This information has actually been around for a long time. I was told back in my 20s (Late '80's) that having a case of the flu can increase the risk of a heart attack considerably because of congestion and coughing force putting severe pressure on the heart, in relation to my father who was high-risk.
Link between heart attacks and inflammatory bowel disease. Medical researchers recently concluded a study of more than 22 million patients that suggests a strong connection between Inflammatory Bowel Disease (IBD) and the development of heart disease and heart attacks. Source 9l.
New insights into why patients have a higher risk of heart attack in the morning. Heart disease patients have lower levels of an important family of protective molecules in their blood in the morning, which could be increasing risk of blood clots and heart attacks at those times, says early research. Source 4g.