Atrial Fibrillation (AFib) is a common type of irregular heartbeat, or arrhythmia. It is characterized by rapid, disorganized electrical activity in the heart’s upper chambers (the atria). This chaotic signaling causes the atria to quiver rather than contract effectively, reducing the heart’s pumping efficiency. Understanding how AFib manifests, through physical sensations or medical tests, is crucial, though only a professional can provide a diagnosis.
Symptoms and Physical Signs
The most common way people experience AFib is through subjective sensations in the chest, often described as the heart beating “out of sync.” Individuals frequently report heart palpitations, which can feel like a fluttering, quivering, thumping, or a sensation of skipped beats.
The heart’s inefficient pumping action causes physical symptoms throughout the body. Individuals may experience fatigue, lightheadedness, or dizziness, especially during activity, because the brain and muscles receive inadequate oxygenated blood. Shortness of breath is also a frequent complaint, sometimes noticeable at rest, as poor blood flow can lead to fluid accumulation in the lungs. A dull chest discomfort or pressure always warrants immediate medical evaluation.
When checking the pulse, a person with AFib typically has a heart rate that is both rapid and highly irregular. Unlike a normal, steady rhythm, the pulse has no set pattern, with the time between beats constantly varying. It is possible to have “silent AFib,” where a person experiences no noticeable symptoms and the condition is only discovered during a routine physical examination or diagnostic test.
Electrical Signature on a Diagnostic Test
A definitive diagnosis of Atrial Fibrillation is made by analyzing the heart’s electrical activity using an electrocardiogram, or ECG. The ECG translates the electrical signals into a visual wave pattern, and AFib presents a distinct signature that differs significantly from a normal, organized heart rhythm.
The key visual feature is the absence of distinct P-waves, which represent the normal electrical contraction of the atria. Instead, the ECG baseline often appears chaotic or “wavy,” displaying small, rapid, and irregular deflections known as fibrillatory or “f-waves.” This chaotic baseline reflects the disorganized electrical activity within the upper chambers.
Electrical signals that pass to the lower chambers (ventricles) do so randomly, resulting in an “irregularly irregular” rhythm. This appears on the ECG as QRS complexes—the tall spikes representing ventricular contraction—occurring at random, unpredictable intervals. The QRS complexes themselves are usually narrow, indicating normal electrical conduction through the ventricles. This combination of absent P-waves and an irregularly timed ventricular response is the electrical hallmark of AFib.
Variability in Frequency and Duration
Atrial Fibrillation is classified based on the frequency and duration of episodes. The classification depends on the temporal pattern of the rhythm. Paroxysmal AFib involves episodes that start spontaneously but stop on their own, typically within seven days of onset.
If an episode lasts for more than seven days, it is classified as Persistent AFib. This type requires medical intervention, such as medication or cardioversion (an electrical shock), to return to a normal rhythm. Long-standing Persistent AFib describes a continuous irregular heart rhythm lasting for twelve months or longer.
The final classification is Permanent AFib, which represents a clinical decision made between the patient and physician. In this scenario, attempts to restore a normal heart rhythm are abandoned, and the heart remains in the irregular rhythm long-term. Regardless of the classification, the risk of stroke remains a concern, and preventative treatment is often needed.
Signs Requiring Immediate Medical Care
AFib increases the risk of serious complications, and certain signs require immediate emergency medical services. AFib significantly raises the risk of stroke, as disorganized movement in the atria can cause blood to pool and form clots. If a clot travels to the brain, it can block blood flow, causing a stroke.
Signs of a potential stroke include sudden weakness or numbness on one side of the body, particularly in the face or an arm. Other neurological signs are difficulty speaking, slurred words, or sudden confusion that makes it hard to understand or communicate. These symptoms require urgent intervention to minimize potential long-term damage.
Severe, acute shortness of breath, especially with severe chest pain or pressure, can indicate a heart attack or acute heart failure. Fainting or a sudden drop in blood pressure, leading to dizziness or loss of consciousness, also warrants emergency care. These indicators suggest the heart’s pumping function has become severely compromised, necessitating immediate medical stabilization.