The cause of death has not been determined, but Wasserstein had entered a hospital earlier this week with an irregular heartbeat.
Wasserstein was widely recognized as a pioneer in the world of leveraged buyouts and was involved in KKR: Kohlberg Kravis Roberts & Co.'s landmark LBO of RJR Nabisco. In the past decade, he was heavily involved in b-to-b media. He founded The Deal LLC, and his private equity firm, Wasserstein & Co., holds stakes in Penton Media and Hanley Wood. The firm sold ALM Media for $630 million in 2007.