NEW YORK (AP) — Bruce Wasserstein, the CEO of Bermuda-based investment bank Lazard Ltd., has died, a company spokeswoman said.

He was 61.

Wasserstein, a prominent Wall Street dealmaker, was hospitalised with an irregular heartbeat on Sunday.

The spokeswoman wouldn't comment beyond confirming Wasserstein's death.

Last night the company named Steven Golub as interim CEO.

Wasserstein had been a fixture on Wall Street since the 1980s. He worked on such landmark deals as Kohlberg Kravis Roberts' takeover of RJR Nabisco, and the Morgan Stanley-Dean Witter and AOL-Time Warner mergers.

In the 1980s, he helped run First Boston Corp. before co-founding an investment bank, Wasserstein Perella Group Inc., with Joseph Perella. Wasserstein was CEO of Wasserstein Perella between 1988 and 2001 before selling it to Germany's Dresdner Bank AG for about $1.4 billion.

Wasserstein took over as head of Lazard in 2002. He took the company public in May 2005, and was under contract to serve as CEO through 2012.

Lazard has remained relatively strong throughout the economic downturn. Its second-quarter profits fell 18 percent to $28.2 million, or 34 cents per share, but easily surpassed expectations. New York-based Lazard's financial restructuring business has thrived during the downturn, offsetting declines in mergers and acquisitions advisory business.

Aside from his work at Lazard, Wasserstein was chairman of Wasserstein & Co., a private investment firm, which targets investments between $30 million and $150 million. It has investments in companies ranging from Penton Media Inc., a publisher of trade magazines, to gourmet food seller Harry & David.

Wasserstein also owns New York Media Holdings LLC, which publishes New York magazine.

Forbes magazine estimates Wasserstein's net worth at $2 billion.

Wasserstein was the brother of Wendy Wasserstein, a Tony and Pulitzer Prize-winning playwright who died in 2006.