Hi Sandra: Generally, a cough is caused by back pressure of blood from the Left Atrium into the pulmonary veins.
When a person has a leaky mitral valve, the pressure rises inside the left atrium. This pressure gets reflected back to the lungs and hence fluid there causes a person to cough. This can be with exercise.
Some cases of a cough reflect mild congestive heart failure. If a person lays flat they cough.
Also a cause can be caused by the medication called an ACE inhibitor.
So a number of ways that a cough can occur with a leaky valve.
I hope this helps.
Dr. Kirk Laman
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