what can cause racing heart and feeling of passing out?
Sudden rapid, irregular and chaotic heartbeats may be a sign of a common heart rhythm problem called atrial fibrillation (. ). Rarely, passing out, or Fainting, may be caused by the most dangerous arrhythmia, ventricular fibrillation (VF). VF is the number one cause of sudden cardiac death. Within seconds, the person loses consciousness and, without immediate emergency treatment, will die within minutes.
1 You are losing a lot of blood. 2  This could include internal bleeding that you can't see. 3  You feel short of breath. 4  You have chest pain. 5  You feel like your heart is racing or beating unevenly (palpitations). 6  It happens along with numbness or tingling on one side of the face or body.