Atrial fibrillation (AFib) is an irregular and often rapid heart rhythm originating in the heart’s upper chambers. It occurs when the electrical signals controlling the heartbeat become disorganized, leading to chaotic contractions. While some individuals may experience minimal symptoms, leaving AFib unaddressed can lead to severe and lasting health problems.
Increased Risk of Stroke
Untreated AFib significantly elevates the risk of stroke, a serious condition where blood flow to the brain is interrupted. The irregular and often rapid beating of the atria prevents them from emptying blood completely into the lower chambers of the heart, the ventricles. This inefficient pumping allows blood to pool and become stagnant, particularly in a small pouch off the left atrium called the left atrial appendage (LAA).
When blood pools, it can thicken and form blood clots. These clots can then dislodge from the heart and travel through the bloodstream. If a clot reaches the brain, it can block a cerebral artery, leading to an ischemic stroke.
AFib-related strokes are often more severe than other types of ischemic strokes, potentially causing more significant neurological damage or even death. Approximately 20% to 25% of all ischemic strokes are attributed to AFib, with the risk increasing with age. For individuals with AFib, the risk of ischemic stroke is elevated by about five times compared to those without the condition.
Progression to Heart Failure
A persistently rapid and irregular heart rate from untreated AFib strains the heart muscle. This continuous overwork can weaken the heart, making it less efficient at pumping blood throughout the body, potentially leading to heart failure. The heart may become enlarged and ineffective.
Heart failure means the heart struggles to meet the body’s demand for oxygenated blood. When the heart beats too quickly or unevenly, it does not have enough time to fill properly with blood before each pump. This can cause blood to “back up” in the pulmonary veins, leading to fluid accumulation in the lungs and other parts of the body.
Symptoms of heart failure include shortness of breath, particularly when lying down, persistent fatigue, and swelling in the feet, ankles, and legs. While heart failure can develop from various causes, untreated AFib is a recognized contributor, and its presence can worsen existing heart failure or lead to its new development.
Other Serious Health Complications
Untreated AFib can lead to a range of other serious health complications beyond stroke and heart failure, affecting both the heart and the brain.
Cardiomyopathy
Chronic, rapid heart rates associated with untreated AFib can directly cause structural damage and weakening of the heart muscle, a condition known as tachycardia-induced cardiomyopathy (TIC). This occurs when the heart’s constant rapid beating leads to changes that decrease its ability to contract effectively.
TIC is a reversible form of left ventricular dysfunction, meaning that if the underlying arrhythmia is controlled, heart function can often improve. Heart rates consistently above 110-120 beats per minute have been observed in many patients who develop the condition. Early identification and treatment are important for reversing heart muscle damage.
Cognitive Impairment and Dementia
Untreated AFib is linked to an increased risk of cognitive decline, including memory problems and dementia, even independent of overt strokes. One mechanism involves silent cerebral ischemia, where tiny blood clots block small arteries and deprive brain tissue of oxygen. Over time, this cumulative damage can lead to a decline in cognitive function.
Another contributing factor is reduced and intermittent cerebral perfusion due to the irregular heart rhythm. The beat-to-beat variations and reduced cardiac output in AFib can result in the brain not consistently receiving adequate blood flow. This chronic lack of sufficient blood flow can impair brain health, leading to issues with memory, language skills, and overall cognitive abilities.
Reduced Quality of Life
The chronic symptoms of untreated AFib can diminish a person’s quality of life. Individuals may experience persistent fatigue, shortness of breath, and dizziness, even during daily activities. These symptoms can lead to reduced exercise tolerance and weakness, making routine tasks or hobbies difficult.
Beyond physical symptoms, untreated AFib can also cause anxiety and fear. The unpredictable nature of irregular heartbeats and the worry about potential complications like stroke or heart failure can be significant. This ongoing apprehension impacts mental well-being, diminishing overall quality of life and affecting social and emotional health.