Whenever our heart doesn't work properly then we started to think that we haven't as much energy as before,that we get tired very soon and out of breath more quickly. This is because the tissues aren’t getting enough oxygen and is due to excess fluid in the tissues..We may feel short of breath when they lie down because of fluid congesting the lungs. Shortness of breath  when you exert yourself or when you lie down, Rapid or irregular heartbeat,Reduced ability to exercise,Sudden weight gain from fluid retention. Lack of appetite and nausea, chest pain are some of the symptoms of heart disease.