Atrial Fibrillation and Atrial Flutter

Description of the Disease

Atrial fibrillation is an irregular, often rapid heart rhythm (arrhythmia) that disrupts the normal flow of blood through the heart and the rest of the body. During atrial fibrillation, the two upper chambers of the heart (the atria) beat rapidly and chaotically, out of sync with the ventricles. Instead of contracting effectively, the atrial muscle fibers quiver (fibrillate), resulting from abnormal electrical impulses continuously circulating through the atria. Atrial fibrillation is one of the most common cardiac arrhythmias, and its prevalence increases with age. It affects approximately 3% of people over the age of 50.

Atrial flutter is a closely related arrhythmia in which the atria beat rapidly but in a more organized pattern than in atrial fibrillation. Both conditions share similar symptoms, risk factors, complications, and treatment approaches.

Risk Factors

The exact cause of atrial fibrillation is not always known. However, it occurs more frequently in older adults and in people with cardiovascular diseases such as hypertension, congenital heart disease, valvular heart disease, and cardiomyopathy. Other conditions associated with atrial fibrillation include hyperthyroidism, bronchial asthma, sleep apnea, and carbon monoxide poisoning. Episodes may also be triggered by excessive alcohol consumption, energy drinks, or the use of recreational drugs.

Classification

Atrial fibrillation is classified according to its duration, as this influences treatment decisions:

• Acute (paroxysmal) atrial fibrillation: Lasts less than 48 hours, most commonly less than 24 hours.
• Persistent atrial fibrillation: Lasts longer than 48 hours but less than 7 days.
• Permanent atrial fibrillation: Persists for more than 7 days or is accepted as permanent.

Symptoms

The most common symptom is palpitations. A normal resting heart rate ranges from 60 to 100 beats per minute, whereas during atrial fibrillation the heart rate may increase to approximately 140 beats per minute or higher. Other symptoms may include dizziness, weakness, low blood pressure, chest pain, shortness of breath, and reduced exercise tolerance.

Some individuals experience no symptoms, and the arrhythmia is detected incidentally during a routine medical examination.

Diagnosis

The primary diagnostic test is an electrocardiogram (ECG), which confirms the abnormal heart rhythm. Additional investigations may include Holter monitoring for continuous heart rhythm recording, echocardiography to evaluate heart structure and function, and blood tests to identify underlying conditions.

Treatment

Atrial fibrillation may occur as occasional episodes or persist continuously. Although it is not always immediately life-threatening, treatment is essential because of the increased risk of complications. Blood clots can form within the fibrillating atria and travel to the brain or other organs, causing stroke or systemic embolism.

The main goals of treatment are:

• Restore or maintain a normal heart rhythm or control the heart rate using medications or electrical cardioversion.
• Prevent blood clot formation and reduce the risk of stroke with anticoagulant (blood-thinning) medications.

Source | Author Doctor Nikas Samuolis, reviewed by Prof. Virginijus Šapoka | Vilnius University | Faculty of Medicine | Head of the Department of Internal Medicine, Family Medicine, and Oncology