Coronary Sinus Flow Is Reduced and Recovered With Time in Viral Myocarditis Mimicking Acute Coronary Syndrome: A Transthoracic Doppler Echocardiographic Study

The clinical presentation of myocarditis often mimics acute coronary syndrome. Coronary sinus flow has been used for detection of the presence of myocardial ischemia. Whether myocarditis is associated with changes in coronary sinus flow remains unknown. The aim of this study was to assess coronary sinus flow at the onset and follow-up of myocarditis mimicking acute coronary syndrome using transthoracic Doppler echocardiography (TTE). Sixty-four patients with clinically diagnosed viral myocarditis mimicking acute coronary syndrome underwent TTE on days 3, 7, 30, 90, 180, and 360 after onset. Coronary sinus flow was compared among different points in time. Compared to healthy participants, all patients with myocarditis had a larger cardiac size, reduced cardiac function, and electrocardiographic and myocardial enzyme abnormalities on days 3 and 7 days (P< .01; P< .05). They later had gradual restoration to normal levels. On days 3 and 7, the coronary sinus flow in patients with myocarditis was extremely lower than that in healthy participants (about one-tenth), although coronary angiography revealed unobstructed arteries. On days 30, 90, 180, and 360, the coronary sinus flow had been increasing; however, it was still far less than that in healthy participants (P < .01). Coronary sinus flow depicted by TTE is reduced but recovers with time in viral myocarditis mimicking acute coronary syndrome, which is a useful indicator in the follow-up of this type of myocarditis.