Two 200ml servings – equivalent to just over a can of drink a day – could increase the risk of heart failure by 23 per cent, a study found.
Sweetened drinks have been linked previously to changes in blood pressure as well as insulin and glucose levels.
Soft drinks have also been linked to high blood pressure, diabetes, heart disease and stroke.
Researchers writing in the journal Heart said this was the first time a link has been made with heart failure. They asked more than 42,000 men in Sweden about their consumption of 96 food and drink items over the previous year.
People were asked: “How many soft drinks or sweetened juice drinks do you drink per day or per week?”
Fruit juice and sugary tea and coffee were not included in the definition. Researchers also did not distinguish between drinks sweetened with sugar and those that were sweetened with artificial sweeteners.
All the men, who were aged 45 to 79 when they entered the study, were tracked for an average of 12 years.
During that time, 3,604 new cases of heart failure were diagnosed, and 509 people died of their condition.
After taking into account factors that may influence the results, two servings of sweetened drinks was associated with a 23 per cent increased risk of developing heart failure compared with drinking none at all.
A deeper analysis, excluding people diagnosed with heart failure in the first five years, showed the link still held true.
The researchers, including from the Karolinska Institute in Stockholm, warned that because it was an observational study, no conclusion could be drawn to say sweetened drinks definitely caused heart failure.
They also stressed that the study only involved older white men and may not be applicable to younger age groups, women, or certain ethnic groups.
But they said the findings could help doctors in giving out dietary advice to prevent heart failure.
They added: “Our study findings suggest that sweetened beverage consumption could contribute to heart failure development.
“These findings could have implications for heart failure prevention strategies.”
Spanish professors Miguel Martinez-Gonzalez and Miguel Ruiz-Canela said people who drink a lot of sweetened drinks often have a poor diet overall.