Middle back pain: Back pain in the middle back area. See detailed information below for a list of 31 causes of Middle back pain, Symptom Checker, Assessment Questionnaire, including diseases and drug side effect causes. Â» Review Causes of Middle back pain: Causes | Symptom Checker Â» | Assessment Questionnaire Â» Causes of Middle back pain:
Valvular Heart Disease. Disorders of certain heart valves can also lead to left atrial enlargement. The mitral valve separates the left atrium from the left ventricle. If the mitral valve becomes narrow -- a condition known as mitral stenosis -- blood accumulates in the left atrium and causes enlargement.
Sometimes the heart enlarges and becomes weak for unknown reasons (idiopathic). A heart condition you're born with (congenital), damage from a heart attack or an abnormal heartbeat (arrhythmia) can cause your heart to enlarge. Other conditions associated with an enlarged heart include: High blood pressure. Your heart may have to pump harder to deliver blood to the rest of your body, enlarging and thickening the muscle. High blood pressure can cause the left ventricle to enlarge, causing the heart muscle eventually to weaken.