Prevalence of myocarditis at autopsy in Turin, Italy

OBJECTIVE: To evaluate the prevalence of myocarditis in a general hospital in Turin, Italy. DESIGN: We retrospectively reviewed 17162 postmortem records from autopsies routinely performed at San Giovanni Battista General Hospital, Turin, between 1965 and 1994. RESULTS: Applying the so-called Dallas criteria, myocarditis was histologically found in 91 cases (0.53%, 95% CI 0.4 to 0.7). The prevalence increased, reaching a peak between 1985 and 1994 (1.2%, 95% CI 0.9 to 1.6). The disease was found more frequently in patients from 20 to 39 years of age, with no difference between males and females. The present data were compared to those of a previous study, performed in 1985 and 1993 to 1994, in which we had prospectively taken into account 605 autopsies (not comprised in the present retrospective study) with standardized myocardial sampling for histological examination: a 5.1% prevalence was found (nearly five times as high as that retrospectively detected in the same period). CONCLUSIONS: If a standardized method of myocardial samples for microscopic examination is not followed, it is possible that myocarditis is overlooked in an unsuspected number of cases.