What happens during atrial fibrillation?
A range of conditions that can cause changes in the electrical conduction system of the heart or the muscle around it can contribute to the disorder.
Lifestyle choices, including an inactive lifestyle, smoking, and consuming alcohol in large amounts, can trigger episodes of A-fib.
In this article, we explore the factors that can contribute to triggering A-fib or a person developing the condition.
Heart tissue changes
Changes in heart tissue can lead to the abnormal rhythms characteristic of A-fib.
When a person's heart is in its normal sinus rhythm, a signal is sent from a spot in the right atrium, called the sinoatrial (SA) node.
This signal travels down specific conduction pathways and spreads uniformly through the atria first and then the two lower chambers of the heart known as the ventricles.
This process causes the heart to squeeze and pump out blood in a sequence that equates to one heartbeat.
The signal occurs and is conducted through the heart in a stepwise, uniform way so that the heart beats regularly.
In A-fib, the SA node does not work correctly, so the signal to start a heartbeat comes from elsewhere in the atrium.
In this scenario, the signal cannot travel down the usual conduction paths, so it travels all over the heart tissue, chaotically. This causes the heartbeat to be irregular.
Characteristics and conditions
A number of factors can increase the risk of having A-fib. It occurs more frequently in men and after they reach the age of 65 years old.
Conditions that increase the risk for A-fib include:
- coronary artery disease
- high blood pressure
- a heart valve problem
- heart failure
- a previous heart attack
- previous heart surgery
- thickened muscle in the heart walls, known as hypertrophic cardiomyopathy
- inflammation of the lining (pericarditis) or muscle (myocarditis) of the heart
- a malfunctioning SA node, called sick sinus syndrome
- the lung condition, chronic obstructive pulmonary disorder (COPD)
- blood clot in the lung, or pulmonary embolism
- sleep apnea
- a viral infection of the heart
- family history of A-fib
- heart problems at birth, known as congenital heart disease
These factors increase the risk of having A-fib, although people can also experience the irregular rhythms of A-fib without having any them.
In one type of A-fib known as paroxysmal A-fib, the episodes can be very short and come and go. Some lifestyle choices can trigger an episode of this type of A-fib.
Possible triggers include:
large amounts of caffeine, such as in coffee or energy drinks, especially if a person is unused to it
- large amounts of alcohol, particularly during binge drinking
- emotional or situational stress
- recreational stimulant drugs, such as cocaine and methamphetamine
- smoking tobacco products
A-fib is more likely to happen when a person has an infection, such as pneumonia, and in the days following surgery, especially heart or lung surgery.
Changes in electrical signaling in the heart and surrounding tissues that control the heartbeat are at the root of A-fib.
Many medical conditions can increase the risk of having A-fib, especially those that involve the heart. Other diseases can also increase the risk, including COPD, hyperthyroidism, and high blood pressure.
Triggers can set off episodes of A-fib, including stress and excessive caffeine. If people have concerns about an irregular heartbeat, they should arrange to see their doctor as soon as possible.
How do I treat or manage A-fib if the doctor cannot find the cause?
The treatment for A-fib depends on the type of A-fib you have, not the factors that may be increasing your risk of getting it. If you do have a condition that puts you at increased risk of A-fib, treating that condition may reduce the number of episodes of A-fib you have.
Depending on the type of A-fib you have and what your symptoms are, one of two choices of treatment are available.
Your doctor will either try to convert back to a regular rhythm or prescribe medications to control the heart rate along with medication to prevent blood clots from forming.Nancy Moyer, MD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.