More people in life-threatening conditions are surviving despite the Scottish Ambulance Service missing response-time targets, MSPs have been told.

Holyrood's Health Committee heard that 61.5% of all life-threatening calls and 71.2% of cardiac arrests were responded to within eight minutes.

The targets, respectively, are 75% and 80%, but ambulance service officials said a new priority system was saving lives despite the targets being missed.

"The proportion of eight-minute response times have reduced significantly," the committee convener Lewis Macdonald said, adding: "The targets for life-threatening responses are not being achieved."

However, the medical director of the Scottish Ambulance Service, Dr James Ward, defended the new system.

Dr Ward explained the model is "based on a huge amount of data and evidence around the requirements of patients," and said: "For the codes that go into our highest category, we know that these people are sick and in immediate life-threatening circumstances.

"If you align your response to accurately identify these patients, it gives you the best opportunity to save lives.

"When we set off at this we had no idea what would happen in terms of 24-hour and 30-day survival, but what we've seen in the first year - from the old system to the new system - is a 43% increase in 30-day survival."

He added: "The eight minute target has lost its relevance to clinicians within the system.

"We get to the sickest people as quickly as we possibly can and that's actually when the role of the paramedic begins."

Asked by the convener whether the service remained committed to the eight-minute target, Dr Ward said: "Absolutely. We are committed to trying our best to deliver every target that has been agreed as part of our delivery plan."

Another change the new response model introduced was that two paramedic crews are now automatically dispatched to those in the highest-risk category, rather than one.

Speaking about the difference this has made for ambulance staff, specialist paramedic Donna Hendry told MSPs: "I'm often used to attend the immediate life-threatening calls as a second responder - the third pair of hands - and in that respect I feel as though it has been really useful.

"The less life-threatening calls - the ones I'm more often sent to as a specialist paramedic - these are the ones that we can hopefully treat at home or have referred to a more appropriate place rather than going through the doors of A&E.

"For that category of calls it's still developing. It's not always right because the people who are taking the calls are basically just working on the information they get.

"Every call that the ambulance service gets is a 999 call so these calls have got to be categorised at the moment."