Shortness of breath
The irregular heartbeats cause ineffective blood circulation, which ultimately leads to the supply of blood lesser in oxygen content. The inability of the heart to deliver oxygen-rich blood results in the shortness of breath or even difficult to breathe properly, making it an emergency medical situation for the patient. In the severe cases of atrial fibrillation, blood starts building up in the pulmonary veins, which results in the backing up of fluid into the lungs, thus causing shortness of breath. Shortness of breath often accompanies other symptoms of atrial fibrillation, such as fainting or chest pain.