What are the diagnostic criteria for ischemic heart disease?

Diagnostic Criteria for Ischemic Heart Disease

The diagnosis of ischemic heart disease begins with a thorough history and physical examination to establish pretest probability, followed by resting ECG, and then risk-stratified stress testing based on the patient's ability to exercise and ECG interpretability. 1

Initial Clinical Assessment

All patients with chest pain must undergo detailed history and physical examination before any testing to assess the probability of IHD. 1 This initial assessment determines the entire diagnostic pathway and prevents unnecessary testing in low-risk patients or delayed diagnosis in high-risk patients.

Critical Risk Stratification Steps

• Immediately categorize patients presenting with acute angina as stable versus unstable; unstable angina patients require further categorization into high, moderate, or low risk. 1
• Obtain a resting ECG in all patients without an obvious noncardiac cause of chest pain for initial risk assessment. 1
• This resting ECG serves as the foundation for determining which stress test modality is appropriate and interpretable. 1

Diagnostic Testing Algorithm Based on Pretest Probability

For Patients with Intermediate Pretest Probability Who Can Exercise

Standard exercise ECG is the initial diagnostic test of choice for patients with intermediate pretest probability of IHD who have an interpretable ECG and at least moderate physical functioning. 1 This represents the highest quality evidence (strong recommendation, high-quality evidence) in the guidelines. 1

• This approach is cost-effective and provides both diagnostic and prognostic information. 1
• Do not use exercise stress with nuclear myocardial perfusion imaging as an initial test in low-risk patients who have an interpretable ECG and can exercise adequately. 1

For Patients with Uninterpretable ECG Who Can Exercise

Exercise stress with radionuclide myocardial perfusion imaging or echocardiography should be used for patients with intermediate to high pretest probability of IHD who have an uninterpretable ECG but can exercise adequately. 1

• Uninterpretable ECG includes conditions such as baseline ST-segment abnormalities, left ventricular hypertrophy with repolarization changes, or digoxin effect. 1
• Standard exercise ECG testing should not be used in patients with uninterpretable ECG as it will not provide diagnostic information. 1

For Patients Unable to Exercise

Pharmacologic stress with radionuclide myocardial perfusion imaging or echocardiography is recommended for patients with intermediate to high pretest probability of IHD who cannot achieve at least moderate physical functioning or have disabling comorbidity. 1

• This includes patients with severe arthritis, peripheral vascular disease, deconditioning, or other limitations preventing adequate exercise. 1
• Do not use pharmacologic stress imaging in patients who can exercise adequately and have an interpretable ECG, as this represents inappropriate testing. 1

Special Circumstances Requiring Echocardiography

Assess left ventricular function using Doppler echocardiography in patients with known or suspected IHD who have any of the following: 1

• Prior myocardial infarction
• Pathologic Q waves on ECG
• Symptoms or signs suggestive of heart failure
• Complex ventricular arrhythmias
• Undiagnosed heart murmur

Conversely, do not routinely assess left ventricular function with any imaging modality in patients with normal ECG, no history of MI, no heart failure symptoms, and no complex arrhythmias. 1

Common Pitfalls to Avoid

Inappropriate Test Selection

• Never use pharmacologic stress imaging as the initial test in patients who can exercise and have an interpretable ECG, even if you think imaging will provide "better" information—this is explicitly contraindicated. 1
• Do not repeat standard exercise ECG in patients with equivocal or artifact-limited results; proceed directly to stress imaging instead. 2

Overuse of Advanced Imaging

• Avoid routine imaging for left ventricular function assessment in low-risk patients with normal ECG and no concerning features. 1
• Do not perform routine reassessment of left ventricular function within one year in patients with no change in clinical status. 1

Management of Equivocal Results

When stress ECG results are equivocal (such as artifact-limited interpretation or borderline ST changes), proceed to stress imaging with either radionuclide myocardial perfusion imaging or stress echocardiography rather than repeating standard exercise ECG. 2

• Equivocal findings combined with medium-risk Duke Treadmill Score require definitive evaluation with imaging. 2
• Exercise-based stress imaging is preferred over pharmacologic stress when the patient can exercise adequately, as it provides additional prognostic information. 2

Shared Decision-Making Requirement

All diagnostic and therapeutic decisions must involve shared decision-making with the patient, explaining risks, benefits, and costs of testing options. 1 This is particularly important when choosing between imaging modalities or deciding whether to proceed with invasive testing based on noninvasive results.