Drinking two or more glasses of fizzy or sweetened drinks a day is linked to an increased risk of heart failure, experts have warned.
Two 200ml servings - equivalent to just over a can of drink a day - could increase the risk of heart failure by 23%, 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% 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."
In an accompanying editorial, Spanish professors Miguel Martinez-Gonzalez and Miguel Ruiz-Canela, said people who drink a lot of sweetened drinks often have a poor diet overall, which is more of a determinant of ill health than any one component.
But they added: "The well-known association of sweetened beverages with obesity and Type 2 diabetes, which are risk factors for heart failure, reinforces the biological plausibility of (the) findings.
"Based on their results, the best message for a preventive strategy would be to recommend an occasional consumption of sweetened beverages or to avoid them altogether."
Francesco Cappuccio, professor of cardiovascular medicine at the University of Warwick, said there were limitations to the study.
He said that high sugary drinks can contribute to heart failure by increasing weight gain and diabetes.
He added: "But an alternative explanation (not discussed in the paper) is that high salt intake (salt intake is higher in low socio-economic groups) increases thirst, hence increased drinking including sweetened drinks.
"The increase in heart failure could therefore be a consequence of higher salt intake, higher blood pressure and higher heart failure risk."
Dr Gavin Sandercock, a reader in clinical physiology at the University of Essex, said: "The results of this study are very interesting because they show there is no difference in the effects of drinks which do or do not contain any sugar (sweetened vs artificially sweetened) on the risk of men developing heart failure.
"The 23% higher risk of developing heart failure is clearly not, therefore, anything to do with sugar per se. The authors quite rightly suggest that drinking more sweetened beverages is simply an indicator of a poor diet overall.
"The adults who drank two sweetened drinks a day also drank the most coffee, ate the most processed meat, ate the least vegetables and they had more family history of heart disease.
"Trying to decide if sweetened drinks are the single cause of heart failure is impossible when diet and heart failure are both such complicated issues."