What is one of the main tests used to diagnose coronary artery disease (CAD)?

Cardiac catheterization is one of the primary tests used to diagnose coronary artery disease (CAD) due to its ability to directly visualize the coronary arteries and assess for the presence of blockages or narrowing. During this procedure, a thin tube called a catheter is inserted into a blood vessel, often through the wrist or groin, and threaded up to the coronary arteries. A contrast dye is then injected, allowing for clear imaging of the arteries via X-ray fluoroscopy. This technique not only helps confirm the diagnosis of CAD but can also be used to guide treatment decisions such as angioplasty and stent placement, if needed.

In contrast, while an electrocardiogram is useful for assessing heart rhythm and detecting damage to the heart, it doesn't provide direct visualization of coronary arteries. Ultrasound can evaluate heart structure and function but is not typically used to diagnose CAD directly. A chest X-ray can show the size of the heart and the condition of the lungs but cannot assess coronary arteries or indicate the presence of blocks like cardiac catheterization can. Thus, cardiac catheterization stands out as the definitive method for diagnosing CAD by allowing healthcare providers to see the extent of the disease directly.