Legendary dealmaker and private equity chieftain Bruce Wasserstein died in New York yesterday. He was 61.

The CEO of investment bank Lazard and head of his own eponymous private equity firm, Wasserstein had been hospitalized on Sunday for an irregular heartbeat. He was initially reported to be “stable and recovering.” Lazard said his cause of death has not yet been determined.

Wasserstein, who practically invented the hostile corporate takeover and brokered more than 1,000 deals during his long career, won fame for Kohlberg Kravis Roberts’ 1989 takeover of RJR Nabisco, which he advised. That deal stood as the largest leveraged buyout in history until just a few years ago.

A lawyer by training, Wasserstein joined First Boston in 1977, building its mergers and acquisitions department with Joseph Perella. A decade later, the two left First Boston and founded their own boutique investment bank, Wasserstein Perella & Co. In 2000, he sold that firm to Dresdner Bank for $1.5 billion, moving two years later to Lazard, which he took public.

His $2 billion p.e. firm, Wasserstein & Co., focused on media. Wasserstein, who was an editor of the student newspaper at the University of Michigan, owned New York magazine and The Deal through the firm.