Heart-transplant operations have been suspended at Zurich University Hospital following the death of a patient a year ago who was given the wrong heart.
The canton’s health director said on Monday that she had taken the decision to protect staff and patients while criminal investigations continued.
Rosmarie Voser, 57, died in April last year just days after being given a new heart incompatible with her blood group.
At the time the hospital said human error was to blame, citing a communications breakdown within the organ-transplant team.
But this weekend the Zurich prosecutors’ office announced that it had widened its inquiry, saying it was not only investigating possible negligent homicide but also wilful murder.
Prosecutor Ulrich Weder said he wanted to establish whether surgeons had deliberately given the patient a new heart that they knew was incompatible.
Marko Turina, the surgeon in charge of Voser’s operation, has categorically denied that this was the case. Turina retired in August last year.
Announcing the suspension, a spokeswoman for health director Verena Diener said heart operations had become "too risky" because of the pressure on doctors and staff.
She said the suspension would remain in place "for a few weeks" until criminal investigations into Voser’s death had been completed.
The spokeswoman confirmed that two members of the hospital’s heart-transplant team had been suspended.
Some politicians in Zurich have rounded on the decision to suspend heart-transplant operations, which they say will damage the hospital's reputation.
The centre-right Radicals and Christian Democrats said the move would only add to the state of uncertainty currently hanging over the hospital.
They also criticised the public prosecutor's office for its protracted investigation which had yet to produce any concrete results.
Only the centre-left Social Democrats have come out in support of the decision, saying it should have come a lot sooner.
Voser had been in hospital for three months awaiting the transplant. She was the subject of regular reports on Swiss television's current-affairs programme, 10vor10, which followed her right up until the failed operation.
swissinfo with agencies
In Switzerland expensive top-level surgery could in future be restricted to fewer hospitals.
But in order for an agreement reached by cantonal health directors to come into force, at least 17 cantons and all cantons with universities have to agree to it.
Resistance is growing in Zurich to the cancellation of heart-transplant operations, which would be performed in Basel, Bern and Lausanne.
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