2007 T. Duckett Jones Memorial Lecture—Inflammatory Viral Heart Disease: A Shifting Epidemiology
Inflammatory heart disease, particularly those disorders caused by viral infection, may result in ventricular dysfunction, ventricular dilation, and cardiac arrhythmias leading to heart failure or sudden death. Hence, these disorders may be important as underlying causes in patients presenting with heart failure, aborted sudden death, or sudden death without known cause or prior signs and symptoms.
The most common cardiac inflammatory disorder is myocarditis, and the underlying etiologies have been well studied for several decades. In the 1970s and 1980s, the major underlying cause of disease was coxsackievirus and other enteroviruses. In the past 10 to 15 years, however, the underlying cause of myocarditis has changed—a shifting epidemiology of etiologic agent. The methods used for identification of the infecting virus have changed as well. However, proof of a cause-and-effect relationship of virus and clinical disease has been difficult to prove. In addition, because of the uncertainty related to this cause and effect, there has been a lack of improvement in new therapies.
Cardiac transplant rejection, another cardiac inflammatory disorder, appears to have similar histopathologic findings as seen in myocarditis. However, the cause of transplant rejection has not necessarily been considered to be similar to that causing myocarditis. Noncompliance with immunosuppressive medication and underdosing of these medications have been considered to be important causes of rejection. In addition, repetitive episodes of cardiac rejection are thought to be responsible for the development of transplant coronary artery disease.
In this lecture, the current etiologies of myocarditis will be discussed. In addition, the link between myocarditis and cardiac rejection will be described. Furthermore, this mechanism (viral-induced rejection) will be correlated with the development of transplant coronary artery disease. Potential novel therapies, based on this knowledge of the viral basis of myocarditis and cardiac rejection, will also be discussed.