What Is a Cardiologist?

Expertise and Training of Adult and Pediatric Heart Specialists

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A cardiologist is a physician who specializes in disorders of the heart and circulatory system. They are trained to diagnose, treat, and prevent conditions ranging from high blood pressure and heart rhythm disorders to potentially life-threatening heart attacks and stroke.

Cardiologists receive extensive education and training, including four years of undergraduate studies, four years of medical school, three years of residency in internal medicine or pediatrics, and three more years in a cardiology fellowship. All told, there are around 31,500 practicing cardiologists in the United States, 71% of whom practice adult (general) cardiology.

Cardiologists are not surgeons. Those who perform surgery are called cardiothoracic surgeons and undergo a surgical, rather than internal medicine or pediatric, residency.


While all cardiologists study disorders of the heart, the study of adult and childhood heart conditions involves entirely different educational pathways. As a result, an adult cardiologist (simply referred to as a cardiologist) would not have the skills to treat children, and a pediatric cardiologist would be ill-equipped to treat adults.

Adult Cardiology

The adult cardiologist only sees adult patients. Although the cardiologist may treat a congenital heart defect in adults, their work is largely composed of disorders that develop in later in life, most often as a consequence of cardiovascular disease. The conditions a cardiologist may treat can be broadly classified as follows:

  • Atherosclerotic diseases are those that develop as a result of atherosclerosis. Atherosclerosis is the buildup of plaque inside arteries that gradually obstructs the blood flow, leading to hypertension (high blood pressure), coronary artery disease (CAD), peripheral artery disease (PAD), heart attack, and stroke.
  • Cardiac arrhythmias are disorders of the heart’s electrical system. The term arrhythmia refers to the abnormal beating of the heart. This includes bradycardia (abnormally slow heartbeat), tachycardia (rapid heartbeat), and atrial fibrillation (irregular heartbeat).
  • Heart valve disease is the dysfunction of the tricuspid, pulmonary, mitral, or aortic valve of the heart. The condition can be caused by the abnormal narrowing of a valve (stenosis) or a leaky valve (regurgitation).
  • Heart infections and heart inflammations are characterized by their location. Pericarditis is the inflammation of the outer membrane around the heart called the pericardium. Endocarditis is the infection of a heart valve or the inner lining of the heart. Myocarditis is a rare disease of the heart muscle, often occurring in healthy people.
  • Heart failure is a condition in which the heart cannot pump enough blood to meet the body's needs. It can affect one or both sides of the heart. Congestive heart failure (CHF) is a type in which blood returning to the heart backs up, causing congestion and the buildup of fluid in tissues (edema).
  • Cardiac arrest is the complete stoppage of the heart. Sudden cardiac arrest is most commonly associated with coronary artery disease but can be caused by any condition that causes the heart's electrical system to suddenly fail.

Pediatric Cardiology

Pediatric cardiologists only treat children. As with adult cardiologists, pediatric cardiologists may be faced with conditions such as cardiac arrhythmia, heart failure, or hypertension, but the causes would not be associated with age, smoking, diet, or other lifestyle factors that contribute to heart disease in adults.

A great many of the cardiovascular conditions seen in children are congenital, meaning that the child was born with it. These include:

  • Patent ductus arteriosus (an abnormal communication between the aorta and the pulmonary arteries)
  • Complete atrioventricular canal defect (a hole between the left and right sides of the heart)
  • Ebstein's anomaly (a defect of the tricuspid valve)
  • Hypoplastic left heart syndrome (the underdevelopment of the left side of the heart)
  • Interrupted aortic arch (an underdeveloped aorta)
  • Atrial septal defect (an abnormal connection between the upper chambers of the heart)
  • Tetralogy of Fallot (a combination of four congenital defects)
  • Partial or total anomalous pulmonary venous return (an abnormal connection of one or more pulmonary veins to the heart)
  • Transposition of the great arteries (a condition in which the aorta and pulmonary arteries connect to the wrong sides of the heart)
  • Tricuspid atresia (a missing tricuspid valve)

Procedural Expertise

Cardiologists are trained in the tools and techniques that can effectively diagnose or treat cardiovascular disease or defects.


A cardiologist will typically perform a variety of tests to diagnose a heart condition. These may include:

  • Auscultation, using a stethoscope to hear normal and abnormal heart sounds
  • Blood pressure (BP) readings to measure your diastolic and systolic blood pressures
  • Blood tests to measure blood lipids, homocysteine, ferritin, natriuretic peptides (BNP or pro-BNP), and generalized inflammation (C-reactive protein) associated with heart disease
  • Electrocardiogram (ECG), which measure electrical activity during a heartbeat
  • Holter monitor, a portable ECG device that continually monitors heart rhythm for 24 hours
  • Event monitor, a portable ECG device that measures heart rhythm when the patient is having symptoms
  • Cardiac stress testing, which measures heart function during exercise (such as running on a treadmill or pedaling a stationary bike)
  • Coronary catheterization, in which a catheter is inserted into the heart through a blood vessel to assess for blockages in the arteries of the heart
  • Echocardiogram, a form of ultrasound that uses sound waves to visualize heart and blood movement
  • Computed tomography angiography (CTA), a type of computerized X-ray that creates three-dimensional "slices" of the heart and major blood vessels
  • Coronary calcium scan, which uses computed tomography (CT) to look for calcium deposits in coronary arteries
  • Magnetic resonance imaging (MRI), a type of imaging study that uses magnets and radio waves to create highly detailed images, particularly of soft tissue


Cardiologists are trained in a variety of non-invasive to minimally invasive treatments. People who require surgery or more invasive procedures would be referred to a cardiothoracic or vascular surgeon.

Many chronic cardiovascular conditions can be treated or managed with medications. These include drugs that reduce your blood pressure (such as ACE inhibitors, angiotensin II receptor inhibitors, beta blockers, and calcium channel blockers) and improve blood cholesterol (statins and cholesterol absorption inhibitors). Heart failure can be treated with a combination of these and other drugs.

The cardiologist would also work with you to make positive lifestyle changes to reduce your heart disease risk, including routine exercise, weight loss, optimization of diet, smoking cessation, and stress reduction.

In addition to medications and preventive health, there are a number of procedures that cardiologists are qualified to perform:

  • Percutaneous coronary intervention (PCI), a procedure involving the insertion of tiny tubes called stents to open narrowed arteries
  • Pacemaker implantation, involving an internal or external device to correct heart rhythm disorders
  • Cardiac defibrillator implantation, involving a small device implanted under the skin of the upper chest to deliver an electric shock when needed to normalize the heart rhythm
  • Cardiac resynchronization therapy (CRT), involving a specialized pacemaker that coordinates the action of the left and right ventricles in people with congestive heart failure


Although many cardiologists practice general cardiology, others will pursue subspecialties that allow them to focus on certain conditions or populations. Examples include:

  • Cardiac electrophysiology, involving the diagnosis and treatment of electrical disorders of the heart
  • Echocardiography, involving the use of two-dimensional, three-dimensional, and Doppler ultrasound to diagnose heart disease
  • Heart failure and transplant cardiology, a subspecialty focused on people with advanced (refractory) heart failure
  • Interventional cardiology, which deals specifically with the catheter-based treatment of heart diseases
  • Nuclear cardiology, which employs radioactive tracers to diagnose heart disease with MRI, CT, or other imaging techniques

These subspecialties typically require one to two years of additional training.

Training and Certification

It takes at least 14 years of education to obtain board certification in cardiology.

4 Years: The training pathway begins with four years of college to obtain a bachelor's degree in a science or a health-related field.

+4 Years: You would then begin medical school, during which you would spend the first two years in classroom study and the second doing clinical rotations in hospitals. This would eventually lead to a degree as either a doctor of medicine (MD) or a doctor of osteopathic medicine (DO).

In order to begin practicing, you would need to obtain a medical license from your state's licensing board. To do so, you would need to pass the United States Medical Licensing Examination (USMLE) and, in some states, an additional state exam. An increasing number of states now allow DOs to take the Comprehensive Osteopathic Medical Licensing Examination (COMLEX) instead of the USMLE.

+3 Years: Once you get your license, you would begin a hospital-based residency program in either internal medicine or pediatrics for the next three years. Before specializing in cardiology, you will need to complete clinical rotations in different fields of practice, such as infectious diseases or gastroenterology. In your third year of residency, you would start making applications to cardiac fellowship programs of your choice.

+3 Years: A cardiac fellowship lasts for three years and exposes you to all aspects of cardiology. Upon completion of your fellowship, you would take the Cardiovascular Disease Certification Examination (CDCE) administered by the American Board of Internal Medicine (ABIM).

The exam takes 14.25 hours to complete; if passed, you would be board certified to practice cardiology in the United States. ABIM certification lasts for 10 years. During this time, you would you need to maintain a certain number of hours in continuing medical education (CME) programs to keep your training updated.

What Do Cardiologists Earn?

According to the 2019 Medscape Cardiologist Compensation Report, cardiologists in the United States earn an average income of $430,000, just below what orthopedic surgeons, plastic surgeons, and ear-nose-and-throat doctors make.

In 2018, around three-quarters of cardiologists were employed by hospitals. Sadly, female cardiologists make roughly 40% less than their male counterparts despite there being slightly more women in the field.

Appointment Tips

To get the most out of a cardiology appointment, arrive early and bring any tests, reports, or imaging studies relevant to your condition. You can also ask your primary care physician to forward these electronically in advance of your appointment.

It also helps to write down all of the medications you take, both pharmaceutical and over-the-counter, and to include any information that can aid in the diagnosis (including past hospitalizations or a family history of heart disease). In this way, you can get the facts straight and avoid forgetting things.

Before your appointment, check that the office accepts your health insurance. You should also find out what labs they used to ensure they are in-network providers. If not, you may be faced with higher out-of-pocket expenses.

Arrive at your appointment prepared to ask questions. It is important for you to understand your condition and the treatments involved so that you can make fully informed decisions. Here are 10 questions to consider:

  • What kind of heart condition do I have?
  • What are the common causes of the condition?
  • Is it something that can be cured or one that needs to be managed?
  • What do my test results mean?
  • What are my treatment options?
  • What is the response rate for the treatment?
  • What are the possible risks and side effects?
  • When will I know if the treatment is working?
  • Are there any lifestyle changes should I make?
  • What might happen if I don't get treated?

A Word From Verywell

Cardiology is an ever-changing field of medicine that requires ongoing training to keep up the technologies, drugs, and techniques that are being introduced each year. While this can keep a practice fresh and exciting, it can also be very stressful.

Because of this, some cardiologists will limit their scope of practice to echocardiography or nuclear medicine which operate during normal office hours. Even so, the personal and financial rewards can still be significant. Most cardiologists report high job satisfaction.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Cegedim Relationship Management. Market Profile of U.S. Cardiologists. 2013.

  2. Mehta LS, Fisher K, Rzeszut AK, et al. Current demographic status of cardiologists in the United States. JAMA Cardiol. 2019;4(10):1029-1033. doi:10.1001/jamacardio.2019.3247

  3. Federation of State Medical Boards. State Specific Requirements for Initial Medical Licensure.

  4. American Board of Internal Medicine. Cardiovascular Disease Certification Exam.

  5. Medscape. Medscape Cardiologist Compensation Report 2019. 2019.

  6. Medscape. Medscape Cardiologist Compensation Report 2018. 2018.

Additional Reading

By Andrea Clement Santiago
Andrea Clement Santiago is a medical staffing expert and communications executive. She's a writer with a background in healthcare recruiting.