Reviewed By: Pramod Kerkar, MD, FFARCSI

Our heart follows a cycle. This is an electric cycle. The QT interval is the time that is measured from the Q wave to the T wave in the heart’s electrical cycle. The electrical conduction system of the heart causes the contraction of the heart muscles. It involves the depolarisation and repolarisation of the ventricles of the heart. These signals are responsible for the contraction of right and left atrium first and then the right and left ventricles. This process is responsible for the proper and regular pumping of the blood throughout the body. This depolarisation and repolarisation of ventricles is represented by the QT interval on an ECG. If this QT interval is prolonged, it may be a potential indicator of ventricular tachycardia. This prolonged QT interval can therefore cause ventricular tachyarrhythmia and hence may result in sudden death.

Long QT syndrome can cause sudden and very serious arrythmias, which may prove to be fatal.

Also, there might be long QT syndrome without any obvious reason for arrythmias. But, it is not necessary that people having long QT syndrome will always have dangerous, irregular heart rhythms.

The QT interval is the electrical activity that takes place in the heart’s ventricles. Ventricles are the lower two chambers of the heart. The electrical activity which takes place between the Q wave and the T wave on an ECG is known as the QT interval.

The working mechanism of the heart’s electrical activity is quite complicated, and it is carefully worked, set and monitored by our body. If we divide each heartbeat cycle, the duration of the QT interval comes to about one third of one heartbeat cycle.

A long QT interval can therefore cause dangerous changes in the heart rhythms as it upsets the heartbeat cycle.

How Common Is Long QT Syndrome?

Long QT syndrome is a rare disorder of the heart. It is not that common in occurrence. But, this is also not certain because most of the times it goes undiagnosed. Long QT syndrome can cause sudden deaths in children and in young people, though in children sudden death is very rare. But, when it happens, most of the times long QT syndrome is seen as the cause.

Long QT syndrome is not very common after 40. It is either witnessed first in the age as young as 12 to 13 years or around 40 years of age.

Women suffer more from long QT syndrome than men. If it is seen in young boys before puberty, it usually gets corrected once they reach puberty. Hence, the future potential risk of getting long QT syndrome again also significantly decreases. In women, who are diagnosed of long QT syndrome, special care needs to be taken during menstruation and child birth, as there are great many chances of such women fainting or dying a sudden death during or immediately after this.

Certain medications can cause a risk of long QT syndrome. A physician is best to guide you along these lines. Also, if there is a history of long QT syndrome in the family, this also increases the risk of one getting it. In some cases, it has been found that congenital deafness in a child is also related to increased risk of acquiring long QT syndrome, as both are a result of same genetic problem.

Certain other conditions like diarrhea, vomiting, dehydration can be a risk factor for long QT syndrome, as the levels of sodium or potassium can become dangerously low in these conditions, and an imbalance of these components can pose as a potential risk factor for long QT syndrome.

As it is evident, that long QT interval can cause dangerous arrhythmias in the heart and can result in unexplained fainting or even sudden deaths, it is of vital importance to report any unnatural changes in your heart’s rhythm, which one may notice. Also, those who are already diagnosed of long QT syndrome should get themselves monitored at regular intervals with proper consultation with the physician and get themselves evaluated for further risks.

Also Read:

Pramod Kerkar

Written, Edited or Reviewed By:

, MD,FFARCSI

Pain Assist Inc.

Last Modified On: October 3, 2018

This article does not provide medical advice. See disclaimer

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