The Napoli midfielder underwent a cardiac ablation procedure in Manchester in September to treat a mild, benign heart arrhythmia that first came to light after the Scots arrived in the United States in early June and then continued to plague him in August while back in Italy playing for his club.

At the time, the Scotland camp, clearly keen to keep McTominay’s situation under wraps, said the 29-year-old had missed training in the lead-up to the World Cup due to a stomach complaint.

But, speaking at a press conference at Hampden on Tuesday, the former Manchester United player said: “I had to go and get the shock on my heart two days before the Haiti game.”

McTominay played all three of Scotland’s matches at the World Cup but struggled to hit the heights as his team exited at the group stage.

“I was 100 per cent (fit), but obviously when you’re sat in a hospital bed two days before the first game of the World Cup about to get put to sleep, it’s not ideal, is it?” he said.

“You’ve prepared so well, I was in such good condition and then something like that happens and you’re thinking, ‘How is this happening to me?’

“It’s nowhere near an excuse, but it’s something that you have to look back on and say, ‘Well, it’s part of the process’.

“Obviously with the way the World Cup went, it was at least two, three weeks of me sitting there disappointed, not quite with it mentally. I needed time to settle down and have a break.

“After the World Cup, it was probably the most disappointed I’ve ever been in my career.

“I’m always one for a glass half full, but that one took a good couple of weeks to get out of my system.”

McTominay returned to action with Napoli at the start of this season, but after playing their first two Serie A matches, he decided surgery was the only option and duly spent all of September on the sidelines after undergoing a corrective procedure.

That meant he missed Scotland’s first four matches under new boss Sebastien Pocognoli, but he is now back with the national team for this month’s Nations League double-header against Macedonia and Switzerland after featuring in all nine of his club’s matches since the last international break.

“I’m good. I’m feeling much, much better than what I was,” he said. “I feel like it was something that needed to be done. In your career you have moments like that where things like that can take you a bit by surprise.

“Obviously, it looks a lot worse to people in the media and family and friends who reach out to you after they’ve seen news relating to a heart issue, but it was a relatively straightforward procedure which went really, really well in Manchester.

“I’m just really happy to be back playing football again. That’s the most important thing in my life and it always will be.”