Coronary Artery Disease Obscuring Giant Cell Myocarditis

A case in which the diagnosis of idiopathic giant cell myocarditis was obscured by the presence of severe coronary artery disease is described. A 47-year-old man presented with recurrent inferior myocardial infarction and complete heart block. Cardiac catheterization confirmed severe 2-vessel disease and left ventricular dysfunction. Incessant ventricular arrhythmia rapidly ensued, which did not respond to anti-arrhythmic therapy and overdrive pacing despite complete surgical revascularization. He eventually died. Autopsy revealed giant cell myocarditis superimposed on coronary artery disease. Acute myocarditis masquerading as myocardial infarction has been well known, but virtually all reported cases had normal coronary arteries. This case illustrated the fact that even in the presence of obvious coronary artery disease the remote possibility of myocarditis should not be entirely disregarded. Although giant cell myocarditis is a rare and frequently fatal disorder, recent studies suggest that combined immunosuppressive therapy may improve the prognosis.