<unk>  can be caused by intrinsic and extrinsic factors that affect the normal functioning of the<unk> <unk> . Intrinsic causes can include degeneration,<unk> , or remodeling of the<unk> <unk>  while extrinsic causes can create or worsen underlying atrial arrhythmias. Intrinsic causes tend to be responsible for permanent<unk>  while extrinsic causes are more commonly temporary. Intrinsic causes Age-related degenerative fibrosis of the<unk> <unk>  is often identified as the most common intrinsic cause. Other intrinsic causes include inherited ion channel<unk> s, remodeling diseases such as heart failure and atrial fibrillation, infiltrative diseases such as sarcoidosis, amyloidosis, hemochromatosis, and connective tissue diseases, inflammatory etiology such as rheumatic fever, Chagas disease, and Lyme disease, as well as atherosclerotic and ischemic changes to the<unk> <unk>  artery. Inherited<unk>  has been associated with mutations of the gene responsible for the formation of the alpha subunit of the sodium channel (SCN5A). Extrinsic causes Common cardiac pharmacology such as beta-blockers, calcium channel blockers, digoxin, sympatholytic medication, and other antiarrhythmics can alter<unk> <unk>  function to create an arrhythmia such as sick<unk>  syndrome. Electrolyte abnormalities such as hyperkalemia, hypokalemia, and hypocalcemia can also alter normal<unk> <unk>  functioning. Hypothyroidism, hypoxia, hypothermia, and various toxins have also been associated with<unk> s.
Sinus node dysfunction
Pacemaker crosstalk
Cardiac fibrosis
Primary tumors of the heart
Ventricular dyssynchrony
Coronary vasospasm
Ectopic pacemaker
Ventricular remodeling