Correlation between R wave amplitude, exercise ischemic electrocardiographic indices and thallium-201 imaging defects in patients with known coronary artery disease

We investigated the relation between R wave amplitude (RWA) and ST depression as well as the presence and extent of reversible ischemia in thallium-201 scanning in patients with known coronary artery disease (CAD) and found that RWA both at rest and during exercise testing (ET) correlates with the magnitude of ST depression in the same leads. Greater ST changes appear on leads with highest RWA. Thus lead selection strongly influences interpretation of ECG ischemic changes during ET in patients with CAD. An electrocardiographic result negative for ischemia in patients with low RWA should prompt the alternative use of echocardiography and scintigraphy.