Johnson & Johnson, which pioneered drug-coated stents for heart patients, is ceding the territory to rivals whose newer, better products have been squeezing its market share for years. Amid intensifying competition and declining total stent sales, the health care giant said yesterday its Cordis business will get out of heart stents and instead will focus on areas such as diagnostics and stents for blood vessels outside the heart. At the same time, J&J will cut hundreds of jobs, shutter two factories, and take a charge of $500 million to $600 million in the current quarter as it restructures Cordis. Cypher had been the market leader, but its market share fell from a 2006 peak of 51% to 16% last year, as sales plunged from about $2.6 billion to just $627 million over that time. Meanwhile, rivals Abbott Laboratories, Boston Scientific Corp., and Medtronic Inc. introduced new stents widely perceived as better than Cypher and grabbed customers, and the increasing competition forced down prices.