Two cases of sudden out of hospital cardiac arrest in last ten days: air pollution??

New Delhi, November 11, 2018:

In last ten days I encountered two cases of out of hospital cardiac arrest, the first one was 28-year-old on 25 mg olanzapine and the second one 70 year old post bypass status. In the first case the air pollution levels PM 2.5 > 300 in preceding few days and in the second case the PM 2.5 levels were > 400 in the preceding two days.

All our readers kindly share all cases of sudden out of hospital cardiac arrest in this forum. May be we have more cases and being passed on as routine deaths, I am convinced in my mind the reason is air pollution. All heart patients with underlying blockages or patients with arrhythmias should consult their doctors for their risk modification.

Here is why

1. Sudden cardiac arrest is a leading cause of cardiovascular death. This study identified OHCA cases that occurred in Seoul between 2006 and 2013 from the nationwide emergency medical service database. The association of the daily incidence of OHCA with air pollutants including PM2.5 (particles ≤ 2.5 μm), PM10, CO, O3, NO2, and SO2 was analysed. A total of 21,509 OHCAs of presumed cardiac origin were identified. An elevation in PM2.5 by 10 μg/m(3) at a moving average of lag 1 and 2 days was shown to increase the risk of OHCA by 1.30%. An exposure-response relationship was present: the risk of OHCA increased significantly with even a mild elevation of PM2.5 (10-15 μg/m(3)) and further increased with higher levels. While PM10, NO2, CO, and SO2 also showed significant associations with OHCA in single-pollutant models, only PM2.5 remained significant after adjustment for other pollutants. Subgroup analyses showed male sex, advanced age, hypertension, diabetes, heart disease, and history of stroke were risk factors for OHCA in response to elevations in PM2.5. The study concluded that increased ambient levels of PM2.5 were significantly associated with increased risk of OHCA within 1 to 2 days of exposure, which had a dose-response relationship. Subjects with conventional cardiovascular risk factors were more susceptible to harm of PM2.5.
2. A case-crossover study, at Brigham Young University, USA, design was used to analyze ischemic events in 12,865 patients who lived on the Wasatch Front in Utah. Ambient fine particulate pollution PM 2.5 elevated by 10 microg/m3 was associated with increased risk of acute ischemic coronary events (unstable angina and myocardial infarction) equal to 4.5%. Effects were larger for those with angiographically demonstrated coronary artery disease.
3. Relative risks (RRs) and 95% CIs were calculated for each increment of 10μg/m(3) in pollutant concentration, with the exception of carbon monoxide, for which an increase of 1 mg/m(3) was considered. After a detailed screening of 117 studies, 34 studies were identified. All the main air pollutants, with the exception of ozone, were significantly associated with an increase in heart attack risk (carbon monoxide, nitrogen dioxide, sulfur dioxide, PM (10), and PM(2.5)

Dr KK Aggarwal

President Heart Care Foundation of India