PORT-AU-PRINCE (Reuters) - The eagerly anticipated results of an autopsy of former Haitian President Rene Preval showed the leader died in March after a heart irregularity cut off his ability to breathe, officials said on Wednesday.

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The 74-year-old Preval, who was the first president in Haitian history to win a democratic election, serve a full term and peacefully hand power to a successor, died unexpectedly on March 3 after falling unconscious at his home.

“Effectively, there had been a certain suspicion because the death was sudden,” Clame-Ocnam Dameus, Haiti’s prosecutor, told journalists.

He said Preval’s heart had swollen and turned black, harming his ability to breathe. Dameus emphasized that chronic disease caused Preval’s death, not foul play.

“There was no violence. There was no trace of violence. There is no one to arrest,” he said, adding that the investigation into the cause of death was now closed.

Jean Armel Demorcy, who had led the medical investigation, said Preval suffered from chronic breathing issues for years. He said laboratory tests had been conducted in both Haiti and the United States.

Preval was a central figure in Haitian politics from the early 1990s through to his second presidency.

His legacy will always be tied to the 2010 earthquake that destroyed much of the capital, Port-au-Prince, killed more than 200,000 people and brought the presidential palace crumbling to the ground.

A soft-spoken agronomist, Preval won support from Haiti’s poor majority when he first was elected president in 1996, after a bout of instability that saw his ally, former President Jean-Bertrand Aristide, toppled in a coup, then brought back to power with the help of U.S. troops.

He served a second term as president starting in 2006.

Haiti has been politically turbulent for much of its history since winning independence from France in 1804, punctuated by dictatorships, coups, invasions and natural disasters.