Can mitral regurgitation (MR) cause backflow into the left ventricle (LV)?

From the Guidelines

Mitral regurgitation does not regurgitate into the left ventricle, but rather from the left ventricle back into the left atrium during ventricular contraction (systole). This condition occurs when the mitral valve, which sits between the left atrium and left ventricle, fails to close properly, causing blood to flow backward into the left atrium instead of forward into the aorta as it should 1. The regurgitation happens from the left ventricle back into the left atrium, not within the left ventricle itself, and can lead to symptoms like fatigue, shortness of breath, and heart failure if severe.

Key Points to Consider

• Mitral regurgitation is characterized by the backward flow of blood from the left ventricle into the left atrium during systole 1.
• The condition occurs due to various factors that can affect the mitral valve, including valve leaflet abnormalities, damage to the chordae tendineae, or problems with the papillary muscles that support the valve structure 1.
• Effective medical therapy leading to reverse remodelling of the left ventricle may reduce functional mitral regurgitation, and every effort should be made to optimize medical treatment in these patients 1.
• Surgical intervention, such as mitral valve repair or replacement, may be considered in certain cases, including those with severe symptoms, left ventricular dysfunction, or evidence of viability 1.

Management and Treatment

• The management of mitral regurgitation involves a multidisciplinary approach, including guideline-directed medical therapy, surgical intervention, and percutaneous edge-to-edge repair in selected cases 1.
• Surgical repair is preferred over replacement for primary mitral regurgitation, especially when the likelihood of successful repair is high and peri-operative risk is low 1.
• Percutaneous edge-to-edge repair may be considered in patients with an indication for valve repair but judged inoperable or at unacceptably high surgical risk 1.

From the Research

Mitral Regurgitation and Left Ventricle

• Mitral regurgitation is a condition where the mitral valve does not close properly, allowing blood to flow backward from the left ventricle into the left atrium 2, 3, 4, 5, 6.
• The left ventricle is the main pumping chamber of the heart, responsible for pumping oxygenated blood to the rest of the body 2, 3, 5.
• Mitral regurgitation can lead to increased pressure and volume in the left atrium, which can cause symptoms such as dyspnea and fatigue 6.
• The condition can also lead to left ventricular dysfunction, where the left ventricle becomes less efficient at pumping blood, leading to decreased cardiac output 2, 5.

Relationship between Mitral Regurgitation and Left Ventricle

• Studies have shown that mitral regurgitation is associated with larger left ventricular volumes and worse left ventricular function 5.
• The severity of mitral regurgitation has been shown to be an independent predictor of adverse outcomes, including total mortality, cardiovascular mortality, and hospitalization for heart failure 5.
• The progression of mitral regurgitation over time has also been associated with increased hospitalizations for heart failure and adverse outcomes 5.
• Echocardiography is a useful non-invasive technique for evaluating patients with mitral regurgitation, allowing for visualization of the mitral apparatus and assessment of left atrial and left ventricular size and function 6.

Clinical Significance

• Mitral regurgitation can have significant clinical implications, including symptoms such as dyspnea and fatigue, and increased risk of adverse outcomes 2, 5, 6.
• Medical therapy, including digitalis, diuretics, and vasodilators, can be used to manage symptoms, but valvular surgery may be necessary in some cases 6.
• Early detection and treatment of mitral regurgitation are important to prevent long-term complications and improve outcomes 2, 5.