Inextricably linked they are, two of the most important organs in our bodies……if something goes wrong with one, the chances of the other suffering the same fate are very high.
What ails the heart causing a heart attack could be a precursor to a brain attack (stroke), warns Consultant Neurologist Dr. Padma Gunaratne of the Institute of Neurology who is also President of the National Stroke Association of Sri Lanka. “Similarly, a person who has suffered a stroke has a higher risk of getting a heart attack.”
Sometimes even if there is no pre-warning with a heart attack, a diseased heart or its valves could have an impact on the brain, sending a clot there which results in a stroke, she points out.
This is why Dr. Gunaratne is attempting to spread the message that not only must we look after both the heart and the brain but also be aware of what can cause them to have an “attack”. Heart and brain attacks (see graphic) result in death or major disability. Therefore, the “deadly contribution” of non-communicable diseases (NCDs) cannot be downplayed, MediScene understands.
Heart or brain attack, how do they occur, asks Dr. Gunaratne, answering that for both the culprit is “blood vessel issues” or cardiovascular diseases (CVDs) caused by hypertension, high cholesterol, diabetes and smoking.
The causes of strokes:
- Diseased capillaries (tiny vessels).
- Diseased major vessels that carry blood to the brain.
- A diseased heart which is not pumping blood properly or not beating regularly or diseased heart valves. Under these conditions, the heart itself may form and generate clots.
Referring to the three types of strokes that could occur, Dr. Gunaratne explains that if large blood vessels are diseased, a clot or thrombus may be generated from the carotid artery (major neck vessel which supplies blood to the brain); the heart itself may become the source of a clot (cardio-embolism) which comes to the brain; or tiny blood vessels (capillaries) in the brain are affected with long-term high blood pressure, causing tiny infarcts (lacunar strokes) on the deep, inner part of the brain.
It is important to clinically differentiate these three types since management decisions will depend on the type of stroke, she stresses.
Citing the example of a cortical infarction seen on a CT (computed tomography) scan, she explains that the finger could be pointed at a clot generated by the heart (cardio-embolism) or from a large vessel that carries the blood to the brain (large vessel disease). However, a deep-seated small infarct caused by a blockage of capillaries will indicate a stroke directly related to high blood pressure.
An important cardio-embolic cause of stroke is atrial fibrillation (AF) that presents itself with an irregular heart rhythm. Usually a person has a regularly-regular heart-beat but AF causes it to be irregularly-irregular. There will be poor contraction of the atria (upper chambers of the heart) and poor coordination of contractions between them and the ventricles (lower chambers). This could cause clots to form, becoming the source of a thrombo-embolism.
Going into the normal workings of the heart, Dr. Gunaratne says that its muscular walls tighten and squeeze to send blood around the body, after which they relax to allow the heart to fill up with blood once again. In a normal heart, when the upper chambers contract the lower chambers relax to receive blood from them.
AF could be valvular when it is associated with rheumatic valvular heart disease or non-valvular when it is associated with atherosclerotic vascular disease, according to her. In young people who have rheumatic heart disease, there may arise stenosis (narrowing) of the mitral valve which in turn could be associated with AF and send out clots. However, under the non-valvular AF category would come older people who may have a stroke due to hypertension causing cardiovascular disease.
In this category of AF, if patients present themselves with the following, they are more likely to develop a stroke caused by cardio-embolism: Age more than 75 years, failing heart with diminished pumping effect, high blood pressure, diabetes, and a previous stroke, MediScene learns.
Meanwhile, in those who have suffered a heart attack, if the heart is pumping less than 30%, there is the possibility of stasis (a stoppage of flow) of blood in the ventricles and a higher risk of a stroke, she says, explaining that as clinicians it is important to recognize cardio-embolism since it is a preventable cause of stroke.
“All who carry a high risk of a cardio-embolism have to be on blood-thinning drugs such as Warfarin. When the patient begins to take Warfarin, he should be monitored closely with the blood test INR (International Normalized Ratio) to maintain him on the optimum thinning effect of the drug. INR should be maintained between 2-3, as an INR less than 2 would facilitate clotting and more than 3 would facilitate bleeding into the body tissues.
In ischaemic large artery stroke, it is important to evaluate the relevant carotid by performing the ultra-sound called carotid duplex. If the stenosis is between 70-99%, as there will be a higher risk of recurrence, the patient should be offered surgery to remove the block of the carotid artery, Dr. Gunaratne adds.
WHO guidelines
While the World Health Organization (WHO) states that according to 2008 estimates more than 17.3 million died of cardiovascular diseases, 80% of premature heart attacks and strokes are preventable.
Here are the WHO’s “keys” to prevention:
Eat a healthy diet: A balanced diet is crucial to a healthy heart and circulation system. This should include plenty of fruit and vegetables, whole grains, lean meat, fish and pulses, and restricted salt, sugar and fat intake.
Take regular physical activity: At least 30 minutes of regular physical activity every day helps to maintain cardiovascular fitness; at least 60 minutes on most days helps to maintain healthy weight.Avoid tobacco use: Tobacco in every form is very harmful to health - cigarettes, cigars, pipes, or chewable tobacco. Exposure to second-hand tobacco smoke is also dangerous.
Check and control cardiovascular risk:
Know your blood pressure: High blood pressure usually has no symptoms, but can cause a sudden stroke or heart attack. Have your blood pressure checked.
Know your blood sugar: Raised blood glucose (diabetes) increases the risk of heart attacks and strokes. If you have diabetes it is very important to control your blood pressure and blood sugar to minimize the risk. Control diet and engage in exercise to control blood sugar.
Know your blood lipids: Raised blood cholesterol and abnormal blood lipids increase the risk of heart attacks and strokes. Blood cholesterol needs to be controlled through a healthy diet and, if necessary, by appropriate medications. |
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