Transient blackouts (Syncope)


Can transient blackouts be a manifestation of heart disease?

Transient loss of consciousness (TLOC) with a fall is called ‘syncope’. It could be due to a variety of causes including heart disease. Causes other than cardiac ailment could be some forms of epilepsy (seizure), anemia (lowering of hemoglobin content of blood) or even a simple faint. Of the lot, the simple faint (vasovagal syncope or neurocardiogenic syncope) if probably the most common. It is quite common in children, especially while standing in school assembly in hot season. Dehydration can predispose to this form of syncope.

Syncope due to ailments of the heart can be due to several causes. Serious obstruction to any heart valve can cause syncope, especially during exertion as the heart is not able to meet the extra demand for blood supply with exercise. High blood pressure in the blood vessels of the lung (pulmonary hypertension) is a rare by serious cause of syncope. Obstruction to blood flow to the lungs due to sudden migration of blood clots from another part of the body like the legs can sometimes cause syncope. Another important group of cardiac illness which can cause syncope are the disorders of heart rhythm. A very fast heart rhythm or a very slow heart rhythm, both can cause syncope. In both cases, heart is not able to pump sufficient amount of blood to maintain the circulation to the brain well. Diseases of the heart muscle which leads to poor function of the heart as a pump can cause syncope, mostly during exertion. Gross thickening of the heart muscle in certain heart diseases (hypertrophic cardiomyopathy) can cause obstruction to blood flow from the left ventricle (lower muscular chamber) to the aorta (largest blood vessel supplying oxygenated blood to the body) can lead to syncope, typically occurring while taking rest after exertion.

What tests are likely to be done in a person with syncope?

The most important aspect of evaluation of person with history of syncope is the detailed history of the event and the narration from an eye witness in case one is available. Usually evaluation needs a multidisciplinary approach. Most cases would need both cardiac and neurological work up as the cause often not very evident. If the history points to one form of disease, priority is given for that workup. Important general test is a routine blood count to rule out anemia. Basic blood investigations are also often done to rule out associated important illnesses. Specific cardiac (related to the heart) tests may include an electrocardiogram (ECG), echocardiogram (ultrasound imaging of the heart) and ambulatory electrocardiographic monitoring (24 or 48 hour Holter monitoring). Neurological (related to the brain and nerves) tests may include electroencephalogram (EEG) and brain imaging studies (computerised tomographic or CT scan and/or magnetic resonance imaging (MRI) of the brain. Further workup will depend on the results of these initial tests.


Symptoms of heart disease


What are the important symptoms of heart disease?

Symptoms depend on the type of heart disease. Sometimes there could even be silent heart disease without any symptoms. Many of the birth defects of the heart remain asymptomatic for long periods. Some become symptomatic during another illness or a major stressful event. Occasionally the very first manifestation of a silent underlying heart disease is sudden death. Apart from these two extremes, most significant heart diseases have some symptom or other though there may be a lot of variation between individuals. The severity of symptoms may not correlate with the severity of heart disease in some cases.

Important symptom of heart disease which every one is familiar with is the severe chest pain of a heart attack. As the name implies, it often occurs out of the blue and is quite disabling. A crushing feeling may be felt instead of chest pain, and it may spread to the arms or jaw. It may be associated with profuse sweating or sometimes breathlessness and dizziness. Some even feel an impending doom.

Classical symptom of reduced blood supply to the heart is chest pain brought on by exertion and relieved by rest (effort angina). This indicates gradually increasing blockage of coronary arteries which supply oxygenated blood to the heart. This pain may also spread to the jaw, neck or the arms. Occasionally pain may be felt in the upper part of the stomach. Rarely jaw pain or pain in the wrist occurs without chest pain.

Breathlessness brought on by exertion and relieved by rest is another important symptom of heart disease, though it can be due to lung disease or even reduced amount of hemoglobin in the blood (anemia). Sudden breathlessness during sleep and breathlessness which gets worse on lying down are also important symptoms of some forms of heart disease.

Palpitation or undue awareness of one’s heart beats is another important symptom of heart disease, though it may occur with anxiety and undue exertion as well. Palpitation can be fast, slow, regular or irregular, depending on the abnormality in the heart rhythm.

Some forms of heart disease, especially birth defects of the heart, produce a bluish discoloration of the skin and lips (cyanosis). This is due to reduced content of oxygen in circulating blood. Spitting out blood can also be a symptom of heart disease, though it is more often a symptom of lung disease.

Prolonged fever can occur with infections of the heart valve. Joint pain and swelling can occur in infections of the heart valves as well as in rheumatic fever, which can affect the heart valves.

Stroke or sudden weakness of one part of the body can be an indirect symptom of heart disease. Atrial fibrillation, an abnormal rhythm of the upper chambers of the heart, can cause clots to form in the heart. These clots can move out of the heart and block a blood vessel in the brain causing stroke. Similar clots can form in diseases of heart valves, where there is obstruction to blood flow.