SUB-CLINICAL RHEUMATIC CARDITIS

Abstract

In a series of 175 biopsy specimens of left atrial appendages from mitral valvotomy operations, active histological lesions were found in 112 (64%). In a necropsy series of comparable age and comparable valve lesions the total incidence of active lesions in the heart was 24%. No correlation was found between the usual clinical criteria of rheumatic activity and the presence of histologically active lesions. Since the earliest forms of rheumatic lesions were found in some specimens in the absence of clinical evidence of rheumatic activity, it is deduced that rheumatic carditis can be sub-clinical. A large difference in the incidence of active lesions was found in patients in sinus rhythm and in atrial fibrillation in the biopsy series and to a lesser extent in the necropsy series. It is suggested that the different proportions of patients in sinus rhythm in biopsy and necropsy series may account in part for the difference in incidence of active lesions in most biopsy and necropsy series. The explanation for the low incidence of active lesions in atrial fibrillation has not been found, but it is suggested that the conditions leading to the development of atrial fibrillation are associated with the healed rheumatic process. In view of the frequent occurrence of sub-clinical rheumatism it is suggested that prophylactic or suppressive measures should be continued throughout life.