So people who had greater risk of AF from consuming fizzy drinks were already engaging in unhealthful behaviours. This study has a poor methodology, with little to no attempt at reconciling confounding variables.
The article mentions drink speficially and does not mention the effect of sweet food in general. Perhaps sugar or aspartame without any accompanying nutrient is especially detrimental, going straight into the system.
To decrease the risk just consume Taurine and/or Caffeine.