​Pathology - Mitral Regurgitation

​Pathology - Mitral Regurgitation 
Pathophysiology 
The holosystolic murmur is caused by regurgitant blood flowing from the left ventricle to the left atrium through the mitral valve. When the patient clenches her fists during the handgrip, the murmur gets louder. This action increases systemic vascular resistance, which in turn causes the mitral valve to regurgitate more during systole and reduces the left ventricle's forward flow into the aorta. Rapid ventricular filling from an enlarged left atrium at the beginning of diastole causes the S3 sound. In line with ECG findings, a chest radiograph reveals left atrial and LV enlargement.
Regurgitation of left ventricle blood flow is accompanied by a rise in left atrial and pulmonary pressures, which are regulated by the left atrium's gradual expansion and greater compliance. LV enlargement is a compensatory mechanism to keep the heart pumping blood. Fatigue and weakness upon exertion are signs that the heart is not working hard enough to raise its output when exercising. PND may be a sign of declining left atrial pressure and maybe the beginning of heart failure.