A way to charge pacemakers using the heart's own muscle

FOR THOSE whose hearts occasionally go off rhythm, pacemakers are, quite literally, life savers. By providing a small electrical jolt at the right moment, they can keep a heart working at the appropriate pace. Their main drawback is that they use batteries. Even the best of them eventually run out of energy, and replacing the batteries requires surgery. Since surgery is generally best avoided, the search has been on for long-lasting power sources. Various options have been explored, including, i...