Hi welcome to the health care magic Your main complaint is fatigue and excess sweating... Continue the treatment prescribed by your doctor for heart failure.... You have not mentioned which drug you are taking as certain medicine can lead such side effects... Second check your hemoglobin level to rule out anemia which might lead fatigue... If diarrhea and heat intolerance present thyroid problem should be ruled out by serum TSH and T4 estimation If specific cause found than treated accordingly Ex. If anemia present than iron or vitamin tablets needed Take care Consult physician for examination Hope your concern solved