Stroke and heart disease

How are stroke and heart disease related?

Stroke is often due to sudden loss of blood supply to a region of the brain which usually results in paralysis of a part of the body. Stroke could also be due to bleeding into a part of the brain. Strokes and heart disease are linked together in various ways. In general, risk factors for stroke and some forms of heart disease are similar. Strokes due to blocks in blood vessels, can be seen along with blocks in blood vessels of the heart. Stroke can occur after a heart attack as well. Heart attack damages a part of the heart muscle. This can lead to damage of the inner lining of the heart in that region. A blood clot can form on the inner surface of the heart as a consequence. These clots can break away into the circulation and get lodged into a blood vessel of the brain. The clot thus blocks a blood vessel of the brain and causes stroke.

Another type of heart disease which leads to stroke is an abnormal rhythm of the heart known as atrial fibrillation. In atrial fibrillation, there is a fast irregular rhythm originating in the upper chambers of the heart. The rhythm is so fast that effective contractions of the upper chambers cease. This leads to stagnation of blood in certain parts of the left atrium (upper chamber of the heart), where a blood clot can form. These clots can also get dislodged and travel to blood vessels of the brain. They in turn block a blood vessel of the brain and cause stroke.

Another reason for stroke is high blood pressure. When the blood pressure goes very high suddenly, small blood vessels in the brain may break leading to a bleed into the brain matter. This form of stroke (hemorrhagic stroke) is generally more dangerous than a stroke due to blockage of a blood vessel. Even without a bleed, brain function can be altered due to high blood pressure, causing alteration in the level of consciousness. But then that is not a stroke, but called as hypertensive encephalopathy (brain disease due to high blood pressure).

Stress and heart disease

How does stress cause heart disease?

Stress and heart disease has various aspects. Stress can lead to increase in risk factors for heart disease as well as precipitate symptoms in a hitherto silent heart disease. Most older persons have build up of plaques in the blood vessels of the heart (coronary arteries). When there is a sudden severe stress, heart rate and blood pressure can shoot up. This can lead to increase of shear stress on the fat plaques in the blood vessels of the heart. A small break may form in the covering of the plaque, exposing the inner cells. Blood components known as platelets adhere to these breaks in the inner surface of the blood vessels and initiate the formation of blood clots. Blood clots in turn block the flow of blood in the vessel, leading to damage of heart muscle known as heart attack.

Sudden stress can sometimes lead to a surge in the blood levels of certain hormones like adrenaline. These contribute to the surges in blood pressure and heart rate. In addition this can upset the heart rhythm leading to life threatening rhythm disorders (cardiac arrhythmia) which can sometimes cause sudden stoppage of the heart (cardiac arrest).

Another manifestation of stress in the heart is the ‘broken heart syndrome’ or stress cardiomyopathy. This was initially described more in elderly females after sudden demise of their spouse. Part of the left ventricle (lower muscular chamber of the heart) becomes enlarged, giving it the name apical ballooning. This occurs in the absence of any blockage to the blood supply. Most of these cases do recover sooner or later. Stress cardiomyopathy has been described along with multiple other forms of stress other than bereavement.

Stress in general changes our life style and we may eat more of carbohydrate and fat. This has long term consequences like increase in body weight, blood sugar and blood pressure. These can further increase the chance of heart disease. Stress increases the blood pressure and blood sugar through hormonal influences even without a change in the diet pattern.

Diagnosis of coronary heart disease

How is coronary heart disease diagnosed?

Coronary heart disease (coronary artery disease, coronary artery heart disease, ischemic heart disease) is usually suspected by the symptoms. Typically it is a central chest pain or discomfort induced by exercise and relieved by rest. But this need not be the case always. Pain of heart attack may appear all of a sudden and does not get relieved by rest. Still it is an important manifestation of coronary heart disease. Other symptoms associated with chest pain could be pain in the jaw or arms, excessive sweating along with pain or sometimes breathlessness or dizziness. First investigation to be done is usually an ECG (electrocardiogram). When a heart attack is suspected, other investigations done in the emergency department are a bedside echocardiogram and a blood test for Troponin, which is released into the blood when heart muscle is damaged. Finally an emergency coronary angiogram may be done if there is evidence of a heart attack. In the outpatient setting, a treadmill exercise ECG (treadmill test) can be done in stable patients resting ECG does not give a diagnosis. Other advanced tests are coronary CT angiogram and nuclear scan of the heart.

Heart attack

What is heart attack?

Heart attack (Myocardial Infarction) is damage to a region of the heart muscle, usually due to sudden blockage of a blood vessel supplying oxygenated blood to the region (coronary artery). Though heart attack can occur due to a mismatch between the supply and demand for blood in the region, the usual heart attack which we are familiar with is due to blockage of a blood vessel. Heart attack is different from cardiac arrest. In cardiac arrest, heart stops beating and it is equivalent to death unless the function of the heart is promptly restored either spontaneously or by chest compression and artificial breathing protocol known as cardiopulmonary resuscitation (CPR).

What are the important symptoms of heart attack?

The most familiar symptom of heart attack is severe central chest pain. It is often associated with sweating, fatigue, dizziness and sometimes breathlessness. Rarely there are no symptoms and then it is known as a ‘silent heart attack’. Some unfortunate victims of heart attack develop a cardiac arrest and may die suddenly (sudden death). Sudden death in heart attack is often due to a sudden change in the heart rhythm which makes the heart stand still (ventricular fibrillation). This abnormal rhythm can be treated by CPR and direct current shock using a device known as defibrillator which shocks the heart back into action. An automatic external defibrillator for use of untrained persons, is now available in many public places like airport.

What to do if you think you are having a heart attack?

First and foremost is to take rest and call for emergency support. In regions where an emergency ambulance service is available, it should be called and one should proceed to the nearest hospital. In well equipped ambulances, it is possible to make a diagnosis and start early treatment even before reaching the hospital. After initial assessment by the paramedic, an electrocardiogram (ECG) is recorded. When facility is available, the ECG is transmitted to the receiving hospital where the team is ready for further action even before arrival of the victim.

It is not advisable to travel in a self driven vehicle to the hospital unless you have no other options. This is because occasionally cardiac arrest can occur en route. Moreover arrival in ambulance speeds up management in the emergency department. Traffic worries are also lesser while travelling in an ambulance. This is in addition to the medical support available in the ambulance.