Long QT Syndrome

By | June 8, 2022

Long QT syndrome is the name of a heart disease that can be life-threatening. This leads to a pathologically prolonged QT interval.

What is Long QT Syndrome?

Long QT syndrome is a life-threatening heart disease that occurs only rarely. It can be hereditary or acquired over the course of life. Long QT syndrome can cause sudden cardiac death in people whose hearts are otherwise healthy.

There are different congenital long QT syndromes, including Jervell and Lange Nielsen syndrome (JLNS) and Romano-Ward syndrome, which are usually inherited in an autosomal dominant manner. The term long QT syndrome comes from a prolongation of the QT time in an ECG (electrocardiogram). The rate-corrected QT time is more than 440 milliseconds. For mmnd – motor neuron disease madras, please visit ablogtophone.com.

A typical feature of the heart disease is heart palpitations, which occur in fits and starts. Torsade de pointes tachycardia, which is considered life-threatening, is not uncommon. The cardiac arrhythmias threaten dizziness, sudden loss of consciousness and ventricular fibrillation with cardiac arrest. In many cases, however, the people affected do not suffer from any symptoms.


The long QT syndrome is triggered by minor deviations in the electrical transmission of signals in the heart muscle cells. There is a delayed repolarization of the action potential, which affects the plateau phase, which is also called phase 2. Prolongation of the plateau phase in congenital (innate) long QT syndrome occurs due to abnormal properties of the ion channels.

The ion transport of the potassium ion channel either decreases or there is an increased transport capacity of the sodium ion channel. The action potential forms an important basis for the excitation of heart muscle cells. It is regulated by the interaction of the ion currents. Phase 0 of the action potential is the depolarization of the heart muscle cells, which is caused by the influx of calcium and sodium ions.

Repolarization is initiated by phase 1, in which the efflux of potassium from the cell occurs. Phase 1 is followed by phase 2 or the plateau phase, during which the long-lasting influx of calcium ions takes place. These ions trigger the release of additional calcium ions from the sarcoplasmic reticulum.

It takes about 100 milliseconds for the calcium channels to close again, for calcium to get out of the cell or back into storage, and the heart muscle to relax. Phase 3 follows, in which the membrane potential returns to its original position. There it remains dormant until the next excitation occurs.

The congenital long QT syndrome is caused by an ion channel dysfunction that is mutational and results in a structural change in an ion channel. In addition to the congenital form, which is caused by a gene mutation, there are also acquired forms of the heart disease. They can be caused by inflammation of the heart muscle ( myocarditis ), circulatory disorders, electrolyte imbalances or the use of various medications.

The drugs responsible include primarily class I, II and III antiarrhythmic drugs, psychotropic drugs and various antibiotics that have an inhibitory effect on repolarization and trigger drug-induced long QT syndrome.

Symptoms, Ailments & Signs

Symptoms caused by long QT syndrome are abrupt onset of torsades de pointes tachycardia. The ventricular tachycardia becomes noticeable through sweating, general malaise, tightness in the chest and cardiac restlessness. A circulatory collapse (syncope) can also occur.

Collapse and tachycardia occur mainly in stressful situations or during physical exertion. If the ventricular tachycardias are not treated medically, there is a risk of ventricular fibrillation, which will result in definitive cardiac arrest and the death of the patient.

Diagnosis & disease progression

If there is a suspicion of long QT syndrome, the doctor treating you will carry out a resting ECG. Sometimes a stress ECG can also be useful. If the QT interval lengthens during the resting ECG, this is regarded as a groundbreaking indication of the syndrome. The QT interval (QTC) corrected for the rate is 450 milliseconds in males and 470 milliseconds in females.

Because the long QT syndrome is usually inherited, the family history is considered very important for the diagnosis. In addition, molecular genetic detection of mutations within the leukocyte DNA is possible. For this purpose, a PCR amplification and the sequencing of the risk genes that are known are carried out. Two to five milliliters of EDTA blood are used for the sample material.

The course of long QT syndrome depends on whether symptoms appear or not. The prognosis is considered negative if symptoms appear and no treatment is carried out. In principle, however, it is possible to help most patients with appropriate therapy.


Long QT syndrome is a very dangerous disease which, in the worst case, can even lead to the death of the patient. For this reason, long QT syndrome always requires treatment by a doctor. As a rule, those affected suffer from severe sweating and also from feeling unwell. This significantly restricts and reduces the quality of life.

In the further course, the affected person can also suffer a circulatory collapse and thereby lose consciousness. A loss of consciousness often leads to injuries that can occur in the event of a fall. Especially in stressful situations, there are significant impairments caused by the long QT syndrome. The patient’s resilience is significantly reduced and fatigue and exhaustion occur.

Heavy loads can also lead to cardiac arrest and thus to the death of the patient. As a rule, the symptoms of long QT syndrome can be limited and treated with medication. In general, no particular complications arise. In acute emergencies, however, the use of a defibrillator is necessary to revive the person concerned. Life expectancy is limited and reduced by long QT syndrome.

When should you go to the doctor?

If seizures or signs of cardiac arrhythmia occur, it is best to call an ambulance. Symptoms of this type indicate a serious condition and, in the worst case, can lead to the death of the patient. If the victim loses consciousness, an ambulance must be called. At the same time, relatives should provide first aid and ensure that the person concerned is able to breathe and has a pulse. Less serious symptoms that require clarification are shortness of breath, rapid exhaustion and an audible heart palpitations.

Chest pain should also be clarified quickly by a doctor. Patients at risk include people who regularly take medication or have low blood serum potassium levels. A slow heart rhythm can also cause long QT syndrome. Anyone who belongs to the risk groups should pay close attention to any warning signs and, if in doubt, arrange a doctor’s appointment. The appropriate doctor is the cardiologist. The individual symptom picture is treated by the family doctor and various medical specialists and specialists (such as neurologists or physiotherapists ).

Treatment & Therapy

The standard treatment for congenital long QT syndrome is beta-blockers. These are able to significantly reduce severe cardiac arrhythmias. If syncope persists, insertion of an implantable defibrillator (ICD) is advisable. The implantation should also take place after cardiac arrest has been recovered.

If long QT syndrome is caused by taking certain medications, the triggering agent must be discontinued immediately. In contrast to the congenital form, the administration of beta-blockers does not make sense because of the risk of bradycardia, which in turn increases the risk of life-threatening cardiac arrhythmias. A proven remedy, on the other hand, is the intake of magnesium.

Physical stress is classified as problematic in long QT syndrome. This is especially true in the case of a sudden onset or end of a load, as well as pressure fluctuations and cold.

Outlook & Forecast

If left untreated, long QT syndrome leads in most cases to circulatory collapse, loss of consciousness and premature death. Since this is a life-threatening health development, there is an acute need for action. Intensive medical care is necessary to ensure that no permanent damage occurs and that the survival of the person concerned is ensured. As soon as the first irregularities in heart activity occur, you should consult a doctor.

If the diagnosis is made early, the further course of the disease is significantly improved and the probability of survival is increased. The patient needs the implantation of a defibrillator. This ensures sufficient cardiac activity in the long term and can regulate restrictions in cardiac activity. Although the surgical procedure is associated with risks, it is still a routine procedure. If no further complications occur, the patient is able to continue living.

However, the mental and physical stress must be adapted to the possibilities of the organism and must be reduced. In many cases, the restructuring of everyday life is necessary so that no disruptions occur and risk factors are minimized. The person concerned must have regular check-ups with a doctor over the long term so that irregularities can be detected and corrected at an early stage. This can lead to emotional states of stress. In addition, medication must be administered once the defibrillator is used. These have side effects.


In order to prevent cardiac arrhythmias caused by long QT syndrome, sports such as diving, swimming, surfing, tennis, weight lifting and bodybuilding should be avoided. On the other hand, moderate physical activities such as skating, walking or jogging are considered sensible.


Since long QT syndrome cannot heal itself, the aftercare focuses primarily on alleviating the existing symptoms. Those affected suffer from severe pain in the heart and continue to suffer from permanent tiredness and exhaustion. As a result, in most cases they are dependent on help from their social environment. Since the burden on everyone involved is sometimes very high, this can lead to depression and other mental upsets.

It is therefore advisable to seek professional, psychological help to make it easier to deal with the disease. A gentle mode in everyday life with many rest phases can help to compensate for the permanent, inner restlessness and any sleep problems that may occur. Since the further course of the disease depends heavily on the time of diagnosis, no general prediction can be made. In addition, the exchange with other people affected by long QT syndrome can counteract their own helplessness and promote a more self-confident handling of the situation.

You can do that yourself

As a rule, the options for self-help in long QT syndrome are severely limited. This is especially the case when the syndrome is not caused by certain medications but is due to a heart condition.

However, if long QT syndrome is triggered by taking medication, it must be discontinued immediately or replaced with other medication. Changing and stopping medication should always be done after consulting a doctor. Furthermore, the symptoms of long QT syndrome can be reduced by taking beta-blockers. The patient should ensure that it is taken regularly. The increased intake of magnesium can also have a positive effect on the course of the disease and alleviate the symptoms. Magnesium can be obtained either through supplements or through various foods such as nuts or fish.

Due to the long QT syndrome, the affected person should continue to avoid heavy physical exertion. This also includes avoiding strenuous sports. Above all, stress should not start suddenly, as this puts unnecessary strain on the heart. Likewise, the affected person should not stay in the cold for too long and avoid pressure fluctuations that can occur, for example, when flying or diving.

Long QT Syndrome