The primary reason for conducting a cardiac catheterization is to diagnose and manage persons known or suspected to have heart disease, a frequently fatal condition that leads to 1.5 million heart attacks annually in the United States.

Symptoms and diagnoses that may lead to performing this procedure include:

• chest pain, characterized by prolonged heavy pressure or a squeezing pain
• abnormal treadmill stress test
• myocardial infarction, also known as a heart attack
• congenital heart defects, or heart problems that originated from birth
• a diagnosis of valvular-heart disease
• a need to measure the heart muscle's ability to pump blood

Typically performed along with angiography, a technique of injecting a dye into the vascular system to outline the heart and blood vessels, a catheterization can aid in the visualization of any blockages, narrowing, or abnormalities in the coronary arteries. If these signs are visible, the cardiologist may assess the patient's need and readiness for coronary bypass surgery, or perhaps a less invasive approach, such as dilation of a narrowed blood vessel either surgically or with the use of a balloon (angioplasty).

When looking at the left side of the heart, fluoroscopic guidance also allows the following diagnoses to be assessed:

• enlargement of the left ventricle
• ventricular aneurysms (abnormal dilation of a blood vessel)
• narrowing of the aortic valve
• insufficiency of the aortic or mitral valve
• the detour of blood from one side of the heart to the other due to septal defects (also known as shunting)