Truths and myths about heart disease

THE social media era is both a boon and a bane for medicine. While the Internet revolution has provided the man in the street unlimited access to health information, the challenge is the ability to distinguish truth from fallacy.

Let us distinguish the truth from fallacy in commonly asked questions to help us have a healthy heart.

It is almost impossible to die of a heart attack

Myth: As lifestyle improves with better economic status, it is inevitable that more people will die of heart attacks.

Truth: In Singapore, the number of deaths from heart disease due to blocked heart arteries (also termed coronary artery disease or CAD) per 100, 000 population has decreased from about 179 in 1970 to about 63 in 2019.

The truth is that with today's medical advances, preventing a death from a heart attack can be true for most people.

The most common underlying cause for sudden death from heart disease is the blockage of the heart arteries.

Hence, avoiding a heart attack is key to preventing sudden death. Besides a healthy lifestyle, early recognition and detection of the underlying blockage of the heart arteries are vital to preventing death from sudden heart attacks.

Once you know the severity of your heart disease and understand whether the blockage is mainly due to cholesterol deposits or calcium, you can change your lifestyle and where necessary, take the appropriate medication to prevent a heart attack.

If the LDL ("bad") cholesterol is optimally controlled, the risk of a heart attack is usually very low.

No chest pain means no heart disease

Myth: If you do not have chest pain, you will not die of a sudden heart attack.

Truth: According to the American Heart Association (AHA), 50 per cent of men and 64 per cent of women who die suddenly from a heart attack have no previous symptoms of the disease. Hence, CAD is also called a "silent killer".

Don't worry, women rarely get heart disease; heart disease predominantly affects males

Myth: If you are a female, your risk of developing CAD is low.

Truth: The lifetime risk of developing CAD if you live to at least 40 years is 49 per cent for men and 32 per cent for women. On the average, women develop CAD a decade later than men.

However, while the increase in CAD is gradual for men over 60 years, it is exponential for women. Hence, contrary to expectations, more women than men die of CAD.

For women, gynaecological problems are more prevalent and important than heart disease

Myth: CAD is less important than other medical problems in women.

Truth: CAD kills more women than cancer, lung disease, Alzheimer's disease, and accidents combined.

Hence, in the United States, for men and women, heart disease remains the No 1 killer. In most developed countries, heart disease is the No 1 or No 2 killer.

The only symptom that can tell you whether you have heart disease is chest pain and you do not need to worry if you have no chest pain

Myth: If there is significant blockage of the heart arteries, the typical symptom is exertional chest pain or discomfort (angina). Other symptoms are not related to the heart.

Truth: While the United States' National Heart Lung and Blood Institute states that angina is the typical symptom of underlying CAD, it also notes that many patients with significant CAD do not exhibit chest pain and may instead display other symptoms such as shortness of breath on exertion, neck pain, jaw pain, back pain or indigestion.

I passed my treadmill test and so I am sure I have no heart disease

Myth: A normal exercise treadmill test with no chest pain and no abnormal changes on the electrocardiogram (ECG or recording of the heart's electrical pattern) means that there is no significant blockage of the heart artery.

Truth: A negative treadmill test only means that there is a lower likelihood of significant CAD; it does not mean that you do not have significantly blocked heart arteries.

For every hundred patients with significant blockage of a major heart artery who undergo treadmill testing, only about 60 to 70 per cent will show an abnormal treadmill test result.

Treadmill testing has its limitations, and it is possible to have a normal result even in the presence of severe disease of all three major heart arteries.

Hence, in those with multiple risk factors, it is useful to discuss the findings of your treadmill result with your regular physician.

I will only get heart attack when I have severe blockage of the heart arteries

Myth: Heart attacks will only occur when there is a significant blockage (narrowing of 70 per cent or more) of the heart artery

Truth: The latest Universal definition of myocardial infarction (heart attack) recognises that heart attacks may not only be due to severe blockage of the heart arteries.

The commonest form of heart attack is due to the presence of CAD and is usually precipitated by disruption (rupture or erosion) of the lining of the narrowed heart artery segment (plaque) followed by the formation of a clot to seal the damaged lining; a mechanism which the body uses to repair damaged linings in vessels.

The clot can then obstruct the heart artery lumen and prevent blood flow to heart muscle tissue, thereby causing damage to the heart muscle.

Hence, a heart attack can occur even if the narrowed segment has less than 70 per cent stenosis as long as there is a plaque rupture and the blood clot that formed is large enough to obstruct blood flow to heart muscle.

In addition, heart attacks can be caused by severe hypertension or sustained fast abnormal heart rhythms.

Heart attacks can occur even in arteries which appear normal on invasive coronary angiography (X-ray imaging of heart arteries via insertion of tubes into the heart).

This condition, termed Takotsubo syndrome, can mimic a typical heart attack and is found in 1-2 per cent of patients presenting with suspected major heart attacks.

The onset of this syndrome is often triggered by intense emotional or physical stresses, such as bereavement. Over 90 per cent of these patients are post-menopausal women.

The latest Universal definition of myocardial infarction has also included a category of heart attacks where there is no angiographic obstructive CAD.

Angiographic obstructive CAD is defined as diameter narrowing of 50 per cent or more in a major heart artery.

Heart attacks of this nature are categorised as myocardial infarction with nonobstructive coronary arteries or MINOCA.

It is estimated that 6-8 per cent of patient with heart attacks fall within this category. MINOCA is commonly seen in women.

Hence, while blockage of the heart arteries account for most cases of heart attacks, in a smaller proportion of patients, heart attacks can occur even in the absence of significant blockage of the heart arteries.

As blood clot formation in the blocked heart artery segments is the main cause of occlusion of the heart artery resulting in cessation of blood supply to heart muscle, keeping yourself well hydrated by drinking at least 2 litres of liquids a day may be useful lifestyle choice, which can reduce the likelihood of dehydration and hence lessen the risk of clot formation.

In summary, the key take-home messages are:

• Heart attacks are potentially preventable.
• While those with severe blockage of the heart arteries usually have chest pain, some patients have no symptoms or have atypical symptoms. Hence, if you have multiple risk factors which are not well controlled, you may be at risk of a heart attack even if you have no typical symptoms.
• While is true that the risk of a heart attack is very low in pre-menopausal women, heart disease remains a major cause of death in post-menopausal women.
• Heart attacks can occur even in the absence of severe blockage of the heart arteries and hence lifestyle changes such as stress reduction, adopting a healthy diet, keeping the cholesterol levels low and getting adequate hydration are simple yet useful ways to prevent the onset of a heart attack.

This article is produced on alternate Saturdays in collaboration with Royal Healthcare Heart, Stroke & Cancer Centre