Smoking is closely related to cardiovascular disease, and numerous trials have confirmed that smoking is an independent risk factor for coronary heart disease, stroke, and other diseases. There is also considerable evidence to confirm that smoking is strongly associated with cardiac arrhythmias (especially atrial fibrillation). A 2011 U.S. study confirmed that smoking increases the risk of atrial fibrillation in 15,000 adults between the ages of 45 and 64, who were followed for an average of 13 years, with 876 of those surveyed developing AF. The researchers compared the odds of AF in smokers and nonsmokers and found that the risk of AF was 32 percent higher in former smokers who quit compared to never smokers, and the risk of AF was twice as high in current smokers as in nonsmokers. A recent European trial found that smoking ten cigarettes a day led to a 14% increased risk of AF. There was a linear dose-response relationship, meaning that for each additional cigarette, the risk increased. Further evidence of a dose-response relationship is provided by the fact that current smokers had a 32% increased risk of AF compared to never smokers, while smokers (current and former smokers) had a 21% increased risk, and ex-smokers had a 9% increased risk. “If you smoke, then stop smoking, and if you don’t smoke, don’t start.” Smoking is a deadly and addictive disease. Lifetime smokers have a 50 percent chance of dying from smoking, reducing their life expectancy by an average of 10 years. Less than half of smokers will continue to smoke until they die. Smoking rates are declining globally, but are still widespread, and are increasing among women, adolescents and socially vulnerable groups. The authors of this study investigated 39,282 AF events in 677785 participants through a meta-analysis of 29 prospective studies from Europe, North America, Australia and Japan. Smoking 5, 10, 15, 20, 25 and 29 cigarettes per day was associated with a 9%, 17%, 25%, 32%, 39% and 45% increased risk of AF, respectively, compared with zero cigarettes per day. Smoking per decade was associated with a 16% increased risk of atrial fibrillation. Pack-years were calculated by multiplying the number of cartons of cigarettes smoked per day by the number of years smoked. Of note: including low-tar (“light” or “light”) cigarettes, filtered cigarettes, and cigarillos are all harmful. Can quitting smoking reduce the risk of atrial fibrillation? The answer is yes! A study evaluating the long-term prognosis of patients with atrial fibrillation after quitting smoking showed that quitting before age 40 reduced the “additional” mortality from smoking by 90 percent. Smokers do have a significantly increased risk of atrial fibrillation; after quitting, the risk of atrial fibrillation is significantly reduced, although it is still higher than in nonsmokers. Therefore, it is never too late to quit smoking.