The drug, which is yet to be licensed, works by blocking calcium, potassium and sodium channels.
The trial included 4,628 patients with AF who were randomly assigned to the drug dronedarone (400mg daily) or placebo for 21 months.
In this time, dronedarone use reduced the risk of death and hospitalisation from AF by 24 per cent, compared with placebo, delegates were told at the Heart Rhythm Society conference in San Francisco last week.
The risk of all-cause death was also reduced by 16 per cent with the AF drug.
Adverse side-effects such as skin rashes were only slightly higher in the dronedarone arm at 10 per cent, compared with 8 per cent in those given the placebo.
Lead researcher Dr Stefan Hohnloser, from the Goethe University in Frankfurt, said: 'This drug has the potential to become the first choice drug for AF sufferers.'
Dorset GP Dr Graham Archard, who has an interest in cardiovascular disease, said: 'My initial reaction is that this drug has shown an extremely good level of risk reduction.
'However, this is the first major test of this drug and would require further studies to back up these findings. We also need to known how much dronedarone would cost before it can become available on the NHS.'
- 24 per cent reduction in death and hospitalisation from AF.
- 45 per cent reduction in arrhythmic death from arrhythmic death.
- 16 per cent reduction in all-cause mortality.