The Napoli midfielder revealed the details while speaking from the Scotland camp, explaining that he had been in excellent physical condition and preparing for the tournament when the problem emerged.
“The World Cup was difficult. Right at the end, I found myself having to get a shock to my heart. It was two days before the match against Haiti and I had prepared myself so well. I was in excellent physical condition, and then something like that happens and you ask yourself: ‘Why me?’” McTominay said.
The 29-year-old had previously undergone a cardiac ablation procedure in Manchester to correct a mild, benign heart arrhythmia. The condition had first become apparent during Scotland's preparations for the tournament, although the nature of the problem was not made public at the time.
McTominay explained that the experience affected him beyond the immediate medical concern. Scotland's World Cup campaign ended in disappointment, and he admitted that the combination of the health scare and the team's results made the weeks afterwards particularly difficult.
“You have to move on. These things happen in football and sometimes things do not go the way you want, but you still have to keep giving your best. I do not want it to sound like an excuse, but looking back, I understand that it is part of the journey,” he said.
“After the competition, I spent at least two or three weeks feeling deeply disappointed. Mentally, I was not completely there. I needed time to find some calm and switch off a little.”
The midfielder said the circumstances surrounding the treatment had been far from ideal, particularly given how close it came to Scotland's opening match.
“Finding yourself in hospital two days before the first World Cup match, about to be put under anaesthetic, is not exactly ideal. When things like that happen, you accept them for what they are. There is nothing you can do about it,” he explained.
Reflecting on the tournament, McTominay described the period as probably the most disappointing of his professional career.
“After the World Cup, I thought about what had happened and the disappointment was enormous, to be honest. It was probably the most disappointing moment of my entire career.”
Despite the difficulties, McTominay was keen to reassure supporters that his subsequent operation had been straightforward and successful. He said the public reaction to reports of a heart problem had sometimes made the situation appear more serious than it was.
“Obviously, for television and newspapers, the situation seemed much worse than it actually was. Friends and family contacted me after reading the reports, but the operation I had in Manchester was very simple. It went extremely well,” he said.
“I'm fine now. I feel much better, much better than before.”
The former Manchester United midfielder also stressed how important it had been to return to playing football. He described the game as the most important part of his life and said his focus was now on improving and reaching an even higher level.
“I am happy to be playing again. Football is the most important thing in my life and always will be. I want to come back, show my value once again and make sure I can reach a higher level. The important thing is to come back stronger than before,” he said.
McTominay also spoke about the standards he sets himself away from matchdays, highlighting the importance of recovery, nutrition and sleep.
“It does not matter how well you play one match. What matters is the next match, recovering your energy, looking after your nutrition and sleep, and pushing yourself beyond your limits,” he added.
The midfielder's return to the Scotland squad is another positive step after a difficult period. Having resumed his Napoli career following the procedure, he is now looking forward rather than dwelling on the events of the summer.
His account provides a clearer picture of what he went through before the World Cup, but his message was ultimately reassuring: the operation was successful, he feels better than before and he is determined to continue progressing.
McTominay also discussed his relationship with Napoli and the influence of Antonio Conte in an interview with Rivista Undici. He was keen to credit the club and its staff for helping him settle in Italy after leaving Manchester United.
“Napoli and Italy gave me the foundations I needed to concentrate on my work. And, of course, I also thank coach Antonio Conte, who helped me enormously. I had a very good relationship with him and with everyone else at the club,” he said.
“We are all a family: all the coaches, the kit staff, the physiotherapists and the doctors.”
Despite his growing status at Napoli, McTominay rejected the idea that he sees himself as a leader or a hero.
“I do not see myself as a leader or a hero at all. It is difficult to explain, but I think people should not see me that way. They should see me as someone who works hard, and that has nothing to do with football or what you can achieve on the pitch,” he said.
His approach, he explained, is to work hard, go home and recover, while embracing the pressure of important matches.
“I think throughout my career I have always managed to raise my level in big matches, in the most important moments. Experiencing those emotions gives me an adrenaline rush. That kind of pressure creates excitement for me.”
McTominay also recalled Napoli's title-winning night against Cagliari, describing the experience as the greatest day of his career.
“Even now, when I think about that match, I get goosebumps. Experiencing moments like that makes you want to achieve even more, because they are the moments you remember with the greatest happiness. It was without doubt one of the best days of my career. In fact, the best day of all,” he said.
He wants to experience another night like it, and believes that reaching the highest level requires an almost obsessive commitment to daily work.
“If you do not treat your career almost like an obsession, you will never reach the highest levels. What matters is what you do every day when you arrive at the training ground. What matters is how you do things away from the pitch.”
There was also time for McTominay to praise Italian food, which has become another part of his life since moving to Naples.
“What you have here is the best in the world, in my opinion. Everything is fresh. It is different from anywhere else, and I realised that even more this summer when I went to the United States,” he said.