Editing Sinus node dysfunction (section)

=== Intrinsic causes ===
Age-related degenerative fibrosis of the sinus node is often identified as the most common intrinsic cause.<ref name="Semelka20132" /><ref name="John2016" /> Other intrinsic causes include inherited ion channel dysfunctions, remodeling diseases such as [[heart failure]] and [[atrial fibrillation]], infiltrative diseases such as [[sarcoidosis]], [[amyloidosis]], [[Hereditary haemochromatosis|hemochromatosis]], and [[connective tissue disease]]s, inflammatory etiology such as [[rheumatic fever]], [[Chagas disease]], and [[Lyme disease]], as well as atherosclerotic and ischemic changes to the sinus node artery.<ref name="Semelka20132" /><ref name="John2016" />

Inherited sinus node dysfunction has been associated with mutations of the gene responsible for the formation of the alpha subunit of the sodium channel ([[SCN5A]]).<ref name="Semelka20132" />