Lown-Ganong-Levine syndrome (LGLS) patients usually have no cardiovascular symptoms between tachycardia crisis. The ailment most often affects men [1] in their second or third decade of life [2], but signs may occur at any age and consist of rapid, regular palpitations caused by a heart rate of 200 beats per minute or more. Episodes typically begin and end suddenly, but the latter may also be perceived as gradual because the episode is followed by sinus tachycardia. Diminished cardiac output caused by the fact that diastole duration is diminished leads to lightheadedness and dyspnea. Chest pain is encountered in victims with coronary artery disease (due to the fact that coronary supply is ensured during diastole), hypertrophic cardiomyopathy or structural heart malformations, such as tricuspid atresia, Ebstein’s anomaly, mitral valve prolapse or corrected transposition of great vessels. Atrial fibrillation may be experienced in such cases, but usually, have short duration [3]. During the attack, arterial hypotension may be recorded. In advanced situations, syncope is noticed by ventricular tachycardia or ventricular fibrillation. Patients sometimes present with heart failure symptoms. The episodes may be followed by polyuria.

The frequency of the crisis tends to diminish with the advancement of age. The death risk is low, however, incidences have been recorded [4]. The demise mechanism is arrhythmic and always appears in patients that have experienced arrhythmia episodes before, so sudden death is never the first symptom [5].

Those who perceive palpitations in the cervical area are more likely to have nodal reentrant tachycardia instead of LGLS [6]. Vagal maneuvers, such as Valsalva or carotid sinus massage may block atrioventricular node conduction and stop the arrhythmia if its technique involves the node, may have no effect or temporarily slow atrioventricular conduction. This clinical response is valuable while trying to establish the process of an paroxysmal tachycardia attack [7].

LGLS diagnosis is mainly based on electrocardiography (ECG). The criteria include a normal or inverted P wave, a short PR interval less than or equal to 0.12 second (120 ms), with normal QRS complex duration, the absence of a delta wave and presence of clinical complaints consisting of tachycardia episodes. However, QRS complexes may also be wide, if the sufferer has a preexisting or functional right bundle or left bundle branch block. A short PR interval may be seen in ectopic atrial rhythms and atrioventricular junctional rhythms [8]. When a patient describes typical supraventricular arrhythmia but normal sinus rhythm is observed on the electrocardiogram, Holter monitorization or implantable loop recorder are indicated. A Holter monitor is useful when symptoms are observed every day, whereas the other method is employed when crisis appear not as often. Obtaining an electrocardiography documentation is particularly important because it can offer important information about the mechanism of the tachycardia.

Blood tests should include serum thyroid-stimulating hormone electrolytes, calcium, and magnesium level. Further information is provided by vagal maneuvers. A carotid sinus massage can only be performed if the subject has no history of cerebrovascular events, has no carotid bruits and the blood pressure is not decreased. It should be done under blood pressure and ECG monitorization. This maneuver can terminate the episode or induce transient atrioventricular block.

A novel technique is represented by noninvasive cardiac mapping using computed-tomography scan–based three-dimensional electroimaging and 252-lead ECG [9]. When the condition becomes intolerable or when a ventricular arrhythmia is suspected, an invasive electrophysiology study is needed.

Treatment for LGL syndrome focuses on managing symptoms and preventing episodes of tachycardia. Lifestyle modifications, such as avoiding caffeine and stress, can help reduce episodes. Medications like beta-blockers or calcium channel blockers may be prescribed to control heart rate. In some cases, catheter ablation, a procedure that destroys the abnormal electrical pathway, may be recommended for patients with frequent or severe symptoms.

The prognosis for individuals with LGL syndrome is generally good, especially with appropriate management. Many people live normal, healthy lives with minimal intervention. However, untreated or severe cases can lead to complications such as heart failure or stroke. Regular follow-up with a healthcare provider is essential to monitor the condition and adjust treatment as needed.

The exact cause of LGL syndrome is not well understood. It is believed to involve an accessory pathway, an extra electrical connection in the heart that bypasses the normal conduction system. This pathway allows electrical impulses to travel more quickly, leading to the rapid heart rates seen in LGL. Genetic factors may play a role, but no specific genetic mutations have been definitively linked to the syndrome.

LGL syndrome is considered rare, with its exact prevalence unknown. It is thought to affect both men and women equally and can occur at any age, though it is often diagnosed in young adults. Due to its rarity and the overlap of symptoms with other heart conditions, LGL may be underdiagnosed.

In LGL syndrome, the heart's electrical system is altered by the presence of an accessory pathway. This pathway allows electrical impulses to bypass the atrioventricular (AV) node, which normally slows down the impulses before they reach the ventricles. As a result, the impulses reach the ventricles more quickly, leading to a short PR interval on the ECG and episodes of tachycardia.

There is no known way to prevent LGL syndrome, as its exact cause is not fully understood. However, individuals with the condition can take steps to minimize symptoms and prevent episodes. These include avoiding known triggers such as caffeine, alcohol, and stress, and adhering to prescribed treatment plans. Regular medical check-ups are important for monitoring the condition.

Lown-Ganong-Levine Syndrome is a rare heart condition characterized by episodes of rapid heart rate due to an accessory electrical pathway. While the exact cause is unknown, the condition can be effectively managed with lifestyle changes, medications, and, in some cases, catheter ablation. The prognosis is generally favorable with appropriate treatment, allowing individuals to lead normal lives.

If you have been diagnosed with Lown-Ganong-Levine Syndrome, it's important to understand your condition and work closely with your healthcare provider. Keep track of your symptoms, follow your treatment plan, and attend regular check-ups. Avoid known triggers like caffeine and stress, and discuss any concerns or changes in your condition with your doctor. With proper management, you can maintain a healthy and active lifestyle.

1. Rodriguez LM, De Chillou C, Schläpfer J, et al. Age at onset and gender of patients with different types of supraventricular tachycardias. Am J Cardiol. 1992;70:1213-5.
2. Tada H, Oral H, Greenstein R, et al. Analysis of age of onset of accessory pathway-mediated tachycardia in men and women. Am J Cardiol. 2002;89:470-1.
3. Sharma MK, Misra S. Anaesthetic management of a patient with Lown-Ganong-Levine syndrome – a case report. Med J Armed Forces India. 2011;67(3):285-7.
4. Santinelli V, Radinovic A, Manguso F, et al. Asymptomatic ventricular preexcitation: a long-term prospective follow-up study of 293 adult patients. Circ Arrhythm Electrophysiol. 2009;2:102-7.
5. Santinelli V, Radinovic A, Manguso F, et al. The natural history of asymptomatic ventricular pre-excitation a long-term prospective follow-up study of 184 asymptomatic children. J Am Coll Cardiol. 2009;53:275-80.
6. González-Torrecilla E, Almendral J, Arenal A, et al. Combined evaluation of bedside clinical variables and the electrocardiogram for the differential diagnosis of paroxysmal atrioventricular reciprocating tachycardias in patients without pre-excitation. J Am Coll Cardiol. 2009;53:2353-8.
7. Marchlinski FE. Diagnosing the mechanism of supraventricular tachycardia: restoring the luster of a fading art. J Am Coll Cardiol. 2009;53:2359-61.
8. Mackenzie R. Short PR interval. J Insur Med. 2005;37:145–152.
9. Shah A, Hocini M, Haissaguerre M, Jaïs P. Non-invasive mapping of cardiac arrhythmias. Curr Cardiol Rep. 2015;17(8):60.