Heart block with viral myocarditis

H1N1 influenza A virus induced atrioventricular block

We report a case of an 18-year-old female who presented with respiratory failure secondary to H1N1 infection, and who subsequently developed high-degree atrioventricular (AV) block. The conduction abnormalities persisted over 2 weeks following complete resolution of respiratory symptoms. A permanent pacemaker was implanted for safety and subsequent pacemaker follow-up suggested reversibility of the conduction abnormality. This case highlights the potential impact of the H1N1 influenza virus on the cardiac conduction system.

The clinical course of acquired complete heart block in children with acute myocarditis

A case of biopsy-proven myocarditis in a 7-year-old complicated by advanced atrioventricular (AV) block prompted a review of the medical literature to determine the prognosis for recovery of AV conduction or need for pacemaker implantation. A total of 40 patients younger than 20 years of age were identified, with return of AV conduction within 7 days in 27 patients (67%), permanent pacing in 11 patients (28%) with persistent AV block, and death in 2 patients (5%).

Complete AV-block in two children with immunohistochemical proven myocarditis

We report two children with acquired third degree AV-block caused by acute myocarditis. The diagnosis was proven by endomyocardial biopsy. Severe lymphocytic myocardial infiltration was shown using immunohistological methods. One of the children was treated with prednisone During therapy conduction disturbance nearly disappeared and infiltration was markedly reduced in a subsequent biopsy. In the other patient the parents refused immunosuppressive treatment and a permanent pacemaker was necessary for persistent bradycardia.

CONCLUSION

Immunohistological staining of an endomyocardial biopsy can be used to establish the diagnosis of myocarditis in patients with atypical clinical manifestation, such as complete AV-block, and can support the decision for therapy. In one patient improvement was documented by the disappearance of inflammatory activity in a repeated biopsy.

The scale of myocardial involvement in varicella myocarditis

Two patients with varicella myocarditis are described. An arrhythmia associated with complete recovery occurred in the first patient whereas intractable congestive heart failure complicated by hemiplegia resulted in a fatal outcome in the other case. We stress the extent of myocardial involvement produced by the herpes zoster virus in the setting of varicella.