Golf superstar Rory McIlroy says a heart defect will not prevent him from challenging again to be world number one and add to his tally of four majors.

The 28-year-old Northern Irishman, who begins his year in Abu Dhabi next week ranked 11 in the world, told The Daily Telegraph he doesn't lose too much sleep over it.

"I have a flat T-wave and I'll have to get an echo (cardiogram) on my heart every six months and an MRI scan every year," he said.

"I suffered a really bad viral infection in China 18 months ago and they told me that's the reason that I have this thickening of my left ventricle and there's a bit of scar tissue.

"For now, I just need to stay on top of it and have to stay fit. Hey, I was planning on doing that anyway."

McIlroy, whose marriage last year to Erica was a high point while on the course he failed to win a tournament, accepts he has to regain his brio on the circuit.

"I won four majors from 2011 to 2014 and everyone was saying 'that's Tiger pace'," said McIlroy.

"I realise everyone knows I haven't won one in the last three years and that is a worry, yeah.

"I need to get back on that track and this year my goals are to add to my major tally and get back to world number one, winning more times than anyone else.

"It's simple, there are no excuses with my game or my private life. I've had the best time of my life in the last few months," added McIlroy, who spent his honeymoon with Erica on a road trip through Italy.

McIlroy, who recently bought South African star Ernie Els's house in Florida, believes he has the mental strength now to take on all comers and not to freeze.

"I still feel that on my day, if I'm on my roll, and especially if I'm playing with them...I just crave to be in that position again.

"That hasn't always been the case with me. The first three years with my career I struggled when it came to that head-to-head stuff down the stretch, with the big guys, but now I actually think it's when I am at my best."