The answer to this question would be: Brain Natriuretic Peptide(BNP) and or Atrial Natriuretic Peptide(ANP)
Both BNP and ANP can be found in heart tissue. But BNP is more frequently used because its level is higher, thus the laboratory result could be better. Both BNP and ANP has diuretic, natriuretic and antihypertensive effect that can counter the fluid overload in congestive heart failure. That is why they are secreted when the cells are stretched.