Transient ventricular wall thickening in acute myocarditis - A serial echocardiographic and histopathologic study

The present study was designed to determine whether the wall thickening see n in acute myocarditis is caused by interstitial edema. The study group com prised 25 patients (idiopathic myocarditis, 17; eosinophilic myocarditis, 8 ) in whom acute myocarditis was diagnosed histologically and who underwent echocardiography and endomyocardial biopsy during both the acute and conval escent phases. The following echocardiographic parameters were measured: in terventricular septum and left ventricular posterior wall thickness, left v entricular end-diastolic dimension, and left ventricular ejection fraction. Based on the myocardial biopsy specimens, the degree of interstitial edema was classified into 3 grades [(-), 1(+), 2(+)] and the transverse diameter of cardiac myocytes was measured using light microscopy. The thickness of both the interventricular septum and left ventricular wall decreased from 1 4.3 +/-3.7 mm and 13.3 +/-2.4 mm in the acute phase to 9.7 +/-1.7 mm (p <0. 001) and 10.2 +/-1.7 mm (p <0.0001), respectively, in the convalescent phas e. Edema was present in 22 patients (88.0%) in the acute phase, but in the convalescent phase, edema was present in only 7 patients (28.0%), indicatin g a significant reduction in the degree of edema (p <0.0001). Cardiac myocy te diameter did not differ significantly between the acute (13.6 +/-1.1 mum ) and convalescent (13.8 +/-1.8 mum) phases.