Lev's disease
Synonyms and keywords: Lenegre-Lev disease, Lenegres disease, Maladie de Lenegre, Acquired complete heart block

# Overview
Lev's disease is an acquired complete heart block due to idiopathic fibrosis and calcification of the electrical conduction system of the heart.  Lev's disease is most commonly seen in the elderly and is often described as senile degeneration of the conduction system.
One form has been associated with SCN5A.
Lev's Syndrome is a rare, progressive cardiac conduction defect (PCCD) due to myocardial fibrosis first described by Maurice Lev in 1964. This condition, proposed to start in the fourth decade of life, involves a sclerotic fibro-fatty degeneration of the Bundle of His and Purkinje fibers, which Lev proposed caused increasing AV delay with age. With the prevalence of electrocardiogram (ECG) use in the emergency department (ED) for cardiac- and non-cardiac complaints, dysrhythmias can be incidentally found and confuse diagnosis and disposition. We highlight the case of an 84-year-old male who presented to the ED for acute onset of diffuse facial paresthesias with elevated blood pressure at home and was found to be significantly bradycardic on initial evaluation. On serial ECGs, the conduction rhythm changed from an initial new first-degree atrioventricular (AV) block with left bundle branch block (LBBB), to a later first-degree AV block without LBBB. Cardiology was consulted. Serial ECGs demonstrated an evolving conduction block arrhythmia consistent with Lev's Syndrome. Here we describe a case of symptomatic bradycardia found to be consistent with Lev's Syndrome.

# Historical Perspective
- In 1954, Lenegre published the condition in French, hence, it is also referred to as Lenegres disease or Maladie de Lenegre in French, after his name.
- In 1964, it was described independently by the two researchers, Jean Lenegre and Maurice Lev in English, but the condition is generally called after Lev.

# Pathophysiology
One form has been associated with SCN5A
- Fibrous transformation progressive and slow, of degenerative origin, of the two branches of the bundle of His, resulting in progressive conductional disorders:
block of branch with or without hemibloc of the opposite side
then complete, paroxysmal then permanent block of auriculoventricular (disease of Adams-Stokes).
- block of branch with or without hemibloc of the opposite side
- then complete, paroxysmal then permanent block of auriculoventricular (disease of Adams-Stokes).

## Associated Conditions
Stokes-Adams attacks can be precipitated by this condition. These involve a temporary loss of consciousness due to ventricular fibrillation or asystole.

## Pathophysiology of AV Block
- Fibrosis and sclerosis of the conduction system, which appears idiopathic, accounts for about one-half of cases of AV block.
- Conduction system fibrosis and sclerosis may be induced by several different conditions that often cannot be distinguished clinically.
- Additionally, some degree of fibrosis and sclerosis occurs as part of the normal aging process, with the prevalence increasing progressively with age with approximately a 2:1 male:female predominance.
- Among a prospective cohort of more than half a million United Kingdom residents, the prevalence of conduction system disease (which included all levels of AV block, as well as bundle branch blocks) was approximately 11 per 10,000 persons under age 55 and increased to between 55 per 10,000 persons 65 years of age.
- Idiopathic  Apparently idiopathic progressive cardiac conduction defects are the most common cause of AV block, occurring in approximately 50 percent of cases. Idiopathic AV conduction abnormalities are characterized by progressive impairment of the conduction system which occurs gradually over decades:
Lenegre's disease  The term Lenegre's disease has been traditionally used to describe a progressive, fibrotic, sclerodegenerative affliction of the conduction system in younger (age <60 years) individuals. Lenegre's disease is frequently associated with slow progression to complete heart block and may be hereditary.
Lev's disease  The term Lev's disease has been used to refer to "sclerosis of the left side of the cardiac skeleton" in older patients (age >70 years old), such as that associated with calcific involvement of the aortic and mitral rings. Lev's disease is caused by fibrosis or calcification extending from any of the fibrous structures adjacent to the conduction system into the conduction system.
Depending upon the anatomic location of the areas of fibrosis and sclerosis, various conduction abnormalities can result with the following causing Lev's disease:
Involvement of the mitral ring or the central fibrous body, for example, may be the most common cause of complete heart block with a narrow QRS complex in the elderly.

# Related Chapters
- Heart block