Are you feeling dizzy?

A  62-year-old gentleman had an episode of sweating followed by dizziness and transient loss of consciousness. After a while, he felt normal and got back to his routine activities, believing overwork and stress were the cause. One week later, he was found dead in sleep.

Does this mean that an episode of unconsciousness or a transient fainting could be a warning symptom of cardiac fatalities?

Clinically, this is called syncope and following are the people most prone to such episodes:
n Patients with underlying heart disease, especially a previous heart attack, are prone to develop episodes of malignant arrhythmias, in which the heart beat becomes chaotic. During this period, the pumping function of heart becomes ineffective and the brain does not get enough blood supply. This usually means cardiac arrest and if it lasts for more than three to four minutes, the subject dies, even if the heart recovers after this.

Such patients are the perfect candidates for getting a cardiac defibrillator implanted, so as to prevent sudden death. Cardiac defibrillator recognises this arrhythmia and delivers an electric shock inside the heart and aborts the episode instantaneously. 

n Subjects with abnormal ECG, especially bundle branch blocks, who get episodes of unconsciousness, dizziness or black outs, could feel dizzy every now and then. This is when they feel like their heart is blocked and has stopped beating totally. Here, the eyes of the patient roll into their head and they also suffer from fits. These episodes, if prolonged, can be a cause of sudden death. The diagnosis can be arrived by getting an ECG done during the episode.

If the episodes are transient, then prolonged rhythm monitoring by a Holter monitoring (monitors the ECG for 24 to 48 hours through a recorder which is attached to the chest through electrodes) is recommended. 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 country. Such patients can also have a cardiac pacemaker implanted in their bodies. For those who have irregular episodes, their best bet is cardiac electrophysiology.

n Subjects with relatively slow heart rate (less than 40-45 per minute) can sometimes feel dizzy and may even faint. They are also prone to long periods of very slow heart rate and at times, no beats for a few minutes, which could lead to lack of perfusion to brain. This rhythm disorder can also be diagnosed by ECG during the episode or by prolonged monitoring of the rhythm by Holter technique or ELR. This rhythm disorder is often termed as sick sinus syndrome.

Once diagnosed, it can be treated by implanting a permanent pacemaker. But not every syncope is fatal. In fact, the most common cause of syncope, especially in children and young adults is related to a reflex mechanism called neuro cardiogenic syncope or a simple faint. Any instance of pain, shock or fright can cause your heart and breathing to stop, eyes to roll up into the head and complexion to turn white. But after a while, everything returns to normal.

Sometimes, such people are known to fall into a deep sleep after such instances. The episodes are often associated with a premonition or feeling of weakness. Such people should be asked to sit or lie down for a while.

Because of the symptoms, syncope is often unfortunately misdiagnosed as temper tantrums, cyanotic breath-holding (prolonged expiratory apnea) or epilepsy.  A physician’s advice should be sought if these episodes are becoming frequent.

The symptom 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 — but is amenable to prevention and treatment.

(The author is dean and executive director, cardiology, Fortis Hospital, New Delhi)