Chart review for potential features of myocarditis, pericarditis, and cardiomyopathy in children and adolescents treated with clozapine.

Clozapine is known to cause cardiac side effects, including myocarditis, pericarditis, and cardiomyopathy. Prompted by a case of clozapine-related pericarditis in an adolescent, we undertook a retrospective chart review to discover whether any unrecognized cases of myocarditis, pericarditis, or cardiomyopathy were among the children, adolescents, and young adults we had treated with clozapine. The sample comprised a total of 36 patients, who were monitored regularly over a period ranging from 2.5 to 79 months. The average observation period was 7.5 months. Patients were assessed for potential indicators of myocarditis, pericarditis, or cardiomyopathy. In more than 66% of all patients, at least one of several parameters potentially indicative of pericarditis, myocarditis, or cardiomyopathy was abnormal in at least one instance during the observation period. In all cases in which abnormalities were discovered, the abnormalities were found to be unspecific for myocarditis, pericarditis, or cardiomyopathy. With the exception of the case which prompted our study, none of the patients were found to have developed any such disorder in the course of further treatment with clozapine.