How is atrial fibrillation (A Fib) diagnosed without symptoms?

People who do not have symptoms and developed atrial fibrillation often receive the diagnosis when they present for other medical evaluations, such as a routine check-up, maybe for treatment of a head cold or a runny nose, or something of that sort. The physician evaluating that patient would notice the faster heart rate or potentially an irregular heart rhythm. That physician or provider would obtain an EKG that would lead to the diagnosis of atrial fibrillation.