Long QT Syndrome

Long QT Syndrome – Disorder of the Heart’s Electrical System

Long QT syndrome is a disorder of the heart’s electrical system causing fainting and episodes of an abnormally rapid heart rhythm known as arrhythmia. It could be either inherited or acquired later in life. Everyone with long QT syndrome will not experience arrhythmia but when it does occur, it could be serious. It has got its name from the way the heart’s electrical activity gets recorded during an electrocardiogram – ECG or EKG.

The electrical activity which is recorded produces a characteristic pattern while the different parts of the pattern are named with the letters P, Q, R, S and T. The space between the Q and the T or the interval between Q and T indicate the time taken for the electrical signal to pass through the lower chambers of the heart till the heart is ready for its next beat.

 If it tends to take longer than the normal time it is diagnosed as a prolonged or long Q-T interval. Individuals with LQTS do not have a prolonged Q-T interval all the time and it is possible for people with this syndrome to have an ECG with normal or borderline Q-T interval. They may also show prolonged Q-T interval during physical exercise at the time of intense emotion or when startled.

Abnormal Heart Beat – Torsade De Pointes

In another form of inherited LQTS, the person is born with hearing impaired. It is often inherited and is present from birth and could also bedue to some medication which can prolong the Q-T interval thus disrupting the heart rhythms.

At times some people with QT syndrome would find that their heart suddenly tends to beat fast in an abnormal manner which according to doctors refer this arrhythmia as `torsade de pointes’ and when this occurs, the heart is unable to pump the blood properly resulting in the brain being temporarily deprived of oxygen resulting in the person to temporarily pass out or faint.

The torsade pointes rhythm tends to return to normal within a few minutes and the person then gains consciousness and these instances could take place at any age which could be triggered due to certain situations like stress, sudden noise like an alarm bell, exercise particularly swimming, or a slow heart rate while sleeping.

Ventricular Fibrillations – Rapid Uncoordinated Episodes of Contractions

At times the abnormal heart rhythm may continue which could lead to ventricular fibrillation, which is a rapid uncoordinated episodes of contractions and this rarely reverts to normal without the help of treatment. If this condition is not treated, it could cause the heart to stop pumping or a cardiac arrest resulting in death and long QT syndrome is the main cause of sudden cardiac death in young healthy person which is often considered to be an underlying reason of sudden infant death syndrome.

Medication and lifestyle changes are effective in preventing long QT syndrome causing arrhythmia and treatment could start with beta-blockers while some may need a medical device implanted. Beta-blockers control irregular heartbeats by blocking the electrical nerve impulses which stimulate the heart and decreases the activity of the heart slowing down the heart rate.

If the beta-blockers are unable to control the abnormal heart rhythm and the fainting episodes, a small device known as implantable cardioverter defibrillator – ICD may be fitted which is similar to a pacemaker. If the ICD detects that the heart is beating at a dangerous abnormal rate, it delivers an electric shock and helps the heart to return to its normal rhythm or start pumping at a normal rate.