Broadcaster Paul Holmes is in an induced coma after open-heart surgery.
It is a less than usual move, not without risk, a leading cardiac surgeon said.
In a statement, Holmes' employer Newstalk ZB said he was likely to remain in an induced coma through the weekend to allow his body to recover following open heart surgery at Auckland City Hospital earlier this week.
His doctors said this could sometimes be expected after such an operation and hospital staff said he remained in a serious, but stable condition.
His family have been reading him the many letters and emails received from the public and wanted to thank people for their support.
Earlier, doctors said there were no complications with the four-hour surgery to remove a blockage in his heart and that he would spend several days in hospital before recovering at home.
Holmes was diagnosed with a heart disorder - hypertrophic cardiomyopathy - which is usually inherited and results in the heart muscle becoming thick. The thickening makes it harder for blood to leave the heart, forcing the heart to work harder to pump blood.
The 62-year-old Q+A host and radio broadcaster was flown from Hawke's Bay to Auckland City Hospital last week after a Hastings cardiologist confirmed the extent of the condition.
An initial, more-routine operation in Auckland, involving the use of alcohol to kill the problematic muscle, was stopped after the surgery team became concerned the alcohol might seep to other, healthy areas.
While it is standard practice to put a patient in an induced coma for a few hours after heart surgery, it is less usual to let it continue for several days, internationally recognised cardiac surgeon Adam el Gamel said.
Heart surgery patients are typically placed under general anaesthetic to allow their organs to rest, requiring less bloodflow and allowing the heart time to recover.
Patients are placed on a machine which carries out their basic functions including breathing and exchanging of gases, the clinical director of cardiac surgery at Waikato Hospital said.
Normally this takes place for around six hours overnight following surgery, but the process could carry on for a few days in more serious cases or when there have been complications.
An extended induced coma carries the risk of infection. The lungs cannot easily be cleared because the patient cannot cough while they have a breathing tube, el Gamel said.
''The patient's chance of survival might be reduced if they are under anaesthetic for a few days.''
Hypertrophic cardiomyopathy is a serious condition which carries the risk of sudden death due to an enlarged heart and can be exacerbated with exercise. Athletes with the disease have been known to collapse suddenly from this.
The condition usually presents itself later in adult life. There is added risk of death if the patient has other health issues such as diabetes.
Auckland City Hospital staff are continuing to say that Holmes is in a serious but stable condition and that there have been no significant changes since his operation.
A reformed smoker, Holmes was diagnosed with prostate cancer in 1999.
In January, Holmes had surgery related to the cancer, telling a women's magazine at the time that it was to ''correct some old stuff'' following his earlier treatment and radiotherapy ''which tends to churn things up inside''.
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