therapy
— Strongly positive exercise test— Unstable angina
— Angina occurring after myocardial infarction
— Patients under 50 years with angina or myocardial infarction
— Where the diagnosis of angina is uncertain
— Severe left ventricular dysfunction after myocardial infarction
— Non Q-wave myocardial infarction
— Treatment of angina
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