Particulate Matter of heart disease in patients with abnormal electrocardiogram

Environmental factors in human health, the role is more and more attention. Air pollution and respiratory diseases and cardiovascular diseases are closely related, but also may lead to myocardial infarction, but its exact mechanism is not clear. Recently, the United States, a study confirmed that some patients with heart disease appear ECG ST segment depression with exposure to air pollutants in the fine particulate matter related. The results in September 9, 2008 published online in the "cycle" (Circulation) journal.


Air particulate matter health hazards


According to the World Health Organization, air pollution is hazardous to health the main environmental factors, causing about two million people die around the world. Survey shows that air pollutants in particulate matter (PM), ozone, nitrogen dioxide (NO2), sulfur dioxide (SO2) is the main reason for the disease. Indoor air, especially in bedroom air pollution by such substances will lead to more serious health problems. According to the World Health Organization report, the world each year due to indoor air pollution resulted in 1.6 million deaths.


The study found, PM to human health risks far more than other contaminants. PM is a kind of solid and liquid from the organic and inorganic components of complex mixture, suspended in the air, the main components are sulfate, nitrate, ammonium, sodium, chlorine, carbon, mineral dust and water. Particulate matter in accordance with aerodynamic diameter, PM can be divided into PM10 (aerodynamic diameter below 10 μm) and PM2.5 (aerodynamic diameter 2.5 μm) in two categories, of which the latter greater health risks . PM2.5 because the human body after being inhaled into the bronchial, interference pulmonary gas exchange.


Long-term exposure to PM can increase people suffering from cardiovascular disease, respiratory diseases and lung cancer risk. In some developing countries, the use of open flame bedroom or coal stove can be greatly increased, such as acute lower respiratory tract infection can lead to increased child mortality. In addition, indoor air pollution also increase the adults suffering from chronic obstructive pulmonary disease (COPD) and lung cancer risk. Air pollution in cities with less severe compared to the city, residents can be higher than the mortality rate of 15% ~ 20%. In EU countries, PM2.5 exposure will lead to reduction of people's average life expectancy of 8.6 months.


Particulate Matter of heart disease in patients with abnormal electrocardiogram


Many studies have confirmed that particulate matter pollution can trigger a myocardial infarction (MI), myocardial ischemia or injury, however Electrophysiological evidence has been insufficient. Recently, Harvard University School of Public Health Zhuang (Chuang) study found that exposure to PM2.5 and black carbon aerosol (BC) and heart disease occur in patients with ECG ST segment depression-related. Air pollution due to the risk of ST-segment depression in myocardial injury, a month have occurred in patients with cardiac events in the highest.


The study included 48 cases of the discharge diagnosis for patients with coronary heart disease (aged 43 ~ 75 years), study of air pollutants and in patients with ST-segment relations. These patients had MI, myocardial infarction without acute coronary syndrome or stable coronary artery disease and acceptance of percutaneous coronary intervention (PCI) treatment, was discharged from hospital in the forthcoming included in the study. Smoking habits, atrial fibrillation or research before the start of three months to receive coronary artery bypass grafting in patients not included because the study of ECG ST segment indicators for the end.


Researchers in patients with sub-standard 24-hour ECG monitoring. Patients have completed each of 48 times per 30 min of ST-time monitoring. Myocardial ischemia in patients with a view to reflect the adoption of real-time ECG. Compared with resting baseline, ST segment depression in the level of performance for the lower (horizontal) or ramps (downsloping)-type more than 1 mm, continued for more than 1 min interval and with other more than a 5 min or more, is defined as myocardial ischemia period.


The results showed that, PM2.5 and BC level of predictability in patients with ST-changes. 48 hours prior to the average level of PM2.5 and BC growth in a quartile of each pitch (IQR), ST segment depression in the risk of more than 0.1 mm, respectively, 1.43 and 1.72-fold increase. Further analysis showed that, PM2.5 and BC and ECG ST segment depression in the relationship between the MI by the discharge diagnosis, diabetes diagnosis and time of impact. The discharge diagnosis of patients with MI, the ST-segment depression than in patients with undiagnosed MI more significant (P = 0.002). Patients with diabetes, the ECG ST segment changes are more vulnerable to air pollution. PM2.5 levels of ST-induced changes occur more in the daytime.


The newly discharged patients with coronary heart disease should avoid exposure to air pollution


The researchers believe that patients with coronary artery disease in the first month after admission of air pollutants PM most susceptible, high incidence of ECG ST segment depression. Myocardial injury and MI patients and patients with diabetes are also prone to occur PM caused by ST segment depression.


Air pollution can trigger off these susceptible patients ST-segment depression, possibly because of air pollutants caused by local or systemic inflammation, oxidative stress, epithelial damage and (or) the autonomic nervous system damage, making instantaneous vasoconstriction or thrombosis formed, resulting in impaired fibrinolytic activity and myocardial oxygen supply shortage. Diabetes itself chronic vascular epithelial damage, chronic systemic inflammation, oxidative stress and chronic damage to the autonomic nervous system, the effects of air pollution may be more sensitive to the dangers.


The researchers suggested that although the study has certain limitations, but confirmed the air pollution on ST-segment depression in the short-term and long-term role. About the recent events experienced in patients with coronary artery, MI patients and diabetic patients to reduce exposure to air pollutants can help reduce their risk of occurrence of myocardial ischemia.


British Heart Foundation欧沙利text (O'Sullivan) pointed out that the Foundation recommended to reduce heart disease in patients with long exposure to air pollution activities. The University of Edinburgh, UK Newby (Newby) professor also suggested that living in areas with serious air pollution is more susceptible to cardiovascular disease. The study of air pollution level is not very serious, the researchers have found its heart damage. Therefore, people should take more effective measures to reduce air pollution