Echocardiographic findings in fulminant and acute myocarditis.

OBJECTIVES: We sought to use echocardiography to assess the presentation and potential for recovery of left ventricular (LV) function of patients with fulminant myocarditis compared with those with acute myocarditis.
BACKGROUND: The clinical course of patients with myocarditis remains poorly defined. We have previously proposed a classification that provides prognostic information in myocarditis patients. Fulminant myocarditis causes a distinct onset of illness and severe hemodynamic compromise, whereas acute myocarditis has an indistinct presentation, less severe hemodynamic compromise and a greater likelihood of progression to dilated cardiomyopathy.
METHODS: Echocardiography was performed at presentation and at six months to test the hypothesis that fulminant (n = 11) or acute (n = 43) myocarditis could be distinguished morphologically.
RESULTS: Patients with both fulminant (fractional shortening 19 +/- 4%) and acute myocarditis (17 +/- 7%) had LV systolic dysfunction. Patients with fulminant myocarditis had near normal LV diastolic dimensions (5.3 +/- 0.9 cm) but increased septal thickness (1.2 +/- 0.2 cm) at presentation, while those with acute myocarditis had increased diastolic dimensions (6.1 +/- 0.8 cm, p < 0.01 vs. fulminant) but normal septal thickness (1.0 +/- 0.1 cm, p = 0.01 vs. fulminant). At six months, patients with fulminant myocarditis had dramatic improvement in fractional shortening (30 +/- 8%) compared with no improvement in patients with acute myocarditis (19 +/- 7%, p < 0.01 for interaction between time and type of myocarditis).
CONCLUSIONS: Fulminant myocarditis is distinguishable from acute myocarditis by echocardiography. Patients with fulminant myocarditis exhibit a substantial improvement in ventricular function at six months compared with those with acute myocarditis. Echocardiography has value in classifying patients with myocarditis and may provide prognostic information.