However, he was whisked to Auckland by helicopter last week after his Hastings cardiologist, Richard Luke, confirmed the extent of his condition.
An initial, more-routine operation in Auckland - in which surgeons use a balloon catheter and a small dose of 100 per cent alcohol to kill the problematic muscle - was halted on Friday. The surgery team, led by Dr Mark Webster, was concerned the alcohol might seep to other, healthy areas.
Dr David Haydock will perform open-heart surgery on Wednesday. "They'll open my chest and ribs," said Holmes. "As I understand it, they'll bypass the heart and cut the blockage out. They'll open it all up for about four or five hours."
Holmes said he was feeling tired but he had been buoyed by good wishes from several hundred people and the care of hospital staff, led by cardiologist Dr Ivor Gerber.
He is essentially in "shutdown" mode in hospital with limited visitor numbers. Wife Deborah and daughter Millie have been at his bedside, and son Reuben has been sending his support from the south of France.
Holmes is positive about the long-term prognosis, including a return to work as a Newstalk ZB and TVNZ host and Weekend Herald columnist.
In the meantime, he is reading books including Tony Horwitz' Blue Latitudes on Captain James Cook's Pacific voyages - "Cook was completely irrational by the end" - and the biography of Captain Chesley Sullenberger, the pilot who landed his stricken Airbus, with 155 on board, in New York's Hudson River in 2009. No one was killed.
Holmes has had his own near misses in his colourful life. In 1989, he survived a helicopter crash off the east coast - an accident that claimed the life of cameraman Joe Von Dinklage.
In 1973, he was involved in a serious car crash that led to the loss of sight in one eye.
In January this year, he was admitted to Hawkes Bay Hospital after falling ill at his home at Poukawa, near Hastings, as a result of vestiges of his prostate cancer. On that occasion, he recovered quickly and returned to work the following week.
Holmes became a campaigner for prostate cancer awareness after beating the disease more than a decade ago.
To send good wishes, go to Newstalkzb.co.nz. Messages will be bound and sent to Holmes before Wednesday.
WHAT IS IT?
* Hypertrophic cardiomyopathy.
* A usually genetic condition that thickens the heart muscle.
* This leads to blockages of the blood leaving the heart.
* Symptoms include chest pain, dizziness and fatigue.
* Affects around one in 1000 people.