Ga-67 myocardial scintigraphy in patients with acute myocarditis.

Four patients with acute myocarditis were examined by Ga-67 myocardial scintigraphy. Two cases showed positive scintigram. In one of these cases, the first scintigram showed positive one month after onset of acute myocarditis, and three and four months after its onset, Ga accumulation slightly decreased intermittently. However, six months after its onset, the scintigram showed strongly positive again. Endomyocardial biopsy of this case six months from its onset showed some mononuclear cell infiltration in the myocardial interstitium. From these changes of scintigram during the course of the disease and biopsy findings, this case appeared to be one of "smoldering" or "chronic recurrent" myocarditis. Another case showed weakly positive one month after onset of disease, in spite of a negative CRP. In the remaining two cases, Ga-67 scintigram showed negative, although CRP was + and 5+, respectively. The sensitivity of the Ga-67 myocardial scintigram may not be very high. But when it continues to show positive, acute myocarditis seems to be "smoldering" and transferring to DCM. Ga scintigram is a noninvasive examination for myocarditis and is a useful screening test for identifying myocarditis, and serial scans may eliminate the need for frequent biopsies in suspected myocarditis cases.

Histopathological study of the papillary muscles and apex cordis of the hypertrophied left ventricle.

Hypertrophy of the papillary muscle and apex cordis of the left ventricle was studied histopathologically using 84 hearts obtained at autopsy. The hearts were divided into three groups: a hypertrophy group (heart weight more than 350 g); a borderline group (heart weight between 350 and 300 g) and a control group (heart weight less than 300 g). The size of the papillary muscle increased with increase in heart weight. Derangement of myocyte linings and fibrosis at the papillary muscle base became apparent with hypertrophy. In addition derangement and fibrosis extented from the internal to middle layers of the free wall with progressing hypertrophy. Derangement seemed to precede hypertrophy and fibrosis. A cluster of huge myocyte-like Purkinje's cells were associated with the center of the derangement. At the apex, criss-cross derangement developed from right and left side derangement with increasing hypertrophy. It is speculated that the focal derangement plays an important role in producing hypertrophy in response to mechanical stress with subsequent development of hypertrophy and fibrosis with some asymmetry.

Twenty year autopsy statistics of myocarditis incidence in Japan.

In the annuals of autopsy records in Japan, edited by the Japanese Society of Pathology and covering 20 years, from 1958 to 1977, 377841 autopsy cases are registered with a short summary of the pathology findings. Of these, 434 cases with idiopathic, interstitial, viral, non-specific (NSM) and giant cell (GCM) myocarditis were found. The incidences of NSM and GCM were 0.11 and 0.007%, respectively. The annual incidence of NSM showed periodic fluctuations with in 5-year intervals and increased remarkably after 1974. Incidence of GCM showed a similar fluctuation but with a one to two year delay of peaks. The male to female ratio was 1.2: 1 and the age distribution had two peaked patterns for both sexes, though these peaks were scattered widely from neonate to elderly patients. The regional distribution of NSM showed a concentration in the middle portion of Honshu and its regional annual incidence had propagation waves from the central area to peripheral areas. The same tendency was observed in GCM cases. Hokkaido was characterized by a low incidence of NSM and no GCM. Complications of myocarditis included pancreatitis, pneumonitis, interstitial nephritis, meningoencephalitis, hepatitis, hepatic cirrhosis and a considerable incidence of malignancies. Antibiotics, antineoplastic agents, steroids and irradiation therapy were the main forms of treatment applied before or after the start of myocarditis.

Myocarditis in autopsy.

In the Annuals of Autopsy Records for Japan from 1958 to 1977, 377,841 autopsy cases were registered; a short summary of pathologic findings was included. Of the 377,841 cases, 409 (0.11%) were registered as idiopathic, nonspecific, interstitial, or viral myocarditis and 25 cases (0.007%) as giant-cell myocarditis. The annual incidence of the myocarditis varied at 5-year intervals and a remarkable increase was observed after 1974. An analysis of 19 cases of myocarditis and 19 of postmyocarditic cardiomegaly (PMC) showed a preponderance of males. Dilatation of ventricles was found in all cases of acute, subacute, and healing myocarditis, which histologically showed interstitial mononuclear cell infiltration, necrosis, and disarray of myocytes. Hypertrophy with ventricular dilatation, ventricular dilatation without hypertrophy, endo- or epicardial involvement, and right ventricular lipomatosis were found in 70%, 20%, 30%, and 10% of cases with chronic myocarditis and PMC, respectively. In these cases, residual inflammation, fibrosis, and hypertrophy was observed histologically.