Cardiac diagnostic tests

By Editor On Oct 16, 2026

English

“Cardiovascular disease” is a term for a group of diseases that affect your heart and blood vessels, including stroke, coronary artery disease, heart failure, heart valve disease, atherosclerosis (hardening of the arteries), high blood pressure, and cardiac arrhythmias. If your doctor thinks you may have cardiovascular disease, you should expect further testing.

Fortunately, there are many types of cardiac diagnostic tests. Your doctor will order tests based on your specific medical situation. The tests include:

Blood sample

Description: A doctor inserts a syringe into your vein to draw a small amount of blood.
What it evaluates: Cholesterol, proteins such as lipoprotein (a) or troponin and inflammatory markers such as C-reactive protein. Your doctor will order specific tests based on your possible diagnosis.
It is used for: Assess your risk of cardiovascular disease based on a physical exam and your medical history. Specific tests such as troponin levels can confirm whether your heart muscle is already damaged.

Blood pressure monitoring

Description: A bracelet that measures your blood pressure during clinical consultations. You may need to measure your blood pressure at home.
What it evaluates: How much pressure your blood puts on your arteries when your heart pumps blood.
It is used for: Provide an early warning system for heart disease even if there are no symptoms, as high blood pressure can damage your heart muscle and blood vessels over time.
Other uses: During a medical emergency, monitoring blood pressure can alert the medical team to sudden changes in the patient’s condition.

According to the American Heart Association, blood pressure categories are as follows:
Normal: Less than 120 mm Hg systolic pressure (upper number) and less than 80 mm Hg diastolic pressure (lower number) Elevated: 120 to 129 mm Hg systolic pressure and less than 80 mm Hg diastolic pressure Stage 1 Hypertension: 130 to 139 mm Hg systolic pressure or 80 to 89 mm Hg diastolic pressure Stage 2 Hypertension: 140 mm Hg or more systolic pressure or 90 mm Hg or more diastolic pressure Severe hypertension: 180 mm Hg or more systolic pressure or 120 mm Hg or more diastolic pressure

Chest x-ray

Description: An x-ray showing the heart, lungs and chest. It does not show the structures inside the heart.
What it evaluates: A chest x-ray shows the size, shape, and location of the heart and lungs. Nearby blood vessels are also shown in the image.
It is used for: Help diagnose the cause of symptoms such as chest pain, fever, difficulty breathing, or a non-healing cough.

Echocardiography (ultrasound of the heart)

Description: A test that uses ultrasound waves to obtain images of the heart. The most common type is transthoracic echocardiography (TTE), in which a doctor passes the ultrasound probe across your chest. A transesophageal echocardiography (TEE) may also be performed, in which your doctor passes the ultrasound probe down your throat to get a clear view of your heart or aorta.
What it evaluates: The structure of your heart and its effectiveness, including its pumping power and the health of the heart valves.
It is used for: Help diagnose heart muscle injuries, heart valve disease or heart failure.

Electrocardiogram (ECG)

Description: Electrodes connected to an electrocardiograph are attached to your body.
What it evaluates: The electrical waves of the heart and how fast and how often your heart beats. Every time your heart beats, it sends out an electrical wave. This wave causes the heart muscle to contract, pumping blood out of the heart.
It is used for: Diagnose and monitor many heart diseases, including heart attack, heart failure, heart valve disease, coronary artery disease, and cardiac arrhythmia (irregular heartbeat).
Other uses: It may be useful in diagnosing pulmonary embolism, inflammation of the pericardium, or abnormal levels of potassium or calcium in the blood.

Tilt table test

Description: A test in which you lie on a special motorized table that changes from a horizontal position to an angle equivalent to sitting. A technician will monitor your vital signs and symptoms such as slow heart rate, low blood pressure, fainting, dizziness, or nausea.
What it evaluates: When a local accumulation of blood in the veins causes these symptoms.
It is used for: Diagnose postural orthostatic tachycardia syndrome (POTS), neurocardiogenic syncope, and similar disorders.

Stress test

Description: A test that requires walking on a treadmill or riding a stationary bicycle in a medical setting while the patient is connected to a monitoring device. Your doctor will also check your blood pressure after the test.
What it evaluates: How efficiently your heart pumps blood.
It is used for: Diagnose coronary artery disease or determine the cause of symptoms such as chest pain or difficulty breathing.
Other uses: It may also be helpful to determine your risk of heart attack, suitability for surgery, or a safe level of exercise.

Monitor Holter

Description: A small, wearable device that tracks your heart rate for 24 to 48 hours. Your doctor may request the use of a Holter monitor if you have experienced syncope or dizziness, or if an EKG did not provide enough information.
What it evaluates: Your heart rate during the test period.
It is used for: Detect irregular heartbeats (arrhythmias).

Cardiac CT

Description: X-rays taken from many angles and used to create a detailed three-dimensional image of your heart and surrounding blood vessels. Some high-resolution scans can even show your heart moving.
What it evaluates: The anatomy and function of your heart, heart valves, blood vessels, and related structures.
It is used for: Diagnose or monitor chest pain, artery blockages, and problems with the aorta or heart valves.
Other uses: It is often used to plan cardiac procedures, including minimally invasive or robotic heart surgeries.

Cardiac MRI

Description: A magnetic field and radiofrequency waves are used to obtain detailed three-dimensional images of the blood vessels and interior of the heart, including the heart valves.
What it evaluates: The performance of the heart and heart valves and whether enough blood flows through your large blood vessels.
It is used for: Diagnose or monitor advanced or complicated heart disease after other tests have been performed.

Cardiac catheterization

Description: A thin catheter or tube that is inserted into one of your large veins to lead it to your heart. There, the doctor will check the blood flow in your heart or inside your blood vessels to look for problems.
What it evaluates: The performance of your heart and the health of your heart valves and blood vessels.
It is used for: Diagnose blocked or narrowed valves or arteries.
Other uses: Unlike other diagnostic tests, cardiac catheterization allows your doctor to make immediate diagnoses and take corrective measures when necessary. Possible procedures include cleaning out a blocked artery or partially blocked heart valve, or taking samples of heart tissue to examine under a microscope.

Coronary angiography

Description: A special type of cardiac catheterization. Once your doctor inserts the catheter into your heart, he or she will take X-rays with dye to check the large arteries near your heart for blockages.
What it evaluates: The health of the arteries near your heart.
It is used for: Diagnose and treat blocked arteries near your heart.

This educational resource was created with support from Merck.

Darcy Lewis

Darcy Lewis writes about health and medicine from Chicago, focusing on clinical medicine, the business of health care, and health policy. A former National Cancer Reporting Fellow, she also completed the Medicine in the Media Fellowship at Dartmouth College in the summer of 2024.

Darcy focuses on helping patients make better healthcare decisions and helping clinicians stay current on clinical developments. That’s why he was drawn to writing about oncology. She has written about cancer for patient-focused publications such as Everyday Health, Cancer Today, and HealthyWomen.org, as well as professional content and articles for ASCO Daily News, Oncology Live, Targeted Therapies in Oncology, Medscape, MedPage Today, McKesson, Cardinal Health, evi-Core, and many others. One of her articles for Oncology Live won the 2020 ASJA Award for Best Technical Article, while an annual report for the Pulmonary Fibrosis Foundation won the 2024 ASJA Award for Long-Form Content.

Darcy currently serves as President of ASJA, having previously served as Vice President, Secretary and Chair of the Website Task Force, a multi-year effort to modernize ASJA’s communications with members and the public.