The study reports a 13 per cent higher-than-expected occurrence of heart attacks on the first day of the working week.
The research examined data from 10,528 patients between 2013 and 2018.
These patients all received diagnoses of an ST-segment elevation myocardial infarction (Stemi), the most severe type of heart attack, which occurs when a major coronary artery is completely blocked.
The evidence pointed to a significant increase in Stemi heart attacks at the start of the working week, particularly on Mondays.
The study also observed a surge in heart attacks on Sundays, a fact presented at the recent British Cardiovascular Society conference in Manchester.
Scientists have been unable to fully explain this “Blue Monday” phenomenon.
Previous studies have hinted at the possible involvement of our body's circadian rhythm, or sleep-wake cycle, in influencing the likelihood of heart attacks.
In the UK, there are over 30,000 hospital admissions annually due to Stemi, according to the British Heart Foundation.
Immediate assessment and treatment are crucial to reduce heart damage, typically involving an emergency angioplasty procedure to unblock the coronary artery.
“We've discovered a robust statistical correlation between the start of the working week and the incidence of Stemi," said research team leader and cardiologist Dr Jack Laffan, from the Belfast Health and Social Care Trust.
"Although this phenomenon has been previously reported, it remains an intriguing area of study.
“The cause is likely multifactorial, but based on what we know from previous studies, we believe that circadian rhythms might play a significant role.”
Prof Sir Nilesh Samani, medical director at the BHF, said: “Every five minutes, someone is admitted to hospital due to a life-threatening heart attack in the UK, making it crucial for research to continue unravelling the mechanisms underlying heart attacks.
“This study provides further insight into the temporal distribution of particularly severe heart attacks.
"However, we now need to delve deeper into understanding why certain days of the week have higher incidence rates.
"This knowledge could enhance our understanding of this deadly condition and potentially lead to more lives being saved in the future.”