A growing body of research suggests heart attacks, angina and other heart events increase during winter and summer.
Now, a new study could explain why.
Researchers reviewed an international registry of 1,113 people, the majority from Japan, with acute coronary syndrome. Heart attack is a type of acute coronary syndrome, which occurs when the blood supply to the heart muscle is suddenly decreased or blocked.
Using images of the fatty deposits in participants’ coronary arteries, researchers put people into groups: plaque rupture, plaque erosion and calcified plaque. Each plaque scenario can block blood flow and lead to a heart attack or other cardiac event. But a rupture is more immediate and occurs when the calcified plaque breaks off. Erosion can happen over time.
“We looked at those three underlying mechanisms to see whether they were different among the different seasons. As expected, we found a significant difference,” said Dr. Ik-Kyung Jang, lead author of the study published Thursday in the Journal of the American Heart Association. Jang is an interventional cardiologist and director of the Cardiology Laboratory of Integrated Physiology and Imaging at Massachusetts General Hospital in Boston.