Atrial fibrillation (AFib) is a common heart rhythm disorder that affects millions globally. It involves an irregular and often rapid heartbeat, originating from the heart’s upper chambers, the atria. In a healthy heart, electrical signals coordinate the contractions that pump blood effectively. With AFib, these signals become chaotic, causing the atria to quiver rather than contract efficiently. This can lead to inefficient blood pumping throughout the body.
Understanding AFib’s Origins
True congenital AFib, present at birth, is rare. It typically stems from structural heart defects or specific single-gene mutations that affect ion channels. Examples include mutations in genes like KCNQ1 and SCN5A. These genetic changes can disrupt the heart’s normal electrical signaling pathways from an early age.
While true congenital AFib is uncommon, a genetic predisposition for developing it later in life is more prevalent. Individuals may inherit an increased likelihood due to multiple genetic factors. Family history often indicates this; having a parent with AFib can approximately double the risk. This inherited susceptibility interacts with environmental and lifestyle factors, often leading to AFib in adulthood. Genetic testing can identify some of these variants.
Common Causes of Acquired AFib
AFib is most frequently acquired, developing over time due to various risk factors. Advanced age is a significant factor, with risk increasing each decade. High blood pressure is a leading cause, forcing the heart to work harder and disrupting electrical signals. Coronary artery disease, with narrowed arteries, can also damage the heart’s electrical system.
Other heart-related conditions also contribute to acquired AFib. Heart failure creates an environment that predisposes individuals to AFib. Problems with heart valves can also increase the risk. Beyond direct cardiac issues, several systemic conditions are strongly linked. Obesity significantly increases AFib risk, partly due to its association with high blood pressure and diabetes.
Diabetes is a notable risk factor, increasing AFib likelihood by about 40% in type 2 diabetes. Poorly controlled blood sugar can damage heart tissue. Sleep apnea stresses the heart, promoting AFib. Excessive alcohol consumption, including binge drinking, can trigger episodes; chronic use also increases risk. Thyroid disorders, especially hyperthyroidism, can stimulate the heart, leading to an irregular rhythm.
Recognizing AFib
Recognizing the signs of AFib is important for timely diagnosis and management. Many individuals experience heart palpitations, which can feel like a racing, pounding, fluttering, or skipping sensation in the chest. These sensations indicate the heart’s irregular rhythm. Shortness of breath, particularly during activity, can also occur due to the heart’s reduced pumping efficiency.
Fatigue and weakness are also common symptoms. Dizziness or lightheadedness, and in some cases, fainting, can occur if the heart is not pumping enough blood to the brain. Some individuals might also report chest pain or pressure. AFib symptoms can vary greatly, and some people may not experience any noticeable symptoms at all. This “silent AFib” can make diagnosis challenging, often discovered during routine check-ups or when complications like a stroke occur.
Diagnosing AFib
Healthcare professionals use several methods to diagnose AFib, often starting with a thorough review of medical history and a physical examination. The primary diagnostic tool is an electrocardiogram (ECG), which measures the heart’s electrical activity. An ECG can reveal the characteristic irregular and chaotic electrical signals of AFib. However, because AFib episodes can be intermittent, a standard, short ECG might not capture the arrhythmia.
To address this, longer-term monitoring devices are often used. A Holter monitor is a portable ECG device worn for 24 to 48 hours to continuously record the heart’s activity during daily routines. For less frequent symptoms, an event recorder can be used for up to 30 days. This device records the heart’s rhythm when activated by the patient experiencing symptoms, or some can automatically record when an irregular rhythm is detected. An implantable loop recorder, a small device placed under the skin, can continuously monitor the heartbeat for up to three years, useful for detecting very rare episodes.
Beyond electrical monitoring, other tests provide crucial information. An echocardiogram assesses the heart’s structure and function. While it does not directly diagnose AFib, it can identify underlying heart conditions like valve problems or chamber enlargement that contribute to the arrhythmia. Blood tests are also performed to check for underlying conditions that might cause or worsen AFib, such as thyroid issues or electrolyte imbalances. More specialized imaging, such as a cardiac MRI, can assess structural changes in the heart. Electrophysiology studies, which involve mapping the heart’s electrical pathways, may be used in some cases to pinpoint the source of abnormal rhythms.