I Am 71, Fairly Active (I Ride My Horses Regularly,

I am 71, fairly active (I ride my horses regularly, clean stalls, etc.), quite overweight (5'6"-262 lbs) and I have had two pulmonary blood clots. I am taking Xeralto daily, and I am embarking on an exercise regimen using the services of a personal trainer (starts Tuesday.) My question is this: since I have low blood pressure (100/65) and pretty regular incidents of edema in my ankles, what can I do to help my heart? I have been diagnosed with "mild cardiomegaly."