sentences:  The biological pacemaker is intended as an alternative to the artificial cardiac pacemaker that's been in human use since the late 1950s.Despite their success, several limitations and problems with artificial pacemakers have emerged during the past decades such as electrode fracture or damage to insulation, infection, re-operations for battery exchange, and venous thrombosis.The need for an alternative is most obvious in children, including premature newborn babies, where size mismatch and the fact that pacemaker leads do not grow with children are a problem.