A-fib strikes unexpectedly—how a racing heart can signal danger

Atrial fibrillation, or A-fib, is a condition where the heart beats irregularly and often too fast. More than 10 million Americans live with it, and the numbers are growing. For many, the first signs—like shortness of breath or a pounding chest—come as a surprise.

Daniel Moore, a 30-year-old radiologist, experienced A-fib unexpectedly. His symptoms included lightheadedness and a racing heartbeat, which can exceed 200 beats per minute—far above the normal resting rate of 60 to 100. The condition happens when the heart's upper chambers malfunction, disrupting electrical signals.

A-fib can stem from high blood pressure, diabetes, stress, or infections like COVID-19. If untreated, it may cause blood to pool in the heart, forming clots that lead to strokes or heart failure. Many people remain unaware of their symptoms until diagnosed, often with the help of devices like smartwatches.

Globally, around 33.5 million people have A-fib, according to the World Health Organization. While there is no cure, treatments such as cardioversion, ablation, medications, or implanted devices help manage the condition.

Early detection of A-fib is becoming more common thanks to wearable technology. Without treatment, the risks of stroke and heart failure rise significantly. Doctors continue to stress the importance of monitoring heart health and seeking medical advice.