Heart Attacks caused by Infections?

(December 26, 1997) - The way a heart attacks (myocardial infarction) comes about is clear. It involves the death of part of the heart muscle (myocardium) due to blockage of the coronary artery is commonly caused by a clot that forms on the inner wall of the artery at the site of damage by atherosclerotis, the accumulation of the cholesterol deposits on the walls of the artery. These cholesterol deposits cause hardering and thinckening of artery walls and narrowing of their interior diameter. 

Some of the risk factors for atherosclerosis and heart attacks are also quite well know. They include a high blood cholesterol (especially, an elevated level of the "bad" LDL cholesterol), high blood pressure (hypertension), diabetes mellitus, cigarette smoking, and a familly history of coronary artery disease. There is considerable evidence that an elevated blood level of the amino acid homocysteine may be a risk factor, too.

Not infrequently, however, advanced atherosclerosis is found in the coronary arteries of the people with no know added risk factor. Given the absence of a obvious culprit, scientists are examining some new suspects. One of these is infection.

The concept is that certain chronic (long-term) infections may trigger atherosclerosis -- or they may at the least aggravate it -- and lead to heart attacks. In the regard, Drs. Sandeep Gupta and John Camm from St-George's Hospital Medical School in London have weighed the available scientific data associating infectins with the development of atherosclerosis and coronary heart disease. Their comprehensive review was published in the periodical Clinical Cardiology ( vol. 20, pages 829-836, 1997).

In the labotary, for example, chickens infected with a strain of herpesvirus were discovered to have aggressive athersclerosis in their coronary arteries. Prior vaccination against the virus protected against much of the coronary atherosclerosis.  

From epimediology, it is known that there is a higher incidence