They found a faulty gene may interact with alcohol to accelerate heart failure in some patients with the gene – even if they only drink moderate amounts of alcohol.
Their research looked at faulty versions of a gene called titin, which are carried by one in 100 people or 600,000 people in the UK.
Titin is crucial for maintaining the elasticity of the heart muscle and faulty versions are linked to a type of heart failure called dilated cardiomyopathy.
The team, made up of scientists from Imperial College London, Royal Brompton Hospital and MRC London Institute of Medical Sciences, analysed 141 patients with a type of heart failure called alcoholic cardiomyopathy (ACM).
This condition is triggered by drinking more than 70 units a week – roughly seven bottles of wine – for five years or more.
In severe cases the condition can be fatal or leave patients requiring a heart transplant.
But the team discovered the faulty titin gene may also play a role in the condition.
They found 13.5 per cent of the patients they analysed were found to carry the mutation – much higher than the proportion of people who carry it in the general population.
They said the results suggested the condition was not simply the result of alcohol poisoning, but arises from a genetic predisposition – and that other family members may be at risk too.
Study author Dr James Ware, from the National Heart and Lung Institute at Imperial College London, said: “Our research strongly suggests alcohol and genetics are interacting, and genetic predisposition and alcohol consumption can act together to lead to heart failure.
“At the moment this condition is assumed to be simply due to too much alcohol.
“But this research suggests these patients should also be checked for a genetic cause by asking about a family history and considering testing for a faulty titin gene, as well as other genes linked to heart failure.”
Dr Ware added that relatives of patients with ACM should receive assessment and heart scans – and in some cases have genetic tests – to see if they unknowingly carry the faulty gene.
In a second part of the study, the researchers investigated whether alcohol may play a role in another type of heart failure called dilated cardiomyopathy (DCM).
This condition causes the heart muscle to become stretched and thin, and has a number of causes including viral infections and certain medications.
The condition can also be genetic and around 12 per cent of cases are thought to be linked to a faulty titin gene.
The team asked 716 patients with DCM how much alcohol they consumed.
None of the patients consumed the high levels of alcohol needed to cause ACM, but they found that in patients whose DCM was caused by the faulty titin gene, even moderately increased alcohol intake – defined as drinking above the weekly recommended limit of 14 units – affected the heart’s pumping power.
Compared to DCM patients who did not consume excess alcohol – and whose condition was not caused by the faulty titin gene – excess alcohol was linked to reduction in heart output of 30 per cent.
Study co-author Dr Paul Barton, also of the National Heart and Lung Institute at Imperial, said more research was needed to investigate how alcohol may affect people who carry the faulty titin gene, but do not have heart problems.
“Alcohol and the heart have a complicated relationship,” he added.
“While moderate levels may have benefits for heart health, too much can cause serious cardiac problems.
“This research suggests that in people with titin-related heart failure, alcohol may worsen the condition.”
The research is published in the Journal of the American College of Cardiology.