Scientists investigate whether drug could slash the risk of heart attacks in the morning – when they are more common and can be more severe

British researchers are investigating whether an existing drug could save thousands of lives a year by preventing morning heart attacks.

It has long been known that heart attacks are more common, and can be most severe, first thing in the morning.

Many of these are triggered by a life-threatening condition called ventricular arrhythmia, when the heart beats with an abnormal rhythm. It is thought to be linked to up to 80 per cent of the 70,000 sudden cardiac deaths a year in England and Wales.

But scientists have discovered what triggers this potentially fatal arrhythmia to develop – and have found that a drug can block the process. Professor James Leiper, associate medical director at the British Heart Foundation, which funded the research, said the study was ‘intriguing’ and ‘could allow us to explore new treatment options that could reduce arrhythmias in those most at risk’.

Scientists have found that a drug can block the process that causes a potentially fatal arrhythmia to develop (stock image)

The team, led by Dr Alicia D’Souza at Imperial College London and Mark Boyett, honorary professor at the University of Bradford, found that the stress hormone cortisol, which naturally surges to a peak in the morning, binds to heart cells and triggers changes in the electrical signals which control how our heart beats.

In healthy hearts this doesn’t cause a problem. But in diseased hearts, it leads to the development of dangerous ventricular arrhythmia.

When the team injected mice with a drug called RU486, which blocks cortisol from binding to the heart cells, these electrical changes didn’t happen.

The medicine is already used to treat Cushing’s syndrome – where the body produces excess cortisol. Patients often develop increased fat on their chest or stomach, as well as a red, puffy face.

Dr D’Souza said: ‘We’ve known for some time that, because of our natural circadian rhythm or ‘body clock’, levels of cortisol peak in the morning. We also know ventricular arrhythmias are more common in the morning. Now we know the two are linked.

‘Remarkably, when we used a drug to block the effect of cortisol on heart cells in mice, they were no longer susceptible to arrhythmia in the morning.’

The team now plans to replicate these findings in human hearts. Professor Boyett said: ‘If we, or others, were able to develop a drug based on our findings, it could save thousands of lives.’