Mellanie says that she lives in fear every day that her heart will speed up uncontrollably without warning. She suffers from a heart condition called atrial fibrillation, or AFib, the most common heart rhythm problem in which the heart beats too slowly, too fast, or in an irregular way.

“When I’m experiencing AFib, I feel like I’m running a marathon 24 hours a day,” she says.

On Wednesday’s episode of Dr. Phil, Mellanie and Dr. Phil are joined by Dr. Freda Lewis-Hall, Chief Patient Officer of Pfizer, who explains what happens to the body during AFib, the dangers associated with it, risk factors and warning signs.

“The scary thing is that there may be no signs at all,” Dr. Lewis-Hall says.

Learn more in the video above, and get educated at

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