They arrived at 2.45am, said Dr Holt, recalling her last conversation with her son, while nurses prepared him for surgery.
He told her: "I feel really confident about this ... I feel full of joy."
However, Mr Holt died last month, 10 days after the operation, without having regained consciousness.
Rachel Holt said it was a very difficult 10 days.
"There was a little bit of hope at first," she said.
"The surgeons phoned me after the 10-hour operation and said that the heart hadn't started beating again properly on its own, so they had a partial heartbeat but the pressure wasn't good enough to sustain it on its own, so they put him on the ECMO [extra-corporeal membrane oxygenation] machine. It puts oxygen into the blood outside the body.
"At first it was going to be a couple of days, then it might be four or five, and at that point I started thinking this isn't good."
She said it was unclear if there had been a problem with the transplanted heart or with her brother's body - "I don't think they really know".
"There aren't enough donors. Dan waited a hell of a long time. If he had got one earlier he may well have survived, he was so sick by the time he got it."
Dr Holt wondered if it was her son's condition that led to his death following the transplant.
"Dan's health when he went to theatre was worse than they were expecting and he had got much sicker recently."
Transplant cardiologist Dr Peter Ruygrok — who could not comment on Mr Holt's case as he was not involved — said the post-heart-transplant survival rate at Auckland City Hospital was around 90 per cent at one year and that was "as good, if not better" than some units overseas.
He said the main factors affecting survival were the ability of the transplanted heart to cope with the procedure, including being stored on ice for up to six hours, the robustness of the patient, and the increased risk of fatal infections owing to the need to use anti-rejection medicines that weakened the immune system.
Heart failure could lead to liver and kidney problems and could compromise the healing of wounds, Dr Ruygrok said.
Cardiomyopathy, Mr Holt's underlying condition, ran in the family, his sister said.
Their father, historian Dr Jim Holt, died of it in his mid-40s, and his grandfather too, at about the same age.
Friend Mik Smellie told the funeral: "Dan dealt with his heart condition very frankly, both with himself and others — if he was ever angry or depressed, I didn't see it ... "
" ... I would like to acknowledge the heart donor. It didn't come off but someone out there gave our mate a decent shot at more life and I am grateful for that."
Rachel Holt, because of New Zealand's shortage of organ donors, urged people to think about becoming a donor and to discuss their wishes with their family.
The odds
• Heart transplant patient survival rate
• Around 90% at 1 year
• 80% at 5 years
• 65% at 10 years
