Chest radiography was repeated on day 4 and showed no thoracic abnormalities. Transthoracic echocardiography, performed on day 6, revealed a significant reduction of LV wall thickness (interventricular septum, 11 mm; posterior wall, 10 mm), an improvement of LVEF to 44%, and a slight decrease of pericardial effusion (maximum, 8-9 mm). At the time of submission, the patient was hospitalized with progressive clinical and hemodynamic improvement.