Atrial fibrillation (AF or AFib) is a type of heart rhythm disorder that affects the upper chambers of the heart (atria). It is characterised by rapid and irregular electrical impulses in the atria that cause the heart to beat in a fast and irregular manner.
In AF, the normal electrical signals that coordinate the contraction of the atria are disrupted, leading to rapid and irregular contractions. This can cause blood to pool in the atria and increase the risk of blood clots forming, which can potentially lead to stroke or other serious complications.
AF is a common condition, affecting millions of people worldwide. It is more common in older adults, but can occur at any age.
Characteristics
- Rhythm is always irregular – irregularly irregular
- There are no normal shaped or sized P waves – instead there is an “f” wave (fibrillation wave) – represent abnormal, chaotic and incomplete depolarisation of the muscle fibres in the atria (similar to VF but smaller scale)
- The QRS is a narrow complex (<0.12 sec)
- If ventricular rate is faster than 100 the rhythm is called Uncontrolled Atrial Fibrillation
- If ventricular rate is slower than 100 the rhythm is called Controlled Atrial Fibrillation
Atrial fibrillation (AF) appears on an electrocardiogram (ECG) as an irregular and rapid series of small and uneven P waves. The P waves in AF are often difficult to identify, and may be replaced by a baseline oscillation or fibrillatory waves. The ventricular rate in AF can vary and can be either fast or slow, depending on the presence or absence of conduction blocks in the AV node.
In AF, the QRS complex remains normal, but the rhythm is irregular and may be rapid. The ECG may also show evidence of atrial enlargement, including P wave duration >120 ms, P wave amplitude >2.5 mm, or P wave axis deviation.
Atrial fibrillation (AF or AFib) is a type of heart rhythm disorder characterised by several key features, including:
- Rapid and irregular heartbeat: AF is characterised by rapid and irregular electrical impulses in the atria, which can cause the heart to beat in a fast and irregular manner.
- Abnormal electrical signals: The normal electrical signals that coordinate the contraction of the atria are disrupted in AF, leading to rapid and irregular contractions.
- Blood clots: AF can cause blood to pool in the atria, increasing the risk of blood clots forming, which can potentially lead to stroke or other serious complications.
- Increased heart rate: AF can cause the heart rate to increase, which can lead to symptoms such as palpitations, dizziness, and fatigue.
- Common in older adults: AF is more common in older adults, but can occur at any age.
- Can be asymptomatic: AF can be asymptomatic, meaning that some people may have the condition and not experience any symptoms.
- Can cause long-term complications: If left untreated, AF can lead to long-term complications, such as heart failure, stroke, and other serious health problems.
Overall, AF is a complex and potentially serious condition that affects the heart’s electrical and structural function.
Symptoms
Atrial fibrillation (AF or AFib) can cause a range of symptoms, including:
- Palpitations: Many people with AF experience rapid, fluttering, or irregular heartbeats, which can feel like the heart is skipping a beat or racing.
- Dizziness: AF can cause dizziness or lightheadedness, especially when getting up from a lying or sitting position.
- Fatigue: People with AF may feel tired or fatigued, especially after physical activity.
- Shortness of breath: AF can cause shortness of breath, especially during physical activity or when lying down.
- Chest pain: Some people with AF may experience chest pain or discomfort, although this is less common.
- Sweating: AF can cause excessive sweating, especially during episodes of palpitations.
Not everyone with AF will experience all of these symptoms, and some people may have no symptoms at all.
Pathophysiology
The exact pathophysiology of atrial fibrillation (AF) is not fully understood, but it is believed to involve several factors, including:
- Abnormal electrical impulses: In AF, the normal electrical impulses that coordinate the contraction of the atria are disrupted, leading to rapid and irregular contractions.
- Abnormal atrial tissue: Abnormalities in the tissue and structure of the atria, such as fibrosis, inflammation, or scarring, can also contribute to the development of AF.
- Underlying heart disease: AF is more common in individuals with underlying heart disease, such as heart failure, valvular heart disease, or cardiomyopathy.
- Electrolyte imbalances: Electrolyte imbalances, such as low potassium or magnesium levels, can also contribute to the development of AF.
- Age: AF is more common in older adults, and the risk of developing AF increases with age.
- Other factors: Other factors that can increase the risk of developing AF include high blood pressure, obesity, sleep apnea, alcohol consumption, and certain medications.
Overall, the pathophysiology of AF is complex and involves multiple factors that can interact with each other and disrupt the normal electrical and structural function of the heart.
Treatment of AF may involve medications to control the heart rate and prevent blood clots, as well as procedures such as cardioversion, ablation, and anticoagulation therapy to restore normal heart rhythm and prevent complications.