Pacemaker complication during magnetic resonance imaging.

high. We intend to continue follow-up for the next two to five years, while looking for evidence of any long-term sequelae. The utility of endomyocardial biopsy after smallpox vaccination is uncertain. Given the inherent risks and low diagnostic yield of endomyocardial biopsy (1,4), as well as the high likelihood of full objective recovery after smallpox vaccine-associated myopericarditis (3), we would be remiss to recommend a potentially harmful procedure in all patients with depressed left ventricular function. Although there has been one case of eosinophilic myocarditis that improved shortly after receiving corticosteroids (5), this one case is insufficient to conclude that corticosteroids will always be beneficial, even when eosinophils are seen on biopsy. However, the possibility that corticosteroids may uniquely benefit patients with eosinophilic myocarditis does warrant continued evaluation. Therefore, although we support endomyocardial biopsy in patients with symptomatic moderate or worse left-ventricular dysfunction related temporally to smallpox vaccination, we caution that every case must be considered individually.