Heart Disease Articles

Cheat Sheet / Updated 03-27-2016

Even thinking about heart disease is no fun, but preventing it from happening in the first place (or managing heart disease if you do develop it) is often a matter of controlling your risk factors, eating right, exercising, and generally living a heart-healthy life. Lowering your stress levels comes into play as does knowing the warning signs of heart attack — just in case. So if you want the secrets to preventing heart disease and reversing your risk of heart disease in Twitter-sized bites, download these pithy lists to your mobile device and get going!

Article / Updated 03-26-2016

When tests reveal that you have narrowing of one, two, or three of the coronary arteries, your physician develops a plan for how best to treat your unstable angina. This plan may include the use of medicines, angioplasty (PCI), or coronary artery bypass surgery (CABG). Medical therapy A variety of medications that decrease the work of the heart or decrease the propensity of blood to clot at the sites of fatty plaques may be used to treat stable and unstable angina. The most common medications are Nitrates: Nitrates, particularly nitroglycerin, are valuable mainstays for treatment of angina and unstable angina. They relieve pressure on the heart and may also increase blood flow to the heart by causing the coronary arteries to dilate. Nitroglycerin often relieves discomfort quickly. Nitroglycerin/nitrates may come in the form of tablets or sprays that you put under the tongue, a pill that you take by mouth, a cream that you apply to your skin, or a patch that you wear on your skin. Some people may experience headache as a side effect. Beta blockers: These medications, another mainstay of treatment, decrease how hard the heart must work by lowering blood pressure and decreasing heart rate. In about 10 percent of individuals, side effects such as tiredness, dizziness, or depression can occur. Calcium antagonists: This class of medicines blocks calcium flow into the muscle cells of arteries and enables arteries to dilate. These medicines also are called calcium channel blockers. They typically are less effective than nitrates and beta-blockers in angina treatment; however, calcium antagonists may be used in conjunction with them. Calcium antagonists are particularly useful when any significant degree of spasm of the coronary arteries is present. Aspirin: That's right, good old aspirin. Many people know that aspirin can relieve minor pain or fever, but they don't know that aspirin is important in treating angina and unstable angina because it helps prevent platelets from sticking to the walls of blood vessels and thereby contributing to any blood clot that may narrow or block off a coronary artery. Aspirin needs to be part of therapy for individuals with known or suspected CAD who haven't experienced any problems with bleeding. Research and experience show that using enteric, or coated, aspirin, which dissolves in the intestine, often helps lessen potential stomach irritation for individuals who are sensitive to aspirin. Platelet receptor inhibitors: This new category of drugs can enhance aspirin therapy by blocking the ability of platelets to stick to each other. These medicines, which typically are delivered intravenously in the hospital, may further help in the acute setting of unstable angina. Angioplasty An alternative to medical therapy that may be more appropriate to some patients with unstable angina is called angioplasty, PTCA (percutaneous transluminal coronary angioplasty), or PCI (percutaneous coronary intervention). This procedure uses the technique known as heart catheterization. In angioplasty, a catheter is inserted into an artery that is narrowed. Near the tip of this catheter is a small balloon that is inflated by a physician when the catheter reaches the blockage. When the balloon subsequently deflates, the blockage often is dilated enough for more blood to pass through, thus decreasing anginal discomfort. A stent may also be inserted to keep the artery open. Coronary artery bypass surgery When the blockage of multiple coronary arteries is severe or the main branch of the left coronary artery is severely blocked, coronary artery bypass surgery (also called coronary artery bypass grafting or in medical slang, CABG) may be recommended as the most effective therapy. Surgery also is recommended when medical therapy and angioplasty don't control the symptoms of angina. During coronary artery bypass surgery, a piece of vein from the leg or an artery from the chest is grafted onto either side of a blocked coronary artery so that it bypasses the blockage.

Article / Updated 03-26-2016

A stroke occurs when a blood clot or bleeding suddenly interrupts the flow of blood to an area of the brain. When deprived of blood, brain cells lose their ability to function and, if deprived for too long, die. Because brain cells and groups of brain cells have highly specialized functions, the location of stroke damage determines what loss of neurological and bodily function occurs as a result of stroke. Impairment may be temporary or permanent. As is true of coronary artery disease (CAD), a number of factors can increase your risk of having a stroke. Some factors, such as age and heredity, are out of your hands, but you can do much to control risk factors that are related to lifestyle choices. Risk factors you can't change Although you can't change the risk factors in the following list, understanding them may increase your awareness and help you make better choices about the risk factors you can control. Age: Although many people younger than 65 have strokes, the risk of stroke doubles with each decade after age 55. Heredity and family history: Your risk of having a stroke is higher if a parent, grandparent, or sibling has had a stroke. Certain inherited genetic traits, such as blood-clotting disorders, and family lifestyle patterns likely contribute to this elevated risk. Gender: Although men and women have about the same overall risk of having a stroke, women are more likely to die from stroke. Taking birth control pills also slightly increases the risk of stroke particularly when combined with other risk factors like smoking or high blood pressure. Previous stroke: Having had one stroke greatly increases your risk of having another stroke. For this reason, preventing recurrent stroke is an important goal in the long-term health-care plan for stroke survivors. Risk factors you can control Controlling one or more of these risk factors can significantly lower your risk of stroke. Having one of these risk factors will raise your risk of stroke. Having a cluster or two or three factors, which is a fairly common circumstance, dramatically raises your risk of stroke. High blood pressure: Having high blood pressure is perhaps the greatest risk factor for stroke. In fact, the higher your blood pressure, the greater the risk. Controlling blood pressure within normal ranges can lower this risk. Smoking: Because smoking damages the cardiovascular system all over the body, and not just in the heart, it damages vessels in the brain and the carotid arteries leading to the brain and contributes to the narrowing of these vessels. Heart disease: People with heart disease and people who've had heart attacks are at higher risk of stroke. Having atrial fibrillation is a particularly significant risk factor because embolitic clots often form during atrial fibrillation. Diabetes: Not only is having diabetes an independent risk factor for stroke, but people with diabetes often have high blood pressure, high cholesterol, and weight problems, all of which are additional factors that increase stroke risk. Substance abuse: Binge drinking or even drinking beyond recommended moderate levels (no more than one drink daily for women and two for men) raises the risk of stroke. Intravenous drug abuse can lead to cerebral embolisms; cocaine abuse also has been linked to stroke.

Article / Updated 03-26-2016

While you're sitting still, your heart is beating at 70 to 80 contractions per minute (unless you're extremely fit). With each contraction, the right ventricle discharges about three-quarters of the blood it contains into the vessels of the lungs where it receives oxygen. At the same time, the left ventricle is discharging about three-quarters of the blood that it contains into the aorta and arterial system to feed the oxygen to all the organs and muscles. All four heart valves work together to control blood flow into and out of the heart, making sure that no blood flows in the wrong direction. Wouldn't it be nice if traffic systems were so efficient! The arterial system dilates, or expands, each time the left ventricle empties into it and speeds blood on its way to the various working tissues. How much blood goes to each tissue is determined by what that particular muscle or organ needs to do. When you eat a big meal, for example, the heart, brain, parasympathetic nervous system, and arteries all decide that more blood needs to go to the organs in the gastrointestinal tract to help them with the work of digesting that low-fat, cardiac-healthy meal you just ate. Say you decide that you're going to exercise regularly. (Good idea!) Exercise poses a different challenge to the heart compared to rest. Extra blood flow must go to muscles used in exercising and to the coronary arteries that feed the heart muscle itself so that it can pump out the extra blood required during your exercise exertion. Fortunately, this extra work is no problem for a healthy heart. Once again, all systems work in concert. Extra blood is pumped from the heart, and extra blood flows down the coronary arteries, which dilate to accept this extra flow. The heart valves continue to direct the blood in the proper direction, and the electrical system, with a little boost from the nervous system, starts generating more beats per minute. At the same time, the cardiac muscle relaxes a little bit, enabling more blood to be pumped out during each beat. In addition, the nervous system, in conjunction with the arterial system, causes Some parts of the arterial circulation to expand or dilate, sending more blood to the working muscles that need it Other parts to constrict or narrow, diverting blood away from areas where it is not as active during exertion The good news is that if you exert yourself on a regular basis, your heart and the rest of your cardiovascular system begin to become more efficient and prepare for the regular exercise sessions. That's true even if you've been diagnosed with heart disease or had a heart attack or other heart event. For that reason, physicians prescribe specific types of carefully monitored activities and exercises as part of treatment and rehabilitation programs for heart disease. When all parts of the heart and cardiovascular system are healthy and functioning well together, it is a beautiful system. But the heart is a muscle. And like any muscle, it works best when you keep it in shape and avoid injury. The conditioned heart A conditioned heart is stronger and better able to meet the demands the body places on it. Human bodies were designed to be in motion. And the motion of physical activity keeps the heart well tuned, the benefits of which are numerous: Literally hundreds of studies have shown that individuals who adopt the simple habit of daily physical activity substantially reduce their risk of developing various heart problems, most notably coronary artery disease. The conditioned heart enables individuals to accomplish the activities of daily living with comfort and without running out of breath and energy. The more conditioned the heart, the lower the resting heart rate, and the less work the heart has to do in a lifetime. Studies also show that, with appropriate activity, hearts damaged by disease or injury can regain conditioning that enhances health and function and may even contribute to the reversal of some aspects of disease. The deconditioned heart In contrast to the active individual, the individual who leads a sedentary lifestyle can actually experience a deconditioned heart. The deconditioned heart is less efficient at doing its work and has to work harder to get adequate blood flow throughout the body. You're a prime candidate for a deconditioned heart if you answer "yes" to these questions or others like them: Do you avoid the stairs because climbing two or three flights leaves you extremely short of breath? Do you circle a parking lot numerous times looking for a space right in front of the store to make sure that you don't have to walk much? Do you watch sports on television rather than participate in them with friends and family? On a nice day, do you pop a DVD into the player rather than take a walk? For many people a deconditioned heart is the first step in a slow slide down the long slope toward a sick heart. The diseased heart A sedentary lifestyle coupled with unhealthy practices such as poor nutrition, weight gain, cigarette smoking, or certain other health conditions, such as high blood pressure, high cholesterol, or diabetes, can severely alter the basic cardiac structures and lead to a disordered anatomy that can create a very unhappy destiny. A short list of the things that can go wrong includes blocked arteries, high cholesterol, high blood pressure, angina, heart attack, heart failure, and sudden death. The bottom line: Many of the cardiac problems that people experience are brought on by years of neglect and failure to abide by even the most basic of cardiac-healthy lifestyle principles. (Nature makes a few mistakes, too, but even in those cases, personal choices often complicate the problem.) The good news is that even if you've been diagnosed as at risk for heart disease or as having it, and even if you've experienced specific heart problems, paying attention to the basic principles of a cardiac-healthy lifestyle in conjunction with the medications and procedures of your treatment plan can help you turn things around.

Article / Updated 03-26-2016

Hypertension isn't called a killer for nothing. High blood pressure is a significant risk factor for developing coronary artery disease (CAD), the leading cause of death in the United States, and it's considered a significant risk for stroke, heart failure, and kidney failure. Anyone with poorly treated hypertension at least doubles his or her risk of developing all of these conditions. And remember, the higher the blood pressure, the higher the danger. Thus, even individuals who have no symptoms when initially diagnosed with hypertension need to work hard to control blood pressure to prevent these potentially devastating complications. When you're already diagnosed with heart disease and hypertension, then controlling your blood pressure within recommended levels is perhaps the most important step you can take toward preventing or slowing the progress of your heart disease. Determining the causes of hypertension In the vast majority (more than 90 percent) of people with high blood pressure, physicians aren't able to determine its exact cause. In medical terms, this condition is known as idiopathic hypertension. That's not to say that physicians are idiots, but that they haven't yet figured out the precise mechanisms, functions, or agents that cause hypertension. Hypertension of an undetermined cause also is termed essential high blood pressure. In the same way that idiopathic doesn't mean that doctors are idiots, neither does essential mean that having hypertension is essential. Quite the contrary! Treating it is what is essential! Look at some of the factors that appear to contribute to hypertension. Salt intake: Among the theories about what causes essential high blood pressure, most relate to problems that your kidneys appear to have with handling excess salt. Population studies show that societies in which people consume large amounts of salt (such as the United States) have a correspondingly high incidence of high blood pressure. Similarly, in cultures where salt intake is low, the incidence of high blood pressure is extremely low. Other studies show that for most people with hypertension, restricting salt intake helps lower high blood pressure. Inherited predisposition: Hypertension also appears to have a genetic component. Some people may be genetically predisposed to have high blood pressure. However, although hypertension runs in some families, these tendencies may actually result as much from shared lifestyles as they do from shared genetic backgrounds. Doctors certainly know that lifestyle factors, such as obesity (and abdominal obesity, in particular), inactivity, cigarette smoking, and high alcohol consumption all are associated with increased risk of hypertension. Known conditions that cause it: In approximately 10 percent of the people with hypertension, the specific underlying cause can be discovered. This condition is known as secondary hypertension, meaning it's a secondary result of a separate primary condition. If the underlying condition can be treated and corrected, then secondary hypertension usually is corrected, too. Conditions known to cause secondary high blood pressure include • Narrowing of the arteries that supply the kidneys • Other diseases of kidneys • Abnormalities in the endocrine system, such as overactive adrenal glands • Transient conditions such as pregnancy for certain women • Certain medications that can increase the risk of high blood pressure, such as oral contraceptives or estrogen replacement therapy following menopause If you're diagnosed with high blood pressure, your doctor will explore any of these potential underlying causes for hypertension prior to making the diagnosis. Checking out other risk factors Although medical science may not know the exact mechanisms that cause essential hypertension, a number of conditions are strongly associated with increases in high blood pressure. Arresting any one of this gang of probable causes usually leads to lower blood pressure. For many people, controlling these conditions actually returns their blood pressure to normal levels. Obesity: Hypertension is most clearly associated with obesity (weighing more than 20 percent above your desirable body weight). Obesity contributes to an estimated 40 percent or more of all high blood pressure cases in the United States. Although not everyone who is overweight has high blood pressure, the association remains crystal clear. Cigarette smoking: Cigarette smoking and the use of other tobacco products increase blood pressure, both in the short term while you're smoking or chewing and in the long term, because components in the smoke or chewing tobacco, such as nicotine, cause your arteries to constrict. Childhood experiments with the nozzle on a garden hose indicate what happens when you force the same volume of liquid through a smaller opening. That higher pressure isn't a happy thing for your arteries. Alcohol intake: Drinking small to moderate amounts of alcohol (fewer than two beers, two glasses of wine, or one shot of distilled spirits) per day has been shown in a number of studies to reduce mortality from CAD. Higher consumption of alcohol (three or more alcoholic drinks per day), however, clearly is associated with increased blood pressure, not to mention an increased risk of dying from heart disease. Physical inactivity: People who are physically inactive increase their likelihood of developing high blood pressure. In one large study of more than 16,000 individuals, inactive people were 35 percent more likely to develop hypertension than were active people, regardless of whether they had a family history of high blood pressure or a personal history of being overweight.

Article / Updated 03-26-2016

It's no surprise that myths about heart disease often prevail. After all, the heart is a truly mythic organ — the fount of all life. Throughout the world's cultures, heroes and heroines of mythology and legend usually are persons of great heart. The same can be said of persons of great cunning. Their hearts are the embodiment of the courageous lifestyles that inspire the masses. But although myths can and do inspire, they also can kill . . . particularly the many myths surrounding heart disease. So let's bust a few. The myth of modern maturity Heart disease is a disease of middle age and older years. Many people think of heart disease as a problem of middle and older age, because that's when the manifestations of heart disease, such as angina and heart attack, strike. What a dangerous myth. Although the manifestations of coronary artery disease typically occur during the middle and later years of life, the roots of coronary artery disease lie in childhood. Using heart-healthy lifestyle measures not only will help you but also will enable you to set an example for your children and grandchildren. The myth of the old-boy network Men are much more likely to get heart disease than women. Way too many women think that heart disease is mainly a male disease. However, heart disease is by far the leading cause of death for women. Women are six to ten times more likely to die of heart disease than breast cancer (which women fear more). When cardiovascular disease and stroke are combined, these two diseases claim more female lives every year than the next 16 causes of death combined.Even so, many of these deaths are preventable. The Eisenhower Myth After you've had a heart attack, your life will move inexorably downhill. In 1954, President Dwight Eisenhower suffered a heart attack while in office — a first. His cardiologist, Dr. Paul Dudley White, from Harvard Medical School and Massachusetts General Hospital, appeared on national television to assure the anxious public that if President Eisenhower paid attention to what he ate and became involved in a regular walking program, he could continue to fulfill the strenuous duties of the highest office in the land. Most people were surprised to hear it. As Ike proved, you have no reason whatsoever to give up after you've had a heart attack. Modern cardiac rehabilitation can help people who've suffered a heart attack or have other serious forms of heart disease to live full, vigorous lives for many years after they experience the first manifestations of heart disease. The myth of no pain, no gain To get cardiac benefit from exercise, you need to get sweaty and out of breath. Many sedentary individuals (and, indeed, many exercisers!) share the myth that you have to exercise at a fairly intense level to achieve cardiac benefits. To some degree, this myth grew from the advice of well-intentioned exercise physiologists, who said that improving your aerobic fitness requires at least three or four 20- to 30-minute sessions of continuous vigorous exercise every week. Without question, this advice is excellent if your only goal is improving your aerobic capacity. However, if your goal is lowering your risk of heart disease, totally different rules apply . . . you simply need to become more active. Accumulating 30 minutes of moderate physical activity on most, if not all, days is a solid goal.Don't let the myth that you have to sweat like crazy for 30 minutes straight keep you and your heart declining . . . uh, reclining on the couch. The cave man myth If you're having chest pain, the best thing you can do is wait and see whether it goes away. The Peanuts character Linus once asked Charlie Brown how he approached a problem. Did he tackle it right away, or think about it first? Charlie Brown responded, "I try to go into a cave and hope that it will go away." That may work in other areas of your life, but ignoring the symptoms of acute heart disease is a bad idea. The longer the delay before treatment of a heart attack begins, the greater the potential heart damage. If you're having significant chest discomfort, shortness of breath, or any other symptoms that suggest a heart attack, call 911 immediately so you can be transported to the emergency room. Don't hide in a cave! The myth of the stiff upper lip Dying of a broken heart or being scared to death is not possible. Folk wisdom long has suggested that people can be scared to death or die of a broken heart. Many cardiologists, however, say that your emotions and mental state can affect your behavior but not your heart. From this point of view, it doesn't matter whether you keep a stiff upper lip and bury your fears, pain, and stress or deal with them. Multiple scientific studies show that important mind/body connections exist for health in general and cardiovascular health in particular. Your levels of stress, your connection to other people, your sense of giving and receiving love all are extremely important for your cardiovascular health. Your goal should be using these profound linkages to promote cardiovascular health. The myth of Jupiter We all will die of heart disease, if we live long enough. Jupiter, the Roman King of the Gods, killed mere mortals by hurling thunderbolts from the sky. This myth expresses the presumption that heart disease is an act of God. Not so. Dying of heart disease is not inevitable. Recognize that your own habits and actions play the biggest roles in whether you develop heart disease. Take a tip from baseball great Mickey Mantle, who humorously said of his health-destructive lifestyle, "If I knew I was going to live so long, I would have taken better care of myself!"

Article / Updated 03-26-2016

Heart disease is the most common cause of death in the U.S. Maybe that’s because there are so many facets of heart disease. The heart and its accompanying circulatory system can be injured or damaged — not only by trauma, but also by genetic predisposition, viruses, and lifestyle choices. Deaths from heart disease usually are attributed to heart attacks, but heart attacks can be caused by many factors: Atherosclerosis (blockages in the arteries) Ischemia (lack of oxygen) Thromboembolism (blood clots that travel through the bloodstream and block blood vessels elsewhere in the body) Hypertension (high blood pressure) Atherosclerosis occurs when fats, especially cholesterol, accumulate in the lining of the arteries. Cholesterol is part of the fat transport system through the bloodstream, and it is needed as the precursor of steroid synthesis. But, when there is too much cholesterol is in the body, it starts to stick to the vessels, rather than pass through them. The fatty deposits are called plaques. As the plaques increase in size, they fill more and more of the artery, eventually affecting blood flow. If arteries are partially blocked, ischemic heart disease may occur. People with ischemic heart disease have difficulty breathing during exercise or times of stress because the blocked arteries slow the blood flow, which prevents enough oxygen from being delivered to the heart muscle tissues. The lack of oxygen can cause a pain in the chest that radiates to the left arm. This pain is called angina pectoris (pectoris refers to the chest, as in the pectoral muscles). If an artery is blocked by a plaque, blood cells can stick to the plaque, eventually forming a blood clot. A blood clot stuck in a blood vessel is called a thrombus. If the thrombus breaks free and moves around the bloodstream, it is called an embolism. A thromboembolism is a blood clot that breaks free from where it was formed, travels through the bloodstream, and blocks another spot in a blood vessel. Although the heart fills with blood to pump to the rest of the body, it also must have nutrients and oxygen supplied to the tissues that form it. Because your heart is made of living cells and tissues, it needs to have blood vessels running through it so that nutrients and oxygen can be delivered to the cells within the heart. Arteries that bring blood to the tissues and cells of the heart are called coronary arteries. If a clot or plaque blocks a coronary artery, oxygen cannot be delivered to the muscle tissue, and a heart attack occurs. The tissue in the area of the heart where the attack occurs often dies because of the lack of oxygen. The technical term for a heart attack is a myocardial infarction. Myo- means muscle, cardi- means heart, and an infarct refers to dead tissue.

Article / Updated 03-26-2016

You know that you are carrying more pounds that you ought to. You’re ready to start a weight loss plan. But how overweight are you? How much weight overall should you lose? How can you set interim weight loss goals that will help you see progress quickly and stay motivated? You can use your Body Mass Index (BMI) measurement and a BMI chart (or the BMI calculator link) to help you answer all these questions. Body Mass Index is a scientifically validated measurement of adult body fat based on calculations using height and weight. BMI is stated as a single number that shows you where you are on a scale ranging from underweight to obese. Here is the general breakdown: Weight Category BMI Value Underweight Less than 18.5 Normal 18.5 to 24.9 Overweight 25 to 29.0 Obese 30 and over Extreme obesity 40 and over Knowing your BMI can help you assess how much weight you need to lose. Remember losing as little as 5 percent of your body weight can make a big difference in lowering your risk factors for heart disease and other chronic diseases. If you are 5'2" and weigh 180 pounds, 5 percent of your weight is just 9 pounds. Losing 9 pounds could lower your BMI almost 2 whole points. Using BMI to track your progress toward a healthier weight means that you get to notch a victory every time you lose 4 to 8 pounds, depending on your height and starting weight. Seeing those numbers fall can help keep you on track. You can easily calculate your BMI using a calculator provided by the National Heart, Lung, and Blood Institute; the Body Mass Index calculator provides your BMI measurement to the nearest tenth, so you can really see changes. You also can get a quick estimate using this downloadable table.

Article / Updated 03-26-2016

Many people mistakenly think that you either have hypertension or you don’t. In fact, blood pressure readings span a continuum ranging all the way from normal to severely elevated. Experiencing one elevated reading does not mean that you have hypertension. Everyone’s blood pressure tends to spike up in situations that produce anger, pain, fear, or high stress. For example, your blood pressure probably rises when you have a shouting match with a family member, give a speech, or interview for a new position — maybe even when you visit your friendly doctor. Blood pressure also varies during the day. It’s usually lower when you are resting or sleeping, for example. Having hypertension means that your blood pressure is consistently elevated above the normal ranges. (It doesn’t mean that you are super-tense. Even the calmest, most laid-back individuals can have high blood pressure.) And knowing whether you have it is no do-it-yourself diagnosis, either. You need to have your blood pressure checked regularly, ideally as part of a regular periodic checkup. If you happen to check your blood pressure at a health fair, for example, and it’s elevated, be sure to see your physician. Your physician will take your blood pressure readings on several occasions to determine whether your blood pressure is consistently elevated, and if it is, how severely elevated it is.

Article / Updated 03-26-2016

The heart is located in the center of the chest cavity, just to the left of the midline of the body. You need to understand the following important parts: The heart muscle: Called the myocardium (myo = muscle and cardium = heart; pronounced my-o-car-dee-um), this muscle contracts and relaxes to pump blood throughout the cardiovascular system. The coronary arteries: Three large coronary arteries and their many branches deliver a continuous supply of oxygenated blood to the heart. Narrowing of these arteries causes chest pain; blockage causes heart attack. Credit: Illustration by Kathryn Born The pumping chambers: The heart’s job is to pump blood to the lungs to get oxygen and to pump the oxygenated blood to the rest of the body. To fulfill these tasks, the heart has a left and a right side, each with one main pumping chamber called a ventricle located in the lower part of it. Sitting above the left and right ventricles are two small booster pumps called atria (or atrium, when you’re talking about just one). The right ventricle pumps deoxygenated blood from the body to the lungs to receive a new supply of oxygen and back to the heart, through the left atrium to the left ventricle. The left ventricle pumps oxygenated blood through the arterial system to the rest of the body where it feeds every single living cell. Various disease conditions can damage each of these structures. Credit: Illustration by Kathryn Born The valves: Four valves regulate the flow of blood in and out of the heart and from chamber to chamber. They act a bit like cardiac traffic cops by directing the way blood flows, how much of it flows, and when to stop it from flowing. Disease and injury can cause heart valves to leak, narrow, or otherwise malfunction, disrupting the heart’s ability to pump blood efficiently. The electrical system: This electrical system is controlled by a group of specialized cells that spontaneously discharge, sending electrical currents down specialized nerves and tissues, causing the heart to contract. When any of these electrical structures becomes diseased or disordered, arrhythmias (ay-rith-mee-uhz), or heart rhythm disturbances, occur. The pericardium: The entire heart is positioned in a thin sac called the pericardium (peri = around and cardium = heart; pronounced per-ry-car-dee-um). Fluid within the sac lubricates the constantly moving surfaces. Inflammation of the pericardium from an infection or other cause causes pericarditis. Build-up of excess fluid inside the pericardium can cause problems with how the heart functions, a condition called cardiac tamponade.