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Harvard Commentaries
Harvard Commentaries
Reviewed by the Faculty of Harvard Medical School

What Your Doctor Is Saying What Your Doctor Is Saying

The Many Faces of Heart Disease

September 25, 2013

By Robert H. Shmerling M.D.

Beth Israel Deaconess Medical Center

"There's something wrong with your heart."

Now that's a scary thing to hear from your doctor. After all, the heart is the body's "engine." It pumps blood throughout the body so nutrients and oxygen can get to your tissues. 

The term heart disease covers a lot of ground. It's a bit like saying, "There's something wrong with your engine." There are minor problems, such as a dead spark plug, and there are bigger problems, such as needing an entirely new engine. That's why the details matter. Here's a look at the most common types of heart disease and what they mean.

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Heart Attack

People usually think of a heart attack when the subject of heart disease comes up. The medical term for heart attack is myocardial infarction or MI.

Heart muscle dies during a heart attack. This is usually due to atherosclerosis (or "hardening of the arteries"), a condition in which a build up of cholesterol and inflammatory cells narrows one or more arteries. If one of the arteries supplying heart muscle (called coronary arteries) narrows enough or becomes blocked off entirely, there's not enough blood flow to the heart and it dies. If a large portion of heart muscle dies, there can be complications such as heart failure, an unstable heart rhythm or even sudden death.

You can reduce your risk of atherosclerosis by keeping your blood sugar, blood pressure and cholesterol levels in a good range, and by not smoking.

To treat heart attacks, doctors use blood thinners and surgery. Some blocked blood vessels can be opened up with minor surgery. Other blockages require major surgery called bypass to keep blood flowing to heart muscle. Statin medications can also help by reducing inflammation and improving cholesterol levels.

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Heart Failure

The term "heart failure" (or congestive heart failure) describes a heart that isn't pumping as forcefully as it should. This causes fluid to build up in the lungs and the legs. As awful as heart failure sounds, it usually improves with drugs and lifestyle changes (especially cutting back on salt). When medicines don't work well enough, the lungs can become so congested that a heart transplant is needed.

High blood pressure (hypertension) and heart attacks are the most common causes of heart failure. It can also develop for other reasons, including tight or leaky heart valves (see below) or a genetic disease. Sometimes the doctor can't find a reason for heart failure.

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Valve Disease

The heart has four valves to coordinate the flow of blood through its four chambers during each heartbeat. These valves can leak or not open wide enough. Although heart problems related to valve disease can develop suddenly (as after a heart attack), they usually develop slowly over many years. In fact, many people with valve disease don't even know they have a problem until a doctor hears a heart murmur, or a valve problem shows up on a heart test (called a cardiac echo).

Why does valve disease develop? Some people are born with abnormal valves. Others develop an infection (a condition called endocarditis) that can lead to scarring and abnormal valve function. Rheumatic fever used to be a common cause but it's quite rare now.

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Heart Rhythm Problems

Special cells in the heart send well-timed electrical signals so that each part of the heart knows when to fill with blood and when to pump it out. Chambers need to relax briefly to fill with blood. Valves need to open and close at just the right times for blood to flow properly through the heart and out to the rest of the body.

However, sometimes the heart beats too fast or too slow. Sometimes the electrical signals are disrupted. Common conditions related to abnormal heart rhythms include:

  • An abnormally slow heart rate (called bradycardia)
  • An abnormally fast heart rate (called tachycardia)
  • An irregular heart rate (such as atrial fibrillation, in which the upper chambers of the heart are beating in a disorganized way)
  • A chaotic heart rate (such as ventricular fibrillation)

Some people with an abnormal heart rhythm don't know it. A doctor or nurse discovers it when there's an unusual pulse rate or rhythm (as during a routine examination) or when an EKG is performed. Symptoms such as palpitations, dizziness or breathing problems can also lead to the diagnosis.

Abnormal heart rhythms can be harmless or dangerous. It all depends on whether the heart's ability to pump effectively is affected. If it is, blood clots can form in the heart, heart failure or low blood pressure may develop, or the heart may stop beating altogether.

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Like most organs, the heart has a protective lining (called the pericardium) that separates it from nearby organs, such as the lungs. Normally, it's thin and smooth, which allows the heart to swing a bit during each beat. When it's irritated, infected or invaded by tumor cells, the space between the pericardium and the heart can fill with fluid or blood. If the amount of fluid is large or if it builds up quickly, it can affect the heart's ability to pump effectively (a condition called pericardial tamponade).

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The Bottom Line

The heart is a complex organ. But the language that describes it doesn't have to be. Because heart disease can mean many things, we need to talk about it as clearly as possible.

If your doctor says you have heart disease, ask which "layer" of the heart is involved (the lining, the heart muscle or the valves) and whether heart failure or a rhythm problem is present. Sometimes the only way to understand what your doctor is saying is to ask him to say more.

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Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program


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