Dear Sir, My Father Had Bypass In 2000. He Had

Dear sir,

My father had Bypass in 2000. He had twice paralysis attack in 2008 & 2010 respectively but he is normal at the movment. But in past two years his heart pumping gone down to 20% or below and due to that water enter into his lungs twice and he got admitted for the same.

Can you please advice that how his heart rate can be improve?

Thanks in advance
Bhagyesh patel