Harvard Heart Letter

What's at the heart of fainting?

About 15% of fainting episodes are related to heart rhythm problems, including the abnormally slow heartbeat known as bradycardia. Blockages in arteries supplying the heart and heart muscle malfunctions can also temporarily disrupt the flow of blood to the brain and cause fainting. Treatment options might include medications to control abnormal heart rhythms, a pacemaker if your fainting is caused by an abnormally slow heartbeat, or an implantable cardioverter-defibrillator if a more serious rhythm problem exists.
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