What it is
Atrial fibrillation — AFib — is the most common heart rhythm disorder I treat. Normally, the heart's upper chambers get a single organized electrical signal that makes them contract together, pushing blood down into the lower chambers. In AFib, they get 300 to 500 signals a minute instead, firing chaotically. The upper chambers stop contracting and just quiver. I've heard it described as feeling like a bag of worms rather than a steady pump, and that's about right.
Why it matters
Because the upper chambers are quivering instead of squeezing, blood can pool and stagnate — especially in a small pouch called the left atrial appendage. Stagnant blood clots. If that clot leaves the heart and reaches the brain, that's a stroke. AFib carries roughly a five-fold increase in stroke risk, and about 95% of AFib-related strokes trace back to a clot that formed in that appendage. That's the whole reason we take AFib seriously even when it doesn't feel dramatic.
What you might feel
Some people don't feel it at all. When they do, the most common symptoms are a rapid or irregular heartbeat, shortness of breath, dizziness, anxiety, and chest discomfort. Sudden weakness or numbness, trouble speaking, severe chest pain, or severe shortness of breath are stroke or heart-attack warning signs — get emergency care immediately if any of those show up.
How we manage it
Treatment addresses two separate problems: lowering stroke risk (usually blood thinners, sometimes a procedure to close off the left atrial appendage) and trying to keep the rhythm normal (medication, an electrical cardioversion, or catheter ablation). We also go after the risk factors driving it — high blood pressure, obesity, sleep apnea, other heart disease — because managing those slows progression and cuts down on recurrence.