Conditions and Treatments


Alcohol and the heart

Alcohol is a drug that affects all parts of the body. It has important effects on the heart and influences your risk of developing heart disease.

 

 The bottom line:

Long-term excessive drinking increases your risk of developing problems with your heart. Drinking within the daily unit guidelines is unlikely to cause damage and may help protect the heart. 

 

 Safe drinking – What do the guidelines recommend?

For healthy men and women, drinking no more than two standard drinks on any day reduces your risk of harm from alcohol-related disease or injury over a lifetime.

Drinking no more than four standard drinks on a single occasion reduces the risk of alcohol-related injury arising from that occasion.

For more detailed information about alcohol related health issues, visit www.alcohol.gov.au.

 

 Facts

Cardiovascular disease (CVD) is the leading cause of death in Australia, with 45,600 deaths attributed to CVD in Australia in 2011. Cardiovascular disease kills one Australian every 12 minutes. 

 

Women who drink more than three units of alcohol a day and men who drink more than four are more likely to suffer from diseases affecting the heart or blood vessels.

Men nearly double their chances of developing coronary heart disease by regularly drinking more than eight units of alcohol a day.

Women have a 1.3 times greater risk of developing coronary heart disease when they regularly drink more than six units a day.

 

 Long-term, heavy drinking can lead to heart disease

Drinking more than the daily unit guidelines regularly and over a long period of time can increase your risk of developing heart disease. This is because, drinking at this level can:

 

 Increase the risk of high blood pressure. Drinking excessive amounts of alcohol causes raised blood pressure, which is one of the most important risk factors for having a heart attack or a stroke. Alcohol is thought to do this through its effects on the kidneys and the blood vessels. Increases in your blood pressure can also be caused by weight gain from excessive drinking.

Weaken the heart muscle. This means the heart can’t pump blood as efficiently. This condition is known as  known as cardiomyopathy and can cause premature death, usually through heart failure.

Lead to an enlarged heart. This is a sign that the heart is unable to effectively pump blood around the body, and is known as heart failure.

 

 Binge drinking can make your heart beat irregularly.

The name Holiday Heart Syndrome is misleading. People who have it certainly won’t be having a leisurely time. In fact they might feel like they are having a heart attack – characterized by severe pain in the center of the chest. It gets its name because cases of the condition tend to increase around holiday times or after weekends, when people tend to drink more.

Holiday Heart Syndrome tends to come on after episodes of heavy drinking – usually at least 15 units (about seven and a half pints of 4% beer or one and a half bottles of 13% wine).  If this happens, your heart starts to beat irregularly making you feel breathless. Your blood pressure changes, increasing your risk of a heart attack and sudden death.

 

 Alcohol can have protective benefits for the heart – but only if you drink within the daily unit guidelines and are over 45.

Research suggests that small amounts of alcohol can have a protective effect on your heart.  This benefit appears to be restricted to over 45-year-olds drinking well within the recommended guidelines.

Scientists aren’t sure how alcohol has the protective effect but think there are two main mechanisms:

 

Preventing artery damage. Alcohol appears to increase the level of ‘good’ cholesterol (HDL) in the blood. This reduces the amount of fatty deposit (atheroma), which narrows our arteries and makes them more likely to clog.

 

Preventing blood clots. Alcohol can help prevent the formation of blood clots, which can close off the arteries, causing a heart attack. It can stop platelets from clumping together to form clots and a small amount of alcohol with a meal can reduce the sudden rise of a protein (fibrinogen) produced by the liver. This increases the likelihood of harmful blood clots forming, called thrombosis.

 

 Can alcohol ever be good for the heart?

We don’t know yet. More research is needed to show whether drinking red wine is “good for the heart”

Laboratory studies in animals suggest that antioxidants help to prevent thrombosis. Red wine has a high concentration of antioxidant substances called flavonoids. White alcoholic drinks, like vodka and cider, contain the least concentration of flavonoids. But other alcohols, such as beer, have the same antioxidant effect as wine.

Much of the interest in red wine comes from the observation that the French (who have a long tradition of drinking red wine) often have healthy hearts and arteries despite typically having high-fat foods in their diet. But studies show that people who drink wine over other types of alcohol tend to live healthier lives, smoking less, drinking less and having a healthier diet. So these other factors, rather than the red wine, may in fact be responsible for their good health.

 

 Should I start drinking alcohol to protect myself from heart disease?

This is not recommended, as health experts, both in Australia and abroad, agree that the potential benefit is not worth the risk.

For example, alcohol’s anti-clotting ability, potentially protective against heart attack, may increase the risk of hemorrhagic stroke (when a blood vessel bursts inside the brain), or bleeding within the brain.

Beyond the daily unit guidelines, alcohol’s potential benefits on the heart are outweighed by its increased risks of developing other illnesses, such as liver disease or cancer.

There are safer ways to reduce your risk of developing heart disease. See the article in this section titled “prevention of heart disease”.

 

 

 


Atrial fibrillation (AF)

Atrial fibrillation (AF or A-fib) is the most common cardiac arrhythmia (abnormal or irregular heart beat). The prevalence of AF in a population increases with age, with 8% of people over 80 having AF. Chronic AF leads to a small increase in the risk of death. AF is an important cause of stroke. A third of all strokes are caused by AF.

In AF, the normal regular electrical impulses generated by the normal heart rhythm, are overwhelmed by disorganized electrical impulses , leading to an irregular heartbeat.

It may cause no symptoms, or it may be accompanied by palpitations, chest discomfort, or shortness of breath. AF may occur in episodes lasting from minutes to days (“paroxysmal”), or be permanent. It may occur as the only heart problem, or be accompanied by other forms of heart disease.

AF may be diagnosed clinically when taking a pulse, and the presence of AF can be confirmed with an electrocardiogram (ECG).

AF increases the risk of stroke. The degree of stroke risk can be up to seven times that of the average population, depending on the presence of additional risk factors.

Atrial fibrillation may be treated with medications to either slow the heart rate to a normal range (“rate control”) or revert the heart rhythm back to normal (“rhythm control”). Synchronized electrical cardioversion can be used to convert AF to a normal heart rhythm. Surgical and catheter-based therapies may be used to prevent recurrence of AF in certain individuals.

People with AF often take anticoagulants (“blood thinners”) such as warfarin to protect them from stroke, depending on the calculated risk.

Your heart specialist will advise you regarding your risk of stroke and the need for tests, medications and other treatments if you have Atrial Fibrillation.

 

 


High Cholesterol Level (Hyperlipidemia)

Cholesterol is a fat (also called a lipid) that your body needs to work properly. Cholesterol levels that are too high can increase your chance of getting heart disease, stroke, and other problems. The medical term for high blood cholesterol is hyperlipidemia.

There are many types of cholesterol. The ones talked about most are:

  • Total cholesterol – all the cholesterols combined
  • High density lipoprotein (HDL) cholesterol – often called “good” cholesterol
  • Low density lipoprotein (LDL) cholesterol – often called “bad” cholesterol

For most people, abnormal cholesterol levels are the result of an unhealthy lifestyle — most commonly, eating a diet that is high in fat. Other lifestyle factors include being overweight, heavy alcohol use, lack of exercise and leading an inactive lifestyle. Diabetes and an underactive thyroid gland may lead to high cholesterol levels. Other illnesses that may raise cholesterol levels include polycysic ovarian syndrome and kidney disease

Higher levels of female hormones increase or change cholesterol levels. This may include women who take birth control pills or estrogen , or who are pregnant, medicines such as certain diuretics (water pills), beta-blockers, and some medicines used to treat depression may also raise cholesterol levels.Several disorders that are passed down through families lead to abnormal cholesterol and triglyceride levels. Smoking does not cause higher cholesterol levels, but it can reduce your HDL (“good”) cholesterol.

A cholesterol test is done to diagnose hyperlipidemia. Everyone should have their first screening test by age 35 in men, and age 45 in women. General targets for cholesterol levels are:

  • LDL: less than 2.5 mmol/L (lower numbers are better)
  • HDL: more than 1.0 mmol/L (high numbers are better)
  • Total cholesterol: less than 5.5 (lower numbers are better)
  • Triglycerides: less than 1.5 mmol/L (lower numbers are better)

There are steps everyone can take to improve their cholesterol levels, and help prevent heart disease and a heart attack. Some key lifestyle changes include, eating foods that are naturally low in fat, avoiding foods that are high in saturated fat, exercising regularly, losing weight if you are overweight, quitting smoking.

Your doctor may want you to take medicine for your cholesterol if lifestyle changes do not work. This will depend on your age, whether or not you have heart disease or other blood flow problems, whether you smoke or are overweight, whether you have high blood pressure or diabetes.

There are several types of drugs to help lower blood cholesterol levels, and they work in different ways. Some are better at lowering LDL cholesterol, some are good at lowering triglycerides, while others help raise HDL cholesterol. Statins are one kind of drug that lower cholesterol.

High cholesterol levels can lead to hardening of the arteries, also called atherosclerosis. This occurs when fat, cholesterol, and other substances build up in the walls of arteries and form hard structures called plaques. Over time, these plaques can block the arteries and cause heart disease, stroke, and other symptoms or problems throughout the body.

 


How the heart works

 

The heart is responsible for circulating blood throughout the body. It is about the size of your clenched fist and sits in centre of the chest cavity between your two lungs. Its walls are made up of muscle that can squeeze or pump blood out every time the heart “beats” or contracts. Fresh, oxygen-rich air is brought into the lungs every time you take a breath. The lungs are responsible for delivering oxygen to the blood, and the heart circulates the blood through the lungs and out to the different parts of the body.

 

The heart is in effect two pumps, working side by side, the left and the right sides. Each side is subdivided into an upper and a lower chamber. The upper chamber is known as the atrium (pronounced AY-tree-yum) while the lower chamber is referred to as the ventricle (pronounced VEN-trickle). The right atrium (RA) sits on top of the right ventricle (RV) on the right side of the heart while the left atrium (LA) sits atop the left ventricle (LV) on the left side.

 

The right side of the heart (RA and RV) is responsible for pumping blood to the lungs, where the blood cells pick up fresh oxygen. This oxygenated blood is then returned to the left side of the heart (LA and LV). From here the oxygenated blood is pumped out to the rest of the body through the arteries, supplying the fuel that the body cells need to function. The cells of the body remove oxygen from the blood, and the oxygen-poor blood is returned through the veins to the RA, where the journey began. This round trip is known as the circulation of blood.

 

 

 

 

What is a heart attack?

Heart attacks are the most common result of coronary heart disease. Someone has a heart attack when their coronary arteries become blocked. This stops blood flowing freely to the heart, so it can’t get the oxygen it needs. Starved of oxygen, the heart can’t pump properly, and in severe cases it may effectively stop beating altogether, which can kill you. Damage to the heart muscle because of a heart attack can lead to heart failure – when your heart can no longer pump blood around your body normally. This leads to symptoms such as swelling of the ankles and shortness of breath, which affect you for the rest of your life and often become progressively worse. Although there are drugs, which can help limit the impact of heart failure, there isn’t a cure at the moment.

 


Hypertension

Hypertension (HTN) or high blood pressure, is a chronic medical condition in which the blood pressure in the arteries is elevated. This requires the heart to work harder than normal to circulate blood through the blood vessels.

There are often no symptoms or signs of high blood pressure - you can have high blood pressure and feel well. Therefore, it is important that you have regular blood pressure checks.

Blood pressure measurement involves two readings, systolic and diastolic. Normal blood pressure at rest is within the range of 100-140mmHg systolic (top reading) and 60-90mmHg diastolic (bottom reading). High blood pressure is said to be present if it is persistently at or above 140/90 mmHg.

Blood pressure does not stay the same all the time. It is always changing to meetyour body’s needs.  If a reading is high, your doctor will probably measure your blood pressure again on several occasions to confirm the level. Your doctor may also recommend that you measure your blood pressure at home or have a 24-hour blood pressure recording, particularly if he suspects that coming to the clinic makes your blood pressure rise.

Hypertension is classified as either primary (essential) or secondary hypertension; about 90–95% of cases are categorized as “primary hypertension” which means high blood pressure with no obvious underlying medical cause. The remaining 5–10% of cases (secondary hypertension) are caused by other conditions that affect the kidneys, arteries, heart or endocrine system.

Hypertension can lead to serious health problems, such as a heart attack, a stroke, heart failure or kidney disease. Even moderate elevation of arterial blood pressure is associated with a shortened life expectancy.

Dietary and lifestyle changes can improve blood pressure control and decrease the risk of associated health complications, although drug treatment is often necessary in people for whom lifestyle changes prove ineffective or insufficient.

Many people with high blood pressure will need to take medicines for the long-termto help keep their blood pressure under control. It is important that you take any blood pressure medicine exactly as prescribed. Don’t stop taking your medication or change the dose without talking to your doctor first.

 


Prevention of Heart disease

While it is true that a significant percentage of coronary heart disease is genetically influenced, a large percentage of heart attacks are preventable, and are due to lifestyle factors and the influence of other diseases and conditions. Changing these lifestyle and disease factors has been shown time and again to make a significant difference to the risk of developing heart disease. 

The tips below are known to decrease and delay your risk of developing heart disease in the future, and increase your life expectancy. Even if you have already developed heart disease, vascular disease or stroke, following the advice below will decrease your chances of having a repeat cardiac or vascular event.

Decrease calorie intake, including decreasing portion sizes of meals, eliminating or minimizing the consumption of sugary drinks (soft drinks, energy drinks, sports drinks), decrease alcohol consumption.

 Change your diet. Decrease fatty foods, fried foods, take away foods, and swap them for increased fresh fruit and vegetables, and wholegrain foods like whole-meal bread and oats. Visit: http://www.heartfoundation.org.au/healthy-eating/Pages/default.aspx for healthy eating tips.

No smoking. Do not start smoking, and  if you do smoke, even just a few cigarettes per day, quit. Speak to your local GP, if you require support with smoking cessation. Call the Quitline on 137848. Visit: www.quitnow.gov.au.

 No salt. Do not consume salty foods (most packeted snack foods including potato chips, salted nuts). Do not add salt to your food. Added salt increases blood pressure and damages your kidneys over time.

 Move your body. Ditch the TV, or at least put a treadmill in front of it! Be physically active. Do a moderate physical activity at least 1 hour per day. Simple walking, swimming and bike riding all count. Supplement your aerobic exercise with some weight training three days per week. Physical activity is beneficial at all ages- you are never too old or too young, or too busy.

Know your cholesterol profile. Ask your GP to assesss your cardiovascular risk, and as part of this, assess your blood lipid profile with a simple fasting blood test. Knowledge is power- the earlier you treat a high cholesterol level, the lower your risk of heart disease will be. Effective treatment of a high cholesterol level includes healthy diet modification and sometimes requires medication to lower LDL cholesterol.

 Whats your BP? Ask your GP to screen you for high blood pressure. Everyone should see heir GP at least once per year, and blood pressure screening and surveillance should be part of that examination. If you do have high blood pressure, ask your GP if your condition is properly treated and if you are consistently at target blood pressure. Keeping your blood pressure normal decreases your risk of developing heart disease, stroke and kidney failure.

Lose weight , if you are overweight. Being overweight is independently related to your risk of heart disease with or without the presence of other risk factors, and increases your risk of developing diabetes and high blood pressure.

Diabetes- are you at risk? Ask your GP if you are at risk for diabetes. The earlier you know that you are at risk, the earlier treatment and preventive measures can be started to decrease your risk of heart disease. If you have diabetes, ask if your condition is optimally treated, revisit measures to better control your blood sugar level with your GP.

 Stress and depression management is important in the prevention of heart disease. Increased levels of harmful stress, increase stress hormones in the body, affect sleep and diet patterns, and affect our relationships with others. These factors in turn increase the risk of heart and vascular disease. Studies have shown that some people who have depression, are socially isolated and/or do not have quality social support, are at greater risk of developing heart disease. Depression can be treated with medical and non-medical therapies. If you think that you have depression, talking to your health professional is the best first step.

 For more information about depression, visit the beyondblue website.  http://www.beyondblue.org.au


Statins

Statins are drugs that can lower your cholesterol. They work by blocking a substance your body needs to make cholesterol. Statins may also help your body reabsorb cholesterol that has built up in plaques on your artery walls, preventing further blockage in your blood vessels and heart attacks.

Statins include well-known medications such as atorvastatin (Lipitor), simvastatin (Zocor), pravastatin (Pravachol), rosuvastatin (Crestor) and others. Lower cost generic versions of many statin medications are available.

Already shown to be effective in lowering cholesterol, statins may have other potential benefits. But doctors are far from knowing everything about statins.

For example:

Are they right for everybody with high cholesterol?

What happens when you take a statin for decades?

Can statins help prevent other diseases?

Should you be on a statin?

Whether you need to be on a statin depends on your cholesterol level along with your other risk factors for cardiovascular disease.

High cholesterol?If you have high cholesterol, meaning your total cholesterol level is 6.22 millimoles per liter, or mmol/L or higher, or your low-density lipoprotein cholesterol LDL, or “bad” cholesterol level is 3.37 mmol/L or higher, your doctor may recommend you begin to take a statin. But the numbers alone won’t tell you or your doctor the whole story.

If the only risk factor you have is high cholesterol, you may not need medication because your risk of heart attack and stroke could otherwise be low. High cholesterol is only one of a number of risk factors for heart attack and stroke.

Other risk factors?Before you’re prescribed a statin, your cholesterol level is considered along with other risk factors for cardiovascular disease, including:

Family history of high cholesterol or cardiovascular disease

Inactive (sedentary) lifestyle

High blood pressure

Poor general health

Having diabetes

Overweight or obesity

Smoking

Narrowing of the arteries in your neck, arms or legs (peripheral artery disease)

If your doctor decides you should take a statin, you and your doctor will have to decide what dose to take. Statins come in varied doses — from as low as 5 milligrams to as much as 80 milligrams, depending on the medication. If you need to decrease your LDL cholesterol significantly — by 50 percent or more — it’s likely you’ll be prescribed a higher dose of statins. If your LDL cholesterol isn’t as high, you’ll likely need a lower dose.

Lifestyle is still key for lowering cholesterol

Lifestyle changes are essential for reducing your risk of heart disease, whether you take a statin or not. Lifestyle changes you should consider making include:

Quitting smoking

Eating a healthy diet that’s low in fat, cholesterol and salt

Exercising 30 minutes a day on most days of the week

Managing stress

If you’re following the recommended lifestyle behaviors but your cholesterol — particularly your low-density lipoprotein (LDL) cholesterol, the “bad” cholesterol — remains high, statins might be an option for you. Risk factors for heart disease and stroke are:

High cholesterol

High blood pressure

Diabetes

Being overweight or obese

Family history of heart disease

Not exercising

Heavy alcohol use

Poor stress and anger management

Older age

Smoking

Narrowing of the arteries in your neck, arms or legs (peripheral artery disease)

Consider statins a lifelong commitment

You may think that once your cholesterol goes down, you can stop taking medication. But, if your cholesterol levels have decreased after you take a statin, you’ll likely need to stay on it indefinitely. If you stop taking it, your cholesterol levels will probably go back up.

The exception may be if you make significant changes to your diet or lose a lot of weight. Substantial lifestyle changes may help you lower your cholesterol without continuing to take the medication, but don’t make any changes to your lifestyle or medications without talking to your doctor first.

The side effects of statins

Although statins are well tolerated by most people, they can have side effects, some of which may go away as your body adjusts to the medication.

Common, less serious side effects

Muscle and joint aches (most common)

Nausea

Diarrhea

Constipation

Potentially serious side effects

                  Liver damage. Occasionally, statin use causes an increase in liver enzymes. If the increase is only mild, you can continue to take the drug. Rarely, if the increase is severe, you may need to stop taking it. Certain other cholesterol-lowering drugs, such as gemfibrozil , and niacin, increase the risk of liver problems even more in people who take statins.

 

Although liver problems are rare, your doctor will likely order a liver enzyme test before or shortly after you begin to take a statin. You shouldn’t need any additional liver enzyme tests unless you begin to have signs or symptoms of trouble with your liver. Contact your doctor immediately if you have unusual fatigue or weakness, loss of appetite, pain in your upper abdomen, dark-colored urine, or yellowing of your skin or eyes.

                 

 

Muscle problems. Statins may cause muscle pain and tenderness (statin myopathy). The higher the dose of statin you take, the more likely you are to have muscle pains. In severe cases, muscle cells can break down (rhabdomyolysis) and release a protein called myoglobin into the bloodstream. Myoglobin can damage your kidneys. Certain drugs when taken with statins can increase the risk of rhabdomyolysis. These include gemfibrozil, erythromycin , antifungal medications, nefazodone, cyclosporine and niacin . If you take statins and have new muscle aching or tenderness, check with your doctor.

 

Increased blood sugar or type 2 diabetes. It’s possible your blood sugar (blood glucose) level may increase when you take a statin, which may lead to developing type 2 diabetes. The risk is small, but important enough that the US Food and Drug Administration (FDA) requires a warning on statin labels regarding blood glucose levels and diabetes. Despite this possible connection between increased blood sugar and statin use, it’s still safe for most people with high cholesterol, including diabetics, to take statins. Talk to your doctor if you have concerns.

 

Neurological side effects. Some people who take statins have developed memory loss or confusion while taking statins. These side effects reverse once you stop taking the medication. Talk to your doctor if you experience memory loss or confusion. Don’t stop taking your statin medication before talking to your doctor.

 

It’s important to consider the effects of statins on other organs in your body, especially if you have health problems such as liver or kidney disease. Also, check whether statins interact with any other prescription or over-the-counter drugs or supplements you take.

Keep in mind that when you begin to take a statin, you’ll most likely be on it for the rest of your life. Side effects are often minor, but if you experience them, you may want to talk to your doctor about decreasing your dose or trying a different statin. Don’t stop taking a statin without talking to your doctor first.

 

Are there other options?

Statins effectively reduce LDL cholesterol. But, because of genetic differences, the type or dose of statin or combination of statins with other cholesterol-lowering drugs each person takes can vary. For example:

If you are not able to lower your LDL to the desired goal using statin medication, your doctor may add ezetimibe (Ezetrol) to your treatment plan or switch to a combination ezetimibe and simvastatin medication (Vytorin). This combination will help drop your LDL level further, perhaps even another 15 to 20 percent.

If you have both high LDL and high triglycerides, you may benefit from combining the statin with prescription niacin or combining the statin with a fibric acid drug such as fenofibrate (Lipidil) or gemfibrozil (Lopid). The risk of muscle problems is higher when these medications are paired, so your dose of statins may be lowered to less than 20 milligrams.

 

If you have just high triglycerides, use of niacin is very effective. Fibric acid agents are another option. Fish oil (omega-3 fatty acids) supplements  in 2- to 4-gram doses also can help.

 

If your high-density lipoprotein (HDL) cholesterol is low, your doctor might prescribe niacin to raise it, especially if your LDL cholesterol remains high despite taking other medications. Fibric acids also are useful but less effective than niacin. Exercise and weight loss may help, as well.

 

What if taking a statin doesn’t lower your cholesterol?

If a statin doesn’t help lower your cholesterol, your doctor may first suggest trying a different statin or increasing the dose of the statin you currently take. In some cases, one medication may simply not be effective and a different drug must be substituted.

Your doctor may also add other medications, or may suggest that you make more lifestyle changes to help lower your cholesterol.

 

What other benefits do statins have?

Statins may have benefits other than just lowering your cholesterol. One promising benefit of statins appears to be their anti-inflammatory properties, which help stabilize the lining of blood vessels. This has potentially far-reaching effects, from the brain and heart to blood vessels and organs throughout the body.

In the heart, stabilizing the blood vessel linings would make plaques less likely to rupture, thereby reducing the chance of a heart attack. Statins also help relax blood vessels, lowering blood pressure. In addition, statins could reduce your risk of blood clots. For these reasons, doctors are now beginning to prescribe statins before and after coronary artery bypass surgery or angioplasty, and following certain types of strokes.

Statins could also have benefits that help prevent diseases that aren’t related to your heart health, although more research is necessary. Other benefits of statins could include a reduced risk of:

Arthritis and bone fractures

Some forms of cancer

Dementia and Alzheimer’s disease

Kidney disease

Statins may also be helpful in controlling the body’s immune system response after an organ transplant.

Weighing the risks and benefits of statins

When thinking about whether you should take statins for high cholesterol, ask yourself these questions:

Do I have other risk factors for cardiovascular disease?

Am I willing and able to make lifestyle changes to improve my health?

Am I concerned about taking a pill every day, perhaps for the rest of my life?

Am I concerned about statins’ side effects or interactions with other drugs?

 

It’s important to take into account not only your medical reasons for a decision, but also your personal values and concerns. Talk to your doctor about your total risk of cardiovascular disease and discuss how your lifestyle and preferences play a role in your decision about taking medication for high cholesterol.


Supraventricular Tachycardia (SVT)

What is a supraventricular tachycardia?

Tachycardia means a fast heart rate. Supraventricular means coming from above the ventricle. During an episode of SVT, the heartbeat is not controlled by the SA node (the normal timer of the heart). Another part of the heart overrides this timer with faster impulses. The source or trigger of the impulse in an SVT is somewhere above (supra) the ventricles, but the impulse then spreads to the ventricles.

 

Note: the term SVT is usually only used when the heart rate is fast and regular. Another condition which causes a fast but irregular heart rate, and is caused by abnormal impulses in the the atria, is called atrial fibrillation. This is not dealt with further in this article.

There are three main types of SVT: atrioventricular nodal re-entry tachycardia (AVNRT), atrial tachycardia, and Wolff-Parkinson-White (WPW) syndrome.

Atrioventricular nodal re-entry tachycardia

This is the most common type of SVT. It is most commonly seen in people in their twenties and thirties and is more common in women.
This occurs when there is an electrical short circuit in the centre of the heart. It often occurs in people who otherwise have a normal heart. Instead of the normal activation of heart from top to bottom in an orderly and timely manner, an extra impulse starts to race around this short circuit so that the heartbeat may rapidly increase and then produce symptoms of a SVT.

Atrial tachycardia

Atrial tachycardia is a less common type of SVT. It arises from a small area of tissue, anywhere in the atria of the heart. This area starts to fire and drive the heart, more rapidly than the heart’s natural pacemaker.
In most cases, there is no underlying cause for atrial tachycardia to occur. However, it can also occur in those with heart problems (for example, a previous heart attack or heart valve problems).

Wolff-Parkinson-White syndrome

In Wolff-Parkinson-White (WPW) syndrome there is an additional electrical connection (accessory pathway) between the atria and ventricles. This occurs in around 3 out of 1,000 people. See separate leaflet called ‘Wolff-Parkinson-White Syndrome’ for more detail. In addition to causing symptoms of SVT, some people may develop very fast palpitations, resulting in severe dizziness or even a blackout. Sudden death is a complication of this condition, which occurs very rarely.

Who gets supraventricular tachycardia?

Supraventricular tachycardia usually occurs without other medical problems. In many cases, the cause of SVT is unknown. SVT is the most common arrhythmia in infants, children, and pregnant females.

 

In most cases, the first episode of SVT begins in childhood or early adulthood. However, a first episode of SVT can occur at any age. It is an uncommon condition, but the exact number of people affected is not known.

SVT may be associated with a number of medical conditions, such as the following: Hardening of the arteries (atherosclerosis), Heart failure, Thyroid disease, Chronic lung disease, Pneumonia, Pulmonary emboli, or blood clots migrating into the lung arteries from elsewhere in the body, Pericarditis.

 

Certain triggers may increase the risk of developing an episode of SVT, especially in those people who have already had episodes, including certain drugs and social habits, like  cocaine abuse, alcohol abuse, smoking, drinking too much caffeine in coffee, , tea, or soft drinks,

emotional stress, pregnancy. SVT may also occur as a side effect of medications such as digitalis, asthma medications, or cold remedies.

 

What are the symptoms of a supraventricular tachycardia?

Symptoms last as long as the episode of SVT lasts. This may be seconds, minutes, hours or, rarely, longer.

Possible symptoms include the following.

Your pulse rate becomes 140-200 per minute. Sometimes your pulse may be even faster. (The normal pulse is 60-100 beats per minute.)

Palpitations (feeling your heartbeat).

Dizziness, or feeling lightheaded.

You may become breathless.

You may occasionally feel some mild chest discomfort.

If you have angina, then an angina pain may be triggered by an episode of SVT.

You may have no symptoms, or are just aware that your heart is beating fast.

Sometimes your blood pressure may become low with too fast a heart rate, especially if it persists for several hours. In some cases this causes a faint or collapse. This is more likely if you are older and have other heart or lung problems.

An episode of SVT usually starts suddenly for no apparent reason. It may last just a few minutes, but can last several hours. It then stops just as suddenly as it started. Rarely, an episode lasts longer than a few hours.

The time between episodes of SVT can vary greatly. In some cases, short bursts of SVT occur several times a day. At the other extreme, an episode of SVT may occur just once or twice a year. In most cases it is somewhere in between, and an episode (paroxysm) of SVT occurs now and again.

 

Do I need any tests?

Electrocardiograph (ECG)

This traces the rhythm and electrical activity of your heart. It is a painless test and takes a few minutes to do. Small patches are put on your arms, legs and chest and are connected to the ECG machine to take a reading.

If an ECG is done during an episode of SVT, it can usually confirm the diagnosis and rule out other causes of a fast heart rate. (For example, a small area within a ventricle sometimes triggers a tachycardia. It is important to rule out a ventricular tachycardia as this tends to be more serious than SVT, and has different treatments.)

The ECG between episodes of SVT is usually normal. So, doing an ECG between episodes of symptoms may not be much help. However, if SVT is suspected, you may be asked to wear a small portable ECG recorder. Some types record an ECG continuously over 24 hours. Others are designed so that you can switch it on to record when you have symptoms.

Specialist tests

Once it is confirmed that you have episodes of SVT, a number of special tests are sometimes advised. These aim to find the exact location of the excitable part in your heart which is triggering the episodes of SVT. For example, you may be have electrophysiology tests, where doctors insert small electrodes (wires) into your heart via one of your veins. These electrodes measure the electrical signals in your heart and can determine where any abnormal signals are coming from.

What are the treatment options for supraventricular tachycardia?

Stopping an episode of SVT

Many episodes of SVT soon stop on their own, and no treatment is then needed. It is sometimes possible to stop an episode of SVT by various measures, including drinking a cold glass of water, breath holding, straining, etc. However, if an episode of SVT lasts a long time or is severe, you may need to be admitted to hospital to stop it.

Medicines which are given by injection into a vein will usually stop an SVT. Adenosine is commonly used. It works by blocking electrical impulses in the heart. Verapamil is an alternative if adenosine is not advised or is not effective. For example, some people with asthma cannot have adenosine.

Electric shock treatment is sometimes used to stop an episode of SVT.

 

Preventing episodes of SVT

Options include the following:

You can take medication every day to prevent episodes of SVT. Various medicines can interfere with the electrical impulses in your heart. Examples include digoxin, verapamil and betablockers. If one does not work or causes side-effects, another can often be found to suit you.

Catheter ablation (destruction) treatment may be an option for some types of SVT. A catheter (small wire) is passed via a large vein in the top of your leg into the chambers of your heart. It is guided by special X-ray techniques. The tip of the catheter can destroy a tiny section of heart tissue that is the source or trigger of the abnormal electrical impulses. This is only suitable if the exact site of the trigger can be found by special tests, and be located accurately by the catheter tip. It can be very successful, and after the procedure you will not need to take medication to prevent SVT.

Not treating is an option if episodes of SVT are infrequent, only last a short time, or cause few symptoms. The treatments above have to be balanced against the possible side-effects and risks. Some people prefer to put up with symptoms if they not too bad and only occur now and then.

Treatment is generally only recommended for atrial tachycardia if it is causing you symptoms. However, if you experience unpleasant symptoms or a permanently increased heart rate is risking heart enlargement, your doctor may recommend treatment with medication or catheter ablation.

Very rarely,  rarely dangerous heart rhythms may occur in patients with WPW syndrome, and most doctors will recommend treatment with ablation.