This is a rare disorder affecting the electrical system of the heart that can cause fast and chaotic heartbeats. In some of the cases, the erratic heart beat can continue for a long duration causing sudden death. Normally, the electrical activity of the heart is produced by the electrically charged particles of potassium, calcium, sodium and chloride which flow in and out of the heart cells. This condition can develop when either the ion channels are not functioning well or there may be too few of them. Hence, the electrical activity of the heart is disrupted causing the dangerous arrhythmias.
Causes
After each heartbeat, the heart’s electrical system recharges for the next heartbeat in a process known as repolarization. The LQTS develops as the result of a defect in the ion channels which causes the delay in the recharge of the electrical system after each heartbeat. This electrical disturbance can be identified in the electrocardiogram (ECG) and is known as prolonged QT interval. This syndrome can either develop as an acquired form or can be congenital (inherited). Around 17 different genes have been identified that can cause this syndrome and around 20% of the affected cases do not present any genetic mutations. The two types of inherited LQTS include Romano-ward syndrome and the Jervell and Lange-Nielsen syndrome. The acquired form of this syndrome can also develop as the result of various medications such as certain antibiotics, diuretics, diabetic medications, antiarrhythmic medications and antidepressant drugs.
Symptoms
Some of the individuals with this syndrome may not experience any symptoms. The common symptoms that are caused by the interruptions to the heart’s rhythm include seizures or blackouts. Some of the individuals may experience a type of arrhythmia called torsade de pointes which can be life-threatening when the heart cannot effectively pump blood and as the result, the brain doesn’t receive sufficient oxygen. These episodes can occur at any age and can also be triggered by stress, sudden noise, a slow heart rate during sleep or strenuous exercise. Sometimes, the abnormal heart rhythm can cause ventricular fibrillation resulting in cardiac arrest and death.
Diagnosis
The diagnosis is based on the symptoms, medical history of the affected individual, their family history and a physical examination. Various tests may also be necessary to confirm the diagnosis. The electrocardiogram (ECG) records the electrical activity of the heart, a holter monitor or an event monitor which are attached to the body to monitor the heart activity over a period of time. A genetic testing can mostly identify the genetic mutation in around 3 out of 4 cases of this syndrome.
Treatment
The focus of the treatment is to prevent life-threatening complications and the abnormal heart rhythm. Although there isn’t a cure for this disorder, the treatment can improve the chance of survival. The treatment usually involves medications, medical devices or surgery. The treatment for the acquired form of this syndrome involves treating the cause or to stop taking the specific medications that cause the condition. Medications used for this syndrome can slow the heart rate and shorten the QT interval. Depending on the condition, a pacemaker or implantable cardioverter-defibrillator (ICD) can stop the fatal arrhythmia.
References
http://www.mayoclinic.org/diseases-conditions/long-qt-syndrome/basics/treatment/con-20025388
http://my.clevelandclinic.org/health/articles/long-qt-syndrome
http://www.nhs.uk/conditions/long-qt-syndrome/Pages/Introduction.aspx
https://www.nhlbi.nih.gov/health/health-topics/topics/qt/treatment
