What is the cause of my atrial fibrillation?

Q: I am 47 years old. I weigh 65 kg and I am 5 inches 6 feet tall. I have been suffering from slight chest pain on the left side and uneasiness for the past few years. I have hypertension. I stay in a hilly area. I cannot work hard. If I do, I fall sick after 2-3 days. I pass through a lot of stress at office and at home. During my childhood, I got injured in the chest while playing and carrying heavy weight. But no treatment was done and the pain reduced automatically. Recently, I did an ECG and report said: Atrial Fibrillation. A senior medical specialist told me that there is nothing to worry about this. That atrial fibrillation could be due to my shivering in cold at the time of ECG or because of faulty machine. My heart rate is 64/min. I have been taking Atenolol 25 mg for the last 2 years but at the moment I am not taking any medicine for the last 3 months and BP at the moment is 140/90. What is atrial fibrillation?

A:Atrial fibrillation is a disorder of heart beat in which the upper part of the heart (right and left atria) beat at a very rapid rate but the pumping chambers (ventricles) are regulated at a lower but irregular rate usually more than 100 but can be much faster upto 180 to 200 unless treated with drugs.Your heart rate being much lower seems to be normal and the atrial fibrillation reported could be artifactual, being a computer generated report. If atrial fibrillation is confirmed an echocardiography needs to be done to look for any underlying structural cardiac problem.I think you need to be evaluated in view of unexplained fatigue etc.