Atrial fibrillation (AF) is directly caused by inconsistent signals in the heart’s electrical system. Numerous conditions may cause these signals to become irregular. Some conditions that may contribute to AF and are considered risk factors for the condition include:

• High blood pressure.
  
  
• Coronary artery disease.
  
  
• Previous heart attack.
  
  
• Valvular heart disease
  
  
• Congenital heart defects, including valve abnormalities.
  
  
• Cardiomyopathy.
  
  
• Diabetes.
  
  
• Other arrhythmias, including atrial flutter and ventricular fibrillation.
  
  
• Inflammation. This occurs commonly after heart surgery, such as bypass surgery, and less commonly with infections such as pericarditis.
  
  
• Lung problems or disease, including pulmonary embolisms.
  
  
• Excessive alcohol use.
  
  
• Thyroid disease.
  
  
• Viral infections.
  
  
• Obesity.

Many other factors may potential relate to atrial fibrillation, including the use of various drugs or supplements. Recent research has indicated a connection between atrial fibrillation and the presence of Helicobactor pylori, a bacterium that causes peptic ulcers. About 5 percent of the general population harbors this bacterium in their stomachs. In a research study, more than 90 percent of patients with atrial fibrillation had the H. pylori bacteria.