Complete heart block in a young child presumably due to mycoplasma pneumoniae myocarditis

Carditis associated with mycoplasma pneumoniae infection

Among 560 patients with serologically confirmed Mycoplasma pneumoniae infection, 25 (4.5%) had carditis (19 perimyocarditis, 6 pericarditis). During the acute phase 9 patients required intensive care. After an average of 16 months follow-up 11 patients with no previous signs of heart disease still had cardiac symptoms or signs. Thus carditis associated with M. pneumoniae infection is a serious disease, having cardiac sequelae more often than has hitherto been supposed. The pathogenesis of the carditis associated with M. pneumoniae infection is discussed, including the possibility that in some cases the elevated titre in the complement fixation test is non-specific. A summary is given of the 33 cases previously presented in the literature.

Complete atrioventricular block persisting after regression of infectious myocarditis

Atrioventricular block is usually transient during the course of infectious myocarditis. We report the case of a patient presenting with complete infra-hisian atrioventricular block occurring in the setting of infectious myocarditis and in whom a pacemaker should be finally implanted. Borderline serologies for picornavirus were present 6 weeks later. Complete atrioventricular block persisted during the two years of follow-up despite otherwise complete regression of the myocarditis. We then discuss the main features of conduction disturbances complicating infectious myocarditis, including a list as complete as possible of all the causal agents possibly involved.

[Extrapulmonary infections due to Mycoplasma pneumoniae]

Pneumonia is the main site of infection with Mycoplasma pneumoniae in paediatric age. Nevertheless it can also give rise to other manifestations, with or without respiratory involvement. In the present review are described some unusual clinical features of M. pneumoniae in children. Encephalitis and meningoencephalitis is the most frequent neurological manifestation, but cases of meningitis, myelitis, and polyradiculitis, have been reported. Cardiac involvement is potentially severe, including pericarditis and myocarditis. Cold agglutinin haemolytic anaemia is the most frequent haematologic manifestation. Skin, renal, gastro-intestinal, osteoarticular, and other manifestations have also been reported in the literature. The pathogeny of these extrapulmonary infections is not fully elucidated and the treatment remains partly controversial. Extrapulmonary complications can occur as a result of direct invasion and/or autoimmune response.

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 heart block from mycoplasma pneumoniae infection

Complete heart block (CHB) in infants and children is usually congenital. Nonsurgical acquired CHB is rare. Occasionally, transient acquired CHB is seen in association with viral myocarditis. We describe here an unusual case of transient CHB in a 12-year-old boy with endomyocardial biopsy-proven myocarditis and evidence of Mycoplasma pneumoniae infection.

Pacemaker management for acute onset of heart block in childhood

Four children aged 2 to 15 years are described who had Stokes-Adams syndrome as the primary cardiac manifestation of complete heart block. All had mild, nonspecific antecedent symptoms without signs of congestive heart failure. Viral neutralizing antibody titers (coxsackievirus B1 and B2) rose significantly in two patients. Electrocardiography demonstrated complete heart block associated with one or more of the following: right bundle branch block, left anterior hemiblock, left bundle branch block, intraventricular conduction delay, and ventricular standstill. In addition, second-degree heart block was seen during the initial or resolving phases of illness. To prevent further life-threatening episodes of Stokes-Adams syndrome, temporary transvenous pacemakers were placed. Two patients with persisting complete heart block required permanent pacemakers. At last examination, the remaining two patients had sinus rhythm and normal conduction. Nonsurgical acquired complete heart block is unusual in childhood, and may be the only manifestation of myocarditis. Extreme bradycardia, which causes syncope, requires immediate temporary cardiac pacing; if the bradycardia persists, a permanent pacemaker should be implanted.