"The manner of death is natural," Julie Bolcer, a spokeswoman for the medical examiner, said Saturday.
Carr, 58, died Thursday after he collapsed at The Times office in Manhattan.
Shortly before his death, he had moderated a discussion about the film "Citizenfour."
Carr was "one of the most gifted journalists" to ever work at the newspaper, said Arthur Sulzberger Jr., publisher of The Times.
The veteran journalist wrote the weekly "Media Equation" column for the newspaper. His writing style was conversational, analytic and peppered with humor. A reporter's reporter, Carr didn't just write about journalism -- he practiced it, taking on media heavyweights with in-depth pieces that exposed wrongdoing.
Before joining The Times, he worked for The Atlantic Monthly and New York magazine.
But he made his name in the punchy world of alt weeklies -- first as editor of the The Twin Cities Reader, and later the Washington City Paper. He specialized in culture coverage, writing about music, television and film with ease.
In 2008, Carr published "The Night of the Gun," a memoir chronicling his struggle with addiction and subsequent recovery. The account was brutally honest, tracing his journey from troubled drug user to loving family man and successful professional.
In one passage, he describes a night spent at a Minneapolis home of his then-girlfriend and dope dealer. Trapped in a "drug-induced paranoia," he narrowly escapes arrest when police officers arrive in the neighborhood.
Years later, Carr returned to the house.
"Sitting there in a suit with a nice job in a city far away and those twins on their way to college, I almost would have thought I'd made it up," he wrote. "But I don't think I did."
Carr won plaudits for the book, which he reported over the course of two years.
"David was one of the most generous men I've ever known," CNN's Brian Stelter said. Carr and Stelter worked together at The Times for six years and appeared together in the 2011 documentary "Page One: Inside The New York Times."
"David mentored and nurtured countless journalists, and I was so lucky to be one of them," Stelter said. "I loved him like a father, and he treated me like a son."