Researchers from the Leeds University found that carbon monoxide levels found in heavy traffic could affect the way the heart resets itself after every beat, the BBC reported.
Carbon monoxide is produced by faulty boilers, cigarettes and car exhausts. It is deadly at high levels as it "shoulder-barges" oxygen out of the blood, meaning less is transported around the body.
The research found that the gas kept sodium channels, which are important for controlling the heartbeat, open for longer.
Disrupting the sodium channels can disrupt the heart's rhythm, leading to cardiac arrhythmia, which can be fatal.
In collaboration with researchers in France they tested an angina drug - which also affects the sodium channels - on rats.
"It was very exciting for us. When we monitored rats exposed to levels of carbon monoxide similar to heavy pollution, they had the same heart problems and we could reverse them," Professor Chris Peers, from the University, told the BBC.
The study was published in the American Journal of Respiratory and Critical Care Medicine.