What are the other Names for this Condition? (Also known as/Synonyms)

• ATFB (Atrial Fibrillation, Familial)
• Autosomal Dominant Atrial Fibrillation

What is Familial Atrial Fibrillation? (Definition/Background Information)

• Familial Atrial Fibrillation is an inherited heart condition that disrupts the heart's rhythm. It is characterized by erratic electrical activity in the heart's upper chambers (the atria), causing an irregular response in the heart's lower chambers (the ventricles). This causes a fast and irregular heartbeat (arrhythmia)
• Signs and symptoms may include dizziness, chest pain, palpitations, shortness of breath, or fainting. Affected people also have an increased risk of stroke and sudden death. While complications may occur at any age, some affected people never have associated health problems
• Familial Atrial Fibrillation may be caused by changes (mutations) in any of various genes, some of which have not been identified. It is most often inherited in an autosomal dominant manner, but autosomal recessive inheritance has been reported

(Source: Familial Atrial Fibrillation; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Familial Atrial Fibrillation? (Age and Sex Distribution)

• Familial Atrial Fibrillation is a rare congenital disorder. It is the most common type of recurrent arrhythmia
• The presentation of symptoms may occur at any age
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

In the United States, approximately 3 million individuals are affected by this condition.

What are the Risk Factors for Familial Atrial Fibrillation? (Predisposing Factors)

• A positive family history is an important risk factor, since Familial Atrial Fibrillation can be inherited. In general, it has been reported that about 30% of those with idiopathic atrial fibrillation may have a family history of the condition
• Currently, no other risk factors have been clearly identified for the disorder

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Familial Atrial Fibrillation? (Etiology)

Familial Atrial Fibrillation may be caused by mutation(s) in many genes, not all of which have been clearly identified.

• One such gene is KCNQ1, which is important for the functioning of muscle cells in the heart
• Other genes which have been implicated in the development of Familial Atrial Fibrillation are KCNE2 and MYL4
• KCNQ1 gene mutation(s) causing Familial Atrial Fibrillation are inherited in an autosomal dominant manner
• Some causative gene mutation(s) may be inherited in an autosomal recessive manner as well

Autosomal dominant inheritance: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly function gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.

Autosomal recessive mode of inheritance: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).

What are the Signs and Symptoms of Familial Atrial Fibrillation?

The signs and symptoms of Familial Atrial Fibrillation may include:

• Irregular heartbeats (arrhythmia)
• Chest pain
• Dizziness
• Palpitations
• Shortness of breath
• Fainting spells

How is Familial Atrial Fibrillation Diagnosed?

Episodes of Familial Atrial Fibrillation can last for variable time periods, with dormant intervals; and hence, the diagnosis of this condition depends on having ongoing symptoms. If an individual is in the phase of “dormant disease”, the diagnosis may be difficult.

The main diagnostic tools that aid in the detection of Familial Atrial Fibrillation include:

• Physical examination by a healthcare professional that includes listening to the heartbeat, checking for blood pressure and pulse rate, and evaluating family history
• Electrocardiography (EKG or ECG)
• Echocardiography to detect structural abnormalities of the heart
• Trans-esophageal echocardiography is performed in some individuals
• Exercise stress test: This test helps record the heartbeat, blood pressure, and other parameters, while the individual is walking on the treadmill or (exercise) cycling. This is indicative of how well one’s heart works during exercise
• Blood tests: Checking for thyroid hormone level, liver function, kidney function, blood count, and body electrolytes level
• Other tests, such as scanning of the heart (echocardiogram) and chest X-ray, may be needed to check for underlying heart disease
• If Atrial Fibrillation is not continuous and happens intermittently (once a while), special monitors such as a Holter monitor, event recorder, or loop recorder may be required

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Familial Atrial Fibrillation?

Familial Atrial Fibrillation can cause complications (some of which can be serious) such as the following:

• Risks of falls and injury due to dizziness/fainting
• Decreased tolerance to physical exertion
• Impaired cognition
• Tachycardia-induced cardiomyopathy
• Reduced quality of life
• Heart failure: Heart’s inability to pump blood efficiently to meet the body’s demands
• Blood clot formation precipitating stroke: Warning signs of stroke, such as facial drooping, arm weakness, and speaking difficulties, may be noted
• Side effects from treatment medications
• Uncontrolled or recurrent atrial fibrillation in spite of treatment
• Sudden death due to development of ventricular arrhythmia

Note: In case of an emergency and symptoms of stroke being observed, immediately contact your local emergency number (911 in the US).

How is Familial Atrial Fibrillation Treated?

Individuals, who have Familial Atrial Fibrillation without any symptom or any underlying heart conditions, may not need any treatment. 

The treatment of symptomatic Familial Atrial Fibrillation has 3 main goals, as outlined below:

• Controlling the heart rate: Decreasing the rapid heart rate to the optimum level through medications
• Controlling the heart rhythm, which is achieved through:
  • Converting irregular heart rhythm to normal rhythm that is mostly attained through medications
  • But, some cases may require electric shock therapy (electric cardioversion)
  • Minor surgical procedures such as catheter ablation and maze surgery (a type of open heart surgery)
  • Or, implanting special devices (pacemaker) inside the heart to achieve regular rhythm
• Prevention of stroke: All types of atrial fibrillation classes (intermittent or chronic) have equal risk for stroke, irrespective of duration of episodes. By calculating the CHADS2 Score (a scoring system used by healthcare professionals to assess the risk for having a stroke), an individual is advised to start either on aspirin or other powerful blood thinners for stroke prevention

Regular checkups with the healthcare provider at least every 6 months is needed and advised. Some individuals may require more frequent appointments or urgent care to assess the side effects of medications or to evaluate persistent symptoms. Controlling and eliminating the underlying risk factors causing Familial Atrial Fibrillation is an important and recognized method of treatment.

How can Familial Atrial Fibrillation be Prevented?

Familial Atrial Fibrillation may not be preventable, since it is a genetic disorder.

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy), if available, may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited genetic disorders such as Familial Atrial Fibrillation

The following tips may help reduce the risk of complications in symptomatic cases of Familial Atrial Fibrillation:

• Following a healthy lifestyle with regular exercise and a heart-healthy diet
• Avoidance of smoking, alcohol, excess caffeine, and unnecessary medications
• Management of underlying conditions, such as high blood pressure, diabetes, cholesterol, heart failure, heart attack, and thyroid hormone levels
• Managing stress through stress relaxation techniques such as yoga and medication
• Adequate rest and proper sleep
• Regular check up with a healthcare professional or cardiac specialist is recommended

What is the Prognosis of Familial Atrial Fibrillation? (Outcomes/Resolutions)

The long-term outlook (prognosis) for a person with Familial Atrial Fibrillation varies depending on the type of atrial fibrillation the person has, as well as whether another underlying heart condition or disease is present.

• Generally, affected people can live normal, active lives, but ongoing medical care is important
• While a person does not die from atrial fibrillation (AF) itself, a person can die from complications that result from having AF. The main risks in affected people are stroke and heart failure
• Generally, while there is conflicting evidence in younger people with no underlying heart abnormalities, AF is associated with reduced life expectancy in older affected people. In some cases, anti-arrhythmic drugs appear to contribute to increased mortality

(Source: Familial Atrial Fibrillation; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Additional and Relevant Useful Information for Familial Atrial Fibrillation:

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/