How weather affects heart attack outcome

London: Pollution and weather influence outcomes after a heart attack, says a study.

"We performed our research in Silesia, the most urbanized and industrialized region in Poland," said Aneta Cislak, research fellow at the Medical University of Silesia in Zabrze, Poland.

The study examined the relationship between environmental factors and severity of clinical status and short-term prognosis in patients with non- ST-segment elevation acute coronary syndromes (NSTE ACS).

These include NSTE myocardial infarction (NSTEMI), heart attack and unstable angina.

The study enrolled 2,388 patients admitted for NSTE ACS between 2006 and 2012.

The researchers found that patients with high risks of heart attack, bleeding and low left ventricular ejection fraction were admitted on warmer, sunnier, drier and windy days with higher carbon monoxide and ozone air concentrations.

"These were the sickest patients. The findings may be explained by the fact that their organs may be more sensitive to weather changes, leading to de-compensation," Cislak said.

Treatment was more frequently successful when the weather was sunnier and less windy but colder and with lower concentrations of ozone, carbon monoxide and nitric oxides.

"One of the possible explanations for this finding is that air pollutants like carbon monoxide bind irreversibly to haemoglobin and impair blood oxygen transport. This can cause hypoxia and lead to worse clinical status and less successful treatment," Cislak said.

The finding was presented at European Society of Cardiology (ESC) Congress 2015 in London this week.