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.
Tricuspid insufficiency (TI) , a valvular heart disease also called tricuspid regurgitation (TR), refers to the failure of the heart's tricuspid valve to close properly during systole.eft ventricular failure is, in turn, the most common cause of right ventricular dilation. Other common causes of right ventricular dilation include right ventricular infarction, inferior myocardial infarction and cor pulmonale. Other diseases can directly affect the tricuspid valve.