Heart Disease - An Overview

An overview of heart disease

the heart
the heart. SEBASTIAN KAULITZKI/Getty Images

No other organ in the body has such a direct impact on every other organ as the heart. It is the heart’s job to pump blood, with its life-giving oxygen and nutrients, to all the tissues of the body. If this pump falters, vital organs like the brain and kidneys suffer. And if the heart stops working altogether death occurs within minutes. Life itself is completely dependent on the efficient operation of the heart.

This is what makes heart disease such a serious matter.

Heart disease comes in many varieties. Some heart disease affects the heart muscle, some affects the heart valves, some affects the heart’s electrical system, and some affects the coronary arteries. These different kinds of heart disease can affect the heart in several ways.

But the ultimate problem with all varieties of heart disease is that, in one way or another, they can disrupt the vital pumping action of the heart.

Here is a survey of heart disease in its many forms. By following the links on this page you can go as deeply as you want to in learning about the major types of heart disease. This survey is divided into three main parts:

  • Part 1 - How The Heart Works — A brief primer on the anatomy and the function of the heart.
  • Part 2 - Heart Disease In Depth — An introduction to the major forms of cardiovascular disease, with plenty of links to in-depth coverage.
  • Part 3 - How To Prevent Heart Disease — What you can do to help prevent heart disease. 

PART ONE — The Normal Heart 

The heart is fundamentally a powerful and tireless pump. It consists of muscular chambers that contract to push the blood through the vascular system, and a series of valves that keep the blood moving efficiently, and in the right direction.

 Read about the heart’s chambers and valves.

Why does the heart keep beating? And how does it “know” when, and how fast, to beat? The answer is: the heart has a self-regulating electrical system that determines the heart rate, and that co-ordinates the sequential beating of the various cardiac chambers. Read about the cardiac electrical system.

To do all this muscular work around the clock, the heart needs a large and continuous supply of oxygen-rich blood. The coronary arteries are the vessels that supply this blood to the heart muscle. They are critically important to the heart, and to life. Read about the coronary arteries.

PART TWO — Heart Disease in Depth

The normal function of the heart and the vascular system can be disrupted by a large variety of conditions. In this survey we will divide the various kinds of cardiovascular disease into several large categories: coronary artery disease and heart attacks, heart failure, heart valve disease, cardiac arrhythmias, and vascular disorders.

Coronary Artery Disease and Heart Attacks

Coronary artery disease (CAD) is very common in Western societies, and is a leading cause of death and disability. In CAD, atherosclerotic plaques form in the lining of the coronary arteries. Here is a brief overview of coronary artery disease.

Coronary artery plaques cause two major kinds of problems. First, if the plaques become large enough, they can begin to obstruct blood flow through the arteries. During periods of time when the heart muscle being supplied by the damaged artery needs a lot of blood flow (such as during periods of stress or exercise), the muscle can become ischemic, or oxygen-starved. Ischemia causes the heart muscle to work less efficiently, and can produce a disturbing form of chest discomfort known as angina. Doctors often recommend cardiac catheterizations for people who have suspected CAD, specifically to look for these obstructive plaques. If found, the plaques are often treated with angioplasty and stenting. However, current evidence suggests that most people with “significant” plaques may do just as well if they are treated with medications and lifestyle changes. Here is more information on treating coronary artery disease.

Second, coronary artery plaques are subject to sudden rupture. A ruptured plaque often stimulates the blood clotting mechanism, producing a clot that may produce sudden blockage in the artery. The sudden obstruction of a coronary artery caused by a ruptured plaque is known as acute coronary syndrome (ACS). ACS is always a medical emergency. 

If the obstruction caused by a ruptured plaque is only partial or transient, it can produce episodes of unstable angina. If the obstruction is partial but more severe, it can produce a type of heart attack known as non-ST-segment elevation myocardial infarction (NSTEMI). (A heart attack is diagnosed if at least some of the heart muscle supplied by the damaged artery dies.) If the obstruction is complete, it can produce a more severe type of heart attack known as a ST-segment elevation myocardial infarction (STEMI). Here is a more in-depth overview of heart attacks.

All forms of ACS require immediate medical treatment to relieve the obstruction in the coronary artery, and to relieve the stress on the at-risk heart muscle. Once the acute episode has been treated, long-term therapy — both with medication and with aggressive lifestyle optimization — is essential to reduce the odds of having more episodes of ACS. Read about treating an acute heart attackRead about long-term treatment after ACS.

Because ACS can produce permanent heart damage or death, and because immediate treatment can prevent these disastrous outcomes, it is important to recognize the symptoms, and to act quickly if you think you may be having a heart problem. Read about the signs of ACS and heart attacks, and what to do if you think you may be having a heart attack.

Heart Failure

Heart failure is an all too common end result of many different types of heart disease. In heart failure, heart damage of one form or another leaves the heart unable perform all the work it must to do fulfill the body’s needs. Numerous symptoms may result; some degree of disability is common, as is early death. However, treatment of heart failure has advanced significantly in recent decades, and many people with heart failure are now able to live quite well for many years.

The most prominent symptoms of heart failure are dyspnea, easy fatiguability, and symptoms of cardiac arrhythmias (from palpitations to sudden death), but other symptoms can occur as well. Read about the symptoms of heart failure. In many people with heart failure, dyspnea is by far the most prominent symptom. These people are often said to have congestive heart failure

There are several “types” of heart failure. The most prominent of these are dilated cardiomyopathy, hypertrophic cardiomyopathy, and diastolic heart failure. 

The most common form of heart failure is dilated cardiomyopathy, which is characterized by a prominent enlargement of the left ventricle. The reason dilated cardiomyopathy is common is that it is the typical end result of many, many kinds of heart disease. Read about the causes of dilated cardiomyopathy. The treatment of dilated cardiomyopathy has advanced tremendously in recent years, and with aggressive therapy people with this condition are today living much longer, and with fewer symptoms, than they might have not long ago. Read about the treatment of dilated cardiomyopathy.

Hypertrophic cardiomyopathy is a genetic disorder of the heart that produces a thickening (hypertrophy) of the heart muscle. It can produce several kinds of cardiac problems, including heart failure. The severity of hypertrophic cardiomyopathy varies tremendously from person to person, and is related to the specific genetic variant (of which there are many) that is producing it. Its treatment can become quite complex, and most people with hypertrophic cardiomyopathy should be followed regularly by a cardiologist. A common question that comes up in young people with this condition is whether they should be allowed to engage in sports, because sudden death during exertion is a significant possibility in some. Read about exercise recommendations with hypertrophic cardiomyopathy

In diastolic heart failure, while the ability of the heart muscle to pump blood remains normal, the heart muscle becomes excessively “stiff” (a condition called diastolic dysfunction). This stiffness elevates cardiac pressures, which leads to lung congestion and dyspnea, which can often become quite severe. Diastolic heart failure is treated medically. Part of this medical treatment is to aggressively control hypertension and diabetes, if these disorders are present.

Heart Valve Disease

The four heart valves (tricuspid, pulmonary, mitral and aortic) play a critical role in cardiac function. They assure that when the heart beats, the blood moves freely through the cardiac chambers, and flows in the right direction. 

In general, heart valve disease produces two general types of problems. Either the valve becomes partially obstructed, which impedes blood flow (a condition called stenosis); or the valve becomes leaky, allowing blood to flow in the wrong direction when the heart muscle contracts (a condition called regurgitation). In either case, if the valvular disease becomes severe enough heart failure can result, with all its attendant consequences — dyspnea, weakness, and edema. In addition, valvular disease often produces cardiac arrhythmias, especially atrial fibrillation. 

Heart valve disease has many causes. While it can result from infectious endocarditis or rheumatic heart disease, valvular heart disease is more commonly caused by heart dilation (or cardiac remodeling), calcium deposits on the valves that may occur with aging, and congenital cardiac problems. 

Any of the four heart valves can develop either stenosis or regurgitation. Pulmonary stenosis is the most common congenital heart valve problem. Among adults, the most common types of significant heart valve disease are aortic stenosisaortic regurgitationmitral stenosis and mitral regurgitation. The most commonly diagnosed heart valve problem in adults is mitral valve prolapse (MVP), but the large majority of people who are diagnosed with MVP have a very mild form that will never cause significant heart problems. 

Here is an overview of heart valve disease, its causes and treatment.

Cardiac Arrhythmias

Cardiac arrhythmias are disorders of the heart’s electrical system. The electrical system of the heart is responsible for setting the heart rate (how fast the heart beats), and coordinating the organized, sequential contraction of the heart muscle in the atria and the ventricles. 

Disorders of the heart’s electrical system generally tend to produce either heart rates that are too slow (the bradycardias), or heart rates that are too fast (the tachycardias). With either slow or fast cardiac arrhythmias, the normal sequence of heart muscle contraction may also be disrupted. 

While many people with cardiac arrhythmias have no symptoms whatsoever, any type of arrhythmia has the potential to produce palpitations, weakness, or lightheadedness. Some cardiac arrhythmias can produce more dangerous symptoms such as syncope, and some may produce sudden death. Anyone who has symptoms suggestive of a heart arrhythmia should have an evaluation to determine whether an arrhythmia is present, and if so, which arrhythmia it is. Read about diagnosing cardiac arrhythmias

The bradycardias. There are two general types of arrhythmias that produce bradycardia. The first is a disorder of the sinus node (the structure in the heart that originates the heart’s normal electrical impulse). This is called sinus bradycardia. People who are experiencing symptoms caused by sinus bradycardia often are said to have sick sinus syndrome. The second type of bradycardia is heart block, a condition that is sometimes associated with bundle branch block. If a bradycardia is persistent, and is producing symptoms or is threatening to do even worse, the most effective treatment is to insert a pacemaker

The tachycardias. Tachycardias can originate in the atrial chambers of the heart (the supraventricular tachycardias, or SVT) or in the ventricles (ventricular tachycardia or ventricular fibrillation). 

The SVTs are a large family of arrhythmias with different mechanisms and different treatments. They commonly produce a lot of symptoms, but in general are not life-threatening. The most well-known SVT and the most consequential is atrial fibrillation, which is particularly significant because it increases the risk of stroke. Other common varieties of SVT include AV-nodal reentrant tachycardiaWolff-Parkinson-White syndrome, and inappropriate sinus tachycardia.

Ventricular tachycardia, and especially ventricular fibrillation, are the most common causes of cardiac arrest and sudden death. In general the best approach to treating these arrhythmias is to identify people who are at risk, and take steps to reduce the risk of sudden death with medical treatment (if possible), or to insert an implantable defibrillator.

Premature beats. In addition to the arrhythmias that produce bradycardia or tachycardia, many people will experience occasional premature heart beats, originating either in the atria (premature atrial complexes — PACs) or in the ventricles (premature ventricular complexes — PVCs). These arrhythmias commonly produce palpitations, but with rare exceptions there are few other consequences.

Vascular Disorders

While many, many disease processes can affect the blood vessels, the term “cardiovascular disease” commonly encompasses the vascular disorders that are related either to atherosclerosis, hypertension, or heart disease.

Atherosclerosis and hypertension not only produce coronary artery disease, but also peripheral artery disease that can affect almost any other artery in the body. Strokes and transient ischemic attacks (TIAs) are often due to atherosclerotic vascular disease. Aortic aneurysm, which is especially prevalent in smokers, can be a devastating problem that may result in rupture and sudden death. Hypertension is a major risk factor for aortic dissection

Pulmonary hypertension, high pressure in the pulmonary artery, is often caused by underlying heart disease, and typically contributes to more heart disease. Furthermore, pulmonary hypertension can contribute to the development of pulmonary embolus, which, in turn, can worsen pulmonary hypertension. 

PART THREE - Preventing Heart Disease

The most common forms of heart disease are largely preventable, if we would just pay attention to our cardiac risk factors, and take reasonable steps to reduce them.

It is important to take stock of your own risk. Ideally, you should work with your doctor to perform a formal risk assessment. But you can do a reasonably accurate risk assessment yourself. If your risk is low, congratulations! Just keep in mind the things you ought to be doing (and not doing) to keep it that way. On the other hand, if your cardiac risk is substantially elevated, you’ve got some work to do. Here is how you should deal with a high risk of heart disease

Here is some useful information about the most important cardiac risk factors:

Blood lipids. Cholesterol and triglyceride blood levels are strongly associated with cardiac risk. Current guidelines on treating blood lipids focus on the importance of optimizing lifestyle, and on the appropriate use of statin drugs.

Smoking. Smoking tobacco may be the strongest risk factor for early death, because it often produces premature cardiovascular disease, and also greatly increases the risk of cancer. Smoking is especially bad for the heart, and increases both long-term and short-term cardiac risk

Hypertension. High blood pressure, the silent killer, generally causes no symptoms until it has produced damage to the heart, brain, kidneys or some other important body part. It is important for everyone to have their blood pressure checked periodically, and if hypertension is found, to make sure it is treated effectively.

Obesity. Being substantially overweight or obese is bad for the heart and the cardiovascular system. 

Eating healthy. While the concept of a heart-healthy diet has become controversial in recent years (Eggs are now OK?Saturated fat might not be as bad as we thought?), in general experts agree on what a heart-healthy diet ought to look like. 

Exercise. A sedentary lifestyle is bad for the cardiovascular system; getting plenty of exercise is good for the heart

Diabetes. Diabetes is a major risk factor for cardiovascular disease, and if you have diabetes you should make sure you are doing everything you can to keep it under good control. 

Stress. Stress does indeed play a role in in heart health, but it may surprise you to know what kind of stress is involvedand why it has the effect it does. You can de-stress your way to a healthier heart.

A Word From Verywell

People who educate themselves and take an active role in making clinical decisions tend to have the best medical outcomes. This is true for almost any medical disorder; it’s particularly true if you have a heart problem. 

There are many different kinds of heart disease, and they all have different causes, severities, and treatments. If you have heart disease, you are likely to live a much longer and healthier life if you learn all you can about your particular cardiac problem. With that knowledge you will be able to work more closely with your doctor to do the kind of cardiac evaluation and adopt the kinds of treatments that are best suited to you. 

Sources: 

Anderson JL, Adams CD, Antman EM, et al. 2012 ACCF/AHA Focused Update Incorporated into the ACCF/AHA 2007 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction: a Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2013; 61:e179.

Leening MJ, Berry JD, Allen NB. Lifetime Perspectives on Primary Prevention of Atherosclerotic Cardiovascular Disease. JAMA 2016; 315:1449.

Bonow RO, Carabello BA, Chatterjee K, et al. 2008 Focused Update Incorporated into the ACC/AHA 2006 Guidelines for the Management of Patients With Valvular Heart Disease: a Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation 2008; 118:e523.

Fihn SD, Gardin JM, Abrams J, et al. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the Diagnosis and Management of Patients with Stable Ischemic Heart Disease: a Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation 2012; 126:e354.

McMurray JJ, Adamopoulos S, Anker SD, et al. ESC Guidelines for the Diagnosis and Treatment of Acute and Chronic Heart Failure 2012: The Task Force for the Diagnosis and Treatment of Acute and Chronic Heart Failure 2012 of the European Society of Cardiology. Developed in collaboration with the Heart Failure Association (HFA) of the ESC. Eur Heart J 2012; 33:1787.

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