Air Pollution Dangerous For Heart Patients

Armen Hareyan's picture

Air pollution is found to weaken heart's ability to conduct electrical signals and this is especially dangerous for heart patients.

It has already been shown by numerous studies that air pollution is very harmful for heart patients, but the mechanism was unclear. To see how exactly it happens a team of researchers from Harvard University examined 48 patients who were hospitalized to receive treatment for coronary artery disease. The patients were suffering from heart attack, unstable angina, coronary artery disease sufferers. Besides, 40% of them had heart attack and 25% had diabetes.

The patients were monitored regularly with portable electrocardiograph machines, which were tracking changes in heart electrical signals called ST-segment depression. Researchers found that particles from both traffic and non-traffic pollution can lead to ST-segment depression. Among the most dangerous particles researchers mention PM 2.5 and black carbon, which are the main ones coming from traffic, and sulfur dioxide, which mainly comes from combustion and is a non-traffic pollution. The particles were especially harmful for patients recovering from heart attack.


The patients were tracked for a 10 month period and were found to have more heart problems during the first month of hospitalisation. Later, when they were breathing clean air while hospitalised, heart condition was getting better and making it more clear that pollution harm heart seriously.

The study suggests that the depression is caused by worsened heart blood flow or weakened heart muscle, which is a direct result of pollution exposure. However, more needs to be done to clarify the mechanism and to probably propose new acceptable levels of pollution.

Researchers also examined the levels of air pollution that patients were exposed to and found that in Boston, were the patients live, the levels are lower than the normal levels proposed by National Air Quality Standard. Which means that even low levels of pollution are dangerous, and that people exposed to more pollution will suffer even more.

Currently, there is a recommendation for heart patients by American Heart Association and the American College of Cardiology to stay away from pollution during the first month after being discharged from hospital. This study urges that it is extremely important for heart patients to breathe fresh air, and those who can not avoid pollution should be monitored more closely, because they are at high risk.