New UK research has found that severe heart attacks are more likely to be fatal when they occur in colder months, compared to warmer months.
Carried out by cardiologists at Leeds General Infirmary, the team compared information from 4,056 patients who had received treatment for a heart attack over four years.
The results showed that overall, around the same number of heart attacks occurred in the colder months as the warmer months, with 52% of heart attacks happening between November and April.
However, the most severe heart attacks, which lead to cardiac arrest and cardiogenic shock, were more deadly in the coldest six months, compared to the warmest.
The researchers found that the risk of dying within 30 days of a severe heart attack was nearly 50% higher during the six coldest months, 28%, compared to a 20% risk of dying in the warmer months.
Cardiac arrest is when the heart suddenly stops pumping blood around the body, while cardiogenic shock is when the heart can’t pump enough blood to meet the body’s needs.
Both conditions are often caused by a severe heart attack, but not everyone who has a heart attack has a cardiac arrest or cardiogenic shock.
Lead researcher Dr. Arvin Krishnamurthy commented, “There is no physical reason why a heart attack, even the most severe, should be more deadly in winter than in summer so we must do further research to find the cause of this difference and remedy it. The next step is to find out if this trend is seen nationwide.”
“Potential explanations could include longer time to treatment, prolonged hospitalisation and delays to discharge, and increased prevalence of winter-associated infections, which in the sickest patients, could be potentially lethal. Further studies interrogating the association between time of admission and outcomes, especially in the sickest and most vulnerable patients, are certainly warranted.”
Professor Metin Avkiran, Associate Medical Director at the British Heart Foundation, also added, “You obviously can’t choose when you have a major heart attack, but it shouldn’t have such an impact on your chances of surviving. It’s vital we carry out more research to find out why there are these differences, as well as continuing to do all we can to stop people having heart attacks in the first place.”
The findings were presented on Tuesday at the British Cardiovascular Society Conference 2018 taking place June 4-6 in Manchester, UK.