The first that comes to mind with a history of heart disorders is that the heart is not pumping into the system the volume received from the lungs, and fluids backup into the lungs and peripheral areas. That can be the result of left ventricle's wall that has been damaged from the prior heart attack. Or there could be restricted cardiomyopathy indicating blood is backing up as the chamber space is compromised from enlarged heart walls reducing the capacity.
Or there could be a kidney and/or liver diesease. And many more possibilities. I had pulmonary edema about 6 years ago, and I was hospitalized in ICU for several days. I thought I had a respiratory problem with symptoms of a dry cough, but it turned out I had had a silent heart attack and lung edema, and there was some damage to the heart cells (hypokenisis...impaired heart wall movement). Treatment revitalized the heart cells and the heart is now pumping adequately.
Hope this helps.
This causes