Sudden cardiac arrest is a
leading cause of cardiovasculardeath. In the last ten days, I encountered two
cases of out-of-hospital cardiac arrest; the first was a 28-year-old on 25 mg
olanzapine and the second was a 70-year-old post-bypass. In the first case the
PM 2.5 levels were > 300 in the preceding few days and in the second case
the PM 2.5 levels were > 400 in the preceding two days.
I request all our readers to
share all cases of sudden out-of-hospital cardiac arrest. There may be more
such cases, which were considered as routine deaths. However, I am convinced
that the reason is air pollution.
Here is why:
lThis study
identified out-of-hospital cardiac arrest (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 withairpollutants including
PM2.5 (particles ≤ 2.5 μm), PM10, CO, O3, NO2, and SO2 was analyzed. A total of
21,509 OHCAs of presumed cardiac origin were identified. An elevation in PM2.5
by 10 μg/m3at 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/m3) 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 thatincreased
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 (Int J Cardiol.2016;203:1086-92).
lA case-crossover
study design, at Brigham Young University, USA, was used to analyze ischemic
events in 12,865 patients who lived on the Wasatch Front in Utah.Increase in ambient fine particulate
pollution PM 2.5 by 10 μg/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 (Circulation.
2006;114(23):2443).
lRelative risks
(RRs) and 95% CIs were calculated for each increment of 10μg/m3 in pollutant
concentration, with the exception of carbon monoxide, for which an increase of
1 mg/m3 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, PM10 and PM2.5: 1.025. (JAMA. 2012;307(7):713).
All heart patients with
underlying blockages or patients with arrhythmias should consult their doctors
for risk modification in conditions of high pollution levels.
Dr KK Aggarwal
Padma
Shri Awardee
President Elect Confederation of Medical Associations
in Asia and Oceania (CMAAO)
Group
Editor-in-Chief IJCP Publications
President
Heart Care Foundation of India
Immediate Past National President IMA
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