Heart attacks that lead to blockage of the coronary arteries cause major damaged hearts cells.  This damage needs to be repaired by initiating a response in the heart which stimulates the removal of dead cells and cell remains, activation of cellular immunity and the formation of new blood vessels. Al this promotes the arrival of blood the damaged area of the heart. It has now been shown (Nature News and Views 514; 575-576,2014) that cells called cardiac fibroblasts, which are very plastic (in medicine this means that they are capable of growth, repair or differentiation), help in this process of regenerating damaged heart tissue.