From the Guidelines
Backflow of blood from the left ventricle to the left atrium during systole is primarily caused by mitral valve regurgitation, which can occur due to various conditions, including secondary mitral regurgitation resulting from left ventricular enlargement and remodeling, as noted in the 2016 ESC guidelines 1. This condition leads to reduced leaflet closing, allowing blood to flow back into the left atrium during systole. The underlying causes of mitral regurgitation can be diverse, including structural abnormalities such as mitral valve prolapse, rheumatic heart disease, infective endocarditis, and papillary muscle dysfunction following myocardial infarction.
- Key factors contributing to mitral regurgitation include:
- Left ventricular enlargement and remodeling, which can lead to reduced leaflet closing, as mentioned in the 2016 ESC guidelines 1
- Mitral valve prolapse
- Rheumatic heart disease
- Infective endocarditis
- Papillary muscle dysfunction following myocardial infarction
- Degenerative changes due to aging
- Treatment of mitral regurgitation depends on its severity and may include medication to reduce cardiac workload or surgical repair or replacement of the valve in severe cases, with considerations for combined valve and coronary surgery in symptomatic patients with left ventricular systolic dysfunction, as recommended in the 2016 ESC guidelines 1.
From the Research
Causes of Backflow of Blood from Left Ventricle to Left Atrium during Systole
- Mitral regurgitation (MR) is a condition where the mitral valve does not close properly, allowing blood to flow back from the left ventricle to the left atrium during systole 2.
- The main components of the mitral apparatus are the mitral annulus, the mitral leaflets, the chordae tendineae, and the papillary muscles, and abnormal function of any one of these components can result in MR 2.
- Chronic MR causes volume overload on the left ventricle, leading to left ventricular remodeling and heart failure if left uncorrected 3.
- The use of angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) has been shown to reduce the severity of MR by decreasing the regurgitant fraction and regurgitant volume 3.
- Afterload reduction with vasodilators and diuretics has also been shown to decrease MR during upright exercise in advanced heart failure by decreasing pulmonary capillary wedge pressure and systemic vascular resistance 4.
- The benefits of tailored afterload reduction are maintained throughout upright exercise, resulting in a decrease in mitral regurgitant flow and an increase in forward ejection fraction 4.