Persistent abnormal intraventricular conduction after myocarditis revealed by recurrent syncopes.

A 24-year-old male was admitted to our hospital for recurrent syncopes. Several ECG showed paroxysmal second degree atrioventricular block with the QRS axis changing between conducted beats and escape beats. Transvenous cardiac pacing was performed until permanent recapture of atrioventricular conduction (day 4). At day 7, the CMRI showed extensive subepicardial enhancement highly consistent with acute myocarditis. A second CMRI was performed 3months later showing complete regression of subepicardial enhancement despite persistent RBBB and left posterior fascicular block. Although there was no ECG available before the event, the likelihood of a causal relationship between ECG findings and the myocardial disease is high. When it happens, a long follow-up should be advised.