LGL syndrome

The LGL syndrome (Lown-Ganong-Levine syndrome) belongs to the cardiac arrhythmias. It is more precisely a pre-excitation syndrome. This means that the heart chambers are excited a little too early, causing them to contract and pumping blood to the body. This process leads to an uncomfortable racing heart with a significantly increased pulse. However, there are hardly any symptoms.

Causes of LGL Syndrome

There are various theories, none of which have yet been proven. The exact mechanism that leads to the seizure-like palpitations has not yet been clarified.

Accessory pathways were assumed to be the cause by those who discovered the disease. However, this theory is very controversial today. Accessory pathways are additional conduction pathways that transmit the excitation of the heart too quickly. This can change the normal course of excitation in the heart because the ventricles are excited too early. This then leads to tachycardia (a heartbeat that is too fast).
In LGL syndrome, accessory pathways have not yet been proven to be the cause.


As with every diagnosis, a conversation with the doctor and a physical examination in which the heart is listened to takes place first.
The heart's excitation process is mapped using an EKG (echocardiography). It is the method of choice for detecting cardiac arrhythmias. Since the palpitations typical of LGL syndrome only occur in phases, a long-term ECG examination is carried out in order to be able to depict such an event.
Other changes in the heart must have been ruled out with the help of the EKG and the heart ultrasound in order to make a diagnosis of LGL syndrome.

You can see that in the EKG

In the ECG, the palpitations typical of the disease are shown by an increased heart rate (a rapid pulse). Furthermore, the so-called PQ time is shortened. It is less than 0.12 seconds. The PQ time describes the transition time in the heart. This means that by this time the atria of the heart are already excited, while the ventricles have yet to be excited. The PQ time must be 0.12 seconds or less, otherwise it is by definition not an LGL syndrome.

The rest of the ECG must look normal, especially the so-called chamber complex, which reflects the excitation process of the heart chambers, is configured normally. If this is not the case and a so-called delta wave is present, it is Wolf-Parkinson-White syndrome. This can lead to life-threatening ventricular fibrillation.

Is LGL Syndrome hereditary?

There is evidence that LGL syndrome may be inherited. But this is not certain and needs to be researched further.

You can recognize LGL syndrome by these symptoms

The LGL syndrome manifests itself as a sudden palpitations. This attack-like palpitations of the heart is called paroxysmal tachycardia by doctors. The very fast heartbeat has a frequency between 200 and 250 beats per minute. There is no cause for the seizure-like palpitations, such as a stressful or dangerous situation, that would explain such a reaction. A rapid heartbeat for no apparent cause is usually perceived by those affected as very uncomfortable and frightening.

The racing heart manifests itself as a throbbing feeling in the chest and a high pulse. Furthermore, it can be too

  • Dizziness,
  • Nausea,
  • Sweating and clammy hands,
  • rapid breathing or difficulty breathing
  • Trembling and unrest come.

Under certain circumstances it can also be accompanied by syncope, i.e. a short faint. The seizure-like racing heart then stops by itself. How often and for how long the racing heart occurs varies from person to person. The racing heart attacks can be exhausting for those affected, so that many feel very exhausted after an attack.

Find out how you can Recognize arrhythmias.

Therapy for LGL syndrome

As there is currently no explanation for the origin of the disease, no causal therapy is currently possible. In many cases, however, the symptoms are mild and those affected do not have a high level of suffering, so that no therapy is necessary.

However, if the symptoms occur frequently and affect those affected, drug treatment is possible. Beta blockers are the drug of choice here. Beta blockers slow the heartbeat and can be taken if the heart is racing. They then act relatively quickly.

If syncope occurs in addition to the seizure-like palpitations, these must be examined again separately in order to be able to rule out serious causes.

Have you not been diagnosed with LGL syndrome for sure? Learn more about the Therapy of cardiac arrhythmias in general.

Duration and forecast

Studies have not found that patients with LGL syndrome have an increased risk of sudden cardiac death. Other risks are not associated with a diagnosis of LGL syndrome. So far, however, there is still little data on LGL syndrome. How the LGL syndrome develops individually is different. In the worst case, the frequency and duration of the seizure-like palpitations can increase. It is advisable to have a cardiologist on hand.

See if you can exercise for cardiac arrhythmias are allowed to do.