What Is Cardiovascular Diseases (CVD)?

The World Health Organisation Fact Sheet 2013 has stated that cardiovascular diseases (CVDs) is the number one cause of death globally.  More people die annually from cardiovascular diseases then from any other causes.  There is an estimated 17.5 million people who died from cardiovascular diseases in 2013, representing 31% of global deaths.

What are Cardiovascular Diseases?
Many people think that cardiovascular disease with is heart attack.  This is a misconception.  The term “cardiovascular diseases” encompasses a group of medical conditions that affect the heart and the blood vessels of the human body including the brain, arms and legs.  CVDs will include the following :

1. Coronary artery disease – disease of the blood vessels supplying the heart muscles
2. Cerebro vascular disease – disease of the blood vessels supplying the brain
3. Peripheral vascular /arterial disease – disease of the blood vessels supplying the arms and the legs
4. Rheumatic heart disease – damage of the heart valves from infection by a bacteria (streptococcal bacteria) infection (rheumatic fever) and damage to the heart muscles, a term called rheumatic myocarditis
5. Congenital heart disease – malformation of the heart structures and major blood vessels of the heart at birth
6. Myocarditis – infection of the muscles of the heart by virus or bacteria
7. Deep vein thrombosis – inflammation and clots in the veins of the lower limbs (legs)
8. Pulmonary embolism – clots from the leg veins that dislodge and move to the heart and lungs
9. Abnormal rhythms of the heart –abnormal electrical mechanisms that affect the upper or lower chambers of the heart

In Singapore, by far the most common cardiovascular diseases are coronary heart disease and cerebrovascular disease (stroke). Blockages of the coronary arteries will lead to heart attack and blockages of the blood vessels to the brain will result in stroke.  (See others – figure 1)
What is Coronary Artery Disease (also known as Coronary Heart Disease)?

In this condition, there is deposition and the build-up of fatty deposits in the inner walls of the blood vessels that supply the heart muscles.  These blood vessels are called coronary arteries.  The main fear about this condition is the potential development of a heart attack due to blockage of the coronary artery that prevents blood from flowing to the heart muscles leading to extensive damage to the heart pump and can result in death or heart failure.  Heart attack is the number 2 killer in Singapore in 2010.

What is Cerebro-vascular Disease?

This is due again to build-up of fatty deposits in the inner walls of the blood vessels that supply the brain and the main acute event is called a stroke.  This is potentially life-threatening and victims may have permanent disabilities, loss of memory functions, speech, movement of the limbs, incapacitated, even death.  Stroke can be caused by either a blockage of the blood vessel that supplies the brain or a clot that is thrown to the brain from other parts of body (due to abnormal heart rhythm) or a bleed from rupture of one of the blood vessels in the brain.  In Asia especially in China and Japan, the prevalence of stroke is higher than that of heart attack.  However in Singapore heart attack is the number 2 killer, claiming approximately 1 in 5 lives and stroke is the number 4 killer accounting for 8.4% of mortality in 2010.

What is Peripheral Arterial Disease?

This is due to cholesterol (fatty deposits) build up in the blood vessel that supplies both the arms and the legs.   Peripheral arterial disease usually occurs more commonly in the legs.  When the blood supply to the leg is reduced, there is the risk of infection with difficulty of healing due to reduced oxygen and nutrients to that area.  Non-healing may lead to gangrene of the toes, feet and may eventually require amputation.

What is Rheumatic Heart Disease?

This disease is no longer highly prevalent in Singapore.  It usually occurs due to overcrowding in the homes where several adults and children sleep in the same room.  The cause is due to a streptococcal bacteria infection that is cross-transmitted between the family members.  The streptococcal bacteria usually settles on the heart valves, a term called rheumatic heart disease.  If left untreated, the bacteria will destroy the heart valves, leading to either leaky valve or scarring leading to narrowing of the valve.  The bacteria can also damage the heart muscles, leading to heart failure.  This condition usually occurs in the teenage age and carries on to adulthood.

What is Congenital Heart Disease?

This condition arises from birth defects in the structures of heart and blood vessels.  It will require early diagnosis at birth or during neonatal period.  If the structural birth defects are severe the child may not survive.  However modern surgery and interventional procedures can repair/reconstruct many birth defects of the heart and blood vessels.

What is Myocarditis?

This is due to a virus or bacteria infection of the heart muscles.  It can cause abnormal rhythms and heart failure if not diagnosed.

What is Deep Vein Thrombosis and Pulmonary Embolism?

This is due to formation of clots especially in the veins of the legs resulting in infection and inflammation of the wall of the veins.  This vein clots form as a result of prolonged immobility of the legs especially during long distance air flights with very little leg room to move or prolonged rest in bed due to a hip, leg, lower abdomen operations.  When this happens, the clot can be dislodged and it can move to the heart and then to the lungs, blocking off the blood supply to the lungs resulting in damage of the lung tissues and therefore a decrease in the ability of the lung tissue to absorb oxygenation.  If it is a big clot that is thrown into one of the major lung vessels, this could result in fatality.  This condition is called pulmonary embolism.

Abnormal Heart Rhythms

These are due to electrical instabilities of the heart rhythm and most of the time, it is presented as palpitations, i.e. feeling of rapid heart rate or irregular heartbeats.  There are many abnormal heart rhythms, some are non-life threatening and can easily be treated.  Others are more severe and can be life-threatening especially if the origin of the abnormal rhythm is in the lower chambers of the heart (called ventricles).  The cause of this could either be congenital abnormalities of the electric circuits of the heart or secondary to all the above mentioned conditions.

What are the Risk Factors for the Two Most Common Cardiovascular Diseases? (i.e. heart attack and stroke)

There are many risks of cardiovascular diseases (see figure 2) for coronary heart disease and stroke.  The link to heart diseases begins with behavioural risk factors which includes unhealthy diet, physical inactivity, tobacco use and stress.  Behavioural risks will affect the individual and lead to high blood pressure, high cholesterol, high blood glucose, overweight and obesity.

Often, these are the risk factors that doctors talk about in terms of prevention of heart diseases and stroke.  But the behavioural risk factors are in fact responsible for about 80% of the coronary heart disease and stroke and therefore the main control over the development of these 2 forms of diseases is entirely in the hands of the individual because one can easily change to a healthy lifestyle diet, increase physical activities and exercise, destress and of course stop smoking.  If this is done actively, successfully and consistently (i.e. part of the individual’s lifestyle), then the well-known risk factors of high blood pressure, high cholesterol, high sugar levels, overweight and obesity will not evolve and therefore will not lead to coronary heart disease and cerebrovascular disease (doctors call this primordial prevention).

How Do You Recognise Some of the Common Symptoms of Cardiovascular Diseases?

• Heart Attack
  • Symptoms – Heart attack is a condition when one of the blood vessels (known as coronary arteries) that supply oxygen and nutrients to the muscles of the heart is suddenly blocked off.  The mechanism of blocking off a coronary artery is due to a rupture of a fatty plaque (cholesterol) build-up within the inner walls of the blood vessels.  The rupture of the cholesterol plaque exposes the cholesterol material to the circulating blood with the resultant formation of a blood clot that blocks off the channel of the coronary artery leading to a complete shut down of blood supply, oxygen and nutrients to the heart muscles.  Symptoms of heart attack include sudden onset of severe chest pain.  The chest pain is usually described as a “crushing” pain, sometimes also described a “bear hug” – “constricting” and heavy feeling of the chest.  The chest pain may be associated with pain or numbness in the arms (especially left arm), left shoulder, jaw or back.  The patient may experience difficulties in breathing and may sweat profusely described as “cold sweats”.  They may also feel sick or nauseous with vomiting, light-headed and appear pale with a sense of “impending doom”.  Women are more likely to have shortness of breath, nausea, vomiting and back or jaw pain.
  • Treatment – Once these symptoms are recognized the heart attack victim should be rushed to the nearest hospital with facilities to remove the clot from the blocked coronary arteries followed by the deployment of a stent which is a metal scaffolding to hold up and support the artery.   This procedure if applied within 3 hours from time of chest pain will allow for return of blood supply to the heart muscles and therefore abort the heart attack and may save substantial amount of muscles.  The patient then will have a better chance of recovery and survival.
• Stroke – The most common symptom of stroke is a sudden weakness of the face, arm and legs (often on 1 side of the body, either left or right side).  There is also a possibility of difficulty in speaking and understanding speech, sudden loss of vision or blurring of vision, difficulty in walking, dizziness and loss or balance or co-ordination, sudden severe headaches of no known previous cause, fainting or loss of consciousness.  People who experience these symptoms should seek medical care immediately.  Brain scan (either CT or MRI) is the best way to make the diagnosis.  Once again early treatment may improve survival and reduce the deficits mentioned above.
• Peripheral Arterial Disease

Symptoms of peripheral vascular disease (PVD) include :

1. Pain of the lower limbs (legs; especially the calve muscles) when walking
2. Numbness of the feet and legs
3. Chronic ulcer of the feet
4. Blush, dark toes of the feet

An individual with the above symptoms should see their doctors who will then run a series of test to make the diagnosis.  It is important to diagnose early as failure to do so may lead to a loss of the limb (amputation) due to infection and gangrene.

Furthermore PVD is associated with coronary heart disease and stroke and a patient with PVD is 6 times more likely to die within 10 years of diagnosis than those without PVD.

• Rheumatic heart disease
  • Symptoms – Rheumatic heart disease is due to an infection by a bacteria called streptococcus that can cause damage to the heart valves and the heart muscles.  It usually begins with a fever which affects more often children in under-developing countries especially where poverty is widespread and there is over-crowding in the home. Rheumatic fever begins with recurring fever often associated sore throat or tonsillitis and fleeting joint pains.  Globally almost 2% of deaths from cardiovascular diseases is related to rheumatic heart disease (as compared to 42% of deaths from cardiovascular diseases is related to ischemic heart disease and 34% from cerebral vascular disease).  The symptoms of rheumatic heart disease will include shortness of breath, fatigue, palpitations with irregular heartbeats, chest pain and fainting.  Symptoms of rheumatic fever include recurring fever, pain and swelling of the joints, nausea, stomach cramps and vomiting.
  • Treatment – Early treatment of the streptococcal infection throat infection with antibiotics is important to stop the progression and development of rheumatic fever and rheumatic heart disease.  Once rheumatic fever is diagnosed, regular long-term penicillin treatment can prevent repeated attacks of rheumatic fever which will eventually lead to rheumatic heart disease and therefore prevent long-term damage to the heart valves and muscles.

Conclusion

It is important to note that heart diseases encompass a whole range of heart conditions.  The most common and by far the most important are heart attacks and stroke.  These 2 conditions are very preventable and it begins with lifestyle changes that include a healthy diet, regular physical exercise, avoiding tobacco smoking and stress management.  A healthy diet should include choosing diet that is rich in vegetables, fruits, oat, wheat and bran and avoiding foods that contain high fats, trans fats, cholesterol, sugar (carbohydrates) and salt.  Reduction in calories to maintain a healthy body weight is also important. Regular exercise program to burn off the excess calories will have significant benefits.  Avoid tobacco smoking and also avoid areas where there are other people smoking (i.e. “second-hand smoking”).  Cardiovascular risk factors screening programs are widely available in Singapore and if you have reasons to suspect that you may be in the high-risk group as defined in figure 2, you should undergo a cardiovascular screening program.  Most of the screening programs will include a full medical history especially a strong family history of high cholesterol, early heart attacks in the family before the age of 55 years old and history of sudden death in the family.  Blood examination for high cholesterol and blood sugar levels will usually be done.  Basic cardiovascular evaluation will include an ECG and a treadmill exercise stress test.  2D Echo/Doppler study may also be performed if you are suspected to have a heart condition.  Sophisticated imaging techniques are available to diagnose both coronary artery disease as well as cerebrovascular disease and peripheral vascular disease.

There are numerous medications, interventional procedures and surgery to treat most cardiovascular diseases.

Figure 1