Cardiology: Tests & Diagnosis

Introduction

When are diagnostic tests used?

The tests covered in our Tests and Diagnosis section are used in three distinct situations:

  1. To diagnose urgent conditions such as a heart attack or unstable chest pain (e.g., blood tests to diagnose a heart attack, the resting ECG).
  2. To screen patients with an intermediate to high risk for heart disease or those experiencing symptoms such as chest pain or shortness of breath (e.g., exercise stress testing, echocardiography).
  3. To detect very early signs of heart disease. The fatty plaque associated with atherosclerosis begins to buildup on the lining of the arteries in your early 20s, but you will not feel any symptoms or show signs of a problem during typical diagnostic testing until decades later when the blockage is large enough to significantly reduce blood flow.The idea behind these newer tests is to detect very early signs of trouble, such as a loss of elasticity in the lining of the artery, so that steps can be taken to prevent heart problems in the future. Blood tests for emerging risk factors such as C-reactive protein and calcium scans fall into this category.

Do I need to have a diagnostic test?

One in two men, and one in three women will develop heart disease in their lifetime.

Whether you need to undergo diagnostic testing for heart disease is based on your risk of having heart disease. Your risk of heart disease depends on your age, sex, risk factors and what symptoms you have (if any).

Overall, the lifetime risk of heart disease is slightly lower for women than men: One in two men, and one in three women will develop heart disease in their lifetime.

If you have not already been diagnosed with heart disease, your doctor may use a risk calculator to determine whether you have a low, intermediate, or high risk of developing heart disease in the next 10 years.

If your risk score is low and you are not experiencing symptoms, you will not be sent for further testing. However, you should continue to keep your risk factors in check. If you have an intermediate or high-risk score or you have symptoms of heart disease, you may be sent for diagnostic testing.

What are noninvasive and invasive diagnostic tests?

There are various diagnostic tests available to detect heart disease, ranging from noninvasive tests that do not involve cutting through the skin (although some entail injections) to invasive tests where a small incision is made.

In cardiac catheterization, the most common invasive test, a thin flexible tube called a catheter is inserted into your groin or forearm and a thin wire — known as a guidewire — is used to guide the catheter into the different arteries of your heart. The purpose of this test is to find out if there are any blockages in the arteries of your heart.

Noninvasive tests are used first in order to avoid unnecessary invasive testing. This is particularly important in women,since up to 40 percent of women sent for cardiac catheterization do not have significant blockages in the arteries of their heart.

Noninvasive diagnostic testing:

Invasive diagnostic tests: