I was going by the BBC:

The baby's heartbeat stopped on the Wednesday. "I got a call on Wednesday night that Savita's heart rate had really gone up and that they had moved her to ICU," Mr Halappanavar said. "Things just kept on getting worse and on Friday they told me that she was critically ill." Some of Savita's organs stopped functioning and she died on Sunday 28 October.

So it depends on *when* the heart was beating, which initially it was. The hospital used that as their reason for refusing, though why they continued to refuse isn't clear. All they would speak about was the heartbeat, but they didn't mention anything about the time-frame.

I just Wiki'd it, and it sez:

The death of Savita Halappanavar on 28 October 2012, at University Hospital Galway in Ireland, led to nationwide protests . . . Halappanavar, a Hindu of Indian origin, was suffering from a miscarriage when she was some 17 weeks pregnant, and she sought medical attention and treatment at University Hospital Galway. Her husband, Praveen Halappanavar, said that the hospital told them the foetus was not viable, but they could not perform an abortion under Irish Law as the foetus heart was still beating. During the next several days, Halappanavar was diagnosed with septicemia which lead to multiple organ failure and her death.

I think the "during the next several days" is the key. But it's not totally clear.