Myocarditis is an emerging disease. We have investigated a case of focal myocarditis with ventricular thrombus in a patient with Helicobacter pylori infection who came to our attention for the persistence of chest pain one week after previous discharge. The patient was before and otherwise misunderstood as myocardial infarction and recognized in our Centre as myocarditis by magnetic resonance. Diagnostic iter was focused on understanding the pathogenesis of the previous reported cardiac event as well as a link with the persistence of chest pain finally found related to Helicobacter pylori infection. We briefly discuss about role and some caveats of magnetic resonance with late gadolinium enhancement as new diagnostic approach of myocarditis, compared to myocardial biopsy.