The Apprentice tycoon is in “perfect health” apart from “a bit of a cold and a corn on the little toe of his left foot”, his publicist Andrew Bloch said.
The 69-year-old had an angiogram, a check designed to assess the health of blood vessels, when he was in the US four weeks ago.
He had a stent fitted - a tiny tube used to help blood flow - but he “did not have a heart attack” and his heart is “in perfect condition”, Mr Bloch said.
“As part of his normal annual health check routine in the USA, Lord Sugar, four weeks ago had an angiogram and other heart tests,” he said.
“This minor procedure included the fitting of a stent.
“Lord Sugar was on the mend within a day and cleared to resume exercise after a week. He is in perfect medical health and plays tennis and rides his bike for 40 miles regularly.
“For the avoidance of doubt he did not have a heart attack and his heart is in perfect condition.”
He added: “I spoke to him this morning, and he asked me to also mention that he has had a bit of a cold, a corn on the little toe of his left foot and two haircuts.”