Complex sentence: The first successful experiment with biological pacemakers was carried out by Arjang Ruhparwar's group at Hannover Medical School in Germany using transplanted fetal heart muscle cells, first introduced at the scientific sessions of the American Heart Association in Anaheim in 2001 and published in 2002.
Split into simpler sentences: The first successful experiment with biological pacemakers was carried out by Arjang Ruhparwar's group at Hannover Medical School in Germany using transplanted fetal heart muscle cells. The process was first introduced at the scientific sessions of the American Heart Association in Anaheim in 2001, and the results were published in 2002.