Episode of unconsciousness

Mr N A 67-year-old gentleman had an episode of sweating followed by dizziness and transient loss of consciousness (also called syncope) . He got up soon and felt fine and continued his routine activities. He felt that the episode was because of lack of sleep, stress and lack of adequate rest. One week later he was unfortunately found dead in sleep.

Does that mean an episode of unconsciousness or a transient faint could be a warning symptom of impending doom like sudden cardiac death. This symptom of syncope is a commonly seen symptom in clinical practice.

Syncope which can be Life threatening:

1.Patients with an underlying heart disease especially a previous heart attack which leads to weakening of the heart muscle (Left ventricular ejection Fraction < 35%) are prone to develop episodes of malignant arrhythmias in which the heart beat becomes chaotic and in effective (Ventricular tachycardia or Ventricular fibrillation). During this period the pumping function of the heart becomes ineffective and the brain does not get blood supply. This is a cardiac arrest and if it lasts for more than 3 to 4 minutes the subject dies even if the heart recovers after this.

All patients with a poor functioning of the heart are prone for this phenomenon and are candidates for getting a cardiac defibrillator implanted to prevent sudden death. Cardiac defibrillator which is implanted like a pacemaker recognizes this arrhythmia and delivers an electric shock inside the heart and aborts the episode instantaneously and is life saving.

  Such patients should consult their cardiologist for a consultation especially if they have had episodes of dizziness or fainting.

2. Subjects with abnormal ECG especially bundle branch blocks (RBBB or LBBB) who get episodes of unconsciousness, dizziness or black outs possibly could be getting episodes of complete heart block with the activity of the heart stopping transiently leading to unconsciousness during which the eyes of the patient turn up and can have involuntary movements of the body like a fit. Bundle branch blocks are seen commonly in elderly population. All of them are not associated with fainting episodes.

These episodes if prolonged can be a cause of sudden death. The diagnosis can be arrived at by getting an ECG done during the episode.

If the episodes are transient then prolonged rhythm monitoring by a Holter monitoring (Which typically monitors the ECG for 24 to 48 hours through a recorder which is attached to the chest through electrodes). Recent advances in technology enables us to keep a small recording chip attached to the chest wall for 10 to 15 days and it transmits the ECG to a remote sensing machine. This gadget is called Extended Loop Monitoring (ELR) and is available for use in our city. Physicians are informed about any abnormality recorded immediately by the remote centre. The device is very user friendly and the patient need not curb any of his routine activities like bathing etc.

The treatment of this cause of syncope is implantation of a cardiac pacemaker which is a small surgical procedure done under local anaesthesia in hospitals which have cardiac catheterization laboratories. In some patients where the episodes are very infrequent tests like cardiac electrophysiology help in arriving at the diagnosis.

3. Subjects with relatively slow heart rates ( < 40 -45 / minute) if they get episodes of dizziness or fainting may be getting long periods of very slow heart rate and at times no beats for a few minutes leading to lack of perfusion to the brain leading to fainting.

This rhythm disorder can also be diagnosed by ECG during the episode or by prolonged monitoring of the rhythm by Holter technique or prolonged ECG monitoring up to 1 week. His rhythm disorder is often termed Sick Sinus Syndrome.

Once diagnosed the treatment is again implantation of a permanent pacemaker.

Episodic Unconsciousness in People with no heart disease:

These young persons who suffer from a syncope condition, any unexpected stimulus, such as pain, shock or fright, causes the heart and breathing to stop; the eyes to roll up into the head; the complexion to become white, often blue around the mouth and under the eyes; the jaw to clench and the

Prolonged standing at one place, dehydration or hearing bad news can precipitate such an event. These episodes can be very infrequent or often. The episodes are often associated with a premonition or feeling of weakness. These occur because of pooling of blood in lower limbs. Such persons should be asked to sit down or lie down for a short while. The reflex gets interrupted and the person becomes normal.

A physician’s advice should be sought if these episodes are seen in elderly persons for the first time. Their cardiac evaluation, ECG and echocardiogram is normal and tests like prolonged monitoring are all normal. These subjects are reassured and counselled regarding the preventive measures.


The symptoms of unexplained episodes of unconsciousness need to be taken seriously especially in patients with underlying heart disease. The cause could be a serious rhythm disorder which can be fatal and is amenable to prevention and treatment. A full evaluation under care of a heart specialist is needed. Even in the younger population with no heart disease it is desirable to have a medical opinion and not pass it off as innocuous.

Disclaimer: The views and opinions expressed in this article are the personal opinions of the author.

The facts, analysis, assumptions and perspective appearing in the article do not reflect the views of GK 

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