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diabetic heart disease





The term "diabetic heart disease" (DHD) refers to heart disease that develops in people who have diabetes. Compared with people who don't have diabetes, people who have diabetes:
  • Are at higher risk for heart disease
  • Have additional causes of heart disease
  • May develop heart disease at a younger age
  • May have more severe heart disease

What is diabetes?

Diabetes is a disease in which the body's blood sugar level is too high. Normally, the body breaks down food into glucose and then carries it to cells throughout the body. The cells use a hormone called insulin to turn the glucose into energy.

The two main types of diabetes are type 1 and type 2. In type 1 diabetes, the body doesn't make enough insulin. This causes the body's blood sugar level to rise.

In type 2 diabetes, the body's cells don't use insulin properly (a condition called insulin resistance). At first, the body reacts by making more insulin. Over time, however, the body can't make enough insulin to control its blood sugar level.


What heart diseases are involved in diabetic heart disease?

DHD may include coronary artery disease, also called coronary heart disease (CHD); heart failure; and/or diabetic cardiomyopathy.


Coronary heart disease

CHD is a condition in which a substance called plaque builds up inside the coronary arteries. These arteries supply your heart muscle with oxygen-rich blood.

Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. When plaque builds up in the arteries, the condition is called atherosclerosis. Plaque narrows the arteries and reduces blood flow to your heart muscle. It also makes it more likely that blood clots will form in your arteries. Blood clots can partially or completely block blood flow.

CHD can lead to chest pain or discomfort called angina, irregular heartbeats called arrhythmias, a heart attack, or even death.


Heart failure

Heart failure is a condition in which your heart can't pump enough blood to meet your body's needs. It doesn't mean that your heart has stopped or is about to stop working. However, heart failure is a serious condition that requires medical care.

If you have heart failure, you may tire easily and have to limit your activities. CHD can lead to heart failure by weakening the heart muscle over time.


Diabetic cardiomyopathy

Diabetic cardiomyopathy is a disease that damages the structure and function of the heart. This disease also can lead to heart failure and arrhythmias, even in people who have diabetes but don't have CHD.


What causes diabetic heart disease?

The effects of diabetes on the heart and coronary arteries interact with other heart disease risk factors to cause diabetic heart disease (DHD). Researchers continue to study these processes because all of the details aren't yet known.

At least four complex processes, alone or combined, can lead to DHD. These include coronary atherosclerosis; metabolic syndrome; insulin resistance in people who have type 2 diabetes; and the interaction of coronary heart disease (CHD), high blood pressure, and diabetes.


Coronary atherosclerosis

Research suggests that coronary atherosclerosis starts when certain factors damage the inner layers of the coronary (heart) arteries. These factors include:
  • Smoking
  • High amounts of certain fats and cholesterol in the blood
  • High blood pressure
  • High amounts of sugar in the blood due to high blood sugar
When damage occurs, your body starts a healing process. The healing may cause plaque to build up where the arteries are damaged.

The buildup of plaque in the coronary arteries may start in childhood. Over time, plaque can narrow or completely block some of your coronary arteries. This reduces the flow of oxygen-rich blood to your heart muscle.

Eventually, a section of plaque can break open, causing a blood clot to form at the site. The blood clot will narrow the artery even more and may worsen angina (chest pain) or cause a heart attack.


Metabolic syndrome

Metabolic syndrome is the name for a group of risk factors that raises your risk for both CHD and type 2 diabetes. If you have three or more of the five metabolic risk factors, you have metabolic syndrome. The risk factors are:
  • A large waistline (a waist measurement of 35 inches or more for women and 40 inches or more for men)
  • A high triglyceride (blood fat) level
  • A low HDL cholesterol level (sometimes called "good" cholesterol)
  • High blood pressure
  • A high fasting blood sugar level (or you're on medicine to treat high blood sugar)
It's unclear whether these risk factors have a common cause or are mainly related by their combined effects on the heart.

Obesity seems to be one condition that sets the stage for metabolic syndrome. (Obesity is having a high amount of extra body fat.) Obesity can cause harmful changes in body fats and how the body uses insulin.

Chronic inflammation also may occur in people who have metabolic syndrome. Inflammation is the body's response to illness or injury. It may raise the risk of CHD and heart attack. It also may contribute to or worsen metabolic syndrome.

Research is ongoing to learn more about metabolic syndrome and how metabolic risk factors interact.


Insulin resistance in people who have type 2 diabetes

Type 2 diabetes usually begins with insulin resistance. Insulin resistance means that the body can't properly use the insulin it makes.

People who have type 2 diabetes and insulin resistance have higher levels of substances in the blood that cause blood clots. Blood clots can block the coronary arteries and cause a heart attack or even death.


The interaction of coronary heart disease, high blood pressure, and diabetes

Each of these factors alone can damage the heart. CHD reduces the flow of oxygen-rich blood to your heart muscle. High blood pressure and diabetes may lead to harmful changes in the structure and function of the heart.

Having CHD, high blood pressure, and diabetes is even more harmful to the heart. Together, these conditions can seriously damage the heart muscle. As a result, the heart has to work harder than normal. Over time, the heart weakens and isn't able to fill with and/or pump blood as well as it should. This condition is called heart failure.

As the heart weakens, the body may release proteins and other substances into the blood. These proteins and substances also can harm the heart, and they may cause heart failure to worsen.





Who is at risk for diabetic heart disease?

Diabetes affects heart disease risk in three major ways. First, diabetes by itself is a very serious risk factor for heart disease. Second, when combined with other risk factors, diabetes further raises the risk of heart disease. Third, compared with people who don't have diabetes, people who have the disease are more likely to:
  • Have heart attacks and other heart and blood vessel diseases. In men, the risk is double; in women, the risk is triple.
  • Have more complications after a heart attack, such as angina (chest pain or discomfort) and heart failure.
  • Die from heart disease.
If you have diabetes, the higher your blood sugar level is, the higher your risk of DHD. (A higher than normal blood sugar level is a risk factor for heart disease even in people who don't have diabetes.)

Type 2 diabetes raises the risk of having heart disease without any symptoms. This is called "silent" heart disease. A heart attack may even occur without symptoms. Diabetes-related nerve damage that blunts heart pain may explain why symptoms aren't noticed.


Other risk factors

Other factors also can raise the risk of heart disease in people who have diabetes and in those who don't. You can control most of these risk factors, but some you can't.


Risk factors you can control
  • Unhealthy blood cholesterol levels. This includes high LDL cholesterol (sometimes called "bad" cholesterol) and low HDL cholesterol (sometimes called "good" cholesterol).

  • High blood pressure. Blood pressure is considered high if it stays at or above 140/90 mmHg over time. (The mmHg is millimeters of mercury – the units used to measure blood pressure.) If you have diabetes or chronic kidney disease, high blood pressure is defined as 130/80 mmHg or higher.

  • Smoking. Smoking triggers a buildup of plaque in your arteries. Smoking also increases the risk of blood clots forming in your arteries. Blood clots can block plaque-narrowed arteries and cause a heart attack.

  • Prediabetes. This is a condition in which your blood sugar level is higher than normal, but not as high as it is in diabetes. If you have prediabetes and don't take steps to manage it, you'll likely develop type 2 diabetes within 10 years. You're also at increased risk for heart disease.

  • Overweight or obesity. Being overweight or obese can raise your risk of heart disease and heart attack. Overweight and obesity also are linked to other heart disease risk factors, such as high blood cholesterol, high blood pressure, and diabetes. Most people who have type 2 diabetes are overweight.

  • Metabolic syndrome. Metabolic syndrome is the name for a group of risk factors that raises your risk for both coronary heart disease and type 2 diabetes. Metabolic syndrome also raises your risk for other health problems, such as stroke.

  • Lack of physical activity. Inactive people are nearly twice as likely to develop heart disease as those who are active. A lack of physical activity also can worsen other heart disease risk factors.

  • Unhealthy diet. An unhealthy diet can raise your risk of heart disease. Foods that are high in saturated and trans fats, cholesterol, sodium (salt), and sugar can worsen other heart disease risk factors.

  • Stress. Stress and anxiety can trigger your arteries to tighten. This can raise your blood pressure and your risk of heart attack. Stress also may indirectly raise your risk of heart disease if it makes you more likely to smoke or overeat foods high in fat and sugar.

Risk factors you can't control
  • Age. As you get older, your risk of heart disease and heart attack rises. In men, the risk of heart disease increases after age 45. In women, the risk increases after age 55. In people who have diabetes, the risk of heart disease increases after age 40.

  • Gender. Before age 55, women seem to have a lower risk of heart disease than men. After age 55, however, the risk of heart disease increases similarly in both women and men.

  • Family history. Family history plays a role in heart disease risk. Your risk increases if your father or a brother was diagnosed with heart disease before age 55, or if your mother or a sister was diagnosed with heart disease before age 65.

Signs and symptoms of diabetic heart disease

Some people who have diabetic heart disease have "silent" heart disease. This means that they have no signs or symptoms of heart disease. Diabetes-related nerve damage that blunts heart pain may explain why symptoms aren't noticed. Thus, it's very important for people who have diabetes to have regular medical checkups. Tests may reveal a problem before they're aware of it. Early treatment can reduce or delay complications.

Some people who have DHD will have some or all of the typical symptoms of heart disease. Be aware of the symptoms described below and seek medical care if you have them. If you think you're having a heart attack, call immediately for emergency care. Treatment for a heart attack works best when started within 1 hour of the start of symptoms.


Coronary heart disease

A common symptom of coronary heart disease is angina. Angina is chest pain or discomfort that occurs when your heart muscle doesn't get enough oxygen-rich blood. Angina may feel like pressure or a squeezing pain in your chest. You also may feel it in your shoulders, arms, neck, jaw, abdomen, or back.

Other angina symptoms may include nausea (feeling sick to your stomach), fatigue (tiredness), shortness of breath, sweating, light-headedness, or weakness. Stress or physical activity may trigger angina.

See your doctor if you think you have angina. He or she may recommend tests to check your coronary arteries and to see whether you have CHD risk factors.

Some people don't realize they have CHD until they have a heart attack. A heart attack occurs if an area of plaque in a coronary artery breaks open, causing a blood clot to form at the site. The blood clot can block the flow of oxygen-rich blood to part of the heart muscle.

The most common heart attack symptom is chest pain or discomfort. Most heart attacks involve discomfort in the center of the chest that lasts for more than a few minutes or goes away and comes back.

The discomfort can feel like pressure, squeezing, fullness, or pain. It can be mild or severe. Heart attack pain can sometimes feel like indigestion or heartburn. Shortness of breath or fatigue may occur with or before chest discomfort.

Heart attacks also can cause upper body discomfort in one or both arms, the back, neck, jaw, or abdomen. Other heart attack symptoms include nausea, vomiting, light-headedness or fainting, and breaking out in a cold sweat.

Not everyone who has a heart attack will have these typical symptoms. If you've already had a heart attack, your symptoms may not be the same for another one. Also, diabetes-related nerve damage can interfere with pain signals in the body. As a result, some people who have diabetes may have heart attacks without symptoms.

Act quickly if you think you're having a heart attack. Call emergency services right away.


Heart failure

The most common symptoms of heart failure are shortness of breath or trouble breathing, fatigue, and swelling in the ankles, feet, legs, abdomen, and veins in your neck. As the heart weakens, heart failure symptoms worsen.

People who have heart failure can live longer and more active lives if the condition is diagnosed early and they follow their treatment plans. If you have any form of DHD, talk to your doctor about your risk of heart failure.


Diabetic cardiomyopathy

Diabetic cardiomyopathy may not cause symptoms in its early stages. Later, you may have weakness, shortness of breath, a severe cough, fatigue, and swelling of the legs and feet.


Diagnosis of diabetic heart disease

Doctors diagnose diabetic heart disease (DHD) based on a person's signs and symptoms, medical and family histories, a physical exam, and the results of tests and procedures.

Doctors and researchers are still trying to find out whether routine testing for DHD will benefit people who have diabetes but no heart disease symptoms.


Initial tests

No single test can diagnose DHD, which may involve coronary heart disease (CHD), heart failure, and/or diabetic cardiomyopathy. Initially, your doctor may recommend one or more of the following tests.


Blood pressure measurement

To measure your blood pressure, your doctor or nurse will use some type of a gauge, a stethoscope (or electronic sensor), and a blood pressure cuff.

Most often, you'll sit or lie down with the cuff around your arm as your doctor or nurse checks your blood pressure. If he or she doesn't tell you what your blood pressure numbers are, you should ask.


Blood tests

Blood tests check the levels of certain fats, cholesterol, sugar, and proteins in your blood. Abnormal levels of these substances may show that you're at risk for DHD.

A blood test also can check the level of a hormone called BNP (brain natriuretic peptide) in your blood. The heart makes BNP, and the level of BNP rises during heart failure.


Chest X-ray

A chest X-ray takes pictures of the organs and structures inside your chest, such as your heart, lungs, and blood vessels. A chest x ray can reveal signs of heart failure.


EKG (Electrocardiogram)

An EKG is a simple, painless test that detects and records your heart's electrical activity. The test shows how fast your heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through each part of your heart.

An EKG can show evidence of heart damage due to CHD and signs of a previous or current heart attack.


Stress testing

Stress testing gives your doctor information about how your heart works during physical stress. Some heart problems are easier to diagnose when your heart is working hard and beating fast.

During a stress test, you exercise (walk or run on a treadmill or pedal a bicycle) to make your heart work hard and beat fast. Tests are done on your heart while you exercise. If you're unable to exercise, you may be given medicine to make your heart work hard and beat fast.


Urinalysis

For this test, you'll give a sample of urine for analysis. This test checks for abnormal levels of protein or blood cells in the urine. In people who have diabetes, protein in the urine is a risk factor for DHD.


Other tests and procedures

Your doctor may refer you to a cardiologist if your initial test results suggest that you have a form of DHD. A cardiologist is a doctor who specializes in diagnosing and treating heart diseases and conditions.

The cardiologist may recommend other tests or procedures to get more detailed information about the nature and extent of your DHD.


Treatment of diabetic heart disease

Treatments for diabetic heart disease (DHD) may include lifestyle changes, medicines, and medical procedures. The goals of treating DHD include:
  • Controlling diabetes and any other heart disease risk factors you have, such as unhealthy blood cholesterol levels and high blood pressure
  • Reducing or relieving heart disease symptoms, such as angina (chest pain or discomfort)
  • Preventing or delaying heart disease complications, such as a heart attack
  • Repairing heart and coronary artery damage
If you have diabetes, it's very important to follow the treatment plan your doctor recommends. Compared with people who don't have diabetes, people who have the disease are at higher risk for heart disease, have additional causes of heart disease, may develop heart disease at a younger age, and may have more severe heart disease.

Taking action to manage multiple risk factors helps improve your outlook. The good news is that many lifestyle changes help control multiple risk factors.


Lifestyle changes

Following a healthy lifestyle is an important part of treating diabetes and DHD. Some people who have diabetes can manage their blood pressure and blood cholesterol levels with lifestyle changes alone.

Lifestyle changes may include:
  • Following a heart healthy diet. A heart healthy diet includes a variety of fruits, vegetables, and whole grains. It also includes lean meats, poultry, fish, beans, and fat-free or low-fat milk or milk products. A healthy diet is low in saturated fat, trans fat, cholesterol, sodium (salt), and added sugar.

  • Losing weight if you're overweight or obese. Controlling your weight helps you control heart disease risk factors.

  • Doing physical activity regularly. Regular physical activity can lower many heart disease risk factors, including high LDL cholesterol, high blood pressure, and excess weight. Talk to your doctor about how much and what kinds of physical activity are safe for you.

  • Quitting smoking. Smoking can raise your risk of heart disease and heart attack and worsen other heart disease risk factors. Talk to your doctor about programs and products that can help you quit smoking. Also, try to avoid secondhand smoke.

  • Managing stress. Research shows that a common "trigger" for a heart attack is an emotionally upsetting event – particularly one involving anger. Learning how to manage stress, relax, and cope with problems can improve your emotional and physical health.

Medicines

Medicines are an important part of treatment for people who have diabetes only and for people who have diabetes and heart disease. Medicines can help control blood sugar levels, lower blood pressure, reduce the risk of blood clots, improve blood cholesterol levels, reduce the heart's workload, and treat angina symptoms. Your doctor will prescribe medicines based on your specific needs.


Medical procedures

If you have DHD, you may need a medical procedure to treat the type of heart disease you have. Your doctor may recommend angioplasty or coronary artery bypass grafting (CABG) to treat coronary heart disease (CHD). Both of these procedures improve blood flow to your heart, which can reduce CHD symptoms and complications.

If you have heart damage and severe heart failure symptoms, your doctor may recommend a cardiac resynchronization therapy (CRT) device or an implantable cardioverter defibrillator (ICD).

A CRT device is a type of pacemaker. Pacemakers are small devices that are placed under the skin of your chest or abdomen to help control abnormal heart rhythms. A CRT device helps the heart's lower chambers contract at the same time, which may decrease heart failure symptoms.

ICDs are similar to pacemakers. They're small devices that are placed under the skin in the chest or abdomen. ICDs use electrical pulses or shocks to help control life-threatening, irregular heartbeats.

Pacemakers and ICDs also may be used to treat diabetic cardiomyopathy. Doctors also recommend other types of surgery to treat this type of heart disease.


Diabetes-specific treatment issues

The treatments described above may be recommended for people who have diabetes and for people who don't. However, some aspects of heart disease treatment differ for people who have diabetes.


Treatment for high blood pressure and high blood cholesterol

Treatment for high blood pressure and high blood cholesterol often begins earlier in people who have diabetes than in those who don't. Treatment goals also may be more aggressive for people who have diabetes.

For example, your doctor may prescribe medicines called statins even if your blood cholesterol levels are in the normal range. Your doctor also may recommend statins if you're older than 40 and have other heart disease risk factors.

Target goals for LDL cholesterol (sometimes called "bad" cholesterol) and high blood pressure also are lower for people who have diabetes than for those who don't. Studies suggest that most people who have diabetes will need more than one blood pressure medicine to reach their goals.

Research also has shown that some people who have diabetes may benefit more from certain blood pressure and cholesterol medicines than from others.

One example is a group of cholesterol medicines called bile acid sequestrants (such as cholestyramine). This type of medicine may offer advantages for people who have type 2 diabetes. It appears to improve glycemic control and lower LDL cholesterol.


Treatment for heart failure

Some studies suggest that certain medicines may have advantages for treating heart failure in people who have diabetes. These medicines include ACE inhibitors, angiotensin receptor blockers, aldosterone antagonists, and beta blockers.

Evidence shows that two blood sugar medicines (insulin and sulfanylureas) don't seem to reduce the risk of heart failure in people who have type 2 diabetes. A third medicine (metformin) shows promise, but research is still being done.


Heart attack prevention

Doctors may recommend aspirin for people who have diabetes and are older than 30. Taken each day, low-dose aspirin helps prevent blood clots that can block a coronary artery and lead to a heart attack.


Blood sugar control

Controlling blood sugar levels is good for heart health. For example, controlling blood sugar improves everyday heart function for people who have diabetes and heart failure.


Prevention of diabetic heart disease

Taking action to control risk factors can help prevent or delay heart disease in people who have diabetes and in those who don't. The more risk factors you have, the more your risk increases.

To reduce your risk, try to control your risk factors. The good news is that many lifestyle changes help control multiple risk factors. For example, physical activity lowers your blood pressure, helps control diabetes, reduces stress, and helps control your weight.

One step you can take is to adopt a healthy lifestyle. A healthy lifestyle should be part of a lifelong approach to healthy living. A healthy lifestyle includes:
  • Following a heart healthy diet
  • Losing weight if you're overweight or obese
  • Doing physical activity regularly
  • Quitting smoking
  • Managing stress
You also should know your family history of diabetes and heart disease. If you or someone in your family has diabetes, heart disease, or both, let your doctor know.

Your doctor also may recommend medicines to control certain risk factors, such as high blood pressure and high blood cholesterol. Take all of your medicines exactly as your doctor prescribes. It's also important to have good blood sugar control. Controlling your blood sugar level is good for heart health. Talk to your doctor about the best ways to control your blood sugar level.


Living with diabetic heart disease

Diabetic heart disease increases the likelihood of earlier and more severe heart problems. People who have DHD also tend to have less success from certain heart disease treatments, such as coronary artery bypass grafting and angioplasty.

However, if you follow your treatment plans for diabetes and DHD, you can improve your chances of:
  • Preventing severe heart problems, such as a heart attack, sudden cardiac arrest, or sudden death
  • Slowing the progress of atherosclerosis (the buildup of plaque in the arteries)
  • Protecting your heart from damage caused by a lack of oxygen-rich blood reaching the heart muscle
Lifestyle changes and ongoing care can help you manage DHD. It's also important to know the warning signs of heart problems.

People who have diabetes have double the risk of heart attack as the general population. If you have signs and symptoms of a heart attack for more than 5 minutes, you should call emergency services.


Lifestyle changes

Adopting a healthy lifestyle can help you control DHD risk factors. However, making lifestyle changes can be a challenge.

Try to take things one step at a time. Learn about the benefits of lifestyle changes, and make a plan with specific, realistic goals. Reward yourself for your progress.

The good news is that many lifestyle changes help control multiple risk factors. For example, physical activity lowers your blood pressure, helps control diabetes, reduces stress, and helps control your weight.


Ongoing care

If you have DHD, it's important to get ongoing care. Your doctor will track your blood pressure, blood cholesterol and triglyceride levels, and blood sugar level (hemoglobin A1c) with routine tests. These tests will show whether your treatment needs to be adjusted.

Your doctor also will want to check other factors that can contribute to your risk of DHD, such as your weight.

Talk with your doctor about how often you should schedule followup visits or blood tests. Between visits, call your doctor if you have any new symptoms or if your symptoms worsen.

Seek the care and support you need from your health care team to manage your DHD. For example:
  • Check with your doctor before starting any new physical activity.
  • See a nutritionist or dietitian if you need help learning about or following a heart healthy diet that helps control your blood sugar level.
  • Talk to your doctor, nurse, or pharmacist if you're having trouble taking all of your medicines on schedule, or if you're having side effects from your medicines.
You may feel depressed or anxious if you've been diagnosed with DHD. You may worry about heart problems or making lifestyle changes that are necessary for your health.

Your doctor may recommend medicine, professional counseling, or relaxation therapy if you have depression or anxiety. Support from family and friends also can help relieve stress and anxiety. Let your loved ones know how you feel and what they can do to help you.


Warning signs and symptoms

It's important to learn the signs and symptoms of a heart attack. Call for emergency assistance if you have any of these symptoms for more than 5 minutes:
  • Chest pain or discomfort – uncomfortable pressure, squeezing, fullness, burning, or pain in the center of the chest that can be mild or strong. This discomfort or pain lasts more than a few minutes or goes away and comes back.
  • Upper body discomfort in one or both arms, the neck, jaw, abdomen, or back.
  • Shortness of breath.
  • Nausea (feeling sick to your stomach), vomiting, light-headedness or fainting, or breaking out in a cold sweat.
The more signs and symptoms you have, the more likely it is that you're having a heart attack. However, not everyone who has a heart attack has these typical symptoms.

Even if you've already had a heart attack, your symptoms may not be the same for another one. Some people who have diabetes have no symptoms when they have a heart attack. Diabetes-related nerve damage that blunts heart pain may explain why symptoms aren't noticed.

Early treatment can prevent or limit damage to the heart muscle. If you think you're having a heart attack, don't drive yourself or have friends/family drive you to the hospital. Call an ambulance so that medical personnel can begin life-saving treatment on the way to the emergency room.


Related category

   • HEALTH AND DISEASE

Source: National Heart, Lung, and Blood Institute