From the Guidelines
Atrial fibrillation (AFib) is characterized by irregular, chaotic electrical activity with no discernible P waves and an irregularly irregular rhythm on an electrocardiogram (ECG), with rapid, disorganized fibrillatory waves and unpredictable ventricular response intervals. The definition of AFib is based on the 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation, which states that AFib is a supraventricular tachyarrhythmia with uncoordinated atrial activation and ineffective atrial contraction, characterized by irregular R-R intervals, absence of distinct P waves, and irregular atrial activity also known as fibrillatory waves 1.
Key Characteristics of AFib
- Irregular, chaotic electrical activity
- No discernible P waves
- Irregularly irregular rhythm
- Rapid, disorganized fibrillatory waves
- Unpredictable ventricular response intervals
The heart rate in AFib can vary widely, from normal to very rapid, depending on how well the AV node blocks the numerous atrial impulses. This chaotic electrical pattern reflects the underlying pathophysiology of AFib, where multiple electrical wavelets circulate throughout the atria rather than following the normal conduction pathway. The absence of coordinated atrial contraction reduces cardiac output by approximately 20-30% and creates conditions where blood can pool in the atria, potentially forming clots that may lead to stroke or other embolic events.
Clinical Implications
- Reduced cardiac output
- Increased risk of stroke and other embolic events
- Variable symptoms and poor quality of life
- Need for early and dynamic management of comorbidities and risk factors to achieve optimal care, as emphasized in the 2024 ESC guidelines for the management of atrial fibrillation 1.
Overall, the diagnosis and management of AFib require a comprehensive approach, taking into account the patient's individual characteristics, symptoms, and risk factors, as well as the latest evidence-based guidelines and recommendations 1.
From the Research
Characteristics of Atrial Fibrillation (AFib)
- Atrial fibrillation (AF) is characterized by a rapid and irregular heartbeat that can be asymptomatic or lead to symptoms such as palpitations, dyspnoea, and dizziness 2.
- On an electrocardiogram, AF is characterized by the replacement of P waves by rapid oscillations or fibrillatory waves that vary in size, shape, and timing 3.
- AF is a supraventricular tachyarrhythmia characterized by uncoordinated atrial activation with consequent deterioration of atrial mechanical function 3, 4.
- It can be diagnosed on an EKG by lack of a P-wave and irregular QRS complexes 5.
Clinical Presentation
- Acute atrial fibrillation is rapid, irregular, and chaotic atrial activity of less than 48 hours' duration 6.
- Risk factors for acute atrial fibrillation include increasing age, cardiovascular disease, alcohol, diabetes, and lung disease 6.
- AF increases the risk of stroke and heart failure 6, 5.
- Poorly controlled or undiagnosed atrial fibrillation increases the risk of mortality and may decrease quality of life 4.
Diagnosis and Identification
- Identifying and staying abreast of cardiovascular care and current updates in treatment is strongly encouraged as guidelines are revised and updated as new treatments evolve 4.
- The condition can be associated with serious complications, including an increased risk of stroke 2.
- Important recent developments in the clinical epidemiology and management of AF have informed our approach to this arrhythmia 2.