Complete atrioventricular block in experimental murine myocarditis.
BACKGROUND
There were few reports on the pathological characteristics of the conduction system in myocarditis. This study was aimed to clarify the pathological characteristics of complete atrioventricular (AV) block in myocarditis.


RESULTS
We studied serial electrocardiograms in experimental myocarditis in mice and also examined their cardiac pathology. After taking baseline electrocardiograms, mice were inoculated intraperitoneally with the encephalomyocarditis virus. Electrocardiograms were serially recorded until day 360. Serial electrocardiograms revealed the appearance of complete AV block. Myocardial lesions were found in the hearts of mice with these ectopic beats. Mononuclear cell infiltrations into the His bundle and necrotic lesions of the conduction system were found in 10.7% (18/168) of mice with complete AV block. However, 17.3% (29/168) of mice showed no evident pathological lesions except the edematous changes of AV node.


CONCLUSIONS
The appearance of complete AV block in myocarditis may suggest not only significantly comparable pathological lesions of the conduction system but also the trivial edematous changes; in clinical settings, in the former case, permanent pacing therapy is necessary, and in the latter case, the disease may be transient and could be recovered from complete AV block. This study may shed light on the pathological characteristics of complete AV block in myocarditis.
Kochi General Rehabilitation Hospital, Kochi 781-8130, Japan.
Minoru
M
Ohmae
Chiharu
C
Kishimoto
Nobuyoshi
N
Tomioka
D000818:Animals; D001283:Atrioventricular Node / Q000473:pathology / Q000821:virology; D002036:Bundle of His / Q000473:pathology / Q000821:virology; D005117:Cardiac Complexes, Premature / Q000209:etiology / Q000821:virology; D018188:Cardiovirus Infections / Q000821:virology; D004487:Edema / Q000473:pathology / Q000821:virology; D004562:Electrocardiography; D004686:Encephalomyocarditis virus / Q000502:physiology; D006327:Heart Block / Q000209:etiology* / Q000473:pathology / Q000821:virology; D006329:Heart Conduction System / Q000473:pathology / Q000821:virology; D051379:Mice; D008815:Mice, Inbred Strains; D009205:Myocarditis / Q000150:complications* / Q000473:pathology / Q000821:virology; D032383:Myocytes, Cardiac / Q000473:pathology / Q000821:virology; D009336:Necrosis