The mitral valve sits between the left upper chamber and the left pumping chamber. It should open to let blood into the pumping chamber, then close so that blood leaves through the aortic valve to the body. Mitral regurgitation means the valve does not close tightly, so some blood leaks backward into the upper chamber. That extra volume raises pressure there. Over time the pressure can back up toward the lungs, which is why breathlessness appears. This is a different valve from the aortic valve treated by TAVR. A leak on one does not mean the other is diseased.
Mild leaks are often silent
The American Heart Association notes that mild mitral regurgitation often causes no symptoms. It is frequently found because a clinician hears a murmur, then an echocardiogram shows a small backward jet. When symptoms do come, they usually build slowly: breathlessness on activity or when lying flat, tiredness, light-headedness, or a fluttering heartbeat. Some people wake at night short of breath. Sudden severe breathlessness is a different situation and needs emergency care.
- How large the backward leak is
- Whether the left upper chamber or the left pumping chamber has enlarged
- How strongly the left chamber is pumping
- Whether the pressure in the lung arteries has risen
- Whether the leak is from a floppy valve, from rheumatic disease, or from a chamber that has already enlarged
An echocardiogram answers those questions. A heart murmur suggests a leak. It does not measure it. Mitral valve prolapse, in which a leaflet billows backward, is a common cause and often never becomes serious. Some people with prolapse need no treatment at all. The follow-up depends on the amount of leak and on whether the heart is changing, not on the name of the condition.
A murmur is a finding. The echocardiogram decides whether the leak is only being watched.
Medicines do not close the valve
Tablets can ease breathlessness, treat a fast or irregular rhythm, and support a heart that has begun to fail. They do not seal a valve that fails to close. A diseased valve is a mechanical problem. If the leak stays mild and the heart size and pumping strength are stable, regular scans are the treatment. Repair or replacement is discussed when the leak is severe, when symptoms are progressing, when the left chambers are enlarging, when the pumping strength is falling, or when rhythm problems have appeared.
Repair, replacement, or a clip
When a procedure is needed, keeping the person's own valve tissue is generally preferred. The surgeon may tighten the ring around the valve or reshape a leaflet. If the valve is too damaged, it is replaced with a mechanical valve or a tissue valve. Each has different trade-offs for durability and for blood thinners, and that choice is individual. For some people with severe regurgitation who cannot have surgery, a clip can be placed on the leaflets through a vein in the leg. This is called transcatheter edge-to-edge repair. It can reduce the leak and ease symptoms in selected people. It is not a substitute for repair in someone who can safely have an operation. An enlarged upper chamber from a long-standing leak can also lead to atrial fibrillation, which raises the chance of stroke and is treated on its own plan.
Your questions, answered
A murmur does not measure the leak. Many mild leaks are watched with periodic echocardiograms and never need a procedure. Safety depends on the size of the leak and on whether the left side of the heart is enlarging or weakening.
